Hydrogen Evolution Reaction at Anion Vacancy of Two-Dimensional Transition-Metal Dichalcogenides: Ab Initio Computational Screening

Abstract

The catalytic activity for the hydrogen evolution reaction (HER) at the anion vacancy of 40 2D transition-metal dichalcogenides (TMDs) is investigated using the hydrogen adsorption free energy (Δ G) as the activity descriptor. While vacancy-free basal planes are mostly inactive, anion vacancy makes the hydrogen bonding stronger than clean basal planes, promoting the HER performance of many TMDs. We find that ZrSe and ZrTe have similar Δ G as Pt, the best HER catalyst, at low vacancy density. Δ G depends significantly on the vacancy density, which could be exploited as a tuning parameter. At proper vacancy densities, MoS, MoSe, MoTe, ReSe, ReTe, WSe, IrTe, and HfTe are expected to show the optimal HER activity. The detailed analysis of electronic structure and the multiple linear regression results identifies the vacancy formation energy and band-edge positions as key parameters correlating with Δ G at anion vacancy of TMDs.

In-situ visualization of hydrogen evolution sites on helium ion treated molybdenum dichalcogenides under reaction conditions

“…Again, the Au(111) substrate and the basal plane of MoSe 2 display almost no significant noise features in the tunneling current and hence no HER activity. Within the error of the potential of the platinum pseudo reference electrode, the onset potentials found for MoS 2 and MoSe 2 are in good agreement and corroborate theoretical predictions 40,50 and initial experimental results. 51 The natural question arises whether it is possible to create additional active sites on the basal planes of the investigated TMDCs to increase the overall activity.…”

Recent Progress of Vacancy Engineering for Electrochemical Energy Conversion Related Applications

“…[ 122 ] Recently, ionic vacancies, including anodic vacancies, cationic vacancies, and mixed vacancies, have been explored for HER with satisfactory electrocatalytic activity. [ 64,123 ] Promising results indicate the great potential of vacancies on promoting electrocatalytic performance ( Table 2 ).…”

Unveiling Electrochemical Reaction Pathways of CO2 Reduction to CN Species at S‐Vacancies of MoS2

“…[30] The range of charge states in the active site, either bare V S or adsorbed intermediate,d ependso ni ntermediates owing to the electronic coupling between the vacancya nd adsorbates. [22] For instance, *OCHO and *OH shifted down the a 1 state into the valence band whereas the e states remained within the band gap (see FigureS1a,b in the SupportingI nformation). Because an electron from the adsorbates occupied one of the e levels in the neutral state, the possible charge state was from À3t o+ 1f or these intermediates.A sa nother example, in the case of *O, no sub-gap states were identified (see Figure S1 ci nt he Supporting Information).…”

“…The range of charge states in the active site, either bare V S or adsorbed intermediate, depends on intermediates owing to the electronic coupling between the vacancy and adsorbates . For instance, *OCHO and *OH shifted down the a 1 state into the valence band whereas the e states remained within the band gap (see Figure S1 a, b in the Supporting Information).…”

“…[20] This implies that the active site is likely to be present at the basal plane rather than the edges. However,t he clean surfaceo fM oS 2 is known to be inert, [22] and thus, the natureo ft he active site responsible for CO 2 Rt o1 -propanol is still elusive.…”