Study On The Preparation And Photocatalytic Activity Of RGO-TiO₂ Thin Films

Although the photocatalytic TiO2 film with high efficiency and excellent stability, which can