Enhanced Activity and Water Resistance on CuO/SiO2-TiO2 Catalyst for CO Oxidation and NO Reduction by CO: The Promotion Effect of SiO2

Non-precious metal catalysts with enhanced low-temperature activity and improved water resistance are highly demanded for emission control. CuO-based catalysts are promising alternatives to precious metal catalysts due to their acceptable activity and cost-effectiveness. However, there is an urgent need to further enhance their low-temperature activity and water resistance for industrial applications. Herein, CuO catalysts supported by various SiO 2 -TiO 2 supports were prepared and evaluated for CO oxidation and NO reduction by CO reactions under the testing conditions with and without water. Among the studied catalysts with different SiO 2 contents, CuO/5SiO 2 -TiO 2 , in which CuO was supported by SiO 2 -TiO 2 with 5 wt.% SiO 2 , exhibited the best performance for CO oxidation. Compared with CuO/TiO 2 and CuO/SiO 2 reference catalysts, the CuO/5SiO 2 -TiO 2 catalyst showed enhanced catalytic activity in both CO oxidation and NO reduction by CO under dry and wet conditions. Comprehensive characterizations revealed that the presence of SiO 2 in TiO 2 support facilitated the CuO/5SiO 2 -TiO 2 catalyst with a high dispersion and reduced oxidation states of CuO x species. This not only improved the low-temperature reducibility but also enhanced the adsorption of reactive CO species. As a result, the CuO/5SiO 2 -TiO 2 catalyst demonstrated superior catalytic activity. Furthermore, the inclusion of SiO 2 in the catalyst inhibited H 2 O adsorption, contributing to the enhanced water resistance on CuO/5SiO 2 -TiO 2 catalyst. These advantages in catalytic activity and water resistance make CuO/5SiO 2 -TiO 2 a promising candidate for applications in emission control.