CeO2 Nanowires Inserted into Reduced Graphene Oxide as Active Electrocatalyst for Oxygen Reduction Reaction
Fabrication of an interconnected and conductive nano-architecture is a prospective strategy to design a high-performance and low cost electrocatalyst for oxygen reduction reaction (ORR). Herein, a novel nano-architecture assembled by graphene nanosheets and CeO2 nanowires (NWs) with a hierarchical structure was developed by a facile hydrothermal process using ethanol/water as solvents without any organic additives. In this framework, graphene oxide (GO) was reduced to graphene and chemical bonding formed between the GO and CeO2 NWs in a hydrothermal process. The imbedded CeO2 NWs could prevent the restacking of the graphene sheets and improved the electrical conductivity of the hybrid catalyst. The effect of different ratios of GO to CeO2 NWs in the hybrid were studied. The GO3-CeO2 NWs composite exhibited better catalytic performance with slow attenuation and high limiting current density 3.55 and 1.99 times higher than CeO2 NWs and pure GO. The onset potential of GO3-CeO2 NWs is 0.13 V and 0.05 V positive shift from that of CeO2 NWs and pure GO, respectively, suggesting that the GO3-CeO2 NWs hybrid had an excellent stability and activity for ORR. It was found that CeO2 NWs served not only as an effective catalyst but also as an “oxygen buffer” to relieve oxygen insufficiency for ORR.
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