Tuning the Electronic Structure of Se via Constructing Rh-MoSe2

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Tuning the Electronic Structure of Se via Constructing RhMoSe2 Nanocomposite to Generate High-Performance Electrocatalysis for Hydrogen Evolution Reaction Shuai Liu, Mengsi Li, Changlai Wang, Peng Jiang, Lin Hu, and Qianwang Chen ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.8b01467 • Publication Date (Web): 30 May 2018 Downloaded from http://pubs.acs.org on May 30, 2018

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ACS Sustainable Chemistry & Engineering

Tuning the Electronic Structure of Se via Constructing Rh-MoSe2 Nanocomposite to Generate High-Performance Electrocatalysis for Hydrogen Evolution Reaction Shuai Liu1§, Mengsi Li1§, Changlai Wang1, Peng Jiang1, Lin Hu2, Qianwang Chen1,2* 1

Hefei National Laboratory for Physical Science at Microscale, Department of Materials Science &

Engineering, and Collaborative Innovation Center of Suzhou Nano Science and Technology, University of Science and Technology of China, Hefei 230026, China 2

The Anhui Key Laboratory of Condensed Mater Physics at Extreme Conditions, High Magnetic

Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China

*Correspondence to: [email protected]. §These authors contributed equally.

Abstract As one of the most promising acid-stable catalysts for hydrogen evolution reaction (HER), MoSe2 was hampered by the limited quantity of active sites and poor conductivity, which severely impede the efficiency of hydrogen production. Different from heteroatoms doping and conductivity improvement, to address this issues, the electronic structure of active edge sites Se in MoSe2 were modulated by electron injection from ruthenium deposited on MoSe2 nanosheets. The Rh-MoSe2 nanocomposite exhibits great performance enhancement with a low onset potential of 3 mV and quite low overpotential of 31mV (vs. RHE), which is superior to almost all Rh-based and MoSe2-based electrocatalysts. Experimental results and density functional theory (DFT) simulations reveal that the performance improvement stems from the modulated electronic structure of Se atoms at the edge sites by electron transfer from metal Rh to MoSe2 support, which leads to a moderate ∆GH* value of 0.09 eV compared to 0.83 eV for MoSe2 and -0.26 eV for Rh.

Key words MoSe2, Hydrogen evolution reaction, electron transfer, Rh, electronic structure. Introduction Nowadays the increasing consumption of fossil fuel drives people to look for new alternative energy resource.1-2 As one of the most ideal energy carrier, hydrogen has gained great attention as a green and renewable energy with high combustion heat to meet the booming energy demand.3-4 Contrasted with steam reforming of methane for industrial production, the hydrogen gas can be produced by water splitting via

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hydrogen evolution reaction (HER) as an efficient and pollution-free approach.5 Trapped with high electricity cost, it’s of paramount importance to explore powerful and cost-effective electrocatalysts to realize sustainable hydrogen industrialization. Despite the progress of exploring alternative electrocatalysts, platinum (Pt) is still the state of art materials among the transition metals, metal carbides, metallic oxides and metal sulfides.6 Though unequalled performance of Pt, the natural scarcity and expensive price greatly restrict it’s further commercial development and large-scale applications for water-splitting and fuel cells.7 Hence, it is highly desirable to explore cheap and abundant high-performance electrocatalysts to replace the previous Pt-based HER catalysts. As a representative member of two-dimensional graphene-like transition metal dichalcogenides (TMDs), MoSe2 is considered as one of the cost-effective, highly active, and stable material with great potential in the application of electrocatalytic hydrogen production.8-9 It’s well known that the electrocatalyst which processes moderate hydrogen adsorption free energy (∆GH), shows high activity for HER.10 Experimental and theoretical study reveal that the MoSe2 nanosheet with abundant edge sites of Se derived from layer edge or defects, possess favorable ∆GH and high potential for development in HER.11 While, whole reaction process was hindered by the weak hydrogen proton adsorption capacity of catalytic sites, limited active edge sites exposed and poor conductivity. To address these issues, some valid strategies has been, in part, adoped to promote the reaction activity, such as conductivity improvement by directly growing it on conductive substrates(e.g., reduced graphene oxides (rGO),12 carbon fibers,13 carbon nanotubes (CNTs)14), the increase of active sites derived from forming defects by doping with the heteroatoms(e.g., N,15 S,16 B,17 Co,18 Nb19). Unfortunately, the HER activity of the aforementioned MoSe2-based catalysts are still not satisfactory. Though an atomic effort has been afforded in previous research to enhance their HER performance, no much attention has been to paid to study the activity improvement by tuning the intrinsic electronic structure of Se. The activity of catalyst, which is germane to activation energy barriers between the reaction interface at the surface active sites of two-dimensional materials and intermediate participation, mostly correlates with the intrinsic structure of the materials, such as composition structure, and electronic structure (e.g., d-band center energy) of active sites.20-21 For instance, heteroatom doped (such as N and B) graphene can induce asymmetry of the charge distribution around the carbon atoms which are adjacent to dopant, by breaking their electroneutrality,22 thus modulates the adsorption capacity of H* and differs significantly with pristine graphene. And also there have been examples of success to build proper structure of catalyst to modulate the electronic structure of active sites. Our group and Bao’s work have reported that building the perfect structure by implantation of alloy to carbon cages to optimize the electronic structure of carbon atoms which exhibit superior performance compared to individual components.23-25 The strategy was proved great success in acidic electrolyte (e.g., CoIr26) and alkaline electrolyte (e.g., CoRu27) and suggests that the introduction of alloy can facilitate the electron transfer from metal to the N-doped


