Preparation Of Fe/I Co-doped TiO₂ And Its Photocatalytic Degradation Of Gas Phase Benzene

In recent years,semiconductor photocatalytic technology has been widely degraded due to its mild reaction conditions,and the Ability to completely degrade organic matter.TiO₂ is considered to be one of the most promising photocatalysts due to its low price,non-toxicity,thermal stability and strong chemical stability.However,its higher photo-generated carrier recombination rate limits its photocatalytic efficiency maximization;the larger band gap reduces the absorption of visible light.Therefore,based on the traditional TiO₂,a single element doped TiO₂ and Fe/I co-doped TiO₂ were synthesied by sol-gel method with KI and KIO₃ as iodine sources and Fe?NO₃?₃ as iron source.In this experimental study,the spectral absorption range of TiO₂ was successfully extended to the visible light region,and the photocatalytic properties of the prepared catalysts were investigated with benzene as the target.The experimental research is mainly divided into three parts,the research conclusions are as follows:?1?Fe and I single element doped TiO₂ were prepared by sol-gel method.The effects of iodine source,doping amount and calcination temperature on the activity of the catalyst were investigated.The results show that the main crystal form of TiO₂ is anatase phase after doping with single element,and the particle size is obviously reduced;Among the catalysts prepared by different precursors,TI^-₁₀-350?TI₁₀⁵⁺-350and TF_0.5-300 have the highest photocatalytic activity,and their processing ability for benzene were TF_0.5-300>TI^-₁₀-350>TI₁₀⁵⁺-350;Different iodine sources had great influence on the characteristics of the prepared catalyst.Compared with the catalyst prepared by KIO₃ as iodine source,the catalyst prepared by KI as iodine source had higher photocatalytic activity because it had different valence iodine in the catalyst and had more surface-bound hydroxyl groups.Compared with non-metal iodine doping,Fe³⁺-doped TiO₂ had higher photocatalytic activity under visible light but was more susceptible to deactivation.?2?The response surface methodology was designed to determine the optimum iodine doping amount,iron doping amount and calcination temperature of the I/Fe co-doped catalysts.The prepared catalysts were characterized by XRD,XPS and Raman.The results show that the main crystal form of the catalyst after Fe/I co-doping is anatase phase and there is no characteristic peak associated with iron or iodine.The particle size of the catalyst is significantly reduced after doping,and the number of oxygen vacancies in the catalyst is significantly increased.The iodine doping precursor has a great influence on the characteristics of the prepared catalyst:Under the same conditions,the ability of Fe/I co-doped TiO₂ prepared by KI as iodine source for photocatalytic treatment of gas phase benzene was better than that of Fe/I co-doped TiO₂ prepared with KIO₃ as iodine source.There were different valence states of iodine elements in co-doped TiO₂ prepared by using KI as iodine source.The iron elements were evenly distributed on the titanium base,and the surface had a combination of hydroxyl groups or chemical adsorption oxygen.However,The I3d characteristic peak intensity of co-doped TiO₂ prepared by using KIO₃ as iodine source was low,and iron may form oxide on the surface of the catalyst,and the surface had less bound hydroxyl or chemisorbed oxygen.?3?Taking the optimal co-doped catalysts TI^-₁₅F_0.3-400 and TI₁₅⁵⁺F₁-400 with different iodine sources as examples,the effects of residence time,catalyst dosage and initial benzene concentration on the photocatalytic degradation of benzene were studied.The optimum working conditions were as follows:residence time 80s,catalyst dosage 5g,benzene initial mass concentration 100±20mg/m3.At this time,the removal rate of benzene to TI^-₁₅F_0.3-400 was about 60%,the treatment capacity of benzene was 674.55?gC₆H₆/?g2h?;the removal rate of benzene to TI₁₅⁵⁺F₁-400 is about 40%,The treatment capacity for benzene was 462.38?gC₆H₆/?g·h?.