Coordination polymer structure and revisited hydrogen evolution catalytic mechanism for amorphous molybdenum sulfide

Tran, Phong D.; Tran, Thu V.; Orio, Maylis; Torelli, Stéphane; Truong, Quang Duc; Nayuki, Keiichiro; Sasaki, Yukichi; Chiam, Sing Yang; Ren, Yi; Honma, Itaru; Barber, James; Artero, Vincent

doi:10.1038/nmat4588

Cited by 535 publications

(656 citation statements)

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“…In a recent report, Tran et al have identified the formation of metal hydrides from unsaturated Mo atoms as a key step in the HER mechanism from amorphous MoS x (ref. 48). Our results provide additional insight into the origin of HER activity of molybdenum sulfide catalysts and suggest that amorphous MoS x and MoS 2 nanosheets share a similar mechanism involving unsaturated Mo active sites.…”

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confidence: 56%

The role of electronic coupling between substrate and 2D MoS2 nanosheets in electrocatalytic production of hydrogen

et al. 2016

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The excellent catalytic activity of metallic MoS2 edges for the hydrogen evolution reaction (HER) has led to substantial efforts towards increasing the edge concentration. The 2H basal plane is less active for the HER because it is less conducting and therefore possesses less efficient charge transfer kinetics. Here we show that the activity of the 2H basal planes of monolayer MoS2 nanosheets can be made comparable to state-of-the-art catalytic properties of metallic edges and the 1T phase by improving the electrical coupling between the substrate and the catalyst so that electron injection from the electrode and transport to the catalyst active site is facilitated. Phase-engineered low-resistance contacts on monolayer 2H-phase MoS2 basal plane lead to higher efficiency of charge injection in the nanosheets so that its intrinsic activity towards the HER can be measured. We demonstrate that onset potentials and Tafel slopes of ∼-0.1 V and ∼50 mV per decade can be achieved from 2H-phase catalysts where only the basal plane is exposed. We show that efficient charge injection and the presence of naturally occurring sulfur vacancies are responsible for the observed increase in catalytic activity of the 2H basal plane. Our results provide new insights into the role of contact resistance and charge transport on the performance of two-dimensional MoS2 nanosheet catalysts for the HER.

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The role of electronic coupling between substrate and 2D MoS2 nanosheets in electrocatalytic production of hydrogen

et al. 2016

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“…[1][2][3] Among sustainable energy systems, photoelectrochemical (PEC) splitting water into hydrogen and oxygen is a potential way for solar energy conversion and storage. [1][2][3] Among sustainable energy systems, photoelectrochemical (PEC) splitting water into hydrogen and oxygen is a potential way for solar energy conversion and storage.…”

Section: Introductionmentioning

confidence: 99%

Metal–Organic Framework Derived Co₃O₄/TiO₂/Si Heterostructured Nanorod Array Photoanodes for Efficient Photoelectrochemical Water Oxidation

Tang

Zhou

Yuan

et al. 2017

Adv Funct Materials

128

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The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10. 1002/adfm.201701102. photoexcitation of semiconductor photoanode; the separation and migration of photoinduced carriers; the surface water reduction on the cathode; and water oxidation on the photoanode with photoinduced electrons/holes. [8][9][10] Therefore, to achieve effective solar-to-hydrogen (STH) process, all steps stated above should be in very efficient progress, which requires high optical response for the photoanode materials, [11] efficient carrier separation, and surface reaction. [12,13] Metal oxides (MOs), such as TiO 2 , [14] α-Fe 2 O 3 , [15] and WO 3 , [16,17] have been widely investigated as the photoanode materials for PEC water splitting, for their low-cost, environmentfriendly properties. However, as intrinsic semiconductor, the PEC performance of pristine MO photoanode is always hindered by the poor carrier mobility, narrow optical-response range, and slow surface water oxidation kinetics. [18,19] Therefore, designing composited photoanodes with proper band-gap energy structure is considered to be a promising route to overcome these limitations induced poor PEC performance. [20][21][22] For instance, via constructing semiconductor heterojunction with matched band position, the separation and transportation of photoinduced carrier can be effectively enhanced (such as Bi 2 MoO 6 /Si, [23] Ag/Fe 2 O 3 , [24] NiFe-LDH/C 3 N 4[25] heterojunction). Particularly, benefiting from the outstanding visiblelight response performance and carrier mobility within silicon, it has long been regarded as the most suitable material to build the solar energy conversion device. [26] As the conduction band (CB) of silicon is more negative than most of the common MO semiconductors (e.g., TiO 2 , [27,28] WO 3 ), [29] silicon can bring better electron reduction kinetics on the counter electrode. [30] However, it is not efficient to directly use only silicon as anode for PEC water oxidation due to the valence band (VB) of silicon is higher than the water oxidation potential. [23,31] In this regard, constructing MO/Si heterostructured photoanode is proposed to overcome the potential shortcomings of both MO and silicon simultaneously. To further improve the surface water oxidation kinetics of photoanode, introducing oxygen evolution reaction (OER) cocatalysts is regarded as a promising way to accelerate the four-electron water oxidation kinetics during the water splitting process. [8,32,33] Recently, the outstanding OER performance Water Splitting

