Iron-based catalysts have been explored for selective catalytic reduction(SCR)of NO due to environmentally benign characters and good SCR activity.Mn-W-Sb modified siderite catalysts were prepared by impregnation method based on siderite ore,and SCR perfor-mance of the catalysts was investigated.The catalysts were analyzed by X-ray diffrac-tion,H2-temperature-programmed reduction,Brunauer-Emmett-Teller,Thermogravimetry-derivative thermogravimetry and in-situ diffused reflectance infrared Fourier transform spectroscopy(DRIFTS).The modified siderite catalysts calcined at 450℃mainly consist of Fe2O3,and added Mn,W and Sb species are amorphous.3Mn-5W-1.5Sb-siderite catalyst has a wide temperature window of 180-360℃and good N2 selectivity at low temperatures.In-situ DRIFTS results show NH4+,coordinated NH3,NH2,NO3-species(bidentate),NO2-species(nitro,nitro-nitrito,monodentate),and adsorbed NO2 can be discovered on the sur-face of Mn-W-Sb modified siderite catalysts,and doping of Mn will enhance adsorbed NO2 formation by synergistic catalysis with Fe3+.In addition,the addition of Sb can inhibit sulfates formation on the surface of the catalyst in the presence of SO2 and H2O.Time-dependent in-situ DRIFTS studies also indicate that both of Lewis and Br?nsted acid sites play a role in SCR of NO by ammonia at low temperatures.The mechanism of NO removal on the 3Mn-5W-1.5Sb-siderite catalyst can be discovered as a combination of Eley-Rideal and Langmuir-Hinshelwood mechanisms with three reaction pathways.The mechanism of NO,oxidized by synergistic catalysis of Fe3+and Mn4+/3+to form NO2 among three pathways,reveals the reason of high NOx conversion of the catalyst at medium and low temperatures.

Guihuan Yao;Yuliang Wei;Keting Gui;Xiang Ling

School of Mechanical and Power Engineering,Nanjing Tech University,Nanjing 211816,China;School of Energy and Environment,Southeast University,Nanjing 210096,China

环境科学学报（英文版）

[1]Guihuan Yao;Yuliang Wei;Keting Gui;Xiang Ling-.Catalytic performance and reaction mechanisms of NO removal with NH3 at low and medium temperatures on Mn-W-Sb modified siderite catalysts)[J].环境科学学报（英文版）,2022(05):126-139

nitrito,3+to

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