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graphene. The great success via regulating the electronic structure of carbon inspires us to enhance the activity towards HER of other materials (i.e., MoSe2) by this way. The MoSe2 nanosheet, an indispensable member of TMDs with layer morphology similar to graphene, depends on the Van der waals force to maintain the structure. The electronic properties of the TMDs layer in a large part change with the filling degree of d-orbital electrons (e.g., tuning the H* adsorption and desorption energy of S active sites by construction of Cu nanodots decorated Ni3S2 nanotubes28). For two-dimensional materials, such as grapheme applied for HER, heterogeneous catalysis often occurs at the surface defects and the edge of the layer29. For MoSe2 nanosheets, the lone pair electrons of Se atoms distribute near the surface of layer of MoSe2 and unsaturated bonds derived from defects, which give the possibility to change the surface electronic state via introduction of the metal similar to graphene aforementioned. And also the amount of electrons transferred heavily depends on property of introduced metal.30 Based on these considerations, proper component is needed to optimize the H* adsorption on Se atoms of MoSe2 which is too weak due to the suboptimum electronic structure. The metal rhodium (Rh), which process abundant d-band electrons but much lower activity than Pt caught our attention to modify the property of MoSe2.31 Herein, we introduced metal Rh nanoparticles (NPs) to MoSe2 nanosheets by deposition for improving the HER activity of MoSe2. The behavior of Rh-MoSe2 towards HER in acidic electrolyte exhibit the great performance enhancement superior than MoSe2 and Rh and even closer to commercial Pt/C. Structural measurements matches well to Density functional theory (DFT) simulations that electrons transform to MoSe2 contributes to the performance mutation. Results and Discussion The simplified synthesis process of Rh-MoSe2 nanocomposite was illustrated in Figure 1 via two-step approach. First of all, hierarchical porous MoSe2 was synthesized through a simple hydrothermal process. The MoSe2 with flower-like morphology was assembled by ultrathin nanosheets, which is considered to be a tailor-made support. Then, rhodium precursor was reduced to rhodium nanoparticles by ethylene glycol (EG) and Rh NPs in situ grew on the MoSe2 nanosheets in the oil bath process. The Rh-MoSe2 with different contents of rhodium precursor 2ml, 3ml and 4ml were labeled S-2, S-3 and S-4, respectively (see the specific dosages in Supporting Information). The MoSe2 with no further treatment was labeled S-0.



