Low-temperature CO oxidation over different CuO/CeO2 catalysts

CeO2 particles with different physical properties were prepared by thermal decomposition of cerous nitrate and then used as supports for CuO/CeO2 catalysts (CuO content was 6.3% based on the CeO2 mass) prepared by impregnation method. The CeO2 particles and CuO/CeO2 catalysts were comparatively investigated by XRD, HRTEM and TPR measurements. The catalytic properties of the 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 (such as morphology, particle size and distribution) of CeO2 particles. The loading of non-crystal CuO on the CeO2 Supports was different and it was the highest on the CeO2 prepared by thermal decomposition at 500 IC, and the corresponding CuO/CeO2 catalysts exhibited higher activity for CO oxidation than those with CeO2 prepared by thermal decomposition at 400 and 700 IC. A part of non-crystal CuO in CuO/CeO2 catalysts entered CeO2 lattice and the others dispersed over the CeO2 surface. When the calcination temperature was lower than 600 degrees C, it had little effect on the catalytic activity. However, high calcination temperature (e. g. 800 degrees C) resulted in a significant impact on the catalytic activity because of CeO2 crystal growth and CuO aggregation.