Optimizing the activity of hydrogen evolution reaction through controllable synthesis of single crystal or polycrystalline NiXPy

A strategy approach to synthesizing nickel phosphide is essential for enhancing its electrocatalytic performance in hydrogen evolution reactions (HER) through water splitting. Different NiXPy compositions and phases display varying electrocatalytic properties. This study successfully synthesized various NiXPy (Ni2P-Ni (OH)2, Ni5P4-Ni2P, Ni5P4, and Ni2P-Ni12P5 by modulating key parameters. The synthesis of pure-phase Ni5P4/NF nanocrystalline with optimal Ni-P ratio achieved by controlling vital factors: phosphating temperature (350 degrees C) and phosphating duration (3 h), and the precursor to sodium hypophosphite ratio (1: 20). This approach yielded an overpotential of 106 mV at a current density of 10 mA cm-2 and high turnover frequencies (TOF) of 2.49 s-1. This method allows for precise control over the purity and stoichiometry of the nickel phosphide Ni-P ratio, facilitating in-depth investigations into their effects on HER.