Research On The Preparation And Charaterization Of Mn,Fe-based Catalyst And Its Properties For NH₃-SCR

Air pollutants have a great impact on human life,nitrogen oxides is one of its major pollutants.How to effectively reduce the emissions of nitrogen oxides in the atmosphere has become an urgent issue.Because of its high efficiency and mature technology,selective catalytic denitrification?SCR?has become the most effective method for flue gas denitrification.And the study of denitration catalyst performance has been the focus of SCR research.Commercial denitration catalysts have low denitrification efficiency,poor catalyst activity dispersion,and prone to poisoning,which are still the main problems faced by SCR denitration catalysts.This paper mainly focuses on Mn and Fe-based composite nano-metal oxide catalysts with different structures.And the mechanism was also investigated by H₂-TPR,NH₃-TPD,XPS,XRD,In situ DRIFT,SEM and TEM.First,the MnFeOx@TiO₂ catalyst with core-shell structure was prepared by hydrothermal method and its denitrification efficiency and anti-K poisoning effect were studied by comparison with MnFeOx/TiO₂ catalyst.It has been found that the MnFeOx@TiO₂ catalyst greatly improves the denitrification efficiency and the anti-K poisoning effect.The special structure makes it have a larger specific surface area,stronger redox ability,and more acid sites then MnFeOx/TiO₂catalyst.The In situ DRIFT reveals the presence of E-R and L-H mechanisms,and the special structure increases the proportion of L-H mechanism and promotes more efficient reaction.Secondly,the MnOx@FeOx catalyst was synthesized by two steps hydrothermal method and its SO₂ resistance performance was also studied.The MnOx@FeOx catalyst with core-shell mechanism has excellent catalytic performance and inhibits the formation of surface sulfates with a great improvement in the anti-SO₂ poisoning effect.The core-shell structure was found to exhibit better physical and chemical properties by characterization,revealing the reaction mechanism.After that,MnFeOx-Cube with cubic structure,2D-MnFe₂O₄ with 2D structure and 3D-MnFe₂O₄ with 3D structure were also synthesized by different methods.Compared with Mn,Fe-based catalysts,the catalyst with special structure showed better denitrification efficiency.And the denitrification mechanism of the catalyst was studied by characterization.Through characterization studies,it has been shown that catalysts with special structures have greatly improved the redox properties,the adsorption capacity of NH₃ and NO,and promote the reaction.