Catalytic combustion is an efficient method to eliminate CO and volatile organic compound (VOC) pollutants. CuMn2O4 spinel is a high-performance non-noble metal oxide catalyst for catalytic combustion and has the potential to replace noble metal catalysts. In order to further improve the catalytic activity of CuMn2O4 spinel, we propose a simple and low-cost approach to introduce numerous oxygen and metal vacancies simultaneously in situ on the CuMn2O4 spinel surface for the catalytic combustion of CO and VOCs. Alkali treatment was used to generate oxygen vacancies (VO), copper vacancies (VCu), and novel active sites (VO combines with Mn2O3 at the interface between Mn2O3(222) and CuMn2O4(311)) on the CuMn2O4 spinel surface. In the catalytic combustion of CO and VOCs, the vacancies and new active sites showed high activity and stability. The oxidation rate of CO increased by 4.13 times at 160 °C, and that of toluene increased by 11.63 times at 250 °C. Oxygen is easier to adsorb and dissociate on VO and novel sites, and the dissociated oxygen also more easily participates in the oxidation reaction. Furthermore, the lattice oxygen at VCu more readily participates in the oxidation reaction. This strategy is beneficial for the development of defect engineering on spinel surfaces and provides a new idea for improving the catalytic combustion activity of CuMn2O4 spinel.
Keywords: CO oxidation; catalytic combustion; defect engineering; selective dissolution; toluene.