Oneâstep carbothermal synthesis of robust CdS@BPCs

Subscriber access provided by Nottingham Trent University

Article

One–step carbothermal synthesis of robust CdS@BPCs photocatalysts in the presence of biomass porous carbons Haibo Huang, Ning Zhang, Kai Yu, Yu-Qing Zhang, Hai-Lei Cao, Jian Lü, and Rong Cao ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.9b04395 • Publication Date (Web): 05 Sep 2019 Downloaded from pubs.acs.org on September 5, 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 28 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 Sustainable Chemistry & Engineering

One–step carbothermal synthesis of robust CdS@BPCs photocatalysts in the presence of biomass porous carbons Hai–Bo Huang†,‡,§, Ning Zhang†,§, Kai Yu†, Yu–Qing Zhang†, Hai–Lei Cao†, Jian Lü†,‡,* and Rong Cao‡,* †Fujian

Provincial Key Laboratory of Soil Environmental Health and Regulation, College of

Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, P.R. China; ‡State

Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of

Matter, Chinese Academy of Sciences, Fuzhou 350002, P.R. China; §Equal

contribution.

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 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 2 of 28

ABSTRACT Low–cost biomass porous carbons (BPCs) were herein demonstrated as both reducing agents and material supports in the synthesis of robust CdS@BPCs photocatalysts through a simple one–step, solvent free and atom economic carbothermal reaction pathway. Due to the versatile functionality on surfaces of BPCs, the as–prepared CdS@BPCs exhibited excellent interface reaction activity and stability as photocatalysts for carbon dioxide (CO2) photoreduction and oxidative tetracycline (TC) degradation under visible irradiation. The considerably large surface area of BPCs (765 to 1005 m2 g−1) accounted for high CO2 adsorption affinity and TC adsorption, and thus the accessibility of guest molecules (CO2 and TC) to active interfaces of the photocatalysts was favorably promoted. In addition, mechanism study indicated that BPCs, functioned as electron reservoirs, greatly enhanced the separation efficiency of photogenerated carriers and the transportation of electrons due to improved conductivity, for which BPCs could be superior to other conventional carbonaceous supports i.e. granular activated carbons (GACs), carbon nanotubes (CNTs) and graphene oxides (GOs). This work thus provides an alternative pathway to fabricate robust photocatalysts from environmentally friendly and sustainable biomass carbon precursors. KEYWORDS: CdS; biomass carbon; CO2 reduction; antibiotics degradation; photocatalysis

2


Page 3 of 28 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


INTRODUCTION Recently, the production of biomass carbons (BCs, known also as biochar)1 from the pyrolysis of pristine biomass is considered as a popular strategy for carbon cycling and reuse, as well as to discover viable resources for sustainable energy2,3. The outstanding physiochemistry property of BCs, including large specific surface area, abundant surface functionality and compositions, enables them as renewable and environmentally friendly remediation materials4,5. Meanwhile, these materials have been employed as preferable material supports because of their intrinsic adaptability to interact with the nanoparticles (NPs) on surfaces, as well as the particularly stability toward various catalytic reactions6. More importantly, the development of solar energy driven photocatalysts becomes a practical pathway for environmental remediation7,8, due to the increasingly urgent demands on renewable resources and sustainable energy supplies9,10. For this purpose, the cadmium sulfide (CdS), showing generally excellent response to visible light, has been considered as one of the most promising photocatalysts for solar utilization11,12. Unfortunately, the application of CdS as photocatalysis has been hindered by material photocorrosion that potentially produces hazardous Cd2+ ions and causes potential environmental pollution13,14. To overcome these barriers, various modification strategies have been proposed to prevent the recombination of charge carriers and enhance photocatalytic stability and activity of CdS semiconductors, including the use of noble metals and nonmetals as cocatalysts15–18, the formation of composites with other semiconductors19,20 and the coupling of CdS with carbon–based nanomaterials as electron reservoirs21–23. For example, the CdS nanorods/graphene oxide (GO) composites showed considerably higher photocatalytic efficiency under visible light than the bare CdS nanorods thanks to facile charge transportations from CdS to GO24. Moreover, composites based on carbon nanotubes

3



Page 4 of 28

(CNTs) achieved high photocatalytic efficiency by either decreased recombination of photogenerated electron–hole pairs or increased adsorption of substrates at surfaces/interfaces25. Although GO– and CNTs–based photocatalysts are known to improve charge transfer to realize significant light trap enhancement, they can be costly and lack of treatability. Among the promising carbonaceous materials, the use of biomass porous carbons (BPCs) as supports might well satisfy the concept of sustainable development26,27. In this work, a series of CdS@BPC–T (T = 600/700/800) composites were fabricated via a simple one–step and atom economic carbothermal reactions in solvent free systems at elevated temperatures, in which BPCs behaved as both reducing agents and material supports. Due to the in situ growth of CdS NPs and the versatile functionality on surfaces of BPCs, the as–prepared CdS@BPCs exhibited excellent interface reaction activity and stability as photocatalysts for carbon dioxide (CO2) photoreduction under visible light. Meanwhile, oxidative tetracycline (TC) removal was studied in a situation that residues of antibiotics in the aquatic ecosystem might lead to serious effects to the environment and human beings, which became increasingly meaningful to green and sustainable development28,29. More specifically, the CdS@BPCs showed excellent photocatalytic activity toward CO2 photoreduction into CO and CH4 due to much enhanced separation of catalytically active speicies (h+ and e−) and high CO2 adsorption affinity. In addition, the CdS@BPCs was potentially applicable to photocatalytic degradation of tetracycline with high efficiency (ca. 84.6% in 2 h for CdS@BPC–600) due to a high utilization of photogenerated oxidative h+, O2•− and OH•. By contrast, composites with BPCs supports generally displayed higher photocatalytic activity, derived from the unique surface property, than those with other carbonaceous supports i.e. CNTs, GO and granular activated carbon (GAC).

