Transition metal doped WSi2N4 monolayer for water splitting electrocatalysts: a first-principles study

High-performance water splitting electrocatalysts are urgently needed in the face of the environmental degradation and energy crisis. The first principles method was used in this study to systematically examine the electronic characteristics of transition metal (Sc, Ti, V, Cr, Mn, Fe, and Ru) doped WSi₂N₄(TM@WSi₂N₄) and its potential as oxygen evolution reaction (OER) catalysts. Our study shows that the doping of TM atoms significantly improves the catalytic performance of TM@WSi₂N₄, especially Fe@WSi₂N₄shows a low overpotential (η_OER= 470 mV). Interestingly, we found that integrated-crystal orbital Hamilton population and d-band center can be used as descriptors to explain the high catalytic activity of Fe@WSi₂N₄. Subsequently, Fe@WSi₂N₄exhibits the best hydrogen evolution reaction (HER) activity with a universal overpotential of 47 mV on N₁sites. According to our research, Fe@WSi₂N₄offers a promising substitute for precious metals as a catalyst for overall water splitting with low OER and HER overpotentials.