Interfacial effects promote the catalytic performance of CuCoO2-CeO2 metal oxides for the selective reduction of NO by CO

Abstract

The establishment of a strongly coupled heterojunction interface between composite metal oxide interfaces is an important strategy to improve the activity of CO-SCR catalysts. A CuCoO2 modified CeO2 catalyst (H-CuCo-CeO2) was synthesized by a hydrothermal method, which exhibited a wide low-temperature activity window, achieved 100 % NO conversion at 175 °C and showed excellent performance in terms of resistance to H2O and SO2. Based on the results of XPS, Raman, OSC and in situ DRIFTS test, the mechanism of the H-CuCo-CeO2 catalyst in the CO-SCR reaction was systematically investigated to reveal the influence of the heterojunction interfaces of the catalyst on the reaction performance. The results show that the modification of the CuCoO2 structure promotes the migration of Cun+ species between the layers of the H-CuCo-CeO2 catalyst and increases the surface Cu+-O-Cu+ active sites, while greatly promoting the formation of oxygen vacancies (O2–(ads) → O-(ads)) on the catalyst surface. In addition, the increased concentration of oxygen vacancies also effectively promoted the dissociation of NO to [N] to produce N2 and transferred the dissociated [O] species to the active site to further complete the degradation of CO. This work not only provides an idea for the study of strongly coupled CuCoO2-CeO2 heterojunction interfaces, but also provides an efficient denitrification catalyst for air pollution control.