Photoassisted Electrodeposition of Dual-Stabilized Medium-Entropy Films for Robust Water Electrolysis

Water electrolysis remains constrained in combining excellent catalytic activity with long-term robustness, as both are primarily hindered by insufficient intrinsic activity and the mechanical instability induced by poor catalyst adhesion. This work presents the preparation of a medium-entropy boride (Ce-MEB) film electrocatalyst by a one-step photoassisted electrodeposition strategy. This strategy ensures strong catalyst–substrate adhesion, thereby enhancing mechanical durability. Furthermore, Ce incorporation accelerates OH– adsorption kinetics and promotes in situ formation of active oxyhydroxides, contributing to enhanced electrochemical stability. Consequently, Ce-MEB offers an exceptional OER capability, only demanding an overpotential of 218 mV to afford 10 mA cm–2. This electrocatalyst also remained stable for over 550 h at 500 mA cm–2. Notably, its practical viability is evidenced by an anion exchange membrane water electrolyzer cell sustaining ampere-level current densities for over 160 h. This work introduces an efficient synthesis strategy for advanced entropy-engineered materials.