Interface Engineering for Improved Large-Current Oxygen Evolution via Partial Phosphorization of Ce-MOF/NiCo-MOF Heterostructure

Interface engineering for electrocatalysts has proven to be an effective method for modulating electrocatalytic properties, yet a more efficient and straightforward strategy to construct a valid heterointerface for further enhancing interface effects is urgently needed for boosting oxygen evolution reactions (OER) at large current. Herein, a closely compacted heterostructure combining NiCo-metal-organic framework (MOF) and Ce-MOF is in situ formed through a one-step hydrothermal treatment, and partial phosphorization is employed to further enhance the interface effect between the newly formed urchin-shaped NiCoP shells and hexagonal rod-like Ce-MOF cores on nickel foam (NiCoP/Ce-MOF@NF). Experimental and theoretical results indicate that the heterogeneous NiCoP/Ce-MOF@NF, characterized by a more intensive interface rather than a simple physical mixture, generates an OER-beneficial electronic structure, significantly facilitates charge transfer and reaction kinetics, and creates a synergistically stable structure. The optimal NiCoP/Ce-MOF@NF exhibits remarkable electrocatalytic activity for OER, achieving an ultralow overpotential of 268 mV at a current density of 500 mA cm⁻², and also delivers satisfactory large-current stability of up to 120 h. This work offers a novel approach for designing heterogeneous catalysts with strong interface effects for potential applications in industrial water electrolysis.