The Preparation Of Titanium Dioxide Photocatalytic Functional Materials And Its Performance Research

As one of the photocatalysts,nano-TiO2 has the advantages of non-toxicity,has good chemical stability and high catalytic activity.However,the TiO2 nanopowder used at present agglomerates easily and difficult to recover and reuse.In order to overcome the above shortcomings,SiO2 doped TiO2 fiber and SiO2 doped supported TiO2 were prepared using TiCl4 as a titanium source,ethyl orthosilicate as Si source by sol-gel method combined with centrifugal spinning and impregnation method respectively.The preparation method of visible light-responsive Fe3+-doped TiO2 fiber was explored preliminarily using TiCl4 as the titanium source and Fe(NO3)3·9H2O as the iron source.The phase composition,morphology and spectral response characteristics of the catalysts were studied by XRD,Super Depth of Field Digital Microscope,Specific surface analyzer,SEM,UV-Vis,XPS and so on.The photocatalytic activity of the catalyst prepared under different conditions was evaluated using methyl orange solution as a degradation target.The results are as follows:By adjusting the amount of SiO2 doping and heat treatment temperature,transparent nanocrystalline TiO2 fiber could be obtained successfully.The experiment results showed SiO2 doping could inhibit the transformation of anatase TiO2 to rutile TiO2 and the growth of grains,improve the catalytic activity of TiO2 fiber under UV light.When the content of SiO2 was 20 mol%,anatase TiO2 fiber could be obtained by heat treatment at 700 ? in water vapor atmosphere.The specific surface area of the TiO2 fiber with 20 mol%SiO2 doping was 108.489 m2/g,the surface pore size distribution was mainly about 4 nm.The TiO2 fiber with 20 mol%SiO2 doping showed the best photocatalytic activity under UV light.The TiO2 fiber had the best degradation effect on methyl orange under strong acid(pH=2)and strong alkali(pH=13.5),and the acidic condition was more conducive to the degradation of methyl orange.Using 15 ppi Al2O3 open-cell ceramic foam as the photocatalyst carrier,and the loading experiment was carried out in titanium sol with c(Ti4+)=1.5 mol/L and 20 mol%SiO2 doping amount.The performance of the supported TiO2 was the best when the loading process repeated for 4 times.The TiO2 loading layer was firmly bonded to the substrate,had good photocatalytic activity and reusability and easy to recover and reuse.By adjusting the Fe3+ doping amount and the heat treatment temperature,transparent nanocrystalline Fe3+-doped TiO2 fiber could be obtained.The experiment results showed the doping of Fe3+ could promote the transition of anatase TiO2 to rutile TiO2 and inhibit grain growth.With the increasing amount of Fe3+doping,the absorption edge of TiO2 occurred significant redshift and the recombination rate of photogenerated electron-hole could be changed.When the content of Fe3+ was 0.05 mol%,anatase Fe3+-doped TiO2 fiber could be obtained after heat treatment at 450 ? in water vapor atmosphere.The specific surface area of the TiO2 fiber with 0.05 mol%Fe3+ doping was 91.023 m2/g,the surface pore size distribution was mainly about 10 nm,the band gap decreased from 2.99 eV to 2.70 eV.The TiO2 fiber with 0.05 mol%Fe3+ doping had the lowest photogenerated electron-hole recombination rate and exhibited good photocatalytic activity under UV and visible light conditions.