Research on the Influence of Self-Reconstruction Engineering of Ni₂P Catalysts with Different Crystallinities in Alkaline Water Electrolysis for Oxygen Evolution Reaction

Ni₂P catalysts with different crystallinities in the oxygen evolution reaction (OER) and their effects on the catalytic performance were studied. The mechanism of enhancing the OER activity by the surface structure of the catalysts was explored, and Ni₂P catalysts with different crystallinities were synthesized via the hydrothermal method. The crystal layouts, morphological transformations, and electrochemical properties of the catalysts were analyzed by XRD, SEM, XPS, EIS, EPR, and electrochemical tests. The relationship between the formation of oxygen vacancies and the OER performance was investigated by simulating the reconstruction of the catalyst surface during potentiostatic discharge operation. The results show that Ni₂P catalysts with different crystallinities exhibit different surface reconstruction behaviors during the discharge process. In particular, more oxygen vacancies are derived on the surface of the LC-Ni₂P catalyst, which greatly improves the OER activity. In addition, the lower LSV overpotential significantly enhances the OER performance of the catalyst. The discharge process actively promotes the generation of oxygen vacancies and accelerates the charge transfer rate. The conclusions indicate that the surface reconstruction process and the formation of oxygen vacancies are the key factors for improving the OER performance of Ni₂P catalysts. Discharging in the low potential region can induce the formation of oxygen vacancies, thus enhancing the catalytic ability of the catalyst.