Basal Plane Activation in Monolayer MoTe2 for Hydrogen Evolution Reaction via Phase Boundaries

Author(s):  
Yiqing Chen ◽  
Pengfei Ou ◽  
Xiaohan Bie ◽  
Jun Song

<p>Two-dimensional transition metal dichalcogenides (2D TMDCs) have attracted tremendous interest as one prominent material group promising inexpensive <a>electrocatalysts for hydrogen evolution reaction (HER)</a>. In the present study, using <a>monolayer MoTe<sub>2</sub> as a representative, we demonstrated that </a>phase boundaries can provide a viable pathway to activate the basal plane of 2D TMDCs for enhanced HER performance. Comprehensive first-principles calculations have been performed to examine the energetics and structural stabilities of possible 2H/1T’ phase boundary configurations. Three categories of sites, Te, Mo and hollow sites, have been identified in energetically stable phase boundaries, as potential catalytic centers for HER, all indicating enhanced HER activity than the pristine basal lattice. In particular, the hollow sites, a new group of sites induced by phase boundaries, show great promise by exhibiting a Gibbs free energy near the thermoneutral value for hydrogen adsorption, comparable to that of Pt. The mechanisms underlying hydrogen adsorption at phase boundaries were then revealed, shown to be attributed to the unique local hydrogen adsorption geometries and electronic structures at phase boundaries. Our study clarifies the important mechanistic aspects underlying hydrogen activation at phase boundaries, providing valuable theoretical insights towards designing new class of high-performance HER electrocatalysts based on 2D TMDCs.</p>

2020 ◽  
Author(s):  
Yiqing Chen ◽  
Pengfei Ou ◽  
Xiaohan Bie ◽  
Jun Song

<p>Two-dimensional transition metal dichalcogenides (2D TMDCs) have attracted tremendous interest as one prominent material group promising inexpensive <a>electrocatalysts for hydrogen evolution reaction (HER)</a>. In the present study, using <a>monolayer MoTe<sub>2</sub> as a representative, we demonstrated that </a>phase boundaries can provide a viable pathway to activate the basal plane of 2D TMDCs for enhanced HER performance. Comprehensive first-principles calculations have been performed to examine the energetics and structural stabilities of possible 2H/1T’ phase boundary configurations. Three categories of sites, Te, Mo and hollow sites, have been identified in energetically stable phase boundaries, as potential catalytic centers for HER, all indicating enhanced HER activity than the pristine basal lattice. In particular, the hollow sites, a new group of sites induced by phase boundaries, show great promise by exhibiting a Gibbs free energy near the thermoneutral value for hydrogen adsorption, comparable to that of Pt. The mechanisms underlying hydrogen adsorption at phase boundaries were then revealed, shown to be attributed to the unique local hydrogen adsorption geometries and electronic structures at phase boundaries. Our study clarifies the important mechanistic aspects underlying hydrogen activation at phase boundaries, providing valuable theoretical insights towards designing new class of high-performance HER electrocatalysts based on 2D TMDCs.</p>


2020 ◽  
Vol 8 (37) ◽  
pp. 19522-19532
Author(s):  
Yiqing Chen ◽  
Pengfei Ou ◽  
Xiaohan Bie ◽  
Jun Song

The 2H/1T′ phase boundary activated hydrogen evolution reaction on two-dimensional transition metal dichalcogenides is well studied by comprehensive first-principles calculations.


2021 ◽  
Author(s):  
Zhenbin Wang ◽  
Michael Tang ◽  
Ang Cao ◽  
Karen Chan ◽  
Jens Kehlet Nørskov

<p>Understanding the hydrogen evolution reaction (HER) behaviors over 2D transition metal dichalcogenides (2D-TMDs) is critical for the development of non-precious HER electrocatalysts with better activity. In this work, by combining density functional theory calculations with microkinetic modelling, we thoroughly investigated the HER mechanism on 2D-TMDs. We find there is an important dependence of simulated cell size on the calculated hydrogen adsorption energy and the activation barrier for MoS<sub>2</sub>. Distinct from previous “H migration” mechanisms proposed for the Heyrovsky reaction − the rate-determining step for MoS<sub>2</sub>, we propose the Mo site only serves as the stabilized transition state rather than H adsorption. In comparison to transition metal electrocatalysts, we find that the activation barrier of the Heyrovsky reaction on 2D-TMDs scales with the hydrogen adsorption energy exactly as for transition metals except that all activation energies are displaced upwards by <i>ca.</i> 0.4 eV. This higher Heyrovsky activation barrier is responsible for the substantially lower activity of 2D-TMDs. We further show that this higher activation barrier stems from the more positively charged adsorbed hydrogen on the chalcogenides interacting repulsively with the incoming proton. Based on these insights, we discuss potential strategies for the design of non-precious HER catalysts with activity comparable to Pt.</p>


2020 ◽  
Vol 10 (9) ◽  
pp. 3087 ◽  
Author(s):  
Hagyeong Kwon ◽  
Dongyeon Bae ◽  
Hyeyoung Jun ◽  
Byungdo Ji ◽  
Dongyeun Won ◽  
...  

