title: Effect of water vapor on NH3-NO/NO2 SCR performance of fresh and aged MnOx-NbOx-CeO2 catalysts.
abstract: A MnOx-NbOx-CeO2 catalyst for low temperature selective catalytic reduction (SCR) of NOx with NH3 was prepared by a sol-gel method, and characterized by NH3-NO/NO2 SCR catalytic activity, NO/NH3 oxidation activity, NOx/NH3 TPD, XRD, BET, H2-TPR and in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). The results indicate that the MnOx-NbOx-CeO2 catalyst shows excellent low temperature NH3-SCR activity in the temperature range of 150-300°C. Water vapor inhibits the low temperature activity of the catalyst in standard SCR due to the inhibition of NOx adsorption. As the NO2 content increases in the feed, water vapor does not affect the activity in NO2 SCR. Meanwhile, water vapor significantly enhances the N2 selectivity of the fresh and the aged catalysts due to its inhibition of the decomposition of NH4NO3 into N2O.
authors.affiliation: State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
authors.forename: Zhichun
authors.initials: Z
authors.lastname: Si
authors.affiliation: State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wu
authors.affiliation: State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. Electronic address: duanweng@mail.tsinghua.edu.cn.
authors.forename: Duan
authors.initials: D
authors.lastname: Weng
authors.affiliation: State Key Lab of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: Zhenwei
authors.initials: Z
authors.lastname: Wu
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D009556:Niobium / Q000737:chemistry*; D009566:Nitrates / Q000737:chemistry; D009569:Nitric Oxide / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods; D013227:Steam / Q000032:analysis*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D017895:Manganese Compounds; D009566:Nitrates; D010087:Oxides; D013227:Steam; D014874:Water Pollutants, Chemical; D009556:Niobium; D002563:Cerium; D009569:Nitric Oxide; C030583:ceric oxide; C027424:manganese oxide; D000641:Ammonia
keywords: Acid sites; Fast SCR reaction; MnOx–NbOx–CeO(2) catalysts; NO/NO(2) ratio; Water effect