Mass production of Co3O4@CeO2 core@shell nanowires for catalytic CO oxidation

In this study, Co3O4@CeO2 core@shell nanowires were successfully prepared via thermal decomposition of Co(CO3)0.5(OH)·0.11H2O@CeO2 core@shell nanowire precursors. As a CO oxidation catalyst, Co3O4@CeO2 shows remarkably enhanced catalytic performance compared to Co3O4 nanowires and CeO2 nanoparticles (NPs), indicating obvious synergistic effects between the two components. It also suggests that the CeO2 shell coating can effectively prevent Co3O4 nanowires from agglomerating, hence effecting a substantial improvement in the structural stability of the Co3O4 catalyst. Furthermore, the fabrication of the well-dispersed core@shell structure results in a maximized interface area between Co3O4 and CeO2, as well as a reduced Co3O4 size, which may be responsible for the enhanced catalytic activity of Co3O4@CeO2. Further examination revealed that CO oxidation may occur at the interface of Co3O4 and CeO2. The influence of calcination temperatures and the component ratio between Co3O4 and CeO2 were then investigated in detail to determine the catalytic performance of Co3O4@CeO2 core@shell nanowires, the best of which was obtained by calcination at 250 °C for 3 h with a Ce molar concentration of about 38.5%. This sample achieved 100% CO conversion at a reduced temperature of 160 °C. More importantly, more than 2.5 g of the Co3O4@CeO2 core@shell nanowires were produced in one pot by this simple process, which may be beneficial for practical applications as automobile-exhaust gas-treatment catalysts.