Barrier effect of SiO2 shell over hollow CeO2/CuO@SiO2 catalysts for broadening temperature window o

• 作 者: Jinfang Wu Xiaozhou Zhao Lei Xue Haiquan Su Shanghong Zeng
• 机 构: Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, School of Chemistry
• 出 处: 稀土学报（英文版）
• 发表日期: 2004年期
• 关键词: Hollow shell structure CeO2/CuO@SiO2 Barrier effect CO oxidation Rare earths

The hollow inverse CeO2/CuO@SiO2 catalysts with different Ce/Cu mass ratios were synthesized by the two-step hydrothermal and incipient wetness impregnation methods,and characterized by multitechnique characterizations,such as SEM,TEM,XRD,H2-TPR,XPS and N2 adsorption-desorption techniques.It is found that the hollow shell is composed of CuO and SiO2,and CeO2 nanoparticles are coated on the surface of CuO@SiO2 support.And the CeO2/CuO@SiO2 catalyst with the Ce/Cu mass ratios of 1∶1 denoted as 1CeO2/CuO@SiO2,which possesses a maximum amount of highly dispersed copper species and medium-sized CuO as well as the highest concentration of oxygen vacancies,exhibits the highest catalytic activity and widest full CO conversion window.The barrier effect of the SiO2 shell effectively prevents the reduction of CuO species,which broadens temperature window of CO total conversion and enhances CO2 selectivity above 155 ℃ over the 1CeO2/CuO@SiO2 catalyst in comparison with the CuO-CeO2 and CeO2-CuO catalysts.