Figure 1. Schematic illustration of the synthesis process of Rh-MoSe2 nanocoposite. The scanning electron microscopy (SEM) images (Figure 2a) shows that MoSe2 nanosheets with flower like morphology. The transmission electron microscopy (TEM) measurement of as-synthesized MoSe2 nanosheets in Figure S1 displays the typical image of MoSe2 nanosheets. The crosslinked nanosheets exposed more edge and defects which provides the possibility for the growth of nanoparticles. The Figure 2b and c show that the typical morphology of sample S-3 that rhodium nanoparticles were well deposited on the surface of the MoSe2 nanosheets after composite, like dews on a blossom flower. Furthermore, it can be clearly shown that the Rh NPs are approximately 6 nm in size which marked with black arrows grown at edge of MoSe2 nanosheets in Figure 2c, the more image of this morphology is shown in Figure S7. The images of other samples of Rh-MoSe2 nanocomposite are shown in Figure S2. In addition, the high-resolution TEM (HRTEM) image (Figure 2c and f) show that the ultrathin MoSe2 nanosheets are composed of 1-3 layers with a interplanar spacing of 0.68 nm, corresponding to the (002) plane. The spacing is larger than 0.646 nm of pristine bulk MoSe2, in accordance with X-ray diffraction (XRD) results that no obvious corresponded diffraction peak was observed.32 The one layer MoSe2 nanosheet supported Rh nanoparticles was shown in Figure 2d and e, it shows another disparate structure with a lattice spacing of 0.22 nm which corresponds to the (111) plane of face-centered cubic Rh in Figure 2d and the lattice spacing of 0.237 nm corresponding to the (103) plane of 2H-MoSe2 in Figure 2e. The more HRTEM images of S-3 are shown in Figure S3. The high-angle annular dark field scanning TEM (HAADF-STEM) image and corresponding elemental mapping analyses Energy dispersive X-ray (EDS) mapping images (Figure 2g-j ) reveal that the presence of Rh Nps and homogeneous distribution of Mo and Se elements in Rh-MoSe2 sample S-3.The contents of Rh in sample S-3 was detected to be 14.7 wt% by ICP analysis (the contents of Rh in all samples were listed in Table S1).


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Figure 2. Morphology, crystal structure and elemental analysis. SEM images of a) MoSe2, b) S-3 of Rh-MoSe2 nanocomposite. c) HRTEM images of S-3. d, e, f) The enlarged area presents the HRTEM of Rh, one layer of MoSe2 nanosheet, three layers of MoSe2 nanosheets, respectively. g) HAADF-STEM image of S-3. h, i, j) EDS mapping of Se, Mo, Rh, respectively.

The XRD patterns of the pure MoSe2 and Rh-MoSe2 nanocomposite are shown in Figure 3a. As shown in curve (ii), the three broad peaks correspond to (100), (103) and (110) peaks of 2H-MoSe2 (JCPDS No. 77-1715), respectively. There is no obvious peak corresponding to the (002) plane. It’s is consistent with other reports, and further suggests that interlayer spacing of the pure MoSe2 is changed.33 After supporting process, two more diffraction peaks indexing to face-centered cubic Rh crystal plane of (111) and (200) appear on the pattern of sample S-3 in curve (i) of Figure 3a. The XRD patterns of other samples are shown in Figure S4. The intensity ratio of diffraction peaks corresponding to (111) plane assigned to Rh become stronger gradually compared to the (110) plane of MoSe2 in Figure S4c, which suggests an enhanced loading level.34 To determine the interaction of Rh-MoSe2 nanocomposite, X-ray photoelectron spectroscopy (XPS) analyses were conducted. The XPS survey of the as-obtained S-3 sample and the pure MoSe2 is shown in Figure S5, the Mo 3d, Se 3d and Rh 3d spectra of pure MoSe2 and Rh-MoSe2 nanocomposite are compared in Figure 3b-d, the Mo(IV) 3d peaks at 229.21 eV and Se 3d peaks at 54.72 eV of S-0 is shown in Figure 3b and c , which is consistent with the formation of pure MoSe2.35-36 For the composition sample S-3 in Figure 3b-c, the Mo 3d peaks and Se 3d peaks of S-3 with negligible shift after composite gives no more details. However two peaks are apparent in Figure 3d at 307.8 eV and 312.6 eV corresponds to Rh(0) in the Rh(3d) region. The Rh 3d5/2 peak in S-3(insert of Figure 3d) at the binding energy of 307.85



eV is positively shift from that of synthesized Rh NPs (307.67eV), suggests that electron state change of Rh in Rh-MoSe2 nanocomposite and further indicates the state of absence of electrons on the surface of Rh NPs. Furthermore, the Rh 3d peak at 308.2 eV and 313.37 eV corresponds to Rh(+1)23 in Figure 3d which is different from oxidized Rh(+3) at 3d5/2 peak in 308.3-310.5 eV of binding energy37 also indicate the above point of view. The XPS analysis points out not only strong electron interaction at the interface, but also that Rh NPs may donate electrons to the MoSe2 with electron-withdrawing effect, which change the surface electronic state of the MoSe2 and Rh NPs after the composite. The fact of intense interaction between MoSe2 and Rh is strongly supported.

