Preparation Of TiO₂ / Graphene Photocatalyst And Its Performance On Dye Degradation

Nowadays,nano-photocatalysts doped with graphene or its derivatives mainly by titanium dioxide semiconductor materials have attracted wide attention.Graphene doping can overcome the defects of titanium dioxide,reduce the band gap,inhibit the photogenerated-electron hole recombination,and greatly improve the photocatalytic activity of titanium dioxide.However,most of the titanium dioxide/graphene nanocomposites are in powder state,and there are some problems in their application,such as easy to agglomerate and deactivate and difficult to recycle.Membrane photocatalyst can fundamentally solve these problems.Graphene oxide（GO）was prepared through Hummers method.TiO₂/graphene photocatalyst was prepared by hydrothermal method using butyl titanate as titanium source.Based on the existing research in our laboratory,the effects of raw material ratio and calcination temperature in nitrogen atmosphere on the performance of photocatalyst were investigated.XRD characterization showed that all the crystalline phases of titanium dioxide in the photocatalyst were anatase phase.And the GO quality accounts for 3%,and it was calcined at550°C for 2 h in nitrogen atmosphere.After six cycles of degradation of methyl orange dye,the degradation rate could still reach 88%,indicating that the photocatalytic activity of the photocatalyst was high.TiO₂/graphene photocatalyst membrane were prepared by sol-gel method and immersion dip-coating method according to orthogonal test.The optimum conditions of film preparation were selected by reaction rate and degradation rate analysis.The optimal preparation conditions were as follows:the mass of GO was 3%,the ratio of the mass of PEG 2000 to the soliquid was3:160,membrane was coated 3 times,calcination time was 2 h at 450℃in nitrogen atmosphere.In the photocatalytic degradation experiments of thin films,the photocatalytic properties of the membrane photocatalyst were investigated from four aspects:the types of dye,the initial concentration of dye,the amount of membrane added,and the cyclic degradation of the membrane.It was found that the degradation rate of methylene blue solution(100m L,3mg·L^-1)was over 80%after 6 cycles when the amounts of membrane were 5 pieces,which indicated that the photocatalytic properties of the membrane was stable.In a word,it has certain reference value for industrial application.