Bimetal-Organic-Framework-Derived Nanohybrids Cu0.9Co2.1S4

Subscriber access provided by EKU Libraries

Article 0.9

2.1

4

2

Bimetal-Organic-Framework-Derived Nanohybrids Cu Co S@MoS for High-Performance Visible-Light-Catalytic Hydrogen Evolution Reaction Bing Ma, Tian-Tian Chen, Qiu-Ying Li, Hao-Nan Qin, Xi-Yan Dong, and Shuang-Quan Zang ACS Appl. Energy Mater., Just Accepted Manuscript • DOI: 10.1021/acsaem.8b01691 • Publication Date (Web): 18 Jan 2019 Downloaded from http://pubs.acs.org on January 21, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Applied Energy Materials

Bimetal-Organic-Framework-Derived Nanohybrids Cu0.9Co2.1S4@MoS2 for High-Performance VisibleLight-Catalytic Hydrogen Evolution Reaction Bing Ma,a,b Tian-Tian Chen,b Qiu-Ying Li,b Hao-Nan Qin,b Xi-Yan Dong*a,b and Shuang-Quan Zang*b a.College

of Chemistry and Chemical Engineering, Henan Polytechnic University Henan Key

Laboratory of Coal Green Conversion, Jiaozuo 454000, P. R. China. b.College

of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou

450001, P. R. China. KEYWORDS bimetal-organic

frameworks,

photocatalysis,

hydrogen

evolution

reaction,

Cu0.9Co2.1S4@MoS2, flower-like nanohybrids

ABSTRACT

Transition metal dichalcogenides (TMDs) are recognized as greatly promising substitutes for noble-metal-based catalysts for hydrogen evolution reaction (HER). The hybrids containing Co3S4@MoS2 components demonstrate excellent electrocatalytic activity of HER. However,

ACS Paragon Plus Environment

1

ACS Applied Energy Materials 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

the more sustainable photocatalytic HER of two-dimensional (2D) Co3S4@MoS2-based materials remain scarce. In this study, Cu0.9Co2.1S4@MoS2 composites were easily synthesized in situ by using bimetallic (Cu/Co) metal-organic frameworks (MOFs) as precursors through hydrothermal reaction; without extra precious metal and semiconductor as cocatalyst, the MoS2-content-optimized Cu0.9Co2.1S4@MoS2 efficiently catalyzed hydrogen production at a rate of 40156 μmol h-1 g-1 (with a TON of 109) in aqueous solution containing Eosin Y under visible light. The developed strategy of homogeneously alloyed MOFs as precursors caused the adequate hybridization of the object material with homogeneous Cu-doping in Co3S4 lattice, resulting in abundant interfaces and active sites as well as the low resistance of electron transfer, which thus considerably enhances photcatalytic HER performance, compared with undoped Co3S4@MoS2. HER mechanism was further elucidated by fluorescence spectroscopy, fluorescence lifetime test, impedance spectra, and photocurrent response measurements as well as control experiments.

1. INTRODUCTION Depleting fossil fuel resources and the concomitant drastic pollution of the environment have triggered the urgent demand for finding alternative, more sustainable and recyclable ways to store and distribute energy.1-4 The sun is actually the only real and inexhaustible energy source available on our planet and the concept of storing the solar energy in chemical bonds can be used to construct an artificial photosynthetic system:5,6 water can be used to reduce protons to hydrogen, or be oxidized to oxygen.7,8 High-perfomance catalyst is the key to the successful development of hydrogen evolution over water splitting with sunlight.9 Among them, noble Pt-based materials are at the top of the tree, but the concerns related to the higher price and


2

Page 2 of 50

Page 3 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


rarity largely block their application.10 With the abundant catalytic sites, unique optical and electrical properties, MoS2 and its hybrids as one type of important low-cost transition metal dichalcogenides (TMDs), have been widely studied as viable catalysts for HER by water splitting.11-13 After loading other sulfides with molybdenum sulfide, the photocatalytic and electrocatalytic hydrogen evolution efficiency of these materials are improved. Among them, researches on photocatalytic performance are mainly combined with cadmium sulfide. For another, cobalt sulfide materials and their composites with other materials have been extensively studied for a variety of catalytic reactions as well as energy storage devices. However, researches on molybdenum disulfide doped cobalt and cobalt sulfide materials are currently focused on electrocatalytic hydrogen/oxygen production, lithium ion batteries, supercapacitors, zinc-air batteries, etc. Wherein, CoxSy@MoS2-based hybrids are explored for excellent electrocatalytic HER, in which more active interfaces and higher conductivity were created by different approaches. However, CoxSy@MoS2-based hybrids, including twodimensional (2D) Co3S4@MoS2, have never been used for high-performance photocatalytic HER. (See the above comparison in Table 1) Improving hybridization could create more interfaces, active sites and lower electron transfer resistance for photocatalytic HER catalyst. The substitute doping of another transition in Co3S4 lattice of Co3S4@MoS2 materials should be efficient strategy to strengthen conductivity for better photocatalytic HER activity, which are scarcly reported at present.

Metal-organic frameworks (MOFs13-17, also known as porous coordination polymer, PCPs), with highly ordered three-dimensional (3D) framework structure, tailorable chemical components, controllable porous structure and ultrahigh surface area,18-23 have aroused tremendous interests in energy conversion and storage over the past decades.24-27 Periodic


3


configuration of metal nodes and ligands in MOFs bring them to novel pyrolytic precursors for in situ obtaining well-distributed catalysts.28-34 Moreover, homogeneous multimetallic sulfides, unlike surface doping and heterojunction at interface, would facilitate the catalysts to employ the inherent electronic or surface structures of the materials toward enhanced catalytic performance.10,35 MOF-templated method is thought to be an effective approach to synthesize phase- and morphology-controlled nanostructures for catalyst.36-39 However, the preparation of homogeneous bimetallic such materials is still a challenge.14 The template of allomeric MOFs can guarantee the compatibility of homogeneous composition in the resulting catalyst, for reproducible excellent catalytic performance.40-44 Nevertheless, to the best of our knowledge, only a few groups have investigated bimetallic MOF derived active materials as photocatalysts for HER to date.14

Here, the application of a Co-Mo-S hybrids as photocatalyst in high-efficiency photocatalytic hydrogen production was reported for the first time. We select the classical MOF (ZIF-67 (Co)) and allomeric (Co and Cu, Co and Ni, Co and Zn) isomophorous structures as precursors, which hydrothermally reacted with thiourea and sodium molybdate dihydrate to in situ obtain catalysts, MxCo3-xS4@MoS2 (M = Cu, Ni, Zn) for photocatalytic HER. Among them, Cudoping is more efficient in enhancing conductivity of the hybrids and HER performance. Through optimization, the flower-like Cu0.9Co2.1S4@MoS2 nanocatalyst, exhibited rapid visible-light hydrogen generation at a rate of 40156 μmol h − 1 g − 1 in an optimized catalytic system, which is comparable or even better than most MoS2-CdS-based catalysts. Among MoS2- or CoxSy-based materials, the other four more efficient catalysts are Zn0.30Co2.70S4 with 155200 μmol h −1 g −1, MoS2-CdS with 95700 μmol h −1 g −1, 2 wt% MoS2/CdS with 60280 μ mol h −1 g −1 and CoSx/G with 47233 μmol h −1 g −1 in turn (see Table 1). The morphology and


4

Page 4 of 50

Page 5 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


composition of Cu0.9Co2.1S4@MoS2 are characterized by Field-emission scanning electron microscope (SEM), transmission electron microscope (TEM), Powder X-ray powder diffraction (PXRD), X-ray photoelectron spectra (XPS), elemental analysis. The proposed catalytic mechanism of the hydrogen evolution by Cu0.9Co2.1S4@MoS2 in the presence of the Eosin Y is analyzed through photoluminescence emission spectra, fluorescence lifetime test, impedance spectra, and photocurrent response measurements as well as control experiments.

Table 1. MoS2- or CoxSy-based catalysts for energy conversion.

Catalyst

Morphology

Synthetic method

Catalytic efficiency

Conditions

Ref.

Co3S4/Ag2S nanocomposite

graphene-like material

one-pot strategy

dye degradation

A 300W Xe-lamp (λ ≥ 420 nm)

45

CoS1.097/Ndoped Carbon

square-like nanocomposite

sulfidation and carbonization with MOF as precursors

Supercapacitor: a specific capacitance of 360.1 F g−1 at a current density of 1.5 A g−1

2.0 M KOH.

46

CoS

flower-like microspheres

solvothermal route

High discharge capacity: 890 mAh/g

1 M LiPF6

47

MoS2-Co3S4

hollow nanohybrid

multistep solvothermal synthesis

Li-batteries: 880 mA h g−1 at 0.1 A g−1; Supercapacitors: 1369 F g−1 at 1 A g−1.

polypropylene film ; 3 M KOH

48

Co–Mo–S

flower-like nanoparticles

hydrothermal synthesis

HDO of p-cresol;HDS of benzothiophene

/

49

CoS/graphene

nanosheets

solvothermal method

lithium-ion storage and photo-degradation of methylene blue

visible light

50

amorphous CoMoS-A-0.2

parallel dark lines

hydrothermal method

HDO of phenol

/

51

Co9S8@MoS2/ CNFs

core–shell structures

chemical vapor deposition, pyroprocessing

HER/OER: onset potential 64 mV/1.580 V vs RHE.

HER: 0.5 M H2SO4; OER: 1 M KOH

52


5


Page 6 of 50

MoS2 composites (NMP)

quantum dots

sonication and solvothermal treatment

HER: onset overpotential 120 mV

0.5 M H2SO4; scan rate 5 mV s −1

53

MoS2/Ni3S2

Ni3S2 nanoparticles with MoS2 nanosheets

solvothermal method

HER/OER: (vs RHE); onsetpotential 50/175 mV; overpotential 110/217 mV;

1 M KOH; 1 mV s-1

54

MoS2-Ni3S2 HNRs/NF

Ni3S2 nanorods integrated with MoS2 nanosheets

hydrothermal reaction

overpotential 98 mV for HER and 249 mV for OER.

1.0 M KOH; 1 mV s-1

55

Ni0.33Co0.67S2

nanowires

hydrothermal and sulfurization at high temperatures

HER: 0.5 M H2SO4; OER: 1 M KOH.

