Reaction and Characterization of Co and Ce Doped Mn/TiO2 Catalysts for Low-Temperature SCR of NO with NH3

The catalysts of cobalt and cerium doped Mn/TiO2 were tested for low-temperature selective catalytic reduction of NO with NH3, and these samples were characterized by XRD, XPS, Raman, H-2-TPR and NH3-TPD methods. The catalytic activity results showed that the NOx conversion was obviously improved by Co and Ce doping. Ternary metal oxide catalyst Mn-Co-Ce/TiO2 exhibited the highest catalytic activity of 99 % at 423 K. The XRD and Raman analysis indicated formation of MnO2 or CoMnO3 phases on Mn/TiO2 and Mn-Co/TiO2. The XPS results demonstrated that the metal cations existed mainly in the form of Mn4+, Co2+ and Ce4+, respectively. XPS and H-2-TPR results supported the presence of Mn-Co mixed oxides. Doping of Ce could enhance dispersion of Mn-Co oxides on the surface. Addition of Co and Ce led to higher surface Mn4+/Mn3+ ratio, chemisorbed oxygen, acidity and dispersity, which enhanced NH3 adsorption and oxidation of NO to NO2, subsequently, the NOx reduction was accelerated through the Fast SCR reaction. [GRAPHICS] .