Hydrogen evolution reaction activity enhancement from active site turnover mechanism

The active sites during the HER process have turnover by introducing Co into Ni 2 P, significantly boosting the efficiency of hydrogen generation . Although heteroatom doping is an effective way to improve the catalytic activity of transition metal phosphides (TMPs), the mechanism of activity enhancement needs to be further refined. To this end, we synthesized a Co-doped Ni 2 P catalyst as a research model and found that the introduction of heterogeneous Co reconstructed the charge distribution around the P site, which effectively enhanced the hydrogen evolution reaction (HER) activity of the pure Ni 2 P. Based on in-situ Raman real-time monitoring technology, we monitored for the first time that Co doping triggered a switch of the active site (from the original Co-active site to the P-active site), which promoted the adsorption of H 2 O to enhance the HER activity. The density functional theory (DFT) calculations indicated that the P site of Co-Ni 2 P expressed the highest activity and the Ni site of pure Ni 2 P expressed the highest activity, which further confirms the in-situ Raman monitoring results. The active site turnover mechanism discovered in this study will undoubtedly provide more rational and targeted ideas for future catalyst design.