Enhancing the CO Preferential Oxidation (CO-PROX) of CuO–CeO2/Reduced Graphene Oxide (rGO) by Conductive rGO-Wrapping Based on the Interfacial Charge Transfer

Abstract

Reduced graphene oxide supported CuO–CeO2 nanospheres (CuO–CeO2/rGO) were prepared by a facile hydrothermal method. The chemically bonded CuO–CeO2/rGO composites effectively enhanced their activity in the CO preferential oxidation (CO-PROX), while moderate rGO content (7 mg) exhibited an improvement on the catalytic activity. The prepared composite with 14 wt% rGO showed the highest catalytic activity, exceeding that of pure CuO–CeO2 and mechanically mixed CuO–CeO2 and rGO, respectively. The enhancement in the CO-PROX activity was attributed to the synergetic effect between rGO and CuO–CeO2 nanospheres. Besides supported rGO layers as excellent electron transporters, CuO–CeO2 nanospheres in turn act as the skeleton to brace two-dimensional structure to prevent from further curling, crumpling and aggregation of rGO. In the presence of capping agents during synthesis, limited catalytic activities of CuO–CeO2/rGO was observed due to the restrained interfacial charge transfer between CuO–CeO2 and rGO layers. This work, focusing on effective CO-PROX through a chemically bonded interface between CuO–CeO2 and rGO, can provide a new insight for design of new heterogeneous catalysts. Chemical bonded CuO–CeO2/rGO nanocomposites synthesized by a facile hydrothermal approach have shown high CO-PROX activity. Excellent charge transport between rGO layers and CuO–CeO2 nanospheres via their interfaces leads to enhanced catalytic activity for CO-PROX.