Hierarchical bimetal embedded in carbon nanoflower electrocatalysts derived from metal-organic frameworks for efficient oxygen evolution reaction

Abstract Developing high-performance and cost-effective electrocatalysts for oxygen evolution reaction (OER) is crucial to renewable energy conversion and storage technologies. Herein, bimetallic N-doped carbon electrocatalysts with various morphologies are derived from Hofmann-type metal-organic frameworks by carbonization and oxidization. Notably, the flower-like nano-catalyst FeNi@OCNF exhibits core@shell structure, hierarchical pore network and large specific surface area (331.3 m2 g−1), leading to tunable electronic structure, efficient mass transfer as well as abundant exposed active sites. Moreover, the formative FeCx, NiO and FeNi bimetal mutually optimize electronic structure of graphitic layer, conducing to high property. FeNi@OCNF demonstrates an excellent OER performance with a low overpotential of 281 mV at 10 mA cm−2, signally outperforming the other catalyst CoNi@OCNP (373 mV) and commercial IrO2 (308 mV), and also owns long-term stability. The result may inspire more design of MOF-derived catalysts with multiscale structures and multi-components for various electrochemical energy conversion devices.