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Research Highlight

Optimal Electrocatalytic Hydrogen Evolution in 2D TMDs

Optimal Electrocatalytic Hydrogen Evolution in 2D TMDs
The Figure shows the linear correlation of charges on H and ∆GH in the H-Se bonded edges. The yellow boxes are results for non-stoichiometric edges and the basal plane and the white dash line indicates ∆GH of zero.

Scientific Achievement

Non-stoichiometric edges in 2D transition metal dichalcogenides  (TMDs) were created and demonstrated to have near optimal hydrogen evolution reaction (HER) activity (i.e., Gibbs free energy, ∆GH=0).

Significance and Impact

Compared to the stoichiometric TMD edges, there is a wider family of synthesizable non-stoichiometric TMD edges, where the degree of non-stoichiometry can be tuned to dial-in optimal HER activity.

Research Details

- Density functional theory (DFT) was used to study six non-stoichiometric MoSe2 edges that were recently synthesized under a scanning transmission electron microscope. - The high HER activities are not only attributed to the formation of the H-Se/Mo chemical bonds, but also governed by geometric reconstructions and charge redistributions of the edges after H adsorption.   Guoxiang Hu, Victor Fung, Xiahan Sang, Raymond R. Unocic, and P. Ganesh, "Superior Electrocatalytic Hydrogen Evolution at Engineered Non-Stoichiometric Two-Dimensional Transition Metal Dichalcogenide Edges," J. Mater. Chem. A (2019).  DOI: 10.1039/c9ta05546k