Excellent low temperature NH3-SCR activity over MnaCe0.3TiOx (a=0.1-0.3) oxides: Influence of Mn addition

A convenient sol-gel method was used to prepare a series of MnaCe0.3TiOx(a = 0.1, 0.2, 0.3) catalysts and applied in selective catalytic reduction with NH3 (NH3-SCR) for NO removal. XRD, BET, Raman, H-2-TPR, NH3-TPD, SO2 -TPD, XPS and in situ DRIFTS were applied to analyze the texture structure, redox property, acidity and surface properties. The Mn0.1Ce0.3TiOx catalyst exhibited a dramatical performance that 100% NO conversion and above 90% N-2 selectivity were obtained between 175 and 400 degrees C, even under high gas hourly space velocity of 80,000 h(-1) and existence of SO2 and H2O. The results can be attributed to that Mn0.1Ce0.3TiOx catalyst possessed the most chemisorbed oxygen and suitable redox property derived from Ce3+ + Mn4+ -><- Ce4+ + Mn3+ reaction. In situ DRIFTS revealed that the NH3-SCR reaction upon Mn0.1Ce0.3TiOx catalyst took place by L-H and E-R mechanisms below 175 degrees C while only E-R mechanism above 175 degrees C.