Improved catalytic performance of monolayer nano-triangles WS₂ and MoS₂ on HER by 3d metals doping

Recently, monolayer transition metal dichalcogenides (TMDCs) such as MoS₂ and WS₂, exhibit distinguished catalytic performance on hydrogen evolution reaction (HER). Triangular shaped monolayers are the most popular morphology for the chemically synthesized monolayer-TMDCs. In this study, we find a way to further improve the catalytic performance of monolayer nano-triangles (mNT) MS₂ (M = W, Mo) on HER. By adopting the first-principles calculation methods based on the density functional theory, we studied the catalytic activity of the mNT MS₂ with the substitutional doping of Me (Me = Cr, Mn, Co) atoms on the edges. The detailed electronic structures were also investigated to better understand the catalytic activity. Our calculations show that the Me atoms doping on the edge changes the electronic states near the Fermi level. Additionally, the enhancement in the number of active sties and conductivity result in the improvement of the catalytic performance of mNT MS₂ on HER. More importantly, we demonstrate that the electronic structures and edge configurations, particularly the structures on the vertexes of the triangular mNT MS₂ are closely related to the edge composition.