The enhanced SCR performance of Mn/TiO2 catalyst by Mo modification: Identification of the promotion mechanism

In this work, Mo-modified Mn/TiO2 catalysts synthetized by co-precipitation method were applied in the SCR abatement of NOx by NH3. Ranging from 50 to 400 °C, Mn/TiO2 modified with Mo showed higher efficiency in SCR reaction than Mn/TiO2 without Mo. Among Mn/TiO2 catalysts with different Mo doping amount, MnMo/TiO2-0.04 catalyst showed not only the highest SCR activity but also the best N2 selectivity. Furthermore, MnMo/TiO2-0.04 also exhibited stronger resistance to SO2 poisoning compared with Mn/TiO2. On the basis of the characterization means including BET, XRD, H2-TPR, XPS and NH3-TPD, MnMo/TiO2-0.04 was characterized with the decreased crystallinity, the increased reducibility and more surface acid sites, along with the enrichment of surface adsorbed oxygen species and Mn4+ species. Furthermore, the analysis results of in situ DRIFT study showed that Langmuir-Hinshewood (L-H) model should be employed in explaining the accelerated SCR reaction over MnMo/TiO2-0.04.