Figure 3. Structure characterization. a) XRD patterns of MoSe2 and S-3 of Rh-MoSe2 corresponding to curve (i) and (ii), respectively. XPS spectra of the S-0 and S-3: b) Mo 3d core level. c) Se 3d core level. d) Rh 3d core level, inset is the comparision of S-3 and Rh NPs.

The electrocatalytic HER activity of all samples was evaluated by using a simple three-electrode setup in N2-saturated 0.5M H2SO4 solution without I-R corrected. In the experiment, different contents of Rh in situ grew on MoSe2 and commercial 20wt% Pt/C and pure Rh nanoparticles (NPs) as reference were performed by linear sweep voltammetry (LSV) under the scan rate of 5 mV s−1 at first (see the details in SI). The overpotential at 10 mA/cm2 versus a reversible hydrogen electrode (RHE) in the polarization curve is used to evaluate the HER performance of electrocatalyst. As


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illustrated in Figure 4a, the S-0 which indicates pure MoSe2 nanosheets shows unsatisfactory HER activity with an onset potential of 67 mV and the overpotential of 223 mV at 10 mA/cm2, so that the lower activity compared to other samples of hybrids. By contrast, the nanocomposites show lower onset overpotentials, the S-3 catalyst shows the lowest onset potential of 3 mV, which is closed to 0 mV among these samples. Besides, the sample S-3 exhibits the best HER activity among these samples with only 31 mV at the current density of 10 mA/cm2 contrast to 98 mV of S-2 and 42 mV of S-4, which is very close to the commercial 20wt% Pt/C with an overpotential of 26 mV. What’s more, the trend in the overpotential is ranked in the order as follows: S-3 < S-4 < S-2 < S-0, suggests that the HER performance of MoSe2 was improved after compositing with Rh. Interestingly, it also indicates that a further increment of the rhodium amount leads to a decrease of HER performance. The nanocomposite with a moderate content of Rh shows the optimal performance. The remarkably improvement in electrocatalyst activity could be explained by the change of electronic structure derived from composite. To verify the conjecture above and eliminate the influence of the introduced rhodium on HER performance, the Rh nanoparticles (Rh NPs) synthesized by the same method without adding MoSe2 nanosheets (SI) and the commercial 20 wt% Pt/C catalyst were also measured as reference. Surprisingly, as illustrated in Figure 4b, though the Rh NPs show the excellent activity compared with others reported in the literature,38 the S-3 shows the great improvement of HER performance closed to the Pt/C catalyst superior to Rh NPs and S-0. As expected, the advent of electronic structure change of MoSe2 after composite is responsible for the remarkable HER performance. The HER performance are intuitionistic displayed in Figure 4c, the onset overpotential of the S-3 for HER is extremely low to 3 mV, which is comparable to commercial Pt/C of 4 mV and much less than catalyst of S-0 with 67 mV and Rh NPs with 42 mV. The overpotential at 10 mA/cm2 of S-3 is 31 mV, much lower than S-0 of 221 mV and Rh NPs of 84 mV. To shed light on the catalytic behavior of the Rh-MoSe2 nanocomposite, the related Tafel plots are obtained according to the Tafel equation. The Tafel curves were given derived from the polarization curves of the samples in Figure 4b. The rate-determining step can be deduced from the calculated Tafel slope the related Tafel plots are obtained according to the Tafel equation (η = a + b log j, where η, a, b, and j are the overpotential, the intercept, Tafel slope and the current density, respectively) through a Volmer-Heyrovsky reaction mechanism in HER process.39 (1) H3O+ + e− → Hads + H2O. This step is primary discharge process also called Volmer reaction (b ≈ 120 mV dec-1) and followed by either an electrochemical desorption step (Heyrovsky reaction), or a recombination step (Tafel reaction): (2) Hads+ H3O+ + e− → H2 + H2O, b ≈ 40 mV dec-1 or (3) Hads + Hads →H2, b ≈ 30 mV dec-1. As shown in Figure 4d, the pure MoSe2 gives a slope of 85 mV dec-1 and Rh NP shows 44 mV dec-1, while the Rh-MoSe2 nanocomposite S-3 displays a Tafel slope of 40 mV dec-1, which is very closed to that of 27 mV dec-1 for commercial Pt/C. It indicates that the electrochemical desorption is the rate-limiting step for Rh-MoSe2 nanocomposite according to Volmer-Heyrovsky reaction mechanism.40 Except for the catalytic activity and mechanism, the long-term stability is another key electrode parameter to



