General approach to construct hierarchical-structured porous Co–Ni bimetallic oxides for efficient oxygen evolution

Exploration of highly efficient and inexpensive water oxidation electrocatalysts is of importance for promoting sustainable electrochemical energy storage and conversion technologies. Herein, we put forward a general and controllable synthetic strategy to produce a series of hierarchical-structured porous Co–Ni bimetallic oxides (CoNiOx) via facile topochemical transformation from various Co–Ni bimetallic coordination polymers. Our newly developed protocol can realize simultaneous manipulation over the chemical composition and architectural structure, thereby achieving abundant synergistically active sites, optimized electronic configuration, and favorable mass transfer for catalysis. With the above features, the resulting CoNiOx could manifest remarkable electrocatalytic performance towards the oxygen evolution catalysis, competing against the state-of-the-art transition metal-based catalysts reported to date and the noble metal benchmarks. This work presents a simple, yet an effective and comprehensive methodology to develop advanced noble metal-free OER electrocatalysts for future energy systems.