4


Page 5 of 28 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


EXPERIMENTAL SECTION Reagents. Commercial cadmium sulfate (CdSO4·2H2O), potassium hydroxide (KOH), acetonitrile and triethanolamine were used without any further purification. Solutions were prepared with deionized water supplied by UPT–I–5T ultrapure water system. Synthesis of CdS@BPCs. The biomass–derived porous carbons was synthesized from a modified procedure documented in literatures30,31. CdS@BPCs composites were prepared through one–step carbothermal reduction reactions of CdSO4·2H2O and BPC as follows: CdSO4·2H2O (200 mg) and BPCs (200 mg) were first dispersed into deionized water (30 mL), stirred continuously for 1 h and dried at 105 °C overnight in a blast drying oven. The resultant mixture was further calcinated at 600, 700 or 800 °C for 2 h in a tubular furnace with N2. Solid samples were collected and washed three times with water and ethanol before drying at 70 °C overnight. Materials were denoted as CdS@BPC–T (T = 600/700/800). For reference composite materials, commercial granular activated carbon (GAC), carbon nanotubes (CNTs) and graphene oxide (GO) were used as carbon sources to synthesize composites at 700 ºC, which were named as CdS@GAC–700, CdS@CNTs–700 and CdS@GO–700, respectively, and the reference CdS material was prepared according to the lierature.24 Photoelectrochemical tests. In a standard three–electrode system, photoelectrochemical tests were carried out on an electrochemical analyzer (Zahner, Germany). Aqueous Na2SO4 (0.2 M, pH = 6.8) solution was used as the supporting electrolyte. The suspension was prepared by mixing 5.0 mg photocatalyst with 1.0 mL ethanol and 50 μL Nafion; the supersonic reaction time was 1 h; and the indium tin oxide (ITO) glass (deposited area was 1.0 cm2) was used as the working electrode. 5



Page 6 of 28

Transient photocurrent measurements were recorded under visible irradiation. Electrochemical impedance spectra (EIS) were collected at off–line potential with a frequency range of 100 kHz to 0.01 Hz and modulation amplitude of 5.0 mV31,32. Photocatalytic reactions. Photocatalyses were performed by following the standard procedures documented in the literature12,24,26,31 and details were provided in the Supporting Information.

RESULTS AND DISCUSSION Phase composition and surface morphology. Thermogravimetric analysis (TGA) on the CdSO4·2H2O precursor (Figure 1a) indicated two steps of weight losses, in which the first step before 200 °C was assigned to the loss of crystalline water and the second step after 800 °C was attributable to CdSO4 decomposition under nitrogen atmosphere. The reactions of CdSO4·2H2O and BPCs elevated temperatures afforded CdS@BPC–T (T = 600/700/800) composites in an atom economic reaction pathway, in which CdSO4 behaved as both Cd and S sources and BPCs function as reducing agents. PXRD measurements were employed to identify the bulk phases of as–prepared CdS@BPCs and reference composites. As shown in Figure 1b, major diffraction peaks at 26.92°, 26.54°, 27.67°, 36.9°, 43.68°, 49.94° and 52.1° were indexed as (1 0 0), (0 0 2), (1 0 1), (1 0 2), (1 1 0), (1 0 3) and (1 1 2) crystal planes of CdS (hexagonal, JCPDS Card No. 41–1049)33. Moreover, the intensity of CdS characteristics increased significantly at higher temperature of carbothermal reductions, indicating enhanced crystallinity of CdS components. These results indicated that successful carbothermal reductions of CdSO4 in the presence of biomass carbons occurred at elevated temperatures to afford CdS@BPCs composites. Surface morphology of BPC and CdS@BPCs were investigated using the scanning microscopy

