title: Superior Performance of Fe1-xWxOδfor the Selective Catalytic Reduction of NOxwith NH3: Interaction between Fe and W.
abstract: Novel iron-tungsten catalysts were first developed for the selective catalytic reduction of NOxby NH3in diesel exhaust, achieving an excellent performance with a wide operating temperature window above 90% NOxconversion from 225 or 250 to 450 °C (GHSVs of 30 000 or 50 000 h-1). It also exhibited a pronounced stability and relatively high NOxconversion in the presence of H2O, SO2and CO2. The introduction of W resulted in the formation of α-Fe2O3and FeWO4species obtained by HRTEM directly. The synergic effect of two species contributed to the high SCR activity, because of the increased surface acidity and electronic property. The FeWO4with octahedral [FeO6]/[WO6] structure acted as the Brønsted acid sites to form highly active NH4+species. Combining DFT calculations with XPS and UV-vis results, it was found that the fine electron interaction between α-Fe2O3and FeWO4made the electron more easily transfer from W6+sites to Fe3+sites, which promoted the formation of NO2. Judging by the kinetics and SCR activity studies, the Fe0.75W0.25Oδwith an appropriate W amount showed the strongest interaction, and thereby the lowest activation energy of 39 kJ•mol-1and optimal catalytic activity. These findings would be conducive to the reasonable design of NH3-SCR catalysts by adjusting the fabrication.
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Sciences and Technology, Dalian University of Technology , Linggong Road 2, Dalian, 116024, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Sciences and Technology, Dalian University of Technology , Linggong Road 2, Dalian, 116024, China.
authors.forename: Zhenping
authors.identifier: 0000-0003-0948-2029
authors.initials: Z
authors.lastname: Qu
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Sciences and Technology, Dalian University of Technology , Linggong Road 2, Dalian, 116024, China.
authors.forename: Shicheng
authors.initials: S
authors.lastname: Dong
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Sciences and Technology, Dalian University of Technology , Linggong Road 2, Dalian, 116024, China.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Xie
authors.affiliation: Key Laboratory of Industrial Ecology and Environmental Engineering (MOE), School of Environmental Sciences and Technology, Dalian University of Technology , Linggong Road 2, Dalian, 116024, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Tang
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D002384:Catalysis; D005290:Ferric Compounds; D009569:Nitric Oxide / Q000737:chemistry; D010084:Oxidation-Reduction; D014414:Tungsten / Q000737:chemistry
chemical_list: D005290:Ferric Compounds; D009569:Nitric Oxide; D000641:Ammonia; D014414:Tungsten