We report the electrochemical hydrogen evolution reaction (HER) of two-dimensional metallic transition metal dichalcogenides (TMDs). TMTe2 (TM: Mo, W, and V) single crystals were synthesized and characterized by optical microscopy, X-ray diffraction, and electrochemical measurements. We found that TMTe2 acts as a HER-active catalyst due to the inherent catalytic activity of its basal planes. Among the three metallic TMTe2, VTe2 shows the best HER performance with an overpotential of 441 mV and a Tafel slope of 70 mV/dec. It is 668 mV and 137 mV/dec for MoTe2 and 692 mV and 169 mV/dec for WTe2. Even though VTe2 has the lowest values in the exchange current density, the active site density, and turn-over-frequency (TOF) among the three TMTe2, the lowest charge transfer resistance (RCT) of VTe2 seems to be critical to achieving the best HER performance. First-principles calculations revealed that the basal-plane-active HER performance of metallic TMDs can be further enhanced with some Te vacancies. Our study paves the way to further study of the inherent catalytic activity of metallic 2D materials for active hydrogen production.


2018 ◽  
Vol 6 (41) ◽  
pp. 20005-20014 ◽  
Author(s):  
Seung Hyo Noh ◽  
Jeemin Hwang ◽  
Joonhee Kang ◽  
Min Ho Seo ◽  
Daehyeon Choi ◽  
...  

This study establishes big data for the catalytic properties of two-dimensional metal-dichalcogenides (2D-TMDs) toward the hydrogen evolution reaction (HER). In addition to conventionally known active sites of edges, it proposes that terrace sites (or the basal plane) can be substantially activated for the HER.


2017 ◽  
Vol 19 (15) ◽  
pp. 10125-10132 ◽  
Author(s):  
Jinsong Wang ◽  
Jia Liu ◽  
Bao Zhang ◽  
Xiao Ji ◽  
Kui Xu ◽  
...  

Two-dimensional transition metal dichalcogenides (TMDs) have been widely considered as potential hydrogen evolution reaction (HER) catalysts because of their low cost and good electrochemical stability in acid conditions.


2021 ◽  
Author(s):  
Zhenbin Wang ◽  
Michael Tang ◽  
Ang Cao ◽  
Karen Chan ◽  
Jens Kehlet Nørskov

<p>Understanding the hydrogen evolution reaction (HER) behaviors over 2D transition metal dichalcogenides (2D-TMDs) is critical for the development of non-precious HER electrocatalysts with better activity. In this work, by combining density functional theory calculations with microkinetic modelling, we thoroughly investigated the HER mechanism on 2D-TMDs. We find there is an important dependence of simulated cell size on the calculated hydrogen adsorption energy and the activation barrier for MoS<sub>2</sub>. Distinct from previous “H migration” mechanisms proposed for the Heyrovsky reaction − the rate-determining step for MoS<sub>2</sub>, we propose the Mo site only serves as the stabilized transition state rather than H adsorption. In comparison to transition metal electrocatalysts, we find that the activation barrier of the Heyrovsky reaction on 2D-TMDs scales with the hydrogen adsorption energy exactly as for transition metals except that all activation energies are displaced upwards by <i>ca.</i> 0.4 eV. This higher Heyrovsky activation barrier is responsible for the substantially lower activity of 2D-TMDs. We further show that this higher activation barrier stems from the more positively charged adsorbed hydrogen on the chalcogenides interacting repulsively with the incoming proton. Based on these insights, we discuss potential strategies for the design of non-precious HER catalysts with activity comparable to Pt.</p>


CrystEngComm ◽  
2021 ◽  
Author(s):  
Qian Zhang ◽  
Shuihua Tang ◽  
Lieha Shen ◽  
Weixiang Yang ◽  
Zhen Tang ◽  
...  

Developing cost-effective and high-performance electrocatalysts for hydrogen evolution reaction (HER) are imperative thanks to rapid increase of fuel-cell driven vehicles. Tungsten (W) possesses advantages of optimized hydrogen adsorption energy and...


Nanoscale ◽  
2021 ◽  
Author(s):  
Albert Bruix ◽  
Jeppe Vang Lauritsen ◽  
Bjork Hammer

Nanomaterials based on MoS2 and related transition metal dichalcogenides are remarkably versatile; MoS2 nanoparticles are proven catalysts for processes such as hydrodesulphurization and the hydrogen evolution reaction, and transition metal...


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