Se-Doped Ni₅P₄ Nanocatalysts for High-Efficiency Hydrogen Evolution Reaction

Increasing energy consumption and environmental pollution problems have forced people to turn their attention to the development and utilization of hydrogen energy, which requires that hydrogen energy can be efficiently prepared. However, the sluggish kinetics of hydrogen evolution reaction (HER) requires higher overpotential. It is urgent to design and fabricate catalysts to drive the procedure and decrease the overpotential of HER. It is well known that platinum catalysts are the best for HER, but their high cost limits their wide application. Transition metals such as Fe, Co, Mo and Ni are abundant, and transition metal phosphides are considered as promising HER catalysts. Nevertheless, catalysts in powder form are very easily soluble in the electrolyte, which leads to inferior cycling stability. In this work, Ni5P4 anchored on Ni foam was doped with Se powder. After SEM characterization, the Ni5P4-Se was anchored on Ni foam, which circumvents the use of the conductive additives and binder. The Ni5P4-Se formed a porous nanosheet structure with enhanced electron transfer capability. The prepared Ni5P4-Se exhibited high electrochemical performances. At 10 mA cm−2, the overpotential was only 128 mV and the Tafel slope is 163.14 mV dec−1. Additionally, the overpotential was stabilized at 128 mV for 30 h, suggesting its excellent cycling stability. The results show that Se doping can make the two phases achieve a good synergistic effect, which makes the Ni5P4-Se catalyst display excellent HER catalytic activity and stability