6


Page 7 of 28 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


(SEM) and transmission (TEM) electron microscopy techniques. The surfaces of BPC (Figure S1a) displayed considerable roughness; by contrast, the surfaces of CdS@BPCs were fairly smooth (Figure S1b, S2a and S2c). TEM images of CdS@BPCs (Figure 1c, S2b and S2d) clearly demonstrated the formation of CdS on BPC supports. Moreover, HR–TEM image showed lattice fringes with d–spacing of ca. 0.32 nm that corresponded to (1 0 1) crystal plane of CdS (Figure 1d). TEM and HR–TEM images of reference composites were measured (Figure S3), by which the loading of CdS on carbonaceous supports was confirmed. Brunauer–Emmett–Teller (BET) surface area of CdS@BPCs was evaluated by N2 adsorption–desorption isotherms (Figure S4a and 4b) and evaluated to be ranging from 765 to 1005 m2 g−1. By contrast, specific surface area and porosity of the reference composites were much smaller than those of CdS@BPCs composites (Figure S4c and 4d). The considerably high BET surface area and microporosity of CdS@BPCs might provide more catalytically active sites that are beneficial for enhanced catalytic efficiency. X–ray photoelectron spectroscopy (XPS, Figure 2 and S5) analyses were performed to further characterize elemental valence, surface chemical compositions and functionality of CdS@BPCs composites. XPS survey spectra of the representative CdS@BPC–700 (Figure 2a) suggested the presence of C, S and Cd elements. The C 1s peaks (Figure 2b) at 283.4 (Cd–C), 284.6 (C=C), 287.5 (C–O), 287.9 (C=O) and 290.0 (COOR) eV were identified, indicating rich functionality on surfaces of BPC supports34,35. Of note, the formation of Cd–C interactions demonstrated the growth of CdS on surfaces of BPCs. In addition, the doublets at 405.6 for Cd 3d5/2 and 412.4 eV for Cd 3d3/2 were characteristics of Cd2+ species (Figure 2c) and characteristics at 161.6 for S 2p3/2 and 162.8 eV for S 2p1/2 were from the spin–orbit doublets of S2– (Figure 2d). In addition, the atomic ratio of Cd and S was approximately 1:1 (Table 1), which also indicated the formation of CdS. Therefore, the above

7



Page 8 of 28

combinational results verified that CdS NPs were successful loaded on BPC supports via carbothermal reduction. Optical properties. UV–vis diffuse reflectance spectra (DRS) of CdS@BPCs photocatalysts are shown in Figure S6. The absorption bands were red shifted which indicated better light adsorption ability of CdS@BPC, which was expected to promote the photocatalytic reactions36. The band structure of CdS@BPCs in the visible region were calculated based on the converted Kubelka–Munk equation αhv = A (hv – Eg)1/2, where α is the adsorption coefficient, hv is the photon energy, Eg represents the direct band gap (eV), and A is a constant33,37. The Eg for CdS@BPCs were calculated to be 2.32, 2.33 and 2.21 eV, respectively. Photocatalytic activity and stability of CdS@BPC. The photocatalytic activity of CdS@BPCs photocatalysts was evaluated by CO2 reduction in gaseous phases and oxidative degradation of tetracycline (TC) in aqueous solutions under visible irradiation. The rate of CO2 photoreduction followed the order of CdS@BPC–700 > CdS@BPC–800 > CdS@BPC–600 > CdS (Figure 3a), of which the CdS@BPC–700 exhibited the highest CO and CH4 evolution rate of 39.3 and 37.6 μmol h−1 g−1, respectively. Moreover, only a little amount of H2 products was observed for the composite photocatalysts during CO2 photoreduction, therefore, we conclude the hydrogen production was inhibited in current systems. Under similar conditions, the activity of CO2 photoduction for CdS@BPC–700 was considerably higher than other reported CdS composites in the literature, including CdS–MOFs38 and CdS heterojunction structures39,40. To demonstrate the origin of CO and CH4 production, control experiments with Ar gas substrates were conducted. It was found that no CO or CH4 was produced in the absence of CO2 (Figure 3b). Moreover, composites with BPC supports generally displayed photocatalytic activity 8


Page 9 of 28 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


than those with compared other carbonaceous supports i.e. GAC, CNTs and GO (Figure 3c). It should be noted that considerable H2 production with barely any CH4 was observed in systems of GAC, CNTs and GO as supports. Since CdS NPs at interfaces were favorable materials for photocatalytic H2 production, this phenomenon was likely related to the various carbonaceous supports. As such, the rationally high CO2 adsorption capacity of 86.6 (273 K) and 58.7 (298 K) cm3 g–1 shown by the CdS@BPC–700 might account for excellent CO2 adsorption affinity and be beneficial for enhanced photocatalytic activity and selectivity (Figure 3f and S7). In comparison with other carbon material carriers (GAC, CNTs and GO), BPC as support materials generally possessed higher specific surface area and porosity (Figure S4), which might account for their prominent gas adsorption capacities thanks to the excellent affinity to CO2 molecules. Moreover, stability and reusability of the best–performing CdS@BPC–700 were investigated by cycling reactions of CO2 photoreduction. The CO and CH4 yields were approximately in the range of 35 to 40 µmol g−1 h−1, which nearly remained constant after four cycles, as shown in Figure 3d. Further PXRD characterizations testified no obvious structural changes on photocatalysts before and after cycling reactions (Figure 3e), indicating excellent photocatalytic stability and reusability of the CdS@BPC–700. In order to evaluate the possible utilization of photogenerated oxidative h+, CdS@BPCs photocatalysts were applied to the oxidative degradation of tetracycline (TC) in aqueous solutions. Before the photocatalytic TC degradation, the adsorption/desorption equilibrium of catalyst–loaded TC solutions were reached at about 150 minutes in the dark (Figure 4a). The photocatalytic TC degradation efficiency of CdS@BPC–600 was ca. 84.6% in 120 minutes under visible irradiation (Figure 4b and 4c). Moreover, the pseudo–first order model was applied to estimate rate constant (κ)