estimate an electrocatalyst applied in a specific electrochemical environment. The cycling test of S-3 (Figure 4e) in acidic media was conducted with a graphite rod electrode used as counter electrode at an accelerated scanning rate of 50 mV/s, the Rh-MoSe2 catalyst remains high activity after 1000th CV cycles, and only 3 mV decay of cathodic current density at the 10 mA/cm2. The insignificant loss of HER performance may be caused by the slight delamination of the catalyst during testing flowed by massive evolved hydrogen production.7 Additionally, the chronoamperometry measurement for S-3 displays that the sample maintains a stable current density for more than 40 hours (inset of Figure 4e) and 94.5% remained in 0.5 M H2SO4. The XRD, SEM and TEM characterization (Figure S6) of S-3 shows no changes after the chronoamperometry test. The superior long-term stability on HER performance further illustrates the great activity enhancement of the nanocomposite.


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Figure 4. HER activity characterization. a) LSV curves of different contents of Rh in Rh-MoSe2 composites and 20 wt% Pt/C. b) LSV curves of pure MoSe2, Rh NPs, S-3 and 20 wt% Pt/C. c) onset potential and overpotential at 10 mA/cm2 of S-0, S-3, Rh NPs, 20 wt% Pt/C. d) Corresponding Tafel plots derived from b). e) Electrochemical stability test of S-3 with LSV curves at initial state and after 1000th CV cycles, inset is the chronoamperometry test of S-3 at overpotential. f) Nyquist plots of catalysts.

When the electrochemical impedance spectra (EIS) was carried out to investigate the electrode kinetics of the studied samples, it’s clearly shown in Figure 4f that the sample S-3 displays much smaller semicircular diameter in the EIS than the pure MoSe2 S-0, which suggests that, at the same overpotential, the nanocomposite presents the faster electron transfer in the reaction kinetic41. The semicircles of Nyquist plots which is visible in the low frequency range are mainly represented to the charge transfer resistance (Rct) of H+ reduction at the electrode-electrolyte interface, and it’s obvious that Rct of S-3 is apparently decreased than that of pure MoSe2. The result indicates the enhancement of HER activity partly originated from the improvement of conductivity. Generally, electrochemically active surface area (ECSA) is regarded as an indicative reference point to estimate active sites of the HER catalyst, and the value of ECSA is relative to the electrochemical double-layer capacitance (Cdl). The CV curves(Figure S7) and Cdl of the S-0, S-2, S-3 and S-4 were measured by voltammetry, and the consequence is displayed in Figure S8. The rank of Cdl is following as S-0 < S-2 < S-4 < S-3, confirming S-3 with the largest Cdl and the maximum number of functional sites among the four samples. The great enhancement activity towards HER detected by electrocatalytic measurement confirmed our strategy for regulating active sites of MoSe2 which is different from other methods, and make the MoSe2 become a competitive material for HER. The comparison of HER activity among the MoSe2 based materials and Rh containing materials are illustrated in Table 1. It’s obvious that the advantage of this strategy of electronic structure regulation is far exceeds that of other methods, and therefore, the excellent acid HER performance, even comparable to commercial 20 wt% Pt/C, as well as almost all reported Rh-based and MoSe2-based electrocatalysts. Table 1. Comparison of HER performance in acidic media 0.5M H2SO4 for samples in this work with other electrocatalysts. Onset Loading Catalyst

Electrode

(mg cm-2)

potential

Overpotential at 10

Tafel slope

mA cm-2 (mV)

(mV dec-1)

Reference

(mV) Rh-MoSe2 MoSe2

GCE

0.285

3

31

40

This work

GCE

0.285

67

223

85

This work

-

70

182

69

13

0.14

-

152 (iR corrected)

