Hierarchical Flower-like NiFeSbP Electrocatalyst toward Efficient and Stable Urea-Assisted Electrolytic Hydrogen Production

Designing high-performance electrocatalysts for water splitting and urea-assisted electrolysis is of great significance in the hydrogen production industry. Herein, a hierarchical flower-like NiFeSbP electrocatalyst with different Ni/Fe ratios was fabricated on a graphite bar (GB) through a one-step electrodeposition method. By optimizing and regulating the ratios of Ni and Fe in the composition, the NiFeSbP electrocatalyst exhibited excellent hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR) activities with overpotentials of 143, 323, and 272 mV at 100 mA·cm^–2, sequentially, and also demonstrated longevity for over 100 h in an alkaline solution. More impressively, a symmetrical electrolyzer using NiFeSbP/GB as both the anode and cathode to afford a current density of 10 mA·cm^–2 needs 1.72 V for overall water splitting and 1.54 V for urea-assisted electrolysis. The superior catalytic performances of the NiFeSbP/GB catalyst in the urea-added water electrolysis mainly benefit from the synergistic effect between tricomponent metal catalytic centers (Ni, Fe, and Sb) and P atoms, which modulates the chemical and electronic structure of the catalyst. This work opens up new prospects for the rational design of versatile and stable UOR electrocatalysts for hydrogen generation in an efficient manner.