Preparation Of Carbon Nanotube-supported Titanium Dioxide And Study On Its Photocatalytic Properties

Titanium dioxide is a non-toxic,high chemical activity,low,easy to synthesis of nano materials,especially its excellent catalytic activity,can be used as purifying water environment,has attracted extensive attention of the people,therefore,the nano TiO₂ is one of the most suitable catalytic agent.However,due to the laboratory prepared TiO₂ particles may have uneven distribution,easy agglomeration and poor dispersion,TiO₂ is a semiconductor compound,the electron hole pair is very easy to compound,the wide band gap,can only be excited by ultraviolet light,can not effectively use visible light and solar energy.All of these lead to the reduction of the catalytic efficiency of TiO₂.Many studies have pointed out that the metal or non-metallic elements can be added to the TiO₂ to make modification treatment.This paper mainly through the sol-gel method,using tetrabutyl titanate as raw materials,pure TiO₂ photocatalyst was prepared.The modification of nano TiO₂ was carried out by using hydrophilic multi walled carbon nanotubes?oCNTs?to prepare carboxylated carbon nanotubes supported nano titanium dioxide?TiO₂/oCNTs?photocatalyst and the catalytic performance of TiO₂/oCNTs composite photocatalyst was studied and analyzed;through the transition metal Fe doping on TiO₂/oCNTs composite photocatalyst was studied and analyzed.Moreover,the level of photocatalytic activity was evaluated by photocatalytic degradation of TiO₂ photocatalyst,TiO₂/oCNTs composite photocatalyst and Fe-TiO₂/oCNTs composite photocatalyst for methyl orange simulated pollutants.?1?The carboxylated multi walled carbon nanotubes?oCNTs?were being treated by ultrasonic vibration,have better dispersion than the original carbon nanotubes in the organic solvent,and the agglomeration and the entanglement was less;?2?oCNTs and TiO₂/oCNTs were analyzed by TEM,XRD,XPS,FT-IR,UV-vis,and so on.The results showed that oCNTs was functionalized,and the surface of oCNTs was loaded with nano TiO₂ particles;?3?Evaluation of nano TiO₂ photocatalyst on photocatalytic degradation effectively of methyl orange simulated pollutants,confirming the best conditions of TiO₂ photocatalytic degradation of methyl orange was:nano TiO₂ calcination temperature was 450 degree,the concentration of TiO₂ photocatalyst was 0.8 g/L,the concentration of methyl orange solution was 20 mg/L,the pH value of methyl orange solution was 3.64;?4?oCNTs with nano TiO₂ as 3wt%,can effectively improve the photocatalytic performance of TiO₂/oCNTs composite material,however,the oCNTs content was low,to some extent,it promotes the loading of nano TiO₂,enhance the photocatalytic performance of TiO₂/oCNTs composite material;the oCNTs content was high,due to agglomeration tangles,it reduced the photocatalytic activity of TiO₂/oCNTs composite materials.Among them,the photocatalytic efficiency of TiO₂/oCNTs composites can reach 95%;?5?Doping modification of TiO₂/oCNTs composite by the Fe³⁺,it was found that the Fe³⁺ could replace Ti4+ of TiO₂,and then destroy the crystal structure of TiO₂,recombination of electron hole pairs in TiO₂ under illumination,which improved the photocatalytic activity of composite materials.The optimum addition amount of the Fe³⁺ was 6wt%.