Effects of the Crystalline Properties of Hollow Ceria Nanostructures on a CuO-CeO Catalyst in CO Oxidation.

The development of an efficient and economic catalyst with high catalytic performance is always challenging. In this study, we report the synthesis of hollow CeO nanostructures and the crystallinity control of a CeO layer used as a support material for a CuO-CeO catalyst in CO oxidation. The hollow CeO nanostructures were synthesized using a simple hydrothermal method. The crystallinity of the hollow CeO shell layer was controlled through thermal treatment at various temperatures. The crystallinity of hollow CeO was enhanced by increasing the calcination temperature, but both porosity and surface area decreased, showing an opposite trend to that of crystallinity. The crystallinity of hollow CeO significantly influenced both the characteristics and the catalytic performance of the corresponding hollow CuO-CeO (H-Cu-CeO) catalysts. The degree of oxygen vacancy significantly decreased with the calcination temperature. H-Cu-CeO (HT), which presented the lowest CeO crystallinity, not only had a high degree of oxygen vacancy but also showed well-dispersed CuO species, while H-Cu-CeO (800), with well-developed crystallinity, showed low CuO dispersion. The H-Cu-CeO (HT) catalyst exhibited significantly enhanced catalytic activity and stability. In this study, we systemically analyzed the characteristics and catalyst performance of hollow CeO samples and the corresponding hollow CuO-CeO catalysts.