Coexisting oxygen and cobalt vacancies in Co3O4 synergistically boost the selective catalytic reduction of NO by CO

Currently, the primary challenge in industrial applications of CO-selective catalytic reduction of NO (CO-SCR) is the shortage of efficient catalysts that can tolerate the presence of oxygen (O 2 ). In this study, guided by density functional theory (DFT) calculations, we have developed an effective Co 3 O 4 catalyst incorporated with both oxygen vacancies (V O ) and cobalt vacancies (V Co ). This catalyst achieved 100 % NO conversion and 100 % N 2 selectivity at temperatures ranging from 200 to 350 °C, even in the presence of up to 5 vol% O 2 . DFT calculations and experimental results demonstrate a strong interaction between V O and V Co in the CO-SCR process. The presence of V Co enhances the NO adsorption on adjacent O atoms and promotes the formation of nitrite intermediates. Meanwhile, V Co and V O synergistically promote the dissociation of N-O bonds, thereby improving the NO conversion and the N 2 selectivity. This approach opens up new possibilities for designing advanced catalysts tailored for various environmental and industrial applications.