9



Page 10 of 28

of the photocatalytic reactions. As depicted in Figure 4d, the CdS@BPC–600 exhibited the highest TC degradation efficiency (κ = 1.63 × 10–2 min–1) which was ca. 4.2 times of that for CdS (κ = 3.88 × 10–3 min–1). Of note, this was among the highest numbers for photocatalytic TC degradation documented in literatures41–43, and thus the CdS@BPC–600 was potentially applicable to photocatalytic degradation of organic contaminants upon evaluating and addressing possible environmental risks. Mechanism of CO2 photoreduction and tetracycline degradation. Transient photocurrent responses were performed at a bias potential of 0 V to investigate the electron generation and charge carrier transportation characteristics of CdS@BPCs photocatalysts (Figure 5a). Initially, a photocurrent was observed without illumination, and the photocurrent increased and reached steady when visible irradiation was applied. Once the Xe lamp was switched off, the photocurrent returned to the initial value, showing good reversibility of on–off processes. The photoresponse current of CdS@BPC–700 was considerably larger than those of other samples, suggesting noticeable light adsorption efficiency and enhanced electron transfer in this system. Thus, the CdS@BPC–700 was expected with superior photocatalytic performances over other candidates. Moreover, the interfacial charge transfer behavior of CdS@BPCs was studied by Nyquist plots of eletrochemical impedance spectroscopy (EIS). The EIS of CdS@BPC–700 exhibited the smallest arc radius of resistance (Figure 5b) which accounted for the highest charge transfer rate in comparison with other samples. Photoluminescence (PL) quenching was performed to study the electron transfer behavior of CdS@BPCs (Figure 5c). The CdS@BPC–700 showed the weakest PL intensity, which suggested the most effective interfacial charge transportation. These results further indicated that the separation of photogenerated electrons and holes was largely promoted in the nanocomposite systems44,45.

10


Page 11 of 28 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 possible mechanism for CO2 photoreduction over CdS@BPC–700 under visible irradiation is proposed as follows (Figure 5d): first, CO2 and H2O molecules are adsorbed on surfaces of the photocatalyst; upon photoexcitation of CdS NPs, photogenerated carriers (h+ and e–) are produced; meanwhile, electrons are rapidly transferred to catalyst surfaces and participate in CO2 photoreduction, meanwhile, finally, CO2 accumulated on surfaces of the photocatalyst is activated and transformed into CO and CH4 via a photogenerated multi–step and electron–induced reduction process involving electron and proton transfer, C–O bond cleavage and C–H bond formation46–48. In general cases, the consumption of photogenerated h+ would favor the overall utilization of e– by reduced electron–hole recombination, which can be realized by the oxidation of sacrificial agents. At the same time, electrons also take part in the formation of various active species i.e. superoxide (O2•−) and hydroxyl (OH•) radicals38. These catalytically active and oxidative species are preferential for the photocatalytic degradation of organic contaminants. Therefore, we have verified the active species generated in this system through the capture of free radicals during photocatalytic TC degradation. As shown in Figure 5e, O2•− radicals were captured by the ESR technique with the aid of 5,5'–dimethyl–1–pyrroline–N–oxide (DMPO). Furthermore, OH• radicals were detected in fluorescence measurements in the presence of terephthalic acid (TA) 28,38, from which the increased fluorescence intensity of newly formed 2–hydroxyterephthalic acid (emission: 425 nm, excitation: 315 nm) suggested continuous production of OH• (Figure 5f). To further verify the mechanism for TC degradation, scavenger experiments were performed.49 Decreased photocatalytic efficiency for CdS@BPC–600 was expected in the presence of ammonium oxalate (AO), benzoquione (BQ), and isopropanol (IPA) which were typical scavengers for h+, O2•− and OH• radicals, respectively.41,50 Generally, BQ and AO exhibited better quenching effects, which were superior to IPA. These results

11



Page 12 of 28

suggested that O2•− and OH• were dominant active species over h+ (Figure S8). Thus, the mechanism of photocatalytic degradation of tetracycline is proposed as follows: The electrons excited by visible irradiation are first transmitted from the valence band (VB) to the conduction band (CB) of CdS and further to the carbon surface; then superoxide and hydroxyl radicals are formed rapidly; and tetracycline molecules at surfaces of photocatalysts are oxidized into degradation products by oxidative species h+, O2•− and OH•.

CONCLUSIONS In summary, a series of composite photocatalysts (CdS@BPC–T; T = 600/700/800) were successfully prepared by a simple one–step carbothermal reduction method using low–cost biomass porous carbons (BPCs). The as–prepared CdS@BPCs was tentatively applied in CO2 photoreduction and tetracycline degradation with efficient and stable photocatalytic efficiency. In comparison with other carbonaceous supports (GAC, CNTs and GO), the biomass porous carbons (BPCs) were superior candidates to achieve higher photocatalytic activity. In addition, photocatalytic performances of CdS@BPCs could be readily tuned via the control of ratios between cadmium and carbon sources, as well as calcinations temperatures, through which structural development of photocatalysts were optimized and thus catalytically active sites at interfaces could be regulated for CO2 photoreduction into desirable products. Overall, this work provids a facile and atom economic synthetic pathway to prepare photocatalysts for highly efficient CO2 photoreduction and tetracycline degradation under visible irradiation.

