One-pot solvothermal synthesis of mixed Cu-Ce-O_x nanocatalysts and their catalytic activity for low temperature CO oxidation

摘要

One-pot solvothermal method has been developed for the synthesis of high-surface area Cu-Ce-O_x binary nanocatalysts with various Cu contents in the presence of oleylamine as capping agent. The obtained binary nanocatalysts were characterized by different techniques including XRD, H2-TPR, TEM, BET and XPS. The influence of Cu contents on their catalytic performance for the CO oxidation was also studied. Our results revealed that the Cu-Ce-O_x binary nanocatalysts show the better catalytic activity compared to those of the conventional Cu-Ce-O_x, bare nano-CeO2 and nano-CuO catalysts. This is ascribed to mutual interaction and synergistic effect between copper oxide species and cerium oxide. Among the obtained nanocatalysts, the Cu-Ce-O_x nanocatalyst with 5.6 wt % Cu (noted as 5.6-Cu-Ce-O_x) exhibits the best catalytic activity; the 50% CO conversion can be reached at 55 °C. H2-TPR profiles show two reduction peaks at low and high temperatures for these catalysts, which could be attributed to the reduction of highly dispersed CuO on the CeO2 surface and the bulk-like CuO species, respectively. Using the one-pot solvothermal synthesis developed in this study, 6-8 wt% Cu content is needed for the high catalytic activity for the CO oxidation at low temperature.