Effect of silica on generation and stability of Cu+ cations in CuO/CeO2 catalysts for CO oxidation in H2-rich atmosphere.

Developing efficient CuO/CeO 2 catalysts for CO preferential oxidation in H 2 -rich atmosphere (CO PROX) is essential for removing residual CO in the reformate gas. However, achieving robust performance in a wide working temperature window is still a great challenge. Herein, SiO 2 was introduced to modify the CuO/CeO 2 catalysts and the best catalyst exhibited 100 % of CO conversion and >50 % of CO 2 selectivity from 120 to 220 °C over CO PROX reaction. Combined characterization techniques demonstrate the enhanced interaction between copper species and CeO 2 support after deposition of SiO 2 , promoting the generation of active Cu+ sites as well as the reactivity of lattice oxygen in CeO 2 for CO conversion. Besides, in presence of SiO 2 , the main intermediates changed from carbonates to formate species. More importantly, the active Cu+ sites were stabilized by SiO 2 due to formation of Cu+-O-SiO x interface, retarding the competitive H 2 oxidation at high temperatures. [Display omitted] • Silica promotes the interaction between CuO and CeO 2. • High temperature CO 2 selectivity of CuO/CeO 2 catalysts for CO PROX reaction was improved. • Hydroxyl groups of SiO 2 facilitates formation of formate species. • Active Cu+ cations were stabilized by the establishment of Cu+-O-SiO x interface. [ABSTRACT FROM AUTHOR]