One-step Preparation Of CuO-CeO₂-ZrO₂ Catalysts For CO Oxidation

CuO-CeO2-ZrO2 catalyst is widely applied in CO oxidation because of its excellent catalytic activity. CuO-CeO2-ZrO2 catalysts are prepared by different methods. Textures and structures of the as-prepared catalysts were investigated by N2 adsorption-desorption, XRD, XPS, H2-TPR, CO-TPD and Raman techniques. The main contents in this paper include as follows:1. CuO-CeO2-ZrO2 catalysts were obtained via a solid state reactive method and tested for the CO oxidation. The effects of CuO content and calcination temperature on the physicochemical properties were investigated. The results show that the dispersion degree of CuO, SBET and the amount of adsorbed CO of the catalysts exhibit a volcano trend with increasing the CuO content and calcination temperature. The highest activity was achieved over the catalyst with 10 wt.% CuO and calcined at 500℃ with the conversion of CO being 99% at 85 ℃. The superior performance of the catalyst prepared by this method is attributed to the finely dispersed CuO species and the strong interaction of CuO with ceria-zirconia phase.2. A series of CuO-CeO2-ZrO2 catalysts were prepared through co-precipitate techniques and tested for CO oxidation. The effects of different precipitate agents on the physicochemical properties are ivestegated. The catalyst prepared by oxalate-gel method obtained high performance; the CO conversion reached 99% at 75℃ which is similar with the catalysts prepared by traditional coprecipation with NaOH or ammonia as precipitate agents. The superior performance of the catalysts prepared by these methods is attributed to the finely dispersed CuO species and the strong interaction of CuO with ceria-zirconia phase.3. A series of CuO-CeO2-ZrO2 catalysts were prepared via co-precipitate, practical soft reactive grinding route based on oxalate-precursor or citrate-precursor, sol-gel method and combustion method and tested for CO oxidation. The effects of different preparation methods on the physicochemical properties are studied. The results show that the highest dispersion degree of CuO, largest SBET (104.1 m2·g-1), the smallest crystalline size (8.86 nm) and the most amount of adsorbed CO were obtaine over the catalyst prepared by coprecipitation method and resulted in the higest activity. The finely dispersed CuO on the surface of the support and the Cu2+doped into the lattice of the support were responsible for the superior performance of the catalyst prepared by the coprecipatation.