52

42

-

-

84

39

17

Carbon MoSe2/CF fiber 1T-MoSe2

GCE Carbon

B-MoSe2/CC cloth



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graphene N-MoSe2/VG

-

45

98

49

15

0.285

125

195

67

12

-

35

~50

38

43

arrays MoSe2/rGO

GCE Carbon

MoSe2/CC cloth Co, Ni-MoS3

GCE

-

112

171

56.9

44

Co-MoSe2

GCE

0.57

-

305

95.2

45

Rh-Si

GCE

0.193

-

130

24

46

Rh-MoS2

GCE

0.309

-

47

24

34

To understand the nature of the high HER reactivity of Rh-MoSe2, we further performed density functional theory (DFT) calculations by constructing proper Geometric structure of Rh-MoSe2. It’s clearly shown in the HRTEM image of Figure 2c (marked with black arrows) and Figure S9a and b (marked with white arrows) that Rh NPs decorates the edge of MoSe2 nanosheet and enhance the activity of the edge sites of Se atoms in HER as illustrated in Figure S9c. Hence, interfacial model by a Rh nano-cluster supported on MoSe2 surface is built, and the Rh-MoSe2 interfacial structure is shown in Figure 5a. For comparison, a similar calculation was conducted for Rh cluster (111) plane (Figure S10a) and bare MoSe2 (002) plane (Figure S10b) according to the HRTEM and XRD analysis. The computational details are in the Supporting Information. It has been demonstrated that the adsorption free energy of H* (∆GH*) is a key descriptor of the HER activity, and the ∆GH* value which is closer to zero, the activity of the catalytic material for HER is much better. As seen in Figure 5b, the active adsorption site for H* is the edge Se atom, which is consistent with previous work.47 The calculations results of the ∆GH* value on bare MoSe2, Rh cluster and Rh-MoSe2 are shown in Figure 5c. In the DFT calculations, the adsorption of hydrogen on bare MoSe2 is too weak, indicating hydrogen is hard to activate on bare MoSe2. While hydrogen binds much strongly on Rh cluster, which would be disadvantageous to the desorption step. In contrast, the Rh-MoSe2 has a moderate ∆GH* value of 0.09 eV compared to 0.83 eV of MoSe2 and -0.26 eV of Rh (Table S2), which agrees fairly closely with the experimental HER performance.


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Figure 5. DFT simulations. a) Optimized structure of Rh-MoSe2 model. b) H* adsorbed on Rh-MoSe2 model. c) The calculated ∆GH* diagram of MoSe2, Rh and Rh-MoSe2 models. d) electron density of Rh-MoSe2 model calculated by Bader charge analysis.

In order to gain further insight into the electronic structure of the Rh-MoSe2, we additionally performed charge density difference as well as Bader charge calculations. As displayed in Figure 5d, charge transfer from Rh to MoSe2 and a significant increase in electron density (indicated by olive color) has been observed at the surface of MoSe2. According to Bader charge analysis, Rh donated 0.487 e- to MoSe2. Resulting from their different work functions, surface polarization is induced by the Rh-MoSe2 interface, and acts to tailor the surface charge state of MoSe2, consequently tunes the hydrogen adsorption on Rh-MoSe2 to a moderate level instead of too weak on bare MoSe2 and too strong on pure Rh. Our calculation well explains the electron transfer greatly promotes the HER performance of MoSe2 and coincides with the structure characterization of Rh-MoSe2 nanocomposite. Conclusion In summary, we propose electron transfer as a new powerful strategy to tuning the electronic structure of active sites and remarkably boost the HER performance of MoSe2, which has apparently lower electrocatalytic activity by combination with metal Rh. The Rh-MoSe2 nanocomposite presents a great enhancement with an extremely low onset potential of 3 mV and overpotential at 10 mA/cm2 of 31 mV with long-term stability, which is very close to commercial 20 wt% Pt/C. Structure characterization agrees fairly closely to the DFT calculations that Rh donates the



electron to MoSe2 and change the surface charge state of Rh-MoSe2, the moderate hydrogen adsorption capacity which is apparently lower than the Rh and MoSe2 accelerates the whole HER process. This work provides a new route to design the effective catalyst and enhance catalytic activity by change the electronic structure of active sites of catalysts. Supporting Information The Supporting Information is available from the website. Acknowledgements This study was supported by the National Natural Science Foundation (NSFC, 51772283, 21271163), the CAS/SAFEA International Partnership Program for Creative Research Teams and CAS Hefei Science Center (2016HSC-IU011). The calculations were completed on the supercomputing system in the Supercomputing Center of the University of Science and Technology of China. References 1.

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Synopsis: a powerful method to improve the HER performance of MoSe2 via constructing Rh-MoSe2 nanocomposite.


Tuning the Electronic Structure of Se via Constructing Rh-MoSe2

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