Influence of transition metals (M = Co, Fe and Mn) on ordered mesoporous CuM/CeO2 catalysts and applications in selective catalytic reduction of NOx with H2

Abstract

A series of ordered mesoporous Cu/CeO₂ and CuM/CeO₂ (M = Fe, Co and Mn) catalysts were synthesized using mesoporous KIT-6 as a hard template. These materials were characterized by XRD, N₂ physisorption, Raman, TEM, XPS, H₂-TPR and NO-TPD. The N₂ physisorption studies demonstrated high surface areas of 146–193 m² g⁻¹ and a narrow pore size distribution of 3–8 nm for Cu/CeO₂ and CuM/CeO₂. XRD and Raman analyses showed that a Ce–M(Cu)–O solid solution formed in CuM/CeO₂. Surface CoO_x species were also observed on CuCo/CeO₂. NO-TPD and XPS analyses revealed a relatively low NO desorption temperature and abundant oxygen vacancies for CuCo/CeO₂. Their application in selective catalytic reduction of NO_x with H₂ in the presence of oxygen was evaluated. CuCo/CeO₂ showed activity at a wide temperature range, and high NO_x conversion of more than 80% at 200 °C.