Investigation of the promotion effect of Mo doped CuO catalysts for the low-temperature performance of NH_(3)-SCR reaction

摘要

A novel Mo-doped CuO catalyst is developed and used for low-temperature NH_(3)-SCR reaction.Compared with the undoped CuO sample,the Mo doped CuO catalyst shows an increased SCR performance with above 80%NO_(x) conversion at 175℃.The XRD and Raman results have confirmed the incorporation of Mo metal ions into CuO lattice to form Mo-O-Cu species which may be related to the enhanced SCR activity.The XPS and UV-vis results reveal the creation of electron interaction between Cu and Mo in this Mo-O-Cu system which provides an increased amount of Lewis and Brønsted acid sites,thereby promoting the adsorption capacity of NH_(3) and NO_(x) as verified by NH_(3)-TPD and NO_(x)-TPD characterization.Besides,it also promotes the formation of oxygen vacancies,leading to the increasing of chemisorbed oxygen species,which improves the NO oxidation to NO_(2) activity.Furthermore,in situ DRIFTS technology was also used to study the reaction mechanism of this Mo doped CuO catalyst.The formed NO_(2) could react with NHx(x=3,2)species to enhance the low-temperature NH_(3)-SCR activity via the"fast-SCR"reaction pathway.The nitrate and nitrite ad-species may react with NH_(3) and NH4^(+)ad-species through the L-H pathway.