56

CoS microtube /FTO

threedimensional microtube

solutionchemistry and chemical bath deposition

Photoelectrocatalytic HER: overpotential (h < 90 mV).

neutral and pH 13

57

CoS2

nanospheres

hydrothermal route

ORR: OCP of 0.94 V, halfwave potential 0.70 V

0.1 M KOH.

58

20 wt % CoS/C

nanospheres

solvothermal route

ORR: HO2− product of 4.3% at 0.60 V vs. RHE

0.1 M KOH

59

CoNS−C

mesoporous carbons/carbon nanocage

pyrolysis of precursors

HER: overpotential 180 mV at 10 mA cm−2

0.5 M H2SO4

60

CoS2(400)/NSGO

hexagonalshap ed CoS2 particles

Solid state thermolysis

OER: 1.62 V vs RHE; ORR: 0.79 V vs RHE

0.1 M KOH

61

Co3S4

sphere-like nanocrystal

thermal decomposition approach

HER onset overpotential:80 mV vs RHE

0.5 M H2SO4, 5 mV s−1

62

Co-S

Co-S film deposited on FTO

simple potentiodynamic deposition

HER onset overpotential：43 mV

1.0 M potassium phosphate buffer;

63

HER: applied potential −80 mV OER: onset potential 1.56 V


6

Page 7 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Co1-xS/RGO

Co1-xS nanoparticles grown on rGO

mild solutionphase reaction

ORR: onset potential 0.8V, current density : 1.1 mA cm-2 at 0.7 V

0.5 M H2SO4

64

CP/CTs/Co-S

the Co-S sheets on CP and CP/CTs

chronoamperome tric electrodeposition method

HER/OER: TOF 1.2×10-1 s-1/1.6×10-2 s1 at overpotential of 250 mV/300 mV;

1 M KOH.

65

NiCo2S4–rGO

NiCo2S4 NC growth on the GO sheets

hydrothermal method

ORR: half wave potential (E1/2) 0.733 V vs. RHE

0.1 M KOH

66

Ni/Co/MoS2

monolayer

theoretical calculation

ORR calculated by DFT

/

67

Co(OH)2– MoS2/rGO

cauliflowerlike growth pattern

hydrothermal method

ORR: onset potential 0.855 V; E1/2 of 0.731 V vs. RHE

0.1 M KOH

68

Co–MoS3

film

cyclic voltammetry route

HER: current density of 0.1 mA cm-2 at η=84 mV

1 mV s-1 (pH =7); 5 mV s-1 (pH =0)

69

0.1M borate buffer, containing 3.0 mM OER: TON 107/154 for Na2S2O8 and 0.06 mM Co-POM-Mo/Co2[Ru(bpy)3](NO3)2 POM-Mo 3H2O

70

chemical vapor deposition synthesis

HER: current density 2.6 mA/cm2 at 300 mV

0.5 M H2SO4

71

vapor-phase hydrothermal method

HER/OER onset potential −0.02 V/1.45V

5.0 mV s−1 in 1.0 M KOH

72

Co-Mopolyoxometalat es

/

/

Co-doped MoS2

metal 16 nm Mo thin film

Co-MoS2/ carbon fiber

fiber network structure

Co-MoS2-0.5

nanosheets

hydrothermal method

Ni–Co–MoS2

nanoboxes

MOFsolvothermal approach

HER/OER: onset potentials 0.04 V/1.33 V (vs. RHE); overpotentials at 10 mA cm-2: 60mV/190 mV HER: onset potential 125 mV


7

HER: 0.5 M H2SO4; OER: 1.0 M KOH.

0.5 M H2SO4.

73

74


Page 8 of 50

CoS2@MoS2

hierarchical nanoarray

hydrothermal method

HER: onset potential 44 mV, overpotentials 110.5 mV (η=10)

0.5 M H2SO4

75

MoS2/CoS2/ carbon cloth

MoS2 nanosheetcoated CoS2 nanowire

Two-step hydrothermal method

HER: overpotential of −87 mV (η=10)

0.5 M H2SO4.

76

Co9S8@MoS2/ carbon nanofibers

core– shell/carbon nanofibers

S vapor assisted graphitization of polyacrylonitrile nanofibers

onset potential 64 mV/1.580 V for HER/OER overpotential 190 mV (η=10) for HER

CoS2@MoS2/R GO

graphene oxide sheets dotted with nanoparticles

solvothermal approach

HER: overpotentials 98 mV (η=10), Tafel slope 37.4 mV dec−1.

0.5 M H2SO4, 5 mV s−1

78

CoS2MoS2/CNTs

nanoparticles and nanosheets

hydrothermal method

HER: onset potential 70 mV, Talel slope 67 mV dec−1.

0.5 M H2SO4.

79

CoS2/MoS2/Ca rbon fiber cloth

nanospheres/ nanosheets/ /carbon fiber cloth

microwaveassisted hydrothermal technique

HER: overpotentials at 10 mA cm-2 (66 mV), Tafel slope of 177 mV dec−1

0.5 M H2SO4

80

MoS2/CoS2-10

threedimensional hierarchical heterostructure

hydrothermal, electrodeposition , sulfuration procedure

HER: onsetpotential 20 mV, potential 125 mV at 100 mA cm-2

180CoS2/MoS2-2

flower-like nanostructures

hydrothermal method

HER: overpotentials 154 mV (η=10), Tafel slope 61 mV dec−1.

0.50 M H2SO4

82

Co-MoSx/CFP

nanoparticles

hydrothermal method

HER: overpotentials 199 mV (η=10)

0.5 M H2SO4.

83

MoS2/Co3S4

hollow polyhedral structure

templated solvothermal

HER: overpotentials 175 mV (η=10)

0.5 M H2SO4

84

core-shell nanospheres

solvothermal approach and annealing treatment

HER: overpotentials 143 mV (η=10), Tafel slope117 mV dec−1.

Co9S8@MoS2

ORR: ~1.57 V (η=10)


8

HER in 0.5 M H2SO4; ORR in 1 M KOH

0.5 M H2SO4, scan rate 2 mV s-1

HER and OER: in 1.0 M KOH, 2 mV s-1 ORR: 0.1 M KOH, 10 mV s-1.

77

81

85

Page 9 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


CoS2/ MoS2/ rGO

nanoparticles/ amorphous MoS2

hydrothermal method

HER: onset potential -80 mV, Talel slope 56 mVdec−1.

0.5 M H2SO4

86

CoSeMoS2/Ni3 S2/nanofiber

core/shell nanorod arrays

hydrothermal processes and electrodeposition

For HER/OER: overpotentials 85/225 mV; Tafel slope 62.3/ 46.1 mV dec−1.

1.0 M KOH, 1 mV s-1.

87

Co3S4@MoS2

hollow structures

MOF-templated solvothermal route

CoMoSx (x = 4–6)

chalcogel structure

solutionchemistry method

3 wt% MoS2/CuInS2

few-layer MoS2 nanosheetCuInS2

hydrothermal method

MoS2/ZnIn2S4

MoS2 loaded on floriated ZnIn2S4 microspheres

HER/OER: overpotentials 210 mV/330 mV, Tafel slope 81/59 dec−1

HER: 0.5 M H2SO4 OER: 1 M KOH

88

HER: overpotentials 0.23 V at 5 mA cm-2

0.1 M KOH (pH 13)

89

316 μmolh-1g-1

A 300 W Xe lamp (λ> 420 nm), 0.25 M Na2SO3/Na2S as sacrificial agent;

90

in-situ photoassisted deposition

8.047 mmolh-1g-1

A 300 W Xe lamp (λ>420 nm), lactic acid as the sacrificial reagent.

91

MoS2–CdS

MoS2 nanosheets grew on CdS nanocrystals.

hot-injection method

1472 μmolh-1g-1

A 300 W Xe lamp (λ> 420 nm), lactic acid as sacrificial agent

92

2.0 wt% MoS2/CdS

cauliflowerlike morphology

hydrothermal process

4.06 mmolh-1g-1

A 300 W Xenon lamp (λ> 400 nm), lactic acid as sacrificial agent

93

rGO1.5/CdS/M oS2-11

MoS2 deposit on the surface of rGO sheet

photodeposition method

1980 μmolh-1g-1

A 350 W Xe lamp (λ ≥ 420 nm), lactic acid as sacrificial agent

94

2 wt% MoS2/CdS

nanodots-onnanorods

solvothermal method

60280 μmolh-1g-1

A 300 W Xe lamp (λ ≥ 420 nm), lactic acid as hole scavenger

95

MoS2/CdS-20

CdS nanoparticles /MoS2 nanosheets

solvothermal reaction

μmolh-1g-1

A 300 W Xe lamp (λ ≥ 420 nm), lactic acid as sacrificial agent

96

MoS2/G-CdS

CdS nanoparticles

solutionchemistry

9000 μmolh-1g-1

A 300 W Xe lamp (λ ≥ 420 nm), 0.35 M Na2S-

97

6850


9


/layered MoS2

method

0.2 wt % MoS2/CdS

layered MoS2 deposited on CdS

impregnation method and pyroprocessing

MoS2-CdS

uniform nanowires with a rough surface

solvothermal and exfoliation method

CoSx/TiO2

CoSx QDs located on TiO2 particle

depositionprecipitateon method

CoS/CNT

CoS NPs coated on the surface of the CNTs.

Heat solution under N2

CoSx/G

the network linking structure

Zn0.30Co2.70S4

Na2SO3 as hole scavenger 5400 μmolh-1g-1

A 300 W Xe arc lamp, lactic acid as sacrificial agent

98

95700 μmolh-1g-1

A 300 W Xe arc lamp (λ> 400 nm), lactic acid as sacrificial agent

99

50 mL of 20 vol% aqueous solution of ethanol; 300 W Xe lamp (PLS-SXE300)

100

4.7 μmol (stop in 5 min)

H2O/1,2dichloroethane, decamethylferrocene as electron donor .

101

photoreduction and in-situ chemical deposition

47233 μmolh-1g-1

aqueous solution containing TEOA, EY; λ ≥420 nm

102

hollow polyhedra

MOF selftemplated method

155200 μmolh-1g-1

aqueous solution containing TEOA, EY; light (220-400nm)

103

nanoflower

Bimetallic MOF-templated solvothermal method

40156 μmolh-1g-1

Aqueous solution containing TEOA, EY; 300 W Xe lamp (λ ≥420 nm)

This work

Cu0.9Co2.7S4@ MoS2

Page 10 of 50

838

μmolh-1g-1

Here we only compare the efficiency of photocatalytic water reduction for hydrogen evolution. Molybdenum sulfide/cobalt sulfide composites have not been reported in this aspect. Of all the molybdenum sulfide-based catalytic photocatalysts, the loading with CdS showed the best catalytic activity (95700 μmolh-1g-1). On the other hand, among all cobalt sulfide-based photocatalysts, the Zn-doped cobalt sulfide composite is the most excellent with a photocatalytic efficiency of 155200 μmolh-1g-1. While a CoSx/ graphene hybrid also achieved a high catalytic efficiency (47233 μmolh-1g-1). In addition, in the reported MoS2- or


10

Page 11 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


CoSx- based photocatalyst, there is no hydrogen production efficiency superior to the present work.

2. EXPERIMENTAL SECTION 2.1. Chemicals and reagents. All chemicals are commercially available and used without further purification (see Supporting Information for more details). And the catalyst used in all experiments is Cu0.9Co2.1S4@MoS2 (25.8 wt%), unless otherwise stated.

