Silica‐Free Synthesis of Mesoporous Co3O4/CoOxPy as a Highly Active Oxygen Evolution Reaction Catalyst

Abstract Highly active and stable catalysts towards electrochemical oxygen evolution reaction are crucial for the efficient water splitting and sustainable hydrogen generation. Here we report a novel mesoporous Co 3 O 4 with the surface decoration of mixed CoO x P y species towards efficient OER catalysis. The material is synthesized from a simple carbon template derived from p‐phenylenediamine bisulfate followed by low temperature phosphorization. Unlike traditional methods, silica intermediates are not involved during synthesis, improving the overall safety and efficiency. The as‐prepared mesoporous Co 3 O 4 /CoO x P y catalyst shows excellent catalytic activity and stability towards oxygen evolution reaction in 1 M KOH. The overpotential is 295 mV at 10 mA cm −2 , superior to that of commercial IrO 2 /C catalyst. A small Tafel slope of 70 mV dec −1 and high stability are also observed. The excellent electrochemical performance is attributed to the mesoporous structure, strong electronic interaction, and synergistic effect of the mesoporous Co 3 O 4 and CoO x P y phases. Other heterogeneous catalysts with similar structures and compositions may also be fabricated following the same design principle.