Facile hydrothermal synthesis of 3D flower-like NiCo2O4/CeO2 composite as effective oxygen reduction reaction catalyst

Exploiting high-performance and cost-effective non-noble metal catalysts for oxygen reduction reaction (ORR) is still greatly important for energy storage devices such as metal-air batteries and fuel cells. In this work, CeO2, NiCo2O4, and NiCo2O4/CeO2 were synthetized by facile hydrothermal method and used as an ORR catalyst. The as-prepared CeO2, NiCo2O4, and NiCo2O4/CeO2 samples were measured by XRD, XPS, SEM, and TEM. Electrochemical characterization tests exhibit that the ORR activity of NiCo2O4 is evidently enhanced by blending with CeO2 nanoparticles. The NiCo2O4/CeO2 composite exhibits more superior electrocatalytic performances and stability in alkaline solution as compared to the pure CeO2 and NiCo2O4. The electrochemical performance of composite is very near to that of 20 wt% Pt/C. Owing to the synergistic interactions, NiCo2O4/CeO2 favors a four-electron pathway in ORR and exhibits a higher ORR activity than CeO2 and NiCo2O4. The outstanding performance confirms the NiCo2O4/CeO2 composite as a promising efficient ORR catalyst in metal-air batteries and fuel cells.