2.2. Synthesis of the Co3S4@MoS2 and hybrids. The Co-MOF and MCo-MOF (M = Zn, Ni, Cu) were synthesized according to a previous literature with modifications (see Supporting Information).43,44,104 The synthesis process of the series of Co3S4@MoS2 (MoS2 contents are 17.4 wt%, 21.1 wt%, 23.4 wt%, 25.8 wt%, 28.3 wt% and 30.5 wt%) was described as follows. Typically, thiourea (0.228 g, 3 mmol) and Na2MoO4·2H2O (0.242 g, 1 mmol) were dissolved in deionized water and then various amounts of ZIF-67 (Co) were added to form a suspension. The suspension was transferred to a 25 mL Teflon-lined stainless steel autoclave and then heated at 220 °C for 24 h. After cooling naturally, the black Co3S4@MoS2 nanohybrids were harvested by centrifugation, washed with deionized water and ethanol (along with ultrasonic treatment), and dried at 60 °C for 12 h. The MoS2 contents were confirmed by inductively coupled plasma (ICP) analysis and elements analysis. For comparison, pure MoS2 nanosheets were synthesized under the same conditions in the absence of ZIF-67 (Co). The preparation of MxCo(3-x)S4@MoS2 (M = Zn, Ni, Cu, x = 1.5, 0.9) was similar to the process of Co3S4@MoS2.

2.3. Synthesis of the others relevant materials. The pure Co3S4 was obtained from adding 0.873 g (3 mmol) Co(NO3)2∙6H2O and 0.684 g (9 mmol) thiourea into H2O with a


11


hydrothermal process at 220 °C for 24 h. Pure MoS2 was synthesized by heating 0.228 g (3 mmol) thiourea and 0.242g (1 mmol) Na2MoO4·2H2O in H2O at 220 °C for 24 h. The two samples were mixed in a certain ratio (74.2:25.8, wt%) and then mechanically ground to give sample Co3S4/MoS2. For the composite obtained from the raw materials of ZIF-67, we added 0.291 g (1 mmol) Co(NO3)2∙6H2O and 0.164 g (2 mmol) 2-methylglyoxaline, 0.228 g (3 mmol) thiourea and 0.242g (1 mmol) Na2MoO4·2H2O into H2O. After hydrothermal reaction at 220 °C for 24 hours, we got the Co3S4-MoS2.

2.4 Photocatalytic performance for hydrogen evolution. The photocatalytic hydrogen production experiments were performed in a 25 mL quartz cell using a 300 W Xe lamp (PLSSXE300C produced by Beijing perfect light technology Co. Ltd) equipped with UV cut-off filter (λ ≥ 420 nm). A Multichannel Photochemical Reaction System was used for conditions optimization (PCX50A Discover produced by Beijing perfect light technology Co. Ltd). The experiments were performed in aqueous suspension which dissolved photosensitizer and sacrificial reagent, and suspended with catalysts powder following ultrasonic dispersion for 20 min. Prior to irradiation, the system was deaerated by bubbling nitrogen for 15 min. During the photocatalytic reaction, the reactor was tightly sealed to avoid gas exchange and maintained at 25 °C. The generated hydrogen in the head space was sampled (400 μL) and then analyzed using gas chromatography (Agilent Technology 7820A, nitrogen as a carrier gas) equipped with thermal conductivity detector (TCD).

3. RESULTS AND DISCUSSION


12

Page 12 of 50

Page 13 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


3.1 Formation of Homogenous Bimetallic MOFs. Bimetallic precursors (MCo-MOF, M = Zn, Ni, Cu) are produced via co-precipitation reaction of Co(NO3)2 and M(NO3)2 (M = Zn, Ni, Cu) mixtures with 2-methylimidazole in methanol at room-temperature (see the Supporting Information for details). Due to the similar ionic radius and electronegativity, M2+ can be uniformly introduced into the original Co-MOF lattices to replace the cobalt ions. The ICP analytic results of M/Co atomic ratios in MCo-MOFs are approximate to those in the starting materials, which indicates the effective coordination of all metal ions with the ligand. No difference observed in XRD patterns (Figure 1a) between the as synthesized samples and CoMOFs, elucidating the homogeneous incorporation of metal ions into the Co-MOF. Figure 1bd show that the synthesized MCo-MOFs polyhedrons possess identical rhombic dodecahedral morphology with ZIF-67.

Figure 1. (a) PXRD patterns of synthesized ZIF-67, doped ZIF-67 and simulated ZIF-67; and the corresponding TEM images of (b) Ni-ZIF-67, (c) Zn-ZIF-67, (d) Cu-ZIF-67.


13


3.2 Formation of Homogenous MxCo(3-x)S4@MoS2. The formation of homogeneous bimetallic MOF provides the opportunity to correspondingly produce uniform MxCo(3x)S4@MoS2.

In detail, the bimetallic sulfides can be produced by in situ topotactic

transformation of MOFs in methanol solution,14 as follows:

Na2MoO4 + 2NH2CSNH2 + 5H2O→MoO3 + 4NH3 + 2H2S + 2NaHCO3

4MoO3 + 10H2S→4MoS2 + S + SO2 MxCo3 - x(C4H5N2)8 + 4H2S→MxCo3 - xS4 + 8C4H6N2

The formation of the flower-like structure can be discerned unambiguously from scanning electron microscopy (SEM) images. Figure 2 depicts the typical flower-like SEM images that the 2D hybrid nanosheet “ petals ” aligned together with considerable interspace pointing towards one center disorderly to create the spherical product.

Figure 2. SEM images of as-synthesized Cu0.9Co2.1S4@MoS2 hybrid.

To further probe into the morphology, transmission electron microscope (TEM) measurements were carried out for Cu0.9Co2.1S4@MoS2, manifesting the hybrid interior and complicated


14

Page 14 of 50

Page 15 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


detailed structure of the “flowers”. TEM images (Figure 3a-b) also show that flower-like Cu0.9Co2.1S4@MoS2 hybrids are assembled by interconnecting nanosheets. High-magnification TEM images further reveal the microscopic phase of Cu0.9Co2.1S4@MoS2. As illustrated in Figure 3c and Figure 3d, two sets of parallel lattice fringes are distinctly observed; the interplanar distances of 1.66 Å, 1.81Å, 1.92 Å, 2.35 Å, 2.84 Å, 3.33 Å agree well with the (440), (511), (422), (400), (311), (220) planes of cubic Co3S4 respectively, while the interplanar distances of 2.27 Å, 2.50 Å, 2.67 Å, 3.07 Å can be indexed to the (103), (102), (101), (004) planes of hexagonal MoS2 correspondingly. Moreover, no impure phase such as CuS was observed in TEM images or the XRD patterns, indicating a high purity of the assynthesized products. The inner structure of the hybrid materials could be clearly observed from the powder X-ray diffraction. XRD spectrum (Figure 3e) shows that the sulfides can be entirely indexed as hexagonal MoS2 (Powder Diffraction File No. 87-2416, Joint Committee on Powder Diffraction Standards, [1983]) and cubic Co3S4 (Powder Diffraction File No. 471738, Joint Committee on Powder Diffraction Standards, [1993]). As can be seen in Figure S1, the structure of the hybrids does not change under the influence of incorporating second metals (Zn, Ni, and Cu). No new peak originating from other metal sulfides, which indicates that the metal ions take the sites of Co ions of the Co3S4 lattice uniformly. Compared with those of pristine Co3S4, the peaks of doped Co3S4 show no shift indicating the cell parameters are not affected owing to the identical ionic radius.43,44


15


Figure 3. (a-b) TEM images, (c-d) high magnification TEM images and (e) PXRD of assynthesized Cu0.9Co2.1S4@MoS2 hybrid.

Additionally, energy-dispersive X-ray (EDX) elemental mapping analysis verifies the uniform distribution of metal and S species. Figure 4 demonstrates that Co, Mo, Cu and S elements are uniformly distributed in Cu0.9Co2.1S4@MoS2, which is consistent with the expected hybrid design. These results not only show that the Cu ions can be fully involved in the formation of catalysts like Co ions, but also imply high efficiency and accuracy of this synthetic method with MOF-template strategy. At the same time, the sufficient combination of the various elements also provides the necessary and sufficient catalytic activity for the catalytic reaction.


16

Page 16 of 50

Page 17 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 4. (a) STEM-DF image of Cu0.9Co2.1S4@MoS2, (b) selected area and EDS elemental mappings for (c) Co, (d) Mo, (e) Cu, (f) S.

To further explore the chemical composition of the sample surface, the X-ray photoelectron spectroscopy (XPS) was performed to confirm the valence of each element. As shown in Figure 5, binding energies of Co 2p1/2 and Co 2p3/2 are 796.2 eV and 781.2 eV, respectively, confirming the +2 oxidation state of Co.105 Also, peaks centred at 793.7 eV and 778.6 eV could be assigned to 2p1/2 and 2p3/2 orbitals of Co3+.106 The Cu 2p spectrum displayed the atom present in Cu 2p1/2 and Cu 2p3/2 orbitals of Cu–S are located at 952.5 eV and 932.2 eV, respectively, which is in accordance with literature.107 The peaks at 232.2 eV and 229.0 eV belong to the binding energies of Mo 3d1/2 and Mo 3d3/2, confirming that molybdenum is in its Mo(IV) state.108,109 There are also two pairs of characteristic peaks of S atom. 161.5 eV and 162.8 eV belong to Co3S4,46 while 161.9 eV and 163.2 eV belong to MoS2.110


17


Figure 5. X-ray photoelectron spectroscopy survey spectra of Cu0.9Co2.1S4@MoS2: (a) Co 2p (b) Cu 2p (c) Mo 3d and (d) S 2p scan spectra sample.

The ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS) measurements provide more detailed information on the optical properties of the as-prepared samples.111 The corresponding Kubelka–Munk transformed reflectance spectra are shown in Figure 6 where the slops of the tangents on horizontal axis are bandgap energies. The calculated bandgap energy for pure MoS2 and Co3S4 is 2.31 eV and 2.65 eV, respectively, while the MOF-derived Co3S4@MoS2 show a narrower bandgap of 2.09 eV. This is ascribed to the strong light scattering and trapping effect from MoS2 nanosheets identifying the successful hybrid between the MoS2 and Co3S4. Moreover, the narrower bandgap energy of approximately 1.62 eV for the Cu0.9Co2.1S4@MoS2 photocatalyst is more suitable for photocatalytic HER. Expectedly, the broader bandgaps of Co3S4-MoS2 and Co3S4/MoS2 confirm that MOF-derived combining method facilitates the electron transport from photosensitizer to catalyst in the present catalytic system (see Figure S4).


18

Page 18 of 50

Page 19 of 50

2.0

Cu0.9Co2.1S4@MoS2 Co3S4@MoS2 1.5

[F(r)hv]1/2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


MoS2 Co3S4

1.0

0.5

2.65 eV 2.31 eV 0.0

1.62 eV 1.2

1.6

2.09 eV 2.0

2.4

2.8

3.2

3.6

4.0

4.4

4.8

Energy (eV)

Figure 6. The curves of (αhν)2 versus photon energy (hν) of Co3S4, MoS2, MoS2@TiO2 and Cu0.9Mo2.1S4@MoS2, from which the width of band gap can be figured out by linear fitting the absorption edge.

3.3 Photocatalytic HER Performance. To investigate the photocatalytic activities of a series of Co3S4@MoS2 materials, we utilized them for photocatalytic hydrogen production from water under a 300 W Xe lamp. Without photocatalyst (Co3S4, MoS2, Co3S4/MoS2, Co3S4MoS2,

Co3S4@MoS2,

Ni1.5Co1.5S4@MoS2,

Zn1.5Co1.5S4@MoS2,

Cu1.5Co1.5S4@MoS2,

Cu0.9Co2.1S4@MoS2) or light, no H2 was generated, which indicates that this type of H2 evolution is a light-induced reaction.

