CeO2 nanoparticle-decorated reduced graphene oxide as an efficient bifunctional electrocatalyst for oxygen reduction and evolution reactions

Highly efficient bifunctional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are essential for the development of renewable energy technologies such as fuel cells and metal-air batteries. Herein, a ceria (CeO2) - modified reduced graphene oxide (CeO2/rGO) nanocomposite was fabricated via a facile yet cost-effective method under a mild condition. The prepared CeO2/rGO nanocomposite showed remarkable catalytic activity, high tolerance to methanol and durability toward ORR in alkaline media. Meanwhile, the catalyst also displayed remarkable activity for the OER with more negative onset potential and higher current compared with commercial Pt/C catalyst. The high oxygen reaction activity of the catalyst could contribute to synergistic effect of the combination of the oxygen vacancies of CeO2 and excellent electronic conductivity of rGO. The results suggested that the CeO2/rGO nanocomposite has potential advantages as a bifunctional electrocatalyst in the practical applications.