Study On Mn-based Catalysts For SCR DeNO_x At Low Temperature

Because of the development of industrialization in our country,the excessive consumption of fossil fuels led to NO_x into the atmosphere far beyond the scope of atmosphere environment self purification.The excessive emission of NO_x has caused environmental pollution including photochemical pollution,acid rain and ozone depletion and damage to human health.It urgently needed a number of techniques of denitration.For industrial stationary sources,currently the most widely and sophisticated technology is selective catalytic reduction?SCR?denitration technology,the core of which is catalysts.In the field of SCR denitration technology,the traditional commercial catalyst,V₂O₅-WO₃/TiO₃,have many problems including low catalytic performance at low temperature,biological toxicity and so on.Many papers reported that,Mn-based catalysts have good low temperature catalytic performance,which have obtained the widespread attention in the field of SCR denitration technology.Mn-based catalysts have good low temperature catalytic performance,be environment friendly,a variety of manganese oxidation states and could be modified by other metals or materials with large application potentiality.In this paper,Mn-based catalysts were chosen to be the research objects,researching the impact of different channel structure of MnO₂ and internal structure of multiple shell spherical NiMn₂O₄ spinel materials for SCR activity.It researched NH₃-SCR activity performance of the catalysts and measured physical and chemical properties through a series of characterization methods.The main research results summarized as follows:?1?Based on modulation of channel structure,using hard template method to prepare 2D,3D ordered mesoporous MnO₂ catalysts.The templates were selected three kinds of SiO₂?KIT-6,SBA-15 and MCM-41?to synthesis order mesoporous MnO₂ with different channel structure.MnO₂-KIT-6 has clearly 3D channel structure,large specific area,many Lewis acid sites,good reducibility,good catalytic performance and wide temperature window.Its NO_x conversion is up to 100%at the temperature between 75? and 175? and it has good resistance to SO₂ and H₂O,with NO_x conversion around 90%under 150? which could keep for a long time.?2?Based on modulation of internal structure of spherical morphology,using solvothermal method to multiple shell spherical NiMn₂O₄ spinel catalysts.It calcined Ni Mn₂O₄ precursor at different rate,researching the differences of internal structure of spherical materials.NiMn₂O₄catalysts is relatively homogeneous spherical materials,and Ni Mn₂O₄ calcined at 1 ?·min^-1 in is triple-layer shell spherical material,which has large specific area up to 165 m²·g^-1 and has good NH₃-SCR catalytic performance.