As shown in Figure 7a, the pure Co3S4 are practically inactive for the photocatalytic hydrogen evolution reaction with negligible hydrogen products. The pure MoS2 sample also shows a very low photocatalytic activity with a H2 evolution rate of 1580 μmol h-1 g-1. Meanwhile, using cobalt nitrate and 2-methylimidazole of ZIF-67 as precursor, photocayalyst Co3S4-MoS2


19


merely exhibits a H2 evolution rate of 4105 μmol h-1 g-1. After mechanical mixing MoS2 with Co3S4 (Co3S4/MoS2), the hydrogen evolution increase to 3076 μmol h-1 g-1. However, the H2 evolution rates are significantly improved when replacing the photocatalyst with Co3S4@MoS2, which indicates that the combination of Co3S4 and MoS2 not only increases the exposure of the catalytic sites, but also has a complex synergistic effect between the two components, which promotes the rapid photocatalytic progress. This verifies that hybridization method with MOFs as precursor can significant enhance the activity of photocatalysts. The intimate nanojunction between Co3S4 and MoS2 provides an efficient transport route for charge carrier transfer and sufficient catalytic sites, accelerating the hydrogen evolution reaction.

In the natural world, photosynthesis refers to the process that green plants or certain bacteria use photosynthetic pigments to convert carbon dioxide (or hydrogen sulfide) and water into organic compounds then release oxygen or hydrogen under visible light irritation. In this process, pigments adsorb light and transfer photo-excited protons to enzymes, which ensures the occurrence of catalysis. In the optimized system of our experiments, alcoholic Eosin Y is selected as a photosensitiser and triethanolamine (TEOA; 5.3% v/v ) acts as a hole scavenger in aqueous solution at pH 13 (see detailed in Supporting Information, Figures S5–S8).

To further improve the catalytic efficiency, more experiments have been conducted. Figure S9 shows the photocatalytic activities of H2 evolution on Co3S4@MoS2 loaded with different amount of MoS2 co-catalyst. As the MoS2 ratio increasing, the photocatalytic activity of H2 evolution on Co3S4@MoS2 is greatly enhanced, reaching the maximum when the MoS2 loading is about 25.8 wt%. The activity of H2 evolution is increased by up to 270 times in


20

Page 20 of 50

Page 21 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


comparison with that of bare Co3S4. It indicates that the in situ loaded MoS2 acts as an efficient cocatalyst for photocatalytic H2 evolution from water reduction.

Figure 7. (a) Photocatalytic hydrogen evolution curves of different materials; (b). The effect of doping different amounts of Cu ions in ZIF-67 for CuxCo3-xS4@MoS2 on H2 evolution (x = 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, 2.4, 2.7). Conditions: aqueous suspension containing 1.0 mg CuxCo3-xS4@MoS2, 5.3% TEOA (v/v) and 0.15 mM Eosin Y at pH 13.00 under an inert atmosphere. The system was irradiated with a 300 W Xe lamp with a cutoff filter of λ ≥ 420 nm.

To further improve hydrogen generation activity of photocatalysts, by virtue of the ZIF-67 advantages that they can form isoreticular framework with homogeneous different metal nodes, we utilize Ni-ZIF-67, Zn-ZIF-67 and Cu-ZIF-67 (Figure 7a) respectively to prepare hybrid M1.5Co1.5S4@MoS2 (M = Ni, Zn, Cu) composites as photocatalysts. The doped hybrids show remarkably superior catalytic performance compared with Co3S4@MoS2, with the average hydrogen generation rate during 10 hours growing from 13321 μmol g-1 h-1 for pristine Co3S4@MoS2 to 25383 μmol g-1 h-1 for Zn1.5Co1.5S4@MoS2, 28556 μmol g-1 h-1 for Ni1.5Co1.5S4@MoS2, and 34794 μmol g-1 h-1 for Cu1.5Co1.5S4@MoS2.


21


A range of catalysts with different Cu/Co atomic ratios were prepared by using allomeric ZIF-67 as precursors and the approximate Cu/Co atomic ratio in CuxCo3-xS4@MoS2 varies from 1:9 to 9:1, accordingly. A comparison of their photocatalytic performances is shown in Figure 7b. The change in doping amount of Cu evidently has considerable influence on the catalytic performance. Cu0.9Co2.1S4@MoS2 (Cu/Co is 3:7) is optimised to be the most efficient HER catalyst with a rate of 40156 μmol g-1 h-1 which is 3.02 times higher than that of Co3S4@MoS2.

3.4 Proposed photocatalysis mechanism for hydrogen evolution.

In the presence of photosensitizer (PS), it is significant to determine whether the excited state PS* is quenched by the photocatalyst Cu0.9Co2.1S4@MoS2 (Cat.) or by the sacrificial agent (TEOA). Eosin Y quenching measurements in aqueous suspension at pH 13 with increasing concentrations (concentration range similar to that of the photocatalytic experiment) of addition agent (either Cat. or TEOA) were analyzed through the Stern-Volmer equation:

𝐼𝑜 𝐼

= 1 + 𝑘𝑞 𝜏𝑜[𝑄]

Where I0 and I are the fluorescence intensities before and after addition agent, respectively, kq is the apparent quenching rate constant, τ0 is the excited-state lifetime without addition agent, and [Q] is the concentration of addition agent.112


22

Page 22 of 50

Page 23 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 8. (a) Emission spectra of EY as function of TEOA; insert is Stern-Volmer plot for photoluminescence quenching of Fl by TEOA. The calculated quenching rate constant is 2.46 ×

1010

mol-1

s-1;

(b)

Time-resolved

luminescence

measurements

of

Fl

with

Cu0.9Co2.1S4@MoS2 and TEOA in pure water at pH 13.00.

The gradual addition of TEOA resulted in linear variation of the fluorescence ratio (Figure 8a), whereby we calculated an apparent quenching rate constant of kq = 2.46 × 1010 M-1 s-1. The reductive electron transfer between TEOA and EY* is highly efficient in reduction quenching.113,114 On the contrary, the variation of the fluorescence ratio is linear (Figure S10 in Supporting Information) with Cu0.9Mo2.1S4@MoS2 as the quencher, corresponding to the quenching rate constant of 2.04 × 109 M-1 s-1. The oxidation quenching constant is one order of magnitude smaller than the reduction quenching constant, indicating that the reduction quenching is the dominant direction of the reaction in this photocatalytic hydrogen production system.113,115,116

In addition, we tested the transient fluorescence lifetime with the attenuation curve shown in Figure 8b. The transient lifetime of Eosin Y in pure water (adjust the pH to 13) is 1.15 ns.


23


When the catalyst is present, the transient fluorescence lifetime is reduced to 1.00 ns, while the transient fluorescence lifetime is significantly reduced to 0.41 ns with TEOA.

Scheme 1. Photocatalytic pathway for H2 evolution over EY-Cu0.9Co2.1S4@MoS2 photocatalyst under visible light irradiation.

On the basis of above results, the photocatalytic H2 production over EY-sensitized Cu0.9Co2.1S4@MoS2 photocatalyst may proceed via a reductive electron transfer mechanism. (see Scheme 1) Upon excitation (420 nm), electrons are excited simultaneously from the valence band of Cu0.9Co2.1S4@MoS2 to the conduction band and that from highest-occupied molecular orbital (HOMO, -1.349 eV) of EY molecules to their lowest-unoccupied molecular orbital (LUMO, -3.639 eV). The excited EY (*EY) is reductively quenched by TEOA to produce EY•−. Subsequently, electrons are transferred from EY•− to the conduction band of Cu0.9Co2.1S4@MoS2 where the protons are reduced to form molecular H2. Simultaneously, the reduced state dye species return to ground state, accomplishing complete water reduction reaction.


24

Page 24 of 50

Page 25 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 9. Durability tests of hydrogen generation Cu0.9Co2.1S4@MoS2 for cyclic three times under visible irradiation from a 300 W Xe lamp (λ ≥ 420 nm) in aqueous suspension with TEOA and Eosin Y.

Three consecutive photocatalytic reactions were performed (Figure 9) to evaluate the stability of photocatalytic activity of Cu0.9Co2.1S4@MoS2. During 30 hours of irradiation, the hydrogen of three cycles generate steadily and reach approximate amount of hydrogen with negligible differences. The visible-light (λ ≥ 420 nm) quantum efficiency of about 3.2% (see figure S11). Meanwhile, throughout the stability test, the photocatalyst Cu0.9Co2.1S4@MoS2 remains highly stable and shows nearly no difference with XRD spectra before and after 30 h reaction (see Figure S12), further demonstrating the remarkable photocatalytic stability of the hybrid photocatalyst. The experimental result shows that the structure of Cu0.9Co2.1S4@MoS2 hybrid can both fully expose the catalytic sites and maintain the stability of the structure over a long period of time. What’s more, it is a strong evidence that the MOF-templated method helps to get tough materials and promotes the heterogeneous photocatalytic reactions.


25


Page 26 of 50

The electrochemical impedance spectroscopy (EIS) was used to characterize the interfacial impedance between the solid and the charge transfer on the surface, which further shows the superiority of the catalyst in electron conduction.117 The resistance of pure MoS2, pure Co3S4, Co3S4@MoS2

composite

and

composite

catalysts

doped

with

different

metals

(Cu0.9Co2.1S4@MoS2, Zn0.9Co2.1S4@MoS2, Ni0.9Co2.1S4@MoS2) were tested respectively (shown in Figure 10). It can be seen that the impedance values of pure MoS2 (126.1 Ω) and pure Co3S4 (213.5 Ω) are relatively large, and the impedance value of the photocatalyst after recombination is significantly reduced (95.92 Ω for Co3S4@MoS2). This indicates that the hybrid between Co3S4 and MoS2 greatly improves the electron conductivity of the nanomaterials, which significantly facilitates rapid electron transfer.118 Compared with the Co3S4@MoS2 hybrids, the metal doped materials show much faster electron transfer. The Cudoped material presents the smallest impedance (92.8 Ω for Zn0.9Co2.1S4@MoS2, 88.1 Ω for Ni0.9Co2.1S4@MoS2, 76.6 Ω for Cu0.9Co2.1S4@MoS2), corresponding to the highest hydrogen production in the system. In general, the strong interaction between Co3S4 and MoS2 and the sufficient active interfaces between them can promote the electron transfer, while the successful doping of other metals can further improve the charge transfer performance, which is shown as the improved hydrogen production activity of Cu0.9Co2.1S4@MoS2 photocatalyst.


26

Page 27 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 10. EIS response of Co3S4, MoS2, Co3S4@MoS2, Zn0.9Co2.1S4@MoS2 (Cat.-Zn), Ni0.9Co2.1S4@MoS2 (Cat.-Ni), Cu0.9Co2.1S4@MoS2 (Cat.-Cu). Sinusoidal ac perturbation is 5 mV, frequency range is 0.1 – 106 Hz. Insert is the equivalent circuit model of the studied system.