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“…[7][8][9] Recently, there have been important fi ndings regarding (i) the use of amorphous molybdenum sulfi de (a-MoS x ) catalysts for HER [10][11][12][13][14] which exhibits signifi cantly higher HER electrocatalytic activity than its crystalline molybdenum disulfi de [ 15 ] and (ii) the use of Co-based layered double hydroxide for OER due to the formation of catalytic active Co species layer on the surface when driven by electrical energy, [16][17][18][19][20] and (iii) the ability of its layered structure to facilitate the diffusion and proton-coupled electron transfer of electrolytes. [7][8][9] Recently, there have been important fi ndings regarding (i) the use of amorphous molybdenum sulfi de (a-MoS x ) catalysts for HER [10][11][12][13][14] which exhibits signifi cantly higher HER electrocatalytic activity than its crystalline molybdenum disulfi de [ 15 ] and (ii) the use of Co-based layered double hydroxide for OER due to the formation of catalytic active Co species layer on the surface when driven by electrical energy, [16][17][18][19][20] and (iii) the ability of its layered structure to facilitate the diffusion and proton-coupled electron transfer of electrolytes.…”

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confidence: 99%

One‐Step Synthesis of CoS‐Doped β‐Co(OH)₂@Amorphous MoS₂₊_x Hybrid Catalyst Grown on Nickel Foam for High‐Performance Electrochemical Overall Water Splitting

Yoon

Kim

2016

Adv Funct Materials

230

109

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wileyonlinelibrary.comHence, developing effi cient and economical electrocatalysts for overall water splitting is one of the main challenges of current research. [7][8][9] Recently, there have been important fi ndings regarding (i) the use of amorphous molybdenum sulfi de (a-MoS x ) catalysts for HER [10][11][12][13][14] which exhibits signifi cantly higher HER electrocatalytic activity than its crystalline molybdenum disulfi de [ 15 ] and (ii) the use of Co-based layered double hydroxide for OER due to the formation of catalytic active Co species layer on the surface when driven by electrical energy, [16][17][18][19][20] and (iii) the ability of its layered structure to facilitate the diffusion and proton-coupled electron transfer of electrolytes. [ 21 ] However, bifunctional electrocatalysts which are effective for both HER and OER in the same electrolyte environment remain underdeveloped. Such bifunctional electrocatalysts can lead to high performance catalytic activity with drastic cost reduction when applied to the alkaline water splitting which is getting the spotlight as a strong candidate for commercializing large-scale production of hydrogen and oxygen. [22][23][24][25][26][27] Here we demonstrate that the hybrid containing cobalt and molybdenum is a highly active and stable catalyst for both HER and OER in alkaline media. In particular, the HER catalytic activity shows an overpotential of 143 mV at a current density of 10 mA cm −2 for mass loading of 0.2 mg cm −2 (as compared with an overpotential of 70 mV by 20% Pt/C) and the OER catalytic activity shows an overpotential of 380 mV at a current density of 10 mA cm −2 for mass loading of 0.2 mg cm −2 (as compared with overpotential of 325 mV by IrO 2 ). Furthermore, in a two-electrode system of the catalyst, an overpotential of only 1.58 V was required for overall water splitting at a current density of 10 mA cm −2 as well as durability at 1.6-1.8 V during 100 000 s. This performance makes the CoS  Co(OH) 2 @aMoS 2+ x /NF hybrid catalyst as one of the best overall water splitting catalysts. The origins of specialized active species for HER and OER are probed.Developing effi cient and economical electrocatalysts for hydrogen evolution reaction and oxygen evolution reaction with readily available metals is one of the main challenges for large scale hydrogen/oxygen production. This study reports one step synthesis of cobalt and molybdenum hybrid materials for high performance overall water splitting. The binder-free CoS-doped β-Co(OH) 2 @ amorphous MoS 2+ x is coated on nickel foam (NF) to form 3D networked nanoplates that have large surface area and high durability for electrochemical reactions. The catalytic activity of electrocatalyst for hydrogen evolution is mainly attributed to the unsaturated sulfur site of amorphous MoS 2+ x . Meanwhile, the CoS-doped β-Co(OH) 2 plays the major role in oxygen evolution. CoS-doped β-Co(OH) 2 and aMoS 2+ x are strongly bound to each other due to CoS x bridging. This CoS  Co(OH) 2 @aMoS 2+ x /NF hybrid exhibits excel...

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Coordination polymer structure and revisited hydrogen evolution catalytic mechanism for amorphous molybdenum sulfide

Cited by 535 publications

References 52 publications

The role of electronic coupling between substrate and 2D MoS2 nanosheets in electrocatalytic production of hydrogen

The role of electronic coupling between substrate and 2D MoS2 nanosheets in electrocatalytic production of hydrogen

Metal–Organic Framework Derived Co₃O₄/TiO₂/Si Heterostructured Nanorod Array Photoanodes for Efficient Photoelectrochemical Water Oxidation

One‐Step Synthesis of CoS‐Doped β‐Co(OH)₂@Amorphous MoS₂₊_x Hybrid Catalyst Grown on Nickel Foam for High‐Performance Electrochemical Overall Water Splitting

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Coordination polymer structure and revisited hydrogen evolution catalytic mechanism for amorphous molybdenum sulfide

Cited by 535 publications

References 52 publications

The role of electronic coupling between substrate and 2D MoS2 nanosheets in electrocatalytic production of hydrogen

The role of electronic coupling between substrate and 2D MoS2 nanosheets in electrocatalytic production of hydrogen

Metal–Organic Framework Derived Co3O4/TiO2/Si Heterostructured Nanorod Array Photoanodes for Efficient Photoelectrochemical Water Oxidation

One‐Step Synthesis of CoS‐Doped β‐Co(OH)2@Amorphous MoS2+x Hybrid Catalyst Grown on Nickel Foam for High‐Performance Electrochemical Overall Water Splitting

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Metal–Organic Framework Derived Co₃O₄/TiO₂/Si Heterostructured Nanorod Array Photoanodes for Efficient Photoelectrochemical Water Oxidation

One‐Step Synthesis of CoS‐Doped β‐Co(OH)₂@Amorphous MoS₂₊_x Hybrid Catalyst Grown on Nickel Foam for High‐Performance Electrochemical Overall Water Splitting