Promoting effect of transition metal on low-temperature deNO_x activity of CeO₂@TiO₂ catalyst for selective catalytic reduction

Transition metal M(M=Mn, Co, Fe and Cu) modified amorphous CeO₂@TiO₂ catalysts were prepared via a spontaneous deposition strategy. The low-temperature deNO_x activity of M-CeO₂@TiO₂ for selective catalytic reduction was investigated. XRD, TEM, N₂ adsorption-desorption, H₂-TPR, NH₃-TPD and in-situ FT-IR were used to study the structure, surface property and low-temperature NH₃-SCR reaction performance of M-CeO₂@TiO₂. The results showed that the M-CeO₂@TiO₂ had better low-temperature oxidation reducibility and more surface acid. Cu doping had the most significant promoting effect on low-temperature deNO_x activity for selective catalytic reduction. During the low-temperature NH₃-SCR reaction, both the L-H and E-R mechanisms existed over the Cu-CeO₂@TiO₂ and the L-H mechanism could play a pivotal role due to the "fast SCR"process.