Porous Maganese-based Catalyst For Coal-fired Flue Gas O-xylene And Mechanistic Studies

Volatile organic compounds（VOCs）are one of the major pollutants in the atmosphere,both as precursors of photochemical smog and ground-level ozone,and have strong biotoxicity,which are very harmful to the environment.China is a large coal burning country,and coal combustion flue gas usually carries a large amount of pollutants,and coal combustion flue gas is one of the important anthropogenic emission sources of VOCs,so it is necessary to remove VOCs from coal combustion flue gas.Catalytic oxidation is an effective method to catalyze VOCs,which can directly convert pollutants into CO₂ and H₂O.Non noble metal catalysts are widely used for catalytic decomposition of VOCs due to their low cost,high activity,and good stability.In this paper,MnOx catalyst with porous structure was prepared by solvothermal synthesis.Its specific surface area（104.76 m²/g）was three times that of the impregnation catalyst（36.81 m²/g）,But S poisoning cannot be alleviated.MnCo-TiO₂ catalyst was synthesized by solvothermal method.Its porous microsphere structure provides a larger specific surface area（76-86 m²/g）than the impregnation catalyst（43.49 m²/g）.When the content of MnCo is 1:10,anatase TiO₂ in the catalyst is the main component,and has the lowest relative reduction temperature.T90 is 100℃lower than the impregnation catalyst.The main intermediate products in the decomposition of o-xylene are benzoic acid,benzaldehyde,and benzyl alcohol.The reaction mechanism of several flue gas components on the catalyst surface was studied by in situ infrared spectroscopy analysis:SO₂would form S precipitation on the catalyst surface and lead to poisoning,the oxidation ability of NO could enhance the catalytic ability,and H₂O and NH₃ would have slightly competitive adsorption with o-xylene.The porous structure can strengthen the deposition of sulfur and the oxidation of NO,and weaken the competitive adsorption of H₂O and NH₃.This paper has certain reference significance for the preparation of efficient Mnbased catalyst,and has practical application value for catalytic oxidation of VOCs in the atmosphere of complex gas components in industrial coal-fired flue gas.