Hydroxyls on CeO₂ Support Promoting CuO/CeO₂ Catalyst for Efficient CO Oxidation and NO Reduction by CO

Transition metal catalysts, such as copper oxide, are more attractive alternatives to noble metal catalysts for emission control due to their higher abundance, lower cost, and excellent catalytic activity. In this study, we report the preparation and application of a novel CuO/CeO₂ catalyst using a hydroxyl-rich Ce(OH)_x support for CO oxidation and NO reduction by CO. Compared to the catalyst prepared from a regular CeO₂ support, the new CuO/CeO₂ catalyst prepared from the OH-rich Ce(OH)_x (CuO/CeO₂-OH) showed significantly higher catalytic activity under different testing conditions. The effect of OH species in the CeO₂ support on the catalytic performance and physicochemical properties of the CuO/CeO₂ catalyst was characterized in detail. It is demonstrated that the abundant OH species enhanced the CuO_x dispersion on CeO₂, increased the CuO_x-CeO₂ interfaces and surface defects, promoted the oxygen activation and mobility, and boosted the NO adsorption and dissociation on CuO/CeO₂-OH, thus contributing to its superior catalytic activity for both CO oxidation and NO reduction by CO. These results suggest that the OH-rich Ce(OH)_x is a superior support for the preparation of highly efficient metal catalysts for different applications.