Mo–Ni ₂ P/Co ₂ P Nanoheterostructure on Nickel Foam as Bifunctional Electrocatalysts for Efficient Water Splitting

Water electrolysis represents a promising method for producing hydrogen from renewable sources, yet its efficiency is limited by the high overpotentials and sluggish reaction kinetics of conventional catalysts. Herein, we report the rational design and synthesis of hierarchical nanoarchitectures featuring crystalline–amorphous Mo–Ni2P/Co2P heterostructures directly grown on nickel foam (NF). Electrochemical tests reveal exceptional performance: HER overpotentials of 70, 120, and 260 mV at 10, 100, and 300 mA·cm–2, respectively, which surpass those of most reported transition metal phosphides; and an OER overpotential of only 250 mV at 10 mA·cm–2. As a bifunctional catalyst in alkaline overall water splitting (OWS), the system maintains a stable operation for 100 h with only a 3.13% decay in voltage. By leveraging a porous Co-MOF as a sacrificial nanoscale template, we engineered abundant defects and macroporous frameworks, which facilitate the in situ formation of high-density crystalline–amorphous nanointerfaces. Concurrently, the multiphase interfaces within these heterostructures and the transition-metal-mediated synergistic effects enhance charge-transfer kinetics. This work contributes fundamental insights and establishes a paradigm for designing nonprecious electrocatalysts through phase engineering.