Preparation and characterization of CuO/CeO2 catalysts and their applications in low-temperature CO oxidation

CeO2 nanoparticles were prepared by thermal decomposition of cerous nitrate and then used as supports for CuO/CeO2 catalysts prepared via the impregnation method. The samples were characterized by HRTEM, XRD, H2-TPR, and XPS. The catalytic properties of the prepared catalysts for low-temperature CO oxidation were studied by using a microreactor-GC system. The results showed that the thermal decomposition temperature affected the physical properties of the prepared CeO2 particles, such as particle size and morphology. The loading of CuO in non-crystalline forms on CeO2 supports was different in the CuO/CeO2 catalysts. The loading of non-crystalline CuO was higher on the CeO2 prepared via thermal decomposition at 500 °C than those on the CeO2 prepared via thermal decomposition at 400, 600 and 700 °C. One part of the non-crystalline CuO in CuO/CeO2 catalysts entered the CeO2 lattice and the other part dispersed over the CeO2 surface. Calcination temperature had little effect on the catalytic activity when it was lower than 600 °C. However, heating the catalysts to higher temperatures (i.e. 800 °C) had a significant impact on the catalytic activity because the crystallite size rapidly grows and more CuO and CeO2 phase-separation occurs.