Preparation Of Doped TiO₂ Composite Photocatalytic Material And Its Application In Photocatalytic Performance

A series of doped TiO₂ nanocomposite photocatalysts were prepared by modified liquid phase precipitation method with TiOSO₄ as source of Ti and muscovite as matrix.CuSO₄,Na₂SiO₃ and urea were used as Cu source,Si source and N source,respectly.The effects of pH,temperature of water bath,heat treatment temperature,doping ions and their doping amount,muscovite loading on the structure,phase,grain size and morphology of the modified TiO₂ composites were investigated.The photocatalytic performance of different samples was tested with RhB as the target pollutant.Each sample was analyzed and characterized by XRD,XRF,FTIR,TG-DTA,BET,SEM,UV-vis and HPLC-MS.The antibacterial properties of doped TiO₂ composite nano-photocatalysts were tested,and its application in antibacterial coatings film was discussed.The results have shown that the grain size of TiO₂ was small under acidic conditions.When the pH in reaction system was 2,the size of anatase TiO₂ was the smallest,and rutile content in TiO₂ was the lowest.Besides,sample under this condition shown the best photocatalytic performance.The greater the proportion of anatase in TiO₂,the stronger the absorption in the ultraviolet region.While the greater the rutile content,the stronger the absorption in the visible region.A smaller grain size and a suitable crystal phase composition will enhance the photocatalytic effect of TiO₂.The thermal properties of muscovite used in this paper were relatively stable.Its layered structure and smooth surface provided excellent substrate loading surface for TiO₂ nanoparticle.The muscovite matrix had a retarding effect on the growth and phase transformation of TiO₂ in the composite.Si doping significantly limited the growth of TiO₂ and increases the crystal phase transition temperature of TiO₂.Cu²⁺replaced part of Ti⁴⁺into the TiO₂ lattice,causing lattice distortion of TiO₂ and inhibiting the growth of TiO₂ crystals.The optimal Cu²⁺content of Cu-doped samples was 1.5%,and the degradation rate of RhB at 20 mg/L was 97%at 1 h.The anion defect of the O atom during the heat treatment of the N-doped sample was occupied by the N atom,forming an N-doping.When the amount of urea was2,the photocatalytic effect of the material was the best,and the degradation rate of RhB was more than 90%after photocatalytic degradation under visible light for 2 hours.The photocatalytic degradation of RhB by the nanocomposite catalyst followed the pseudo-second-order reaction kinetics.The main reactive species in the degradation process were O₂^-,h⁺and·OH in order of participation.The muscovite matrix loading promoted h⁺to oxidize H₂O to form·OH,which also helped improve the efficiency of catalytic degradation of pollutants.The doped TiO₂/muscovite nanocomposites prepared in this experiment have good sedimentation performance and are easy to be separated and recovered.It is a cheap and efficient photocatalyst with good application prospects.The antibacterial coating film prepared by using the catalyst as an antibacterial agent had good antibacterial property.The sterilization rate increased with the catalyst content in the coating film.The modified TiO₂ composite photocatalyst prepared in this experiment had good photocatalytic performance and exhibited good degradation effect on RhB under visible light.Combining with the antibacterial test,the antibacterial coating film prepared in this experiment had great practical significance and contributed to the practical application of the modified TiO₂ photocatalyst.