Study On The Adsorption-photocatalytic Degradation Performance Of VOCs By Surface Modification Of Mesoporous Single Crystal TiO₂

In recent years,with the development of economy and the improvement of housing conditions,decoration materials have been widely used.However,the indoor air pollution caused by volatile organic compounds?VOCs?released from these decoration materials is becoming more and more serious.Among the control methods of many pollutants,photocatalysis is a new,mild and advanced oxidation technology,which has the advantages that cannot be matched by other technical methods,such as green environmental protection,high activity,no pollution and other advantages,opening up a new way for environmental purification.Titanium dioxide is one of the most commonly used photocatalysts,due to its good chemical stability,low cost and easy availability,titanium dioxide has great potential in photocatalytic removal of pollutants.TiO₂ is stimulated by light irradiation to generate electrons and holes.The strong oxidation of photoinduced holes can oxidize most organic pollutants and convert them into CO₂ and water.Therefore,TiO₂ has a very important significance in the photocatalytic treatment of environmental pollution.Mesoporous single crystal orientational alignment is the basic unit of the mesoscopic size class composed of single crystal crystal,has the unique physical and chemical properties of single crystals of mesoporous TiO₂ and its marked characteristics of porous,high specific surface area,high crystallinity,specific exposed surface,etc.,to make it in many ways,performance is significantly better than that of the nanoparticles,porous monocrystalline or polycrystalline materials.Up to now,there have been a lot of work around mesoporous monocrystalline TiO₂,innovations in synthesis methods,such as hydrothermal or solvent-thermal methods,spray drying methods and so on.There is very little work in the photocatalytic degradation of VOCs by mesoporous single crystal TiO₂,and the first thing to be solved is the adsorption of VOCs on the surface of the catalyst,so the adsorption of VOCs by the catalyst becomes crucial.This paper mainly focuses on the crystal surface exposure and surface modification of mesoporous single crystal TiO₂ to increase the absorption of VOCs and promote photogenic charge separation,so as to improve the efficiency of photocatalytic degradation of VOCs and reduce secondary pollution.The research content is divided into the following three parts:?1?Adopt the method of roasting double liquid titanium source precursor preparation of mesoporous single crystal TiO₂,adjust the proportion of double titanium source by a series of{001}facets exposed ratio of different single crystals of mesoporous TiO₂,by XRD,BET,SEM,TEM and characterization methods for the preparation of materials for the analysis of the morphology and structure,and adsorption and photocatalytic degradation of VOCs gas testing,the results showed that single crystal TiO₂{001}facets is specific for toluene gas adsorption,can promote the photocatalytic degradation of toluene gas.?2?Using non-woven template preparation of mesoporous single crystals TiO₂,and NH₂/MST with amino surface modification of mesoporous single crystals TiO₂?MST?,by XRD,BET,SEM,TEM and characterization methods for the preparation of material for structural analysis,and carries on the adsorption and photocatalytic degradation of VOCs gas test,compared with the polycrystalline TiO₂products,NH₃/MST of toluene adsorption increased significantly,because of the mesoporous single crystals TiO₂{001}facets titanium unsaturated NH₂ adsorption on the surface,forming H₂N���Ti key,C₇H₈ will be formed with NH₂ to adsorb toluene on the surface,using the strong oxidation of{001}facets surface,thus further improving the efficiency of removal of toluene gas.?3?The adsorption and photocatalytic degradation performance of toluene molecules on the catalyst surface was studied by designing Ag/SrSO₄/MST with interlayer structure on the surface of mesoporous single crystal TiO₂ and adjusting the thickness of SrSO₄ and the load of Ag.The results showed that the adsorption and photocatalytic degradation of toluene were improved.The reason is that the modification of SrSO₄ significantly improves the adsorption performance of titanium dioxide on toluene.The modification of noble metal Ag promoted the separation efficiency of surface charges.