In order to investigate the photo-response of these dye-sensitized catalysts in the catalytic system, the photocurrents of the above materials were tested.119 As shown in Figure 11, the response currents of the pure Co3S4 and MoS2 are negligible. After hybridization, the response to light of Co3S4@MoS2 still quickly reach the steady state within 50 s with much stronger photocurrent intensity under visible light irradiation, meaning stronger ability of producing charge carriers and more separated electrons. After five cycles of circulation, this fast and efficient light response still show no significant attenuation and delay. Observing the materials doped with other metals (Zn, Ni, Cu), the light response is improved in different degrees. Among them, the addition of metal copper increases the photo-response current density nearly doubled under the same conditions, which greatly promotes the efficient process of catalytic hydrogen production.120


27


ON OFF

Current density (a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 28 of 50

Cu0.9Co2.1S4@MoS2 Ni0.9Co2.1S4@MoS2 Zn0.9Co2.1S4@MoS2 Co3S4@MoS2

MoS2 Co3S4

0

100

200

300

400

500

600

Time (s)

Figure

11.

Transient

Zn0.9Co2.1S4@MoS2,

photocurrent

Ni0.9Co2.1S4@MoS2,

responses

of

Co3S4,

Cu0.9Co2.1S4@MoS2

MoS2,

Co3S4@MoS2,

composites.

Electrodes

recorded in 0.35 M/0.25 M Na2S–Na2SO3 aqueous solution under with light-on and light-off cycles.

4. CONCLUSION A general allomeric MOF-templated method to synthesize nanoflower-like doping photocatalyst (Cu0.9Co2.1S4@MoS2) has been ascertained. The uniformity of bimetallic MOF precursor guaranteed that homogeneously doped metal ions (Cu2+) in the lattice of Co3S4 in the resultant catalyst. Compared with bulk Co3S4, MoS2 and materials synthesized from other routes (Co3S4-MoS2, Co3S4/MoS2), the incorporation of second metal and the nanoflower hybrid structure increased the catalytic active sites, improved the electrical conductivity, thereby enhancing the photocatalytic hydrogen production. Particularly, under the optimum synthesis and reaction condition, with the help of Eosin Y, Cu0.9Co2.1S4@MoS2 shows excellent visible-light catalytic HER activity at a hydrogen production rate of 40156 μmol h-1


28

Page 29 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


g-1 in aqueous soltion, without any cocatalyst. Relative to other post-modified synthesis for hybrid materials, abundant allomeric MOFs can provide opportunities to homogenously fabricate a wide range of hybrid materials for high-performance HER and other energy conversion reaction. This in situ bi- or multimetallic MOF-derived synthetic strategy is quite encouraging and fascinating for diverse nanocatalyts.

ASSOCIATED CONTENT

Supporting Information. The following files are available free of charge via the Internet at http://pubs.acs.org. [chemicals used in experiments; test methods for synthesis and synthesize methods;

lectrochemical

impedance

spectroscopy;

transient

photocurrent

response;

photocatalytic performance for H2 evolution; PXRD patterns of synthesized Co3S4@MoS2 and MxCo3-xS4@MoS2 (M = Ni, Cu, Zn); The effect of the different MoS2 loadings for Co3S4@MoS2 on H2 evolution; The effect of doping different metal ions (Zn, Ni and Cu) for Co3S4@MoS2 on H2 evolution; The effect of doping different amounts of Cu ions in ZIF-67 for CuxCo3-xS4@MoS2 on H2 evolution; The effect of different photosensitizers on H2 evolution; The effect of different sacrificial agents on H2 evolution; The effect of pH values on photocatalytic H2 production; The effect of the volume ratios of TEOA/H2O on photocatalytic H2 production; Emission spectra of Fl as function of CuxCo3-xS4@MoS2 and responding SternVolmer plot; PXRD spectra of the Cu0.9Co2.1S4@MoS2 nanohybrid before and after photoreaction for three times.] AUTHOR INFORMATION Corresponding Author


29


* E-mail: [email protected] (X.-Y. Dong); [email protected] (S.-Q. Zang); Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Funding Sources This work was supported by the National Natural Science Foundation of China (No. 21501046, 21671175, 21371153), the National Science Fund for Distinguished Young Scholars (No. 21825106), the Program for Science & Technology Innovation Talents in Universities of Henan Province (164100510005), and the Program for Innovative Research Team (in Science and Technology) in Universities of Henan Province (19IRTSTHN022). Notes The authors declare no competing financial interest. REFERENCES 1

Zhang, X. H.; Peng, T. Y.; Song, S. S. Recent Advances in Dye-Sensitized

Semiconductor Systems for Photocatalytic Hydrogen Production. J. Mater. Chem. A 2016, 4, 2365–2402. 2

Chen, Y. Z.; Zhang, R.; Jiao, L.; Jiang, H. L. Metal-Organic Framework-Derived

Porous Materials for Catalysis. Coord. Chem. Rev. 2018, 362, 1–23. 3

Wei, X. J.; Jiang, X. Q.; Wei, J. S.; Gao, S. Y. Functional Groups and Pore Size

Distribution Do Matter to Hierarchically Porous Carbons as High-Rate-Performance Supercapacitors. Chem. Mater. 2016, 28, 445–458.


30

Page 30 of 50

Page 31 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


4

Wei, X. J.; Li, Y. B.; Gao, S. Y. Biomass-Derived Interconnected Carbon

Nanoring Electrochemical Capacitors with High Performance in Both Strongly Acidic and Alkaline Electrolytes. J. Mater. Chem. A 2017, 5, 181–188. 5

Wang, P.; Wang, M. M.; Zhang, J.; Li, C. P.; Xu, X. L.; Jin, Y. D. Shell Thickness

Engineering Significantly Boosts the Photocatalytic H2 Evolution Efficiency of CdS/CdSe Core/Shell Quantum Dots. ACS Appl. Mater. Interfaces 2017, 9, 35712–35720. 6

Ouyang, T.; Huang, H. H.; Wang, J. W.; Zhong, D. C.; Lu, T. B. A Dinuclear

Cobalt Cryptate as a Homogeneous Photocatalyst for Highly Selective and Efficient Visible-Light Driven CO2 Reduction to CO in CH3CN/H2O Solution. Angew. Chem. 2017, 129, 756–761. 7

Serpone, N.; Emeline, A. V.; Ryabchuk, V. K.; Kuznetsov, V. N.; Artem’ev, Y.

M.; Horikoshi, S. Why do Hydrogen and Oxygen Yields from Semiconductor-Based Photocatalyzed Water Splitting Remain Disappointingly Low? Intrinsic and Extrinsic Factors Impacting Surface Redox Reactions. ACS Energy Lett. 2016, 1, 931–948. 8

Wang, J. W.; Sahoo, P.; Lu, T. B. Reinvestigation of Water Oxidation Catalyzed

by a Dinuclear Cobalt Polypyridine Complex: Identification of CoOx as a Real Heterogeneous Catalyst. ACS catal. 2016, 6, 5062–5068. 9

Yan, Y.; Xia, B. Y.; Xu, Z. C.; Wang, X. Recent Development of Molybdenum

Sulfides as Advanced Electrocatalysts for Hydrogen Evolution Reaction. ACS Catal. 2014, 4, 1693–1705.


31


10

Tao, Z. X.; Wang, T.; Wang, X. J.; Zheng, J.; Li, X. G. MOF-Derived Noble Metal

Free Catalysts for Electrochemical Water Splitting. ACS Appl. Mater. Interfaces 2016, 8, 35390–35397. 11

Lu, Q. P.; Yu, Y. F.; Ma, Q. L.; Chen, B.; Zhang, H. 2D Transition-Metal-

Dichalcogenide-Nanosheet-Based Composites for Photocatalytic and Electrocatalytic Hydrogen Evolution Reactions. Adv. Mater. 2016, 28, 1917–1933. 12

Zhu, H.; Zhang, J. F.; Yanzhang, R. P.; Du, M. L.; Wang, Q. F.; Gao, G. H.; Wu,

J. D.; Wu, G. M.; Zhang, M.； Liu, B.; Yao, J. M.; Zhang, X. W. When Cubic Cobalt Sulfide Meets Layered Molybdenum Disulfide: A Core–Shell System Toward Synergetic Electrocatalytic Water Splitting. Adv. Mater. 2015, 27, 4752–4759. 13

Yang, Q. H.; Xu, Q.; Jiang, H. L. Metal-Organic Frameworks Meet Metal

Nanoparticles: Synergistic Effect for Enhanced Catalysis. Chem. Soc. Rev. 2017, 46, 4774–4808. 14

Huang, Z. F.; Song, J. J.; Li, K.; Tahir, M.; Wang, Y. T.; Pan, L.; Wang, L.;

Zhang, X. W.; Zou, J. J. Hollow Cobalt-Based Bimetallic Sulfide Polyhedra for Efficient All-pH-Value Electrochemical and Photocatalytic Hydrogen Evolution. J. Am. Chem. Soc. 2016, 138, 1359–1365. 15

Wei, T.; Zhang, M.; Wu, P.; Tang, Y. J.; Li, S. L.; Shen, F. C.; Wang, X. L.; Zhou,

X. P.; Lan, Y. Q. POM-Based Metal-Organic Framework/Reduced Graphene Oxide Nanocomposites with Hybrid Behavior of Battery-Supercapacitor for Superior Lithium Storage. Nano Energy 2017, 34, 205–214.


32

Page 32 of 50

Page 33 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


16

Wei, Y. S.; Hu, X. P.; Dong, X. Y.; Zang, S. Q.; Mak, T. C. W. Unique Proton

Dynamics in an Efficient MOF-Based Proton Conductor. J. Am. Chem. Soc. 2017, 139, 3505–3512. 17

An, K.; Kwon, S. G.; Park, M.; Na, H. B.; Baik, S. I.; Yu, J. H.; Kim, D.; Son, J.

S.; Kim, Y. W.; Song, I. C.; Moon, W. K.; Park, H. M.; Hyeon, T. Synthesis of Uniform Hollow Oxide Nanoparticles through Nanoscale Acid Etching. Nano Lett. 2008, 8, 4252– 4258. 18

Wu, H. B.; Xia, B. Y.; Yu, L.; Yu, X. Y.; Lou, X. W. Porous Molybdenum

Carbide Nano-Octahedrons Synthesized via Confined Carburization in Metal-Organic Frameworks for Efficient Hydrogen Production. Nat. Commun. 2015, 6, 6512. 19

Liu, H. Y.; Joo, J. B.; Dahl, M.; Fu, L. S.; Zeng, Z. Z.; Yin, Y. D. Crystallinity

Control of TiO2 Hollow Shells Through Resin-Protected Calcination for Enhanced Photocatalytic Activity. Energy Environ. Sci. 2015, 8, 286–296. 20

Martin, D. J.; Qiu, K.; Shevlin, S. A.; Handoko, A. D.; Chen, X. W.; Guo, Z. X.;

Tang, J. W. Highly Efficient Photocatalytic H2 Evolution from Water using Visible Light and Structure-Controlled Graphitic Carbon Nitride. Angew. Chem. Int. Ed. 2014, 53, 9240–9245. 21

Wang, H. L.; Zhu, Q. L.; Zou. R. Q.; Xu, Q. Metal-Organic Frameworks for

Energy Applications. Chem 2017, 2, 52–80.


