A γ to α type transition of CuO species over CeO2-SiO2 composites supported CuO catalysts

Abstract In this report, CeO 2 nanorods and SiO 2 nanospheres were mixed in various ratios and 10 wt% CuO were then impregnated onto these CeO 2 -SiO 2 composite supports using a thermal decomposition method to prepare supported catalysts. In these composites supported catalysts, SiO 2 nanospheres were used as both support and separator to enhance the dispersion and thermal stability of CeO 2 nanorods and CuO catalysts. The agglomeration degree of CeO 2 nanorods support significantly reduces by introducing SiO 2 nanospheres in the catalyst systems, which increases the chance to expose catalytically active low-index crystal facets (110, 100, and 111) of CeO 2 nanorods along with significant surface defects. Different interactions between CuO and SiO 2 nanospheres, CeO 2 nanorods and the CeO 2 -SiO 2 composite supports were identified, leading to the formation of α, β, and γ-type CuO species. A continuous transition of CuO species from β and γ-type CuO on SiO 2 nanospheres to α and β-type CuO on CeO 2 nanorods was discovered and correlated with H 2 -TPR, TEM and other characterization results.