Effects of the Crystalline Properties of Hollow Ceria Nanostructures on a CuO-CeO2 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 CeO₂ nanostructures and the crystallinity control of a CeO₂ layer used as a support material for a CuO-CeO₂ catalyst in CO oxidation. The hollow CeO₂ nanostructures were synthesized using a simple hydrothermal method. The crystallinity of the hollow CeO₂ shell layer was controlled through thermal treatment at various temperatures. The crystallinity of hollow CeO₂ 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 CeO₂ significantly influenced both the characteristics and the catalytic performance of the corresponding hollow CuO-CeO₂ (H-Cu-CeO₂) catalysts. The degree of oxygen vacancy significantly decreased with the calcination temperature. H-Cu-CeO₂ (HT), which presented the lowest CeO₂ crystallinity, not only had a high degree of oxygen vacancy but also showed well-dispersed CuO species, while H-Cu-CeO₂ (800), with well-developed crystallinity, showed low CuO dispersion. The H-Cu-CeO₂ (HT) catalyst exhibited significantly enhanced catalytic activity and stability. In this study, we systemically analyzed the characteristics and catalyst performance of hollow CeO₂ samples and the corresponding hollow CuO-CeO₂ catalysts.