ASSOCIATED CONTENT

12


Page 13 of 28 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


Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: X. SEM, TEM and HR–TEM image of BPCs, CdS@BPCs, CdS@GACs, CdS@CNTs, and CdS@GOs; N2 adsorption/desorption isotherms, pore size distribution of the composite mateirals, XPS survey, and high–resolution XPS spectra of CdS@BPCs; UV–vis DRS and K–M plots of CdS@BPCs; CO2 adsorption isotherms of CdS@BPCs, CdS@GAC–700, CdS@CNTs–700 and CdS@GO–700; and photocatalytic degradation of tetracycline using CdS@BPC–600 with exposure to various scavengers (PDF)

AUTHOR INFORMATION Corresponding Authors *E–mail: [email protected] (J.L.). *E–mail: [email protected] (R.C.) ORCID Jian Lü: 0000–0002–0015–8380 Rong Cao: 0000–0003–2384–791X Notes The authors declare no competing financial interest.

ACKNOWLEDGEMENTS We are grateful for financial support from the NSFC (Nos. 21520102001, 21571177 and 51572260), the Strategic Priority Research Program of Chinese Academy of Sciences (No.

13



XDB20000000),

the

Key

Research

Program

of

Frontier

Page 14 of 28

Sciences,

CAS

(No.

QYZDJ–SSW–SLH045), the State Key Laboratory of Structural Chemistry (No. 20170032), the Fujian Agriculture and Forestry University Program for Distinguished Young Scholar (No. xjq201813), and the International Science and Technology Cooperation and Exchange Project of Fujian Agriculture and Forestry University (No. KXGH17010). J.L is grateful for receipt of the award of New Century Excellent Talents in Fujian Province University.

REFERENCES (1) Singh, B. P.; Cowie, A. L.; Smernik, R. J. Biochar carbon stability in a clayey soil as a function of feedstock and pyrolysis temperature. Environ. Sci. Technol. 2012, 46 (21), 11770−11778. DOI 10.1021/es302545b. (2) Woolf, D.; Amonette, J. E.; Street−Perrott, F. A.; Lehmann, J.; Joseph, S. Sustainable biochar to mitigate global climate change. Nat. Commun. 2010, 1, DOI 110.1038/ncomms1053. (3) Rawal, A.; Joseph, S. D.; Hook, J. M.; Chia, C. H.; Munroe, P. R.; Donne, S.; Lin, Y.; Phelan, D.; Mitchell, D. R. G.; Pace, B.; Horvat, J.; Webber, J. B. W. Mineral–biochar composites: molecular structure and porosity. Environ. Sci. Technol. 2016, 50 (14), 7706−7714. DOI 10.1021/acs.est.6b00685. (4) Bunmahotama, W.; Hung, W. N.; Lin, T. F. Prediction of the adsorption capacities for four typical organic pollutants on activated carbons in natural waters. Water Res. 2017, 111, 28–40. DOI 10.1016/j.watres.2016.12.033. (5) Huggins, T. M.; Haeger, A.; Biffinger, J. C.; Ren, Z. J. Granular biochar compared with activated carbon for wastewater treatment and resource recovery. Water Res. 2016, 94, 225–232. DOI

14


Page 15 of 28 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


10.1016/j.watres.2016.02.059. (6) Liu, W.; Ling, L..; Wang, Y.; He, H.; He, Y.; Yu, H.; Jiang, H. One–pot high yield synthesis of Ag nanoparticle–embedded biochar hybrid materials from waste biomass for catalytic Cr(VI) reduction. Environ. Sci.: Nano. 2016, 3 (4),745–753. DOI 10.1039/C6EN00109B. (7) Xiang, Q.; Yu, J.; Jaroniec, M. Synergetic effect of MoS2 and graphene as cocatalysts for enhanced photocatalytic H2 production activity of TiO2 nanoparticles. J. Am. Chem. Soc. 2012, 134 (15), 6575–6578. DOI 10.1021/ja302846n. (8) Panneri, S.; Ganguly, P.; Mohan, M.; Nair, B. N.; Mohamed, A. A. P.; Warrier, K. G.; Hareesh, U. S. Photoregenerable, bifunctional granules of carbon–doped g–C3N4 as adsorptive photocatalyst for the efficient removal of tetracycline antibiotic. ACS Sustainable Chem. Eng. 2017, 5 (2), 1610–1618. DOI 10.1021/acssuschemeng.6b02383. (9) Poizot, P.; Dolhem, F. Clean energy new deal for a sustainable world: from non–CO2 generating energy sources to greener electrochemical storage devices. Energ. Environ. Sci. 2011, 4 (6), 2003–2019. DOI 10.1039/C0EE00731E. (10) Arico, A. S.; Bruce, P.; Scrosati, B. Tarascon, J. M.; Van Schalkwijk, W. Nanostructured materials for advanced energy conversion and storage devices. Nat. Mater. 2005, 4, 366–377. DOI 10.1038/nmat1368. (11) Zheng, D.; Zhang, G.; Wang, X. Integrating CdS quantum dots on hollow graphitic carbon nitride nanospheres for hydrogen evolution photocatalysis. Appl. Catal. B: Environ. 2015, 179, 479–488. DOI 10.1016/j.apcatb.2015.05.060. (12) Cho, K. M.; Kim, K. H.; Park, K.; Kim, C.; Kim, S.; Al–Saggaf, A.; Gereige, I.; Jung, H. T. Amine–functionalized graphene/CdS composite for photocatalytic reduction of CO2. ACS Catal.

