MOF-on-MOF-derived hollow FeNi3/N-doped carbon nanorods for efficient oxygen evolution.

[Display omitted] • A hollow MOF-on-MOF nanostructure could be obtained by balanced etching and growth rate. • FeNi 3 -NC-700 endows rich N-doping, dispersive FeNi 3 particles, and large porosity. • The synergistic effect between Ni and Fe species greatly promotes water oxidation. To achieve the carbon peak and neutrality targets, the facile synthesis of highly active and robust catalysts for efficient oxygen evolution reaction (OER) is urgently demanded. Herein, a series of metal–carbon nanomaterials (FeNi 3 -NC-T , T = 600–1000 °C) with the hollow N-doped carbon nanorod incorporated FeNi 3 nanoparticles are reasonably prepared via balancing epitaxial growth and etching rate. These synthesized OER catalysts exhibit effective synergies of multiple components, large specific surface area, high conductivity, abundant exposed active sites, and intrinsic activity enhanced by carbon confinement and interconnected nanostructure. Among them, the optimized FeNi 3 -NC-700 only requires low overpotentials of 262/327 mV to reach the current density of 10/50 mA cm−2 in an alkaline medium, which is obviously better than these control samples. Owing to the aforesaid structural virtues, it exhibits high activity and good stability, fast catalytic kinetics and easy formation of active species evidenced by in-situ experiments as well as theoretical calculations. This study would provide a new idea for the easy fabrication of multifunctional MOF derivatives in electrochemistry with the desired properties. [ABSTRACT FROM AUTHOR]