A review with transition-metal phosphide electrocatalysts in hydrogen evolution reaction: Doping perspective

With the soaring price of traditional energy and environmental pollution, it is important to find reliable and environmentally friendly clean energy. Transition Metal Phosphides (TMPs) have been shown to perform well compared to other non-precious metal catalysts for hydrogen evolution reaction (HER) electrocatalysts. The modifications of transition metal phosphides can obtain better catalytic performance. Among that, metal doping has become a commonly used method for modifying transition metal phosphides, because it can control the amount of doping and the synthesis method is simple. Metal atom doping greatly changes the intrinsic properties of transition metal phosphides, such as adding Electrochemical Active Surface Area (ESCA), adjusting the electronic structure, etc. Transition metal phosphides can also improve catalytic activity by constructing composite materials such as NiCoP/rGO. Polymetallic doping can also improve the catalytic performance of TMPs, such as CoMo(Al)-P. Through the synergy between polymetals, the catalytic activity of the catalyst is greatly improved. Therefore, it can be developed in the direction of high-entropy alloys to produce catalysts with excellent performance. And TMPs also have good catalytic activity in seawater, such as Fe–Co2P BNRs. A series of modification methods such as metal doping will greatly tap the hydrogen evolution reaction potential of transition metal phosphides, and are expected to be applied in industry.