Preparation And Physicochemical Properties Of TiO₂ & TiO₂/GR Composite Photocatalyst

Titanium dioxide?TiO₂?photocatalyst has superior photocatalytic performance,nontoxicity and no pollution.Graphene possesses larger specific surface area and stronger adsorption capacity.The composite of graphene and TiO₂ can make up for the shortage of the TiO₂,and it will be helpful to improve its photocatalytic performance.In this paper,the preparation and its physicochemical properties of TiO₂,graphene oxide?GO?and TiO₂/graphene composites had been studied.The samples were characterizated by SEM,TEM,XRD,FT-IR and TG-DTA.The photocatalytic degradation of rhodamine B solution experiment was as the probe reaction for evaluating photocatalytic performance of the above catalysts,and the obtained results are as follows:TiO₂ photocatalyst was prepared by the sol-gel method.It is a mixture of anatase and rutile phase,and most of them are anatase phase.The appearance of sample is spherical.The proper preparation conditions for TiO₂ are as follows: the volume ratio of H2 O to TBOT is 10:1,the volume ratio of C4H9 OH to TBOT is 6:1,the mole ratio of TBOT to TX-100 is 0.5:1,the crystallization temperature is 650 °C and the crystallization time is 5 h.When the concentration of rhodamine B solution is 4 mg/L,the dosage of TiO₂ photocatalyst is 0.04 g,the photocatalytic time is 2.5 h,the decolorization rate of rhodamine B can be up to 99%.Graphene oxide was prepared by Hummers method.Graphene oxide is transparent and irregular,presenting a fold and curly.The thickness is about 1.2 nm,close to a single layer of graphene oxide.The proper preparation conditions for graphene oxide are as follows: the raw material is graphite powder,the dosage of NaNO3 is 1.5 g,the adding way of KMnO4 is small amount of way for many times,the dry temperature is 40 °C.TiO₂/graphene composites could be successfully prepared using the solvent thermal methord.The proper preparation conditions for TiO₂/graphene are as follows: the dosage of TiO₂ is 0.1 g,the dosage of GO is 0.02 g,the crystallization temperature is 180 °C and the crystallization time is 6 h.When the concentration of rhodamine B solution is 4 mg/L,the dosage of TiO₂/graphene photocatalyst is 0.04 g.In ultraviolet light source,the photocatalytic time is 0.5 h,the decolorization rate of rhodamine B can be up to 79.7%.The photocatalytic time is 1.5 h,the decolorization rate of rhodamine B can be up to 98.1%.In ultraviolet-visible light source,when the dosage of TiO₂/graphene photocatalyst is 0.04 g,the photocatalytic time is 0.25 h,the decolorization rate of rhodamine B can be up to more than 94.5%.The photocatalytic time is 0.75 h,the decolorization rate of rhodamine B can be up to more than 98.1%.The same sample degradation rhodamine solution,when the decolorization rate is the same value,ultraviolet-visible under the irradiation of photocatalytic degradation time is less than the photocatalytic degradation under UV irradiation time.