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.