NiCoO₂@CMK-3 composite with nanosheets-mesoporous structure as an efficient oxygen reduction catalyst

Exploiting high efficient non-noble metal catalysts with low-cost and good stability for oxygen reduction reaction (ORR) is vital for fuel cells and metal-air batteries. In this work, we successfully constructed a novel nanosheets-shaped NiCoO₂ hierarchical structure supported on CMK-3 support (i.e., NiCoO₂@CMK-3 composite) via a facile hydrothermal method. Electrochemical characterization results reveal that the as-prepared NiCoO₂@CMK-3 composite exhibits remarkable ORR electrocatalytic activity with a positive peak potential of 0.81 V (vs. RHE), an onset potential of 0.90 V (vs. RHE), a high current density of 4.10 mA cm⁻² at 0.4 V, and a nearly four-electron reduction pathway, which are comparable to the state-of-the-art Pt/C catalyst with the same mass. In addition, the NiCoO₂@CMK-3 composite possesses excellent methanol-tolerance and electrochemical stability, which are better than Pt/C. The outstanding performance confirms the NiCoO₂@CMK-3 composite as a promising efficient ORR catalyst in fuel cells and metal-air batteries.