Boosting the efficiency and stability of cerium-doped trimetallic phosphides for overall water splitting

Transition metal phosphides (TMPs) are becoming attractive and cost-effective alternatives to noble-metal catalysts for efficient water splitting. We developed a cerium atom doping on the surface nanowire-structured trimetallic phosphide catalyst, Ce-(FeCoNi)P, grown directly on nickel foam (NF), featuring integrated Fe₂P, CoP, and Ni₂P crystalline phases. This significantly alters the electronic structure, enhances charge transfer, and boosts both catalytic activity and stability. Density functional theory indicates that Ce doping improves hydrogen adsorption and lowers energy barriers for hydrogen evolution. Notably, a significant charge transfer from Ce to P atoms occurs, and this charge redistribution may alter the electron density at the Co active sites, further promoting catalytic performance. Precise adjustment of precursor concentrations enables morphological control and optimization of electrocatalytic behavior. As a result, the Ce-(FeCoNi)P@NF catalyst achieves excellent water splitting performance, requiring only 1.42 V to reach 10 mA cm⁻² and maintaining 95 % of its initial activity after 200 h at 100 mA cm⁻² in alkaline media. Its performance surpasses standard Pt-C and RuO₂ catalysts, highlighting the potential of Ce-doped multimetal phosphides as efficient, durable electrocatalysts for sustainable hydrogen production.