Insights into Hydrogen Evolution Reaction on 2D Transition Metal Dichalcogenides

26 May 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


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 MoS2. Distinct from previous “H migration” mechanisms proposed for the Heyrovsky reaction − the rate-determining step for MoS2, 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 ca. 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.


hydrogen evolution reaction
transition metal dichalcogenides
density functional theory
microkinetic modelling
electrochemical barrier
kinetic activity volcano

Supplementary materials

HER activity SI


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.