Effect of surface reconstruction induced by different electrochemical methods on hydrogen evolution performance of Ni2P array catalysts

The design and development of electro-catalyts is of importance to the industrial hydrogen production through water splitting. Among various catalysts, nickel-based component has been widely applied due to its excellent catalytic performance. The activity of such catalyst could be improved relative chemical reactions, including Selenization, sulfurization, phosphating and hydroxylation, but their surface structure might be rebuilt, further affecting the catalytic performance. Herein, sheet-like phosphide-based material was synthesized on the nickel foam, and the phenomenon of surface rebuilding was investigated through three different electrochemical methods, chronoamperometry (It) and chronopotentiometry (CP), and Cyclic voltammetry (CV). Results showed the significantly difference in surface morphology due to the utilization of the three electrochemical methods. Crystal component could be completely transferred to amorphous after CP and It, with the reduction of overpotential by 44 and 49 mV respectively. Compared to these two electrochemical methods, CV could enable the occurrence of whole oxidative and reductive reactions on the surface, inducing the formation of heterostructure, crystal NiO and amorphous NiP, on the surface. This structure achieves 58 mV reduction of overpotential, which is 58 mV lower than precursor. And the stability test also showed only 0.08% of attenuation, indicating a better electrochemical performance.