Structural Regulation Of Perovskite-like Photocatalytic Materials And Their Purification Performance And Mechanism Of NO

Human activities such as industrial production,burning of fossil energy,and vehicle exhaust will produce a large amount of air pollutants.Typical air pollutants include suspended particulate matter,nitrogen oxides（NO_x）,sulfur dioxide（SO₂）,volatile organic compounds（VOCs）,etc.Among them,NO_x emissions are large,which will not only cause environmental problems such as photochemical smog,acid rain,and ozone layer holes,but also NO_x is toxic and harmful,which can cause the decline in human lung function,hemoglobin degeneration and other respiratory diseases and skin diseases.Therefore,it is necessary to strictly control NO_x emissions and strengthen their governance.As a green,clean and efficient air pollution purification technology,photocatalytic technology can oxidize NO_x to nitrate under mild conditions,so as to achieve the purpose of pollutant purification.Therefore,photocatalytic technology shows broad application prospects of NO_x purification.Sr Sn（OH）₆ and Zn Sn（OH）₆ are typical perovskite-like photocatalytic materials,but their wide band gap and narrow photo-response range,they cannot be excited by visible light,which greatly limits their application for the field of photocatalysis.This study intends to modify perovskite-like with narrow-bandgap semiconductor materials to broaden their photo-response range and improve their photocatalytic performance.Meanwhile,the important role of material edge OH^-in photocatalysis is investigated.The main research contents of this paper are as follows:1.In order to improve the visible light utilization of the wide-bandgap perovskite-like Sr Sn（OH）₆,Ag/Ag₂O-Sr Sn（OH）₆ composite catalyst is synthesized.Ag/Ag₂O nanoparticles can modify the energy band structure,broaden light absorption range,reduce the recombination probability of e^-/h⁺,and significantly improve the photocatalytic NO oxidation performance.Ag/Ag₂O nanoparticles can broaden the light absorption range of photocatalysis and inhibit carrier recombination,thereby significantly improves the photocatalytic performance of NO oxidation.The research shows that the interfacial charge transfer transition channel is successfully constructed between Ag₂O and Sr Sn（OH）₆,which effectively reduces the recombination probability of e^-/h⁺,and makes the purification efficiency of NO under visible light irradiation reach 45.10%.The photocatalytic reaction mechanism and NO purification process is elucidated through characterization analysis test,and the composite catalyst effectively inhibited the formation of toxic by-product NO₂,and could purify air pollutants safely and efficiently.2.Ag₂O-Zn Sn（OH）₆ is synthesized by photo-deposition methods.Compared with pristine Zn Sn（OH）₆,the NO purification efficiency of the composite catalyst（Ag₂O-Zn Sn（OH）₆）under visible light irradiation is the best 69.81%.The morphology,composition and optical properties of the catalysts are characterized by SEM,XRD,XPS,ESR and PL,etc.Through the combination of vacuum in-situ DRIFTS and DFT theoretical calculations,the participation mechanism of the edge hydroxyl group of the composite catalyst in the reaction process is elucidated,that is,the edge hydroxyl group of A-ZSOH can lose e^-to generate·OH（·OH will participate in the NO oxidation process）.Hydroxyl defects are generated on the surface of the catalyst,and the catalysts containing hydroxyl defects will preferentially adsorb H₂O to restore the original surface structure.