Cobalt-Doped Ceria/Reduced Graphene Oxide Nanocomposite as an Efficient Oxygen Reduction Reaction Catalyst and Supercapacitor Material

Design and development of highly active and durable oxygen reduction reaction (ORR) catalyst to replace Pt- and Pt-based materials are present challenges in fuel cell research including direct methanol fuel cells (DMFC). The methanol crossover and its subsequent oxidation at the cathode is another unwanted issue that reduces the efficiency of DMFC. Herein we report cobalt-doped ceria (Co-CeO2) as a promising electrocatalyst with competent ORR kinetics mainly through a four-electron reduction pathway, and it surpasses Pt/C by a great margin in terms of stability and methanol tolerance. The Co-CeO2 nanoparticles of diameter 4–7 nm were uniformly grown on reduced graphene oxide (rGO) by a facile single-step hydrothermal process. The as-synthesized Co-CeO2 nanoparticles/rGO nanocomposites are further demonstrated as active energy storage materials in supercapacitors, underscoring the importance of the studied materials in renewable energy industries.