Optimized electronic structure and p-band centre control engineering to enhance surface absorption and inherent conductivity for accelerated hydrogen evolution over a wide pH range

Abstract

Numerous experiments have demonstrated that an appropriate electronic configuration can effectively activate the electrocatalytic activity. However, systematic studies on the effects of non-metallic elemental doping and its p-orbital center (ε_p) on electrocatalysis have not yet been carried out. Combining theoretical and experimental methods, we demonstrate an electronic configuration and p-orbital center control engineering for promoting the HER course in both acid and alkaline solutions over group VA elements doped into the inert basal plane of nanoMoS₂. In acidic solutions, As-doped MoS₂ has the best electrocatalytic activity. Theoretically, the calculated ΔG_H of the As atom is only −0.07 eV, indicating that it has excellent catalytic performance. Furthermore, the p-orbital center under and near the Fermi level plays a significant role in the H adsorption course, and the closer the ε_p value is to the Fermi level, the weaker the H- non-metallic atom bond is. An appropriate ε_p can insure a proper strength of bond with H and further influence the catalytic activity of the HER. In alkaline solutions, P-doped MoS₂ has the best electrocatalytic activity, which is due to the engineering of water dissociation sites by doping P atoms into MoS₂ nanosheets. These findings pave the path to develop a rational strategy to trigger the activity of the inert basal plane of MoS₂, to enhance the conductivity of inherent MoS₂ towards the HER and provide a new idea that can be extended to other layered dichalcogenides.