33


22

Dong, X. Y.; Wang, R.; Wang, J. Z.; Zang, S. Q.; Mak, T. C. W. Highly Selective

Fe3+ Sensing and Proton Conduction in a Water-Stable Sulfonate-Carboxylate TbOrganic-Framework. J. Mater. Chem. A 2015, 3, 641–647. 23

Zhang, F. M.; Dong, L. Z.; Qin, J. S.; Guan, W.; Liu, J.; Li, S. L.; Lu, M.; Lan, Y.

Q.; Su, Z. M.; Zhou, H. C. Effect of Imidazole Arrangements on Proton-Conductivity in Metal-Organic Frameworks. J. Am. Chem. Soc. 2017, 139, 6183–6189. 24

Yin, Y.; Rioux, R. M.; Erdonmez, C. K.; Hughes, S.; Somorjai, G. A.; Alivisatos,

A. P. Formation of Hollow Nanocrystals Through the Nanoscale Kirkendall Effect. Science 2004, 304, 711–714. 25

Xiao, C.; Xie, Y. The Expanding Energy Prospects of Metal Organic Frameworks.

Joule 2017, 1, 25–28. 26

Li, B.; Wen, H. M.; Cui, Y. J.; Zhou, W.; Qian, G. D.; Chen, B. L. Emerging

Multifunctional Metal-Organic Framework Materials. Adv. Mater. 2016, 28, 8819–8860. 27

Furukawa, H.; Cordova, K. E.; O’Keeffe, M.; Yaghi, O. M. The Chemistry and

Applications of Metal-Organic Frameworks. Science 2013, 341, 1230444. 28

Li, S. W.; Peng, S. J.; Huang, L. S.; Cui, X. Q.; Al-Enizi, A. M.; Zheng, G. F.

Carbon-Coated Co3+-Rich Cobalt Selenide Derived from ZIF-67 for Efficient Electrochemical Water Oxidation. ACS Appl. Mater. Interfaces 2016, 8, 20534–20539.


34

Page 34 of 50

Page 35 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


29

Ma, T. Y.; Cao, J. L.; Jaroniec, M.; Qiao, S. Z. Interacting Carbon Nitride and

Titanium Carbide Nanosheets for High-Performance Oxygen Evolution. Angew. Chem. Int. Ed. 2016, 55, 1138–1142. 30

Malgras, V.; Ji, Q.; Kamachi, Y.; Mori, T.; Shieh, F.; Wu, K.; Ariga, K.;

Yamauchi, Y. Templated Synthesis for Nanoarchitectured Porous Materials. Bull. Chem. Soc. Jpn. 2015, 88, 1171–1200. 31

Chaikittisilp, W.; Ariga, K.; Yamauchi, Y. J. A New Family of Carbon Materials:

Synthesis of MOF-Derived Nanoporous Carbons and Their Promising Applications. J. Mater. Chem. A 2013, 1, 14–19. 32

Li, X. Y.; Niu, Z. G.; Jiang, J.; Ai, L. H. Cobalt Nanoparticles Embedded in

Porous N-rich Carbon as an Efficient Bifunctional Electrocatalyst for Water Splitting. J. Mater. Chem. A 2016, 4, 3204–3209. 33

Li, B.; Chen, Y.; Ge, X. M.; Chai, J. W.; Zhang, X.; Hor, T. A.; Du, G. J.; Liu, Z.

L.; Zhang, H.; Zong, Y. Mussel-Inspired One-pot Synthesis of Transition Metal and Nnitrogen Co-doped Carbon (M/N–C) as Efficient Oxygen Catalysts for Zn-Air Batteries. Nanoscale 2016, 8, 5067–5075. 34

Jiao, L.; Wang, Y.; Jiang, H. L.; Xu, Q. Metal-Organic Frameworks as Platforms

for Catalytic Applications. Adv. Mater. 2018, 30, 1703663. 35

Gao, M. R.; Liang, J. X.; Zheng, Y. R.; Xu, Y. F.; Jiang, J.; Gao, Q.; Li, J.; Yu, S.

H. An Efficient Molybdenum Disulfide/Cobalt Diselenide Hybrid Catalyst for Electrochemical Hydrogen Generation. Nat. Commun. 2015, 6, 5982.


35


36

Pan, Y.; Liu, Y. Q.; Liu, C. G. Phase- and Morphology-Controlled Synthesis of

Cobalt Sulfide Nanocrystals and Comparison of Their Catalytic Activities for Hydrogen Evolution. Appl. Surf. Sci. 2015, 357, 1133–1140. 37

Wang, R.; Dong, X. Y.; Du, J.; Zhao, J. Y.; Zang, S. Q. MOF-Derived

Bifunctional Cu3P Nanoparticles Coated by a N,P-Codoped Carbon Shell for Hydrogen Evolution and Oxygen Reduction. Adv. Mater. 2018, 30, 1703711. 38

Yang, J.; Zhang, Y.; Sun, C. C.; Guo, G. L.; Sun, W. P.; Huang, W.; Yan, Q. Y.;

Dong, X. C. Controlled Synthesis of Zinc Cobalt Sulfide Nanostructures in Oil Phase and Their Potential Applications in Electrochemical Energy Storage. J. Mater. Chem. A 2015, 3, 11462–11470. 39

Ma, B.; Guan, P. Y.; Li, Q. Y; Zhang, M.; Zang, S. Q. MOF-Derived Flower-like

MoS2@TiO2 Nanohybrids with Enhanced Activity for Hydrogen Evolution. ACS Appl. Mater. Interfaces 2016, 8, 26794–26800. 40

Wu, R. B.; Qian, X. K.; Rui, X. H.; Liu, H.; Yadian, B. L.; Zhou, K.; Wei, J.; Yan,

Q. Y.; Feng, X. Q.; Long, Y.; Wang, L. Y.; Huang, Y. Z. Zeolitic Imidazolate Framework 67-Derived High Symmetric Porous Co3O4 Hollow Dodecahedra with Highly Enhanced Lithium Storage Capability. Small 2014, 10, 1932–1938. 41

Tang, J.; Salunkhe, R. R.; Liu, J.; Torad, N. L.; Imura, M.; Furukawa, S.;

Yamauchi, Y. Thermal Conversion of Core-Shell Metal-Organic Frameworks: A New Method for Selectively Functionalized Nanoporous Hybrid Carbon. J. Am. Chem. Soc. 2015, 137, 1572–1580.


36

Page 36 of 50

Page 37 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


42

Wu, R. B.; Wang, D. P.; Rui, X. H.; Liu, B.; Zhou, K.; Law, A. W.; Yan, Q. Y.;

Wei, J.; Chen, Z. In-Situ Formation of Hollow Hybrids Composed of Cobalt Sulfides Embedded within Porous Carbon Polyhedra/Carbon Nanotubes for High‐Performance Lithium-Ion Batteries. Adv. Mater. 2015, 27, 3038–3044. 43

Wu, R. B.; Qian, X. K.; Zhou, K.; Wei, J.; Lou, J.; Ajayan, P. M. Porous Spinel

ZnxCo3–xO4 Hollow Polyhedra Templated for High-Rate Lithium-Ion Batteries. ACS Nano 2014, 8, 6297–6303. 44

Chen, Y. Z.; Wang, C. M.; Wu, Z. Y.; Xiong, Y. J.; Xu, Q.; Yu, S. H.; Jiang, H. L.

From Bimetallic Metal-Organic Framework to Porous Carbon: High Surface Area and Multicomponent Active Dopants for Excellent Electrocatalysis. Adv. Mater. 2015, 27, 5010–5016. 45

Xu, M. Y.; Niu, H. L.; Huang, J. J.; Song, J. M.; Mao, C. J.; Zhang, S. Y.; Zhu, C.

F.; Chen, C. L. Facile Synthesis of Graphene-like Co3S4 Nanosheet/Ag2S Nanocomposite with Enhanced Performance in Visible-light Photocatalysis. Appl. Surf. Sci. 2015, 351, 374–381. 46

Cao, F. F.; Zhao, M. T.; Yu, Y. F.; Chen, B.; Huang, Y.; Yang, J.; Cao, X. H.; Lu,

Q. P.; Zhang, X.; Zhang, Z. C.; Tan, C. L.; Zhang, H. Synthesis of Two-Dimensional CoS1.097/Nitrogen-Doped Carbon Nanocomposites Using Metal–Organic Framework Nanosheets as Precursors for Supercapacitor Application. J. Am. Chem. Soc. 2016, 138, 6924–6927.


37


47

Wang, Q. H.; Jiao, L. F.; Du, H. M.; Peng, W. X.; Han, Y.; Song, D. W.; Si, Y. C.;

Wang, Y. J.; Yuan, H. T. Novel Flower-like CoS Hierarchitectures: One-pot Synthesis and Electrochemical Properties. J. Mater. Chem. 2011, 21, 327–329. 48

Lei, X.; Yu, K.; Qi, R.; Zhu, Z. Fabrication and Theoretical Investigation of MoS2-

Co3S4 Hybrid Hollow Structure as Electrode Material for Lithium-Ion Batteries and Supercapacitors. Chem. Engin. J. 2018, 347, 607–617. 49

Wang, W. Y.; Zhu, G. H.; Li, L.; Ta, S.; Wu, K.; Zhan, X. Y.; Yang, Y. Q. Facile

Hydrothermal Synthesis of Flower-like Co-Mo-S Catalysts and Their High Activities in the Hydrodeoxygenation of p-cresol and Hydrodesulfurization of Benzothiophene. Fuel 2016, 174, 1–8. 50

Kong, S. F.; Jin, Z. T.; Liu, H.; Wang, Y. Morphological Effect of Graphene

Nanosheets on Ultrathin CoS Nanosheets and Their Applications for High-Performance Li-Ion Batteries and Photocatalysis. J. Phys. Chem. C 2014, 118, 25355–25364. 51

Yoosuk, B.; Tumnanton, D.; Prasassarakich, P. Unsupported MoS2 and CoMoS2

Catalysts for Hydrodeoxygenation of Phenol. Chem. Engin. Sci. 2012, 79, 1–7. 52


J. D.; Wu, G. M.; Zhang, M.； Liu, B.; Yao, J. M.; Zhang, X. W. When Cubic Cobalt Sulfide Meets Layered Molybdenum Disulfide: A Core–Shell System Toward Synergetic Electrocatalytic Water Splitting. Adv. Mater. 2015, 27, 4752–4759.


38

Page 38 of 50

Page 39 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


53

Xu, S. J.; Li, D.; Wu, P. Y. One-Pot, Facile, and Versatile Synthesis of Monolayer

MoS2/WS2 Quantum Dots as Bioimaging Probes and Efficient Electrocatalysts for Hydrogen Evolution Reaction. Adv. Funct. Mater. 2015, 25, 1127–1136. 54

Zhang, J.; Wang, T.; Pohl, D.; Rellinghaus, B.; Dong, R.; Liu, S.; Zhuang, X.;

Feng, X. Interface Engineering of MoS2/Ni3S2 Heterostructures for Highly Enhanced Electrochemical Overall-Water-Splitting Activity. Angew. Chem. 2016, 128, 6814–6819. 55

Yang, Y. Q.; Zhang, K.; Lin, H. L.; Li, X.; Chan, H. C.; Yang, L. C.; Gao, Q. S.

MoS2-Ni3S2 Heteronanorods as Efficient and Stable Bifunctional Electrocatalysts for Overall Water Splitting. ACS Catal. 2017, 7, 2357–2366. 56

Peng, Z.; Jia, D. S.; Al-Enizi, A. M.; Elzatahry, A. A.; Zheng, G. From Water

Oxidation to Reduction: Homologous Ni–Co Based Nanowires as Complementary Water Splitting Electrocatalysts. Adv. Energy Mater. 2015, 1402031. 57

Lin, C. Y.; Mersch, D.; Jefferson, D. A.; Reisner, E. Cobalt Sulphide Microtube

Array as Cathode in Photoelectrochemical Water Splitting with Photoanodes. Chem. Sci. 2014, 5, 4906–4913. 58

Zhao, C.; Li, D. Q.; Feng, Y. J. Size-controlled Hydrothermal Synthesis and High

Electrocatalytic Performance of CoS2 Nanocatalysts as Non-precious Metal Cathode Materials for Fuel Cells. J. Mater. Chem. A 2013, 1, 5741–5746. 59

Zhong, H. H.; Xi, J. M.; Tang, P. G.; Li, D. Q.; Feng, Y. J. Positive Effect of Heat

Treatment on Carbon-Supported CoS Nanocatalysts for Oxygen Reduction Reaction. Catalysts 2015, 5, 1211–1220.


39


60

Deng, W. F.; Jiang, H. M.; Chen, C.; Yang, L.; Zhang, Y. M.; Peng, S. Q.; Wang,

S. Q.; Tan, Y. M.; Ma, M.; Xie, Q. J. Co-, N-, and S-Tridoped Carbon Derived from Nitrogen- and Sulfur-Enriched Polymer and Cobalt Salt for Hydrogen Evolution Reaction. ACS Appl. Mater. Interfaces 2016, 8, 13341–13347. 61

Ganesan, P.; Prabu, M.; Sanetuntikul, J.; Shanmugam, S. Cobalt Sulfide

Nanoparticles Grown on Nitrogen and Sulfur Codoped Graphene Oxide: An Efficient Electrocatalyst for Oxygen Reduction and Evolution Reactions. ACS Catal. 2015, 5, 3625–3637. 62

Pan, Y.; Liu, Y. Q.; Liu, C. G. Phase- and Morphology-Controlled Synthesis of

Cobalt Ssulfide Nanocrystals and Comparison of Their Catalytic Activities for Hydrogen Evolution. Appl. Surf. Sci. 2015, 357, 1133–1140. 63

Sun, Y.; Liu, C.; Grauer, D. C.; Yano, J.; Long, J. R.; Yang, P.; Chang, C. J.

Electrodeposited Cobalt-Sulfide Catalyst for Electrochemical and Photoelectrochemical Hydrogen Generation from Water. J. Am. Chem. Soc., 2013, 135, 17699–17702. 64

Wang, H. L.; Liang, Y. Y; Li, Y. G.; Dai, H. J. Co1−xS-Graphene Hybrid: A High-

Performance Metal Chalcogenide Electrocatalyst for Oxygen Reduction. Angew. Chem. 2011, 123, 11161–11164. 65

Zhang, X. B.; Wang, J.; Zhong, H. X.; Wang, Z. L.; Meng, F. L. Drying Enhanced

Adhesion of Polythiophene Nanotubule Arrays on Smooth Surfaces. ACS Nano 2010, 2, 2342–2348.


40

Page 40 of 50

Page 41 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


66

Wu, J. H.; Dou, S.; Shen, A.; Wang, X.; Ma, Z. L.; Ouyang, C. B.; Wang, S. Y.

One-step Hydrothermal Synthesis of NiCo2S4–rGO as an Efficient Electrocatalyst for the Oxygen Reduction Reaction. J. Mater. Chem. A 2014, 2, 20990–20995. 67

Xiao, B.B.; Zhang, P.; Han, L. P.; Wen, Z. Functional MoS2 by the Co/Ni Doping

as the Catalyst for Oxygen Reduction Reaction. Appl. Surf. Sci. 2015, 354, 221–228. 68

Illathvalappil, R.; Unni, S. M.; Kurungot, S. Layer-separated MoS2 Bearing

Reduced Graphene Oxide Formed by an in-situ Intercalation-cum-anchoring Route Mediated by Co(OH)2 as a Pt-free Electrocatalyst for Oxygen Rreduction. Nanoscale 2015, 7, 16729–16736. 69

Merki, D.; Vrubel, H.; Rovelli, L.; Fierro, S.; Hu, X. Fe, Co, and Ni ions Promote

the Catalytic Activity of Amorphous Molybdenum Sulfide Films for Hydrogen Evolution. Chem. Sci. 2012, 3, 2515–2525. 70

Tanaka, S.; Annaka, M.; Sakai, K. Visible Light-induced Wwater Oxidation

Catalyzed by Mmolybdenum-based Polyoxometalates with Mono- and Dicobalt(III) Cores as Oxygen-evolving Centers. Chem. Commun. 2012, 48, 1653–1655. 71

Wang, H.; Tsai, C.; Kong, D.; Chan, K.; Abild-Pedersen, F.; Nørskov, J. K.; Cui,

Y. Transition-metal Doped Edge Sites in Vertically Aligned MoS2 Catalysts for Enhanced Hydrogen Evolution. Nano Res. 2015, 8, 566–575. 72

Xiong, Q. Z.; Wang, Y.; Liu, P. F.; Zheng, L. R.; Wang, G. Z.; Yang, H. G.;

Wong, P.; Zhang, H. M.; Zhao, H. J. Cobalt Covalent Doping in MoS2 to Induce Bifunctionality of Overall Water Splitting. Adv. Mater. 2018, 1801450.


41


73

Xiong, Q. Z.; Zhang, X.; Wang, H. J.; Liu, G. Q.; Wang, G. Z.; Zhang, H. M.;

Zhao, H. J. One-step Synthesis of Cobalt-doped MoS2 Nanosheets as Bifunctional Electrocatalysts for Overall Water Splitting under Both Acidic and Alkaline Conditions. Chem. Commun. 2018, 54, 3859–3862. 74

Yu, X. Y.; Feng, Y.; Jeon, Y.; Guan, B.; Lou, X. W.; Paik, U. Formation of Ni–

Co–MoS2 Nanoboxes with Enhanced Electrocatalytic Activity for Hydrogen Evolution. Adv. Mater. 2016, 28, 9006–9011. 75

Zhang, H. C.; Li, Y. J.; Xu, T. H.; Wang, J. B.; Huo, Z. Y.; Wan, P. B.; Sun, X. M.

Amorphous Co-doped MoS2 Nanosheet Coated Metallic CoS2 Nanocubes as an Excellent Electrocatalyst for Hydrogen Evolution. J. Mater. Chem. A 2015, 3, 15020–15023. 76

Huang, J. L.; Hou, D. M.; Zhou, Y. C.; Zhou, W. J.; Li, G. Q.; Tang, Z. H.; Li, L.

G.; Chen, S. W. MoS2 Nanosheet-coated CoS2 Nanowire Arrays on Carbon Cloth as Three-Dimensional Electrodes for Efficient Electrocatalytic Hydrogen Evolution J. Mater. Chem. A, 2015, 3, 22886–22891. 77

Zhu, H.; Zhang, J. f.; Yanzhang, R. P.; Du, M. L.; Wang, Q. F.; Gao, G. H.; Wu, J.

D.; Wu, G. M.; Zhang, M.; Liu, B.; Yao, J. M.; Zhang, X. W. When Cubic Cobalt Sulfide Meets Layered Molybdenum Disulfide: A Core-Shell System Toward Synergetic Electrocatalytic Water Splitting. Adv. Mater. 2015, 27, 4752–4759. 78

Guo, Y. X.; Gan, L. F.; Shang, C. S.; Wang, E. K.; Wang, J. A Cake-Style

CoS2@MoS2/RGO Hybrid Catalyst for Efficient Hydrogen Evolution. Adv. Funct. Mater. 2017, 27, 1602699.


42

Page 42 of 50

Page 43 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


79

Liu, Y. R.; Hu, W. H.; Li, X.; Dong, B.; Shang, X.; Han, G. Q.; Chai, Y. M.; Liu,

Y. Q.; Liu, C. G. Facile One-pot Synthesis of CoS2-MoS2/CNTs as Efficient Electrocatalyst for Hydrogen Evolution Reaction. Appl. Surf. Sci. 2016, 384, 51–57. 80

Su, C.; Xiang, J. Y.; Wen, F. S.; Song, L. Z.; Mu, C. P.; Xu, D. Y.; Hao, C. X.;

Liu, Z. Y. Microwave Synthesized Three-dimensional Hierarchical Nanostructure CoS2/MoS2 Growth on Carbon Fiber Cloth: A Bifunctional Electrode for Hydrogen Evolution Reaction and Supercapacitor. Electrochim. Acta 2016, 212, 941–949. 81

Ouyang, C. B.; Feng, S.; Huo, J.; Wang, S. Y. Three-Dimensional Hierarchical

MoS2/CoS2 Heterostructure Arrays for Highly Efficient Electrocatalytic Hydrogen Evolution. Green Energy & Environment 2017, 2, 134–141. 82

Chen, L. L.; Yan, W. X.; Liu, X. J.; Jia, J. B. Flower-like CoS2/MoS2

Nanocomposite with Enhanced Electrocatalytic Activity for Hydrogen Evolution Reaction. Int. J. Hydrogen Energy 2017, 42, 12246–12253. 83

Bose, R.; Jin, Z.; Shin, S.; Kim, S.; Lee, S.; Min, Y. Co-catalytic Effects of CoS2

on the Activity of the MoS2 Catalyst for Electrochemical Hydrogen Evolution. Langmuir 2017, 33, 5628–5635. 84

Lei, X.; Yu, K.; Li, H. L.; Zhu, Z. Q. A Functional Design and Synthesization for

Electrocatalytic

Hydrogen

Evolution

Material

on

MoS2/Co3S4

Nanostructure. Electrochim. Acta 2018, 269, 262–273.


43

Hybrid

Hollow


85

Bai, J.; Meng, T.; Guo, D. L.; Wang, S. G.; Mao, B. G.; Cao, M. H. Co9S8@MoS2

Core-Shell Heterostructures as Trifunctional Electrocatalysts for Overall Water Splitting and Zn-Air Batteries. ACS Appl. Mater. Interfaces 2018, 10, 1678−1689. 86

Liu, Y. R.; Shang, X.; Gao, W. K.; Dong, B.; Chi, J. Q.; Li, X.; Yan, K. L.; Chai,

Y. M.; Liu, Y. Q.; Liu, C. G.; Ternary CoS2/MoS2/RGO Electrocatalyst with CoMoS Phase for Efficient Hydrogen Evolution. Appl. Surf. Sci. 2017, 412, 138–145. 87

Lu, W. Q.; Song, Y.; Dou, M. L.; Ji, J.; Wang, F. Self-supported Ni3S2@MoS2

Core/Shell Nanorod Arrays via Decoration with CoS as a Highly Active and Efficient Electrocatalyst for Hydrogen Evolution and Oxygen Evolution Reactions. Int. J. Hydrogen Energy 2018, 43, 8794−8804. 88

Guo, Y.; Tang, J.; Qian, H.; Wang, Z.; Yamauchi, Y. One-Pot Synthesis of

Zeolitic Imidazolate Framework 67-Derived Hollow Co3S4@MoS2 Heterostructures as Efficient Bifunctional Catalysts. Chem. Mater. 2017, 29, 5566−5573. 89

Staszak-Jirkovský, J.; Malliakas, C. D.; Lopes, P. P.; Danilovic, N.; Kota, S. S.;

Chang, K.; Genorio, B.; Strmcnik, D.; Stamenkovic, V. R.; Kanatzidis, M. G.; Markovic, N. M. Design of Active and Stable Co-Mo-Sx Chalcogels as pH-Universal Catalysts for the Hydrogen Evolution Reaction. Nat. Mater. 2016, 15, 197–203. 90

Yuan, Y. J.; Chen, D. Q.; Huang, Y. W.; Yu, Z. T.; Zhong, J. S.; Chen, T. T.; Tu,

W. G.; Guan, Z. J.; Cao, D. P.; Zou, Z. G. MoS2 Nanosheet-Modified CuInS2 Photocatalyst for Visible-Light-Driven Hydrogen Production from Water. ChemSusChem 2016, 9, 1003–1009.


44

Page 44 of 50

Page 45 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


91

Chen, G. P.; Ding, N.; Li, F.; Fan, Y. Z.; Luo, Y. H.; Li, D. M.; Meng, Q. B.

Enhancement of Photocatalytic H2 Evolution on ZnIn2S4 Loaded with In-situ PhotoDeposited MoS2 under Visible Light Irradiation. Appl. Catal. B: Environ. 2014, 160, 614620. 92

Chen, J.; Wu, X.; Yin, L.; Li, B.; Hong, X.; Fan, Z.; Chen, B.; Xue, C.; Zhang, H.

One-pot Synthesis of CdS Nanocrystals Hybridized with Single-Layer Transition-Metal Dichalcogenide Nanosheets for Efficient Photocatalytic Hydrogen Evolution. Angew. Chem. Int. Ed. 2015, 54, 1210–1214. 93

Xu, J.; Cao, X. J. Characterization and Mechanism of MoS2/CdS Composite

Photocatalyst Used for Hydrogen Production from Water Splitting under Visible Light. Chem. Engin. J. 2015, 260, 642–648. 94

Li, Y. X.; Wang H.; Peng, S. Q. Tunable Photodeposition of MoS2 onto a

Composite of Reduced Graphene Oxide and CdS for Synergic Photocatalytic Hydrogen Generation. J. Phys. Chem. C 2014, 118, 19842−19848. 95

Yin, X. L.; He, G. Y.; Sun, B.; Jiang, W. J.; Xue, D. J.; Xia, A. D.; Wan, L. J.; Hu,

J. S. Rational Design and Electron Transfer Kinetics of MoS2/CdS Nanodots-onNanorods for Efficient Visible-Light-Driven Hhydrogen Generation. Nano Energy 2016, 28, 319–329. 96

Zhang, J.; Zhu, Z. P.; Feng, X. L. Construction of Two-Dimensional MoS2/CdS p-

n Nanohybrids for Highly Efficient Photocatalytic Hydrogen Evolution. Chem. Eur. J. 2014, 20, 10632–10635.


45


97

Chang, K.; Mei, Z. W.; Wang, T.; Kang, Q.; Ouyang, S. X.; Ye, J. H.

MoS2/Graphene Cocatalyst for Efficient Photocatalytic H2 Evolution under Visible Light Irradiation. ACS Nano 2014, 8, 7078–7087. 98

Zong, Xu.; Yan, H.; Wu, G. P.; Ma, G. J.; Wen, F. Y.; Wang, L.; Li, C.

Enhancement of Photocatalytic H2 Evolution on CdS by Loading MoS2 as Cocatalyst under Visible Light Irradiation. J. Am. Chem. Soc. 2008, 130, 7176–7177. 99

He, J.; Chen, L.; Wang, F.; Liu, Y.; Chen, P.; Au, C. T.; Yin, S. F. CdS Nanowires

Decorated with Ultrathin MoS2 Nanosheets as an Efficient Photocatalyst for Hydrogen Evolution. ChemSusChem 2016, 9, 624–630. 100

Yu, Z. M.; Meng, J. L.; Xiao, J. R.; Li, Y.; Li, Y. D. Cobalt Sulfide Quantum Sots

Modified TiO2 Nanoparticles for Efficient Photocatalytic Hydrogen Evolution. Int. J. Hydrogen Energy 2014, 39, 15387–15393. 101

Aslan, E.; Akin, I.; Patir, I. H.; Highly Active Cobalt Sulfide/Carbon Nanotube

Catalyst for Hydrogen Evolution at Soft Interfaces. Chem. Eur. J. 2016, 22, 5342–5349. 102

Kong, C.; Min, S. X.; Lu, G. X. Dye-sensitized Cobalt Catalysts for High Efficient

Visible Light Hydrogen Evolution. Int. J. Hydrogen Energy 2014, 39, 4836–4844. 103

Huang, Z. F.; Song, J. J.; Li, K.; Tahir, M.; Wang, Y. T.; Pan, L.; Wang, L.;

Zhang, X. W.; Zou, J. J. Hollow Cobalt-Based Bimetallic Sulfide Polyhedra for Efficient All-pH-Value Electrochemical and Photocatalytic Hydrogen Evolution. J. Am. Chem. Soc. 2016, 138, 1359–1365.


46

Page 46 of 50

Page 47 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


104

Shi, Q.; Chen, Z.; Song, Z.; Li, J.; Dong, J. Synthesis of ZIF-8 and ZIF-67 by

Steam-Assisted Conversion and an Investigation of Their Tribological Behaviors. Angew. Chem. 2011, 123, 698–701. 105


J. D.; Wu, G. M.; Zhang, M.; Liu, B.; Yao, J. M.; Zhang, X. W. When Cubic Cobalt Sulfide Meets Layered Molybdenum Disulfide: A Core-Shell System Toward Synergetic Electrocatalytic Water Splitting. Adv. Mater. 2015, 27, 4752–4759. 106

Li, L. L.; Tian, T.; Jiang, J.; Ai, L. H. Hierarchically Porous Co3O4 Architectures

with Honeycomb-Like Structures for Efficient Oxygen Generation from Electrochemical Water Splitting. J. Power Sources 2015, 294, 103–111. 107

Du, J. L.; Chen, Z. F.; Ye, S. R.; Wiley, B. J.; Meyer, T. J. Copper as a Robust and

Transparent Electrocatalyst for Water Oxidation. Angew. Chem. Int. Ed. 2015, 54, 2073– 2078. 108

Jia, L. P.; Sun, X.; Jiang, Y. M.; Yu, S. J.; Wang, C. M. A Novel MoSe2-Reduced

Graphene Oxide/Polyimide Composite Film for Applications in Electrocatalysis and Photoelectrocatalysis Hydrogen Evolution. Adv. Funct. Mater. 2015, 25, 1814–1820. 109

Zhu, Y. Y.; Ling, Q.; Liu, Y. F.; Wang, H.; Zhu, Y. F. Photocatalytic H2 Evolution

on MoS2-TiO2 Catalysts Synthesized via Mechanochemistry. Phys. Chem. Chem. Phys. 2015, 17, 933–940.


47


110

Chen, S. F.; Zhao, W.; Liu, W.; Zhang, S. J. Preparation, Characterization and

Activity Evaluation of p–n Junction Photocatalyst p-ZnO/n-TiO2. Appl. Surf. Sci. 2008, 255, 2478–2484. 111

Huang, T.; Luo, Y. T.; Chen, W.; Yao, J. C.; Liu, X. H. Self-assembled MoS2-GO

Framework as an Efficient Cocatalyst of CuInZnS for Visible-Light Driven Hydrogen Evolution. ACS Sustain. Chem. Eng. 2018, 6, 4671–4679. 112

Bonin, J.; Robert, M.; Routier, M. Selective and Efficient Photocatalytic CO2

Reduction to CO Using Visible Light and an Iron-Based Homogeneous Catalyst. J. Am. Chem. Soc. 2014, 136, 16768–16771. 113

Han, Z. J.; McNamara, W. R.; Eum, M.S.; Holland, P. L.; Eisenberg, R. A Nickel

Thiolate Catalyst for the Long--Lived Photocatalytic Production of Hydrogen in a NobleMetal-Free System. Angew. Chem. Int. Ed. 2012, 51, 1667–1670. 114

Lazarides, T.; McCormick, T.; Du, P. W.; Luo, G. G.; Lindley, B.; Eisenberg, R.

Making Hydrogen from Water Using a Homogeneous System Without Noble Metals. J. Am. Chem. Soc. 2009, 131, 9192–9194. 115

McCormick, T. M.; Calitree, B. D.; Orchard, A.; Kraut, N. D.; Bright, F. V.; Detty,

M. R.; Eisenberg, R. Reductive Side of Water Splitting in Artificial Photosynthesis: New Homogeneous Photosystems of Great Activity and Mechanistic Insight. J. Am. Chem. Soc. 2010, 132, 15480–15483. 116

Zhang, P.; Wang, M.; Dong, J. F.; Li, X. Q.; Wang, F.; Wu, L. Z.; Sun, L. C.

Photocatalytic Hydrogen Production from Water by Noble-Metal-Free Molecular Catalyst


48

Page 48 of 50

Page 49 of 50 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Systems Containing Rose Bengal and the Cobaloximes of BFx-Bridged Oxime Ligands. J. Phys. Chem. C 2010, 114, 15868–15874. 117

Zhang, G.; Liu, H. J.; Qu, J. H.; Li, J. H. Two-Dimensional Layered MoS2:

Rational Design, Properties and Electrochemical Applications. Energy Environ. Sci. 2016, 9, 1190–1209. 118

Huang, J. L.; Hou, D. M.; Zhou, Y. C.; Zhou, W. J.; Li, G. Q.; Tang, Z. H.; Li,

L. G.; Chen, S. W. MoS2 Nanosheet-Coated CoS2 Nanowire Arrays on Carbon Cloth as Three-Dimensional Electrodes for Efficient Electrocatalytic Hydrogen Evolution. J. Mater. Chem. A 2015, 3, 22886–22891. 119

Kong, C.; Min, S. X.; Lu, G. X. Dye-Sensitized NiSx Catalyst Decorated on

Graphene for Highly Efficient Reduction of Water to Hydrogen under Visible Light Irradiation. ACS Catal. 2014, 4, 2763–2769. 120

Yuan, Y. J.; Ye, Z. J.; Lu, H. W.; Hu, B.; Li, Y. H.; Chen, D. Q.; Zhong, J. S.; Yu,

Z. T.; Zou, Z. G. Constructing Anatase TiO2 Nanosheets with Exposed (001) Facets/Layered MoS2 Two-Dimensional Nanojunctions for Enhanced Solar Hydrogen Generation. ACS Catal. 2016, 6, 532–541.


49


Table of Contents graphic


50

Page 50 of 50

Bimetal-Organic-Framework-Derived Nanohybrids Cu0.9Co2.1S4

Recommend Documents