Efficient N-P type charge compensatory synergistic effect for hydrogen production from water splitting: Theoretical design of V/Nb-Re co-doping MoX(X=S or Se)2 photocatalyst

Abstract

The photocatalytic hydrogen evolution reaction (HER) is a promising method for solving the current environmental and energy crisis. Photocatalysts based on two-dimensional (2D) transition metal dichalcogenides (TMDCs) have received extensive attention in this field, and methods such as doping have been developed to further improve their photocatalytic efficiency. However, the photocatalytic efficiency is limited by the fact that the photogenerated carriers in a single doping system can easily recombine at impurity levels. Designing crystal structures of 2D TMDCs that can efficiently split water for hydrogen evolution is an important problem to solve for photocatalytic efficiency. Herein, we design the crystal structures of MoX(X=S or Se)2 co-doped with V/Nb and Re atoms using the density functional theory (DFT). Through N-P type co-doping, we deduce that this charge compensation effect indeed eliminates the impurity levels introduced by single-atom doping, not only expanding the visible light response range but also matching the thermodynamic conditions of photocatalytic water splitting, exhibiting excellent HER performance. The successful design of a V/Nb-Re co-doped MoX(X=S or Se)2 crystal structure is a key step for the practical application of 2D TMDC-based photocatalysts.