Low-Temperature Selective Catalytic Reduction of NO with NH3 Over Mn–Ti Oxide Catalyst: Effect of the Synthesis Conditions

A series of Mn–Ti oxide catalysts were synthesized by the sol–gel method and the effects of different synthesis conditions were investigated in sequence. The microstructures and properties of the catalysts were characterized by using N2 adsorption–desorption, XRD, SEM, H2-TPR, NH3-TPD, Raman and XPS. The catalytic performance over Mn–Ti oxide catalysts prepared under different synthesis conditions for the low-temperature SCR of NO with NH3 were also comparatively evaluated. The results reveal that the calcination temperature and metal source play a significant role in the characteristics and the SCR activities of the catalysts. A relatively low calcination temperature is beneficial to low-temperature SCR activity. Manganese nitrate or manganese acetate as the Mn source combining with tetrabutyl titanate as Ti source can achieve high SCR activities. The excellent low-temperature NH3-SCR activity can be ascribed to the appropriate textural properties, amorphous Mn-oxides with equal ratio of Mn3+/Mn4+, good low-temperature reducibility and abundant surface B-acid sites.