Mechanistic Study on Electrocatalytic Hydrogen Evolution by High Efficiency Graphene/MoS2 Heterostructure

Improved efficiency of N-doped graphene in van der Waals heterostructure (vdW) for hydrogen evolution reaction (HER) can complement future hydrogen economy. The local electronic environment of layered graphene/MoS2 interface is significantly influenced by doping with foreign atoms. Moreover, electrochemical robust hydrogen evolution at basal planes of vdW heterostructure and the underneath atomic-scale reaction mechanism is yet to be realised. We have investigated the mechanism of substitutional N-doping and its catalytic efficiency towards HER process on the basis of density functional theory. By analysing the electronic structure, free-energy diagrams, Volmer reaction paths and volcano plot analysis, it is inferred that nitrogen doping on graphene layer significantly modulate the hydrogen binding energies resulting in numerous orders of magnitude enhancement in HER activity. This study shows an optimal way to tune hydrogen binding on graphene/MoS2 heterostructure, an efficient electrocatalyst tending towards the value gained by platinum.