Ni₅P₄-CeO₂ heterointerface-stabilized Ru nanoparticles for efficient electrochemical water splitting

Anion exchange membrane water electrolysis (AEMWE) represents a pivotal technology for green hydrogen production, yet its commercialization is still subjected to the development of electrocatalysts qualified for efficient and durable electrolysis. Herein, a Ru@Ni₅P₄-CeO₂/NF bifunctional electrocatalyst is rationally constructed via an innovative heterostructure engineering, featuring preferential anchoring of Ru nanoparticles at the Ni₅P₄-CeO₂ heterointerfaces grown on nickel foam (NF) for highly efficient and durable overall water splitting. In situ experimental results reveal that the strong interfacial coupling in Ru@Ni₅P₄-CeO₂/NF effectively modulates the local electronic structure of Ru nanoparticles, facilitates interfacial charge transfer and accelerates the hydrogen evolution reaction (HER) kinetics. For the oxygen evolution reaction (OER), the multicomponent synergistic interplay among RuO_x species, γ-NiOOH-CeO₂ heterointerface reconstructed from Ni₅P₄-CeO₂ and their strong interfacial coupling stabilizes high-valence metal centers and facilitates charge transport, ultimately leading to markedly improved OER kinetics. As a result, Ru@Ni₅P₄-CeO₂/NF exhibits outstanding bifunctional electrocatalytic performance, requiring overpotentials of only 30 ± 1 mV for HER and 220 ± 2 mV for OER at 10 mA cm^-2. More importantly, an AEMWE assembled with Ru@Ni₅P₄-CeO₂/NF as both the cathode and anode deliver an industrial-level current density of 1000 mA cm^-2 at a low cell voltage of 1.86 ± 0.01 V and maintains stable operation at 500 mA cm^-2 for 300 h with negligible degradation. This work demonstrates an effective heterointerface-engineering strategy for boosting electrochemical water splitting and provides a generalizable approach for designing multifunctional electrocatalysts toward practical AEMWE applications.