15



Page 16 of 28

2017, 7 (10), 7064–7069. DOI 10.1021/acscatal.7b01908. (13) Cao, A. N.; Liu, Z.; Chu, S. S.; Wu, M. H.; Ye, Z. M.; Cai, Z. W.; Chang, Y. L.; Wang, S. F.; Gong, Q. H.; Liu, Y. F. A facile one–step method to produce graphene–CdS quantum dot nanocomposites as promising optoelectronic materials. Adv. Mater. 2010, 22 (1), 103–106. DOI 10.1002/adma.200901920. (14) Yan, H.; Yang, J.; Ma, G..; Wu, G..; Zong, X.; Lei, Z.; Shi, J.; Li, C. Visible–light–driven hydrogen production with extremely high quantum efficiency on Pt–PdS/CdS photocatalyst. J. Catal. 2009, 266 (2), 165–168. DOI 10.1016/j.jcat.2009.06.024. (15) Yang, T. T.; Chen, W. T.; Hsu, Y. J.; Wei, K.; Lin, T.; Lin, T. Interfacial charge carrier dynamics in core−shell Au–CdS nanocrystals. J. Phys. Chem. C. 2010, 114 (26), 11414–11420. DOI 10.1021/jp103294c. (16) Xiao, J. D.; Jiang, H. L. Thermally stable metal–organnic framework–templated synthesis of hierarchically porous metal sulfides: enhanced photocatalytic hydrogen production. Small, 2017, 13, 1700632. DOI 10.1002/smll.201700632. (17) Hu, Y.; Gao, X. H.; Yu, L.; Wang, Y. R.; Ning, J. Q.; Xu, S.; Lou, X. W. Carbon–coated CdS petalous nanostructures with enhanced photostability and photocatalytic activity. Angew. Chem., Int. Ed. 2013, 52 (21), 5636–5639. DOI 10.1002/ange.201301709. (18) Xu, H. Q.; Yang, S. Z.; Ma, X.; Huang, J. E.; Jiang, H. L. Unveiling charge separation dynamics in CdS/MOF composites for enhanced photocatalysis. ACS Catal. 2018, 8 (12), 11615-11621. DOI 10.1021/acscatal.8b03233. (19) Bessekhouad, Y.; Robert, D.; Weber, J. V. Bi2S3/TiO2 and CdS/TiO2 heterojunctions as an available configuration for photocatalytic degradation of organic pollutant. J. Photochem.

16


Page 17 of 28 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


Photobiol. A. 2004, 163 (3), 569–580. DOI 10.1016/j.jphotochem.2004.02.006. (20) Jang, J. S.; Li, W.; Oh, S. H.; Lee, J. S. Fabrication of CdS/TiO2 nano–bulk composite photocatalysts for hydrogen production from aqueous H2S solution under visible light. J. Photoch. Photobio. A. 2007, 188 (1), 112–119. DOI 10.1016/j.cplett.2006.05.031 (21) Liu, X.; Pan, L.; Lv, T.; Zhu, G.; Sun, Z.; Sun, C. Microwave–assisted synthesis of CdS–reduced graphene oxide composites for photocatalytic reduction of Cr(VI). Chem. Commun. 2011, 1 (7), 1245–1249. DOI 10.1039/c1ra00298h. (22) Cao, J.; Sun, J. Z.; Hong, J.; Li, H.; Chen, H.; Wang, M. Carbon nanotube/CdS core—shell nanowires prepared by a simple room–temperature chemical reduction method. Adv. Mater. 2010, 16 (1), 84–87. DOI 10.1002/adma.200306100. (23) Wu, W. M.; Liu, G. D.; Xie, Q. H.; Liang, S. J.; Zheng, H. R.; Yuan, R. S.; Su, W. Y.; Wu, L. A simple and highly efficient route for the preparation of p–phenylenediamine by reducing 4–nitroaniline over commercial CdS visible light–driven photocatalyst in water. Green Chem. 2012, 14 (6), 1705–1709. DOI 10.1039/c2gc35231a. (24) Yu, J. G.; Jin, J.; Cheng, B.; Jaroniec, M. A noble metal–free reduced graphene oxide–CdS nanorod composite for the enhanced visible–light photocatalytic reduction of CO2 to solar fuel. J. Mater. Chem. A. 2014, 2 (10), 3407–3416. DOI 10.1039/c3ta14493c. (25) Woan, K.; Pyrgiotakis, G.; Sigmund, W. Photocatalytic carbon–nanotube–TiO2 composites. Adv. Mater. 2009, 21 (21), 2233–2239. DOI 10.1002/adma.200802738. (26) Kim, J. R.; Kan, E. Heterogeneous photocatalytic degradation of sulfamethoxazole in water using a biochar–supported TiO2 photocatalyst. J. Environ. Manage. 2016, 180, 94–101. DOI 10.1016/j.jenvman.2016.05.016.

17



Page 18 of 28

(27) Dwivedi, P.; Gaur, V.; Sharma, A.; Verma, N. Comparative study of removal of volatile organic compounds by cryogenic condensation and adsorption by activated carbon fiber. Sep. Purif. Technol. 2004, 39 (1–2), 23–37. DOI 10.1016/j.seppur.2003.12.016. (28) Boxall, A. B.; Kolpin, D. W.; Halling–Sørensen, B.; Tolls, J. Are veterinary medicines causing environmental

risks?

Environ.

Sci.

Technol.

2003,

37

(15),

286A−294A.

DOI

10.1021/es032519b (29) Kim, S.; Eichhorn, P.; Jensen, J. N.; Weber, A. S.; Aga, D. S. Removal of antibiotics in wastewater: effect of hydraulic and solid retention times on the fate of tetracycline in the activated sludge process. Environ. Sci. Technol. 2005, 39 (15), 5816−5823. DOI 10.1021/es050006u. (30) Li, R.; Wang, Z.; Guo, J.; Li, Y.; Zhang, H.; Zhu, J.; Xie, X. Enhanced adsorption of ciprofloxacin by KOH modified biochar derived from potato stems and leaves. Water Sci. Technol. 2018, 77 (4), 1127–1136. DOI 10.2166/wst.2017.636. (31) Huang, H. B.; Wang, Y.; Jiao, W. B.; Cai, F. Y.; Shen, M.; Zhou, S. G.; Cao, H. L.; Lü, J.; Cao, R. Lotus–leaf–derived activated carbon supported nano–CdS as energy–efficient photocatalysts under visible irradiation. ACS Sustain. Chem. Eng. 2018, 6 (6), 7871–7879. DOI 10.1021/acssuschemeng.8b01021. (32) Hao, X.; Zhou, J.; Cui, Z.; Wang, Y. C.; Wang, Y.; Zou, Z. Zn–vacancy mediated electron–hole separation in ZnS/g–C3N4 heterojunction for efficient visible–light photocatalytic hydrogen production. Appl. Catal. B: Environ. 2018, 229, 41–51. DOI 10.1016/j.apcatb.2018.02.006. (33) Yu, J.; Yu, Y.; Zhou, P.; Xiao, W.; Cheng, B. Morphology–dependent photocatalytic H2–production activity of CdS. Appl. Catal. B: Environ. 2014, 156, 184–191. DOI

18


Page 19 of 28 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


10.1016/j.apcatb.2014.03.013. (34) Matos, J.; Laine, J.; Herrmann, J. M. Effect of the type of activated carbons on the photocatalytic degradation of aqueous organic pollutants by UV–irradiated titania. J. Catal. 2001, 200 (1), 10–20. DOI 10.1006/jcat.2001.3191. (35) Xia, Y.; Li, Q.; Lv, K. L.; Tang, D. G.; Li, M. Superiority of graphene over carbon analogs for enhanced photocatalytic H2–production activity of ZnIn2S4. Appl. Catal. B: Environ. 2017, 206, 344−352. DOI 10.1016/j.apcatb.2017.01.060. (36) Xu, Y.; Zhang, W. CdS/g–C3N4 hybrids with improved photostability and visible light photocatalytic

activity.

Eur.

J.

Inorg.

Chem.

2015,

10,

1744–1751.

DOI

10.1002/ejic.201403193. (37) Wang, S. B.; Guan, B. Y.; Lou, X. W. Construction of ZnIn2S4−In2O3 hierarchical tubular heterostructures for efficient CO2 photoreduction. J. Am. Chem. Soc. 2018, 140 (15), 5037–5040. DOI 10.1021/jacs.8b02200. (38) Wang, S. B.; Wang, X. C. Photocatalytic CO2 reduction by CdS promoted with a zeolitic imidazolate

framework.

Appl.

Catal.

B:

Environ.

2014,

162,

494–500.

DOI

10.1016/j.apcatb.2014.07.026. (39) Song, G. X.; Xin, F.; Chen, J. S.; Yin, X. H. Photocatalytic reduction of CO2 in cyclohexanol on CdS–TiO2 heterostructured photocatalyst. Appl. Catal. A: Gen. 2014, 473, 90–95. DOI 10.1016/j.apcata.2013.12.035. (40) Ljaz, S.; Ehsan, M. F.; Ashiq, M. N.; Karamat, N.; He, T. Preparation of CdS@CeO2 core/shell composite for photocatalytic reduction of CO2 under visible–light irradiation. Appl. Surf. Sci. 2016, 390, 550–559. DOI 10.1016/j.apsusc.2016.08.098.

19



Page 20 of 28

(41) Cao, H. L.; Cai, F. Y.; Yu, K.; Zhang, Y. Q.; Lü, J.; Cao, R. Photocatalytic degradation of tetracycline antibiotics over CdS/nitrogen–doped–carbon composites derived from in situ carbonization of metal–organic frameworks (MOFs). ACS Sustain. Chem. Eng. 2019, 7 (12), 10847–10854. DOI 10.1021/acssuschemeng.9b01685. (42) Wang, H.; Yuan, X. Z.; Wu, Y.; Zeng, G. M.; Dong, H. R.; Chen, X. H.; Leng, L. J.; Wu, Z. B.; L. Peng, J. In situ synthesis of In2S3@MIL–125(Ti) core–shell microparticle for the removal of tetracycline from wastewater by integrated adsorption and visible–light–driven photocatalysis, Appl. Catal. B: Environ., 2016, 186, 19–29. DOI 10.1016/j.apcatb.2015.12.041. (43) Mboula, V. M.; Hequet, V.; Gru, Y.; Colin, R.; Andres, Y. Assessment of the efficiency of photocatalysis on tetracycline biodegradation, J. Hazard. Mater., 2012, 209, 355–364. DOI 10.1016/j.jhazmat.2012.01.032. (44) Zhang, H.; Lv, X.; Li, Y.; Wang. Y.; Li, J. P25–graphene composite as a high performance photocatalyst. ACS Nano, 2010, 4 (1), 380–386. DOI 10.1021/nn901221k. (45) Yang, M. Q.; Xu, Y. J.; Lu, W. H.; Zeng, K. Y.; Zhu, H.; Xu, Q. H.; Ho, G. W. Self–surface charge exfoliation and electrostatically coordinated 2D hetero–layered hybrids. Nat. Commun. 2017, 8, 14224. DOI 10.1038/ncomms14224. (46) Chen, S.; Hu, Y.; Meng, S.; Fu, X. Study on the separation mechanisms of photogenerated electrons and holes for composite photocatalysts g–C3N4–WO3. Appl. Catal. B: Environ. 2014, 150–151 (9), 564–573. DOI 10.1016/j.apcatb.2013.12.053. (47) Pan, P. W.; Chen, Y. W. Photocatalytic reduction of carbon dioxide on NiO/InTaO4 under visible

light

irradiation.

Catal.

Commun.

2007,

10.1016/j.catcom.2007.01.006.

20


8

(10),

1546–1549.

DOI

Page 21 of 28 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


(48) Lehn, J. M.; Ziessel, R. Photochemical generation of carbon monoxide and hydrogen by reduction of carbon dioxide and water under visible light irradiation. Proc. Natl. Acad. Sci. USA. 1982, 79 (2), 701–704. DOI 10.1073/pnas.79.2.701. (49) Hou, Y.; Yang, J.; Lei, C. J.; Yang, B.; Li, Z. J.; Xie, Y.; Zhang, X. W.; Lei, L. C.; Chen, J. H. Nitrogen vacancy structure driven photoeletrocatalytic degradation of 4–chlorophenol using porous graphitic carbon nitridenanosheets. ACS Sustainable Chem. Eng. 2018, 6 (5), 6497–6506. DOI 10.1021/acssuschemeng.8b00279. (50) Zhou, C. Y.; Lai, C.; Xu, P.; Zeng, G. M.; Huang, D. L.; Li, Z. H.; Zhang, C.; Cheng, M.; Hu, L.; Wan, J.; Chen, F.; Xiong, W. P.; Deng, R. Rational design of carbon-doped carbon nitride/Bi12O17Cl2

composites:

a

promising

candidate

photocatalyst

for

boosting

visible–light–driven photocatalytic degradation of tetracycline. ACS Sustainable Chem. Eng. 2018,

6

(5),

6941–6949.

DOI

21


10.1021/acssuschemeng.8b00782.


Page 22 of 28

Table 1 Elemental analyses and BET surface area of BPC and CdS@BPCs. Samples BPC CdS@BPC–600 CdS@BPC–700 CdS@BPC–800

C 67.7 29.2 29.2 29.7

H 4.2 0.6 0.5 0.4

S N.A. 6.74 9.25 10.2

Content (%) Cd CdS (normalized) N.A. N.A. 32.7 30.4 29.9 38.4 25.7 33.0

22


SBET (m2/g) 1529 782.3 828.3 1006

Page 23 of 28 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 1. (a) Thermogravimetric analysis (TGA) of CdSO4·2H2O precursor; (b) PXRD patterns of CdS, CdS@BPCs and reference composites; (c) TEM; and (d) HR–TEM images of CdS@BPC–700.

23



Page 24 of 28

Figure 2. (a) XPS survey scan; high–resolution XPS of (b) Cd3d; (c) Zn 2p; and (d) S 2p of CdS@BPC–700.

24


Page 25 of 28 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 3. (a) CO2 photoreduction activity of CdS and CdS@BPCs; (b) cycling CO2 photoreduction using CdS@BPC–700; (c) H2 evolution during the photoreduction of CO2 by CdS and CdS@BPCs; (d) photocatalytic activities of CdS@BPC–700, CdS@GAC–700, CdS@CNTs–700 and CdS@GO–700 samples; (e) PXRD patterns of CdS@BPC–700 before and after cycling reactions; and (f) CO2 adsorption isotherms of CdS@BPC–700 at 273 and 298 K.

25



Page 26 of 28

Figure 4. (a) Tetracycline (TC) adsorption performance of CdS@BPCs (initial TC concentration = 40 mg/L, solution volume = 100 mL, photocatalysts = 10 mg); (b) UV–vis absorption spectra of TC using CdS@BPC–600 as photocatalyst; (c) photocatalytic TC degradation efficiency of various photocatalysts under visible irradiation; (d) plot of –ln (C/C0) as a function of irradiation time in the presence of CdS and CdS@BPCs.

26


Page 27 of 28 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 5. (a) Transient photocurrents; (b) EIS Nyquist plots; (c) room–temperature photoluminescence (PL) spectra of CdS@BPCs; (d) a schematic illustration on the photocatalytic process in systems of CdS@BPCs; (e) DMPO−O2•− spin–trapping ESR spectra; and (f) time–dependent fluorescence intensity of TAOH by using CdS@BPC–600 under visible irradiation (excitation wavelength: 315 nm).

27



Page 28 of 28

For Table of Contents Use Only

CdS@BPCs composites, which are employed as visible–light–driven photocatalysts toward both carbon dioxide photoreduction and oxidative tetracycline degradation, have been developed via a simple one–step, solvent free and atom economic carbothermal reaction pathway.

28


Oneâstep carbothermal synthesis of robust CdS@BPCs

Recommend Documents

Oneâstep carbothermal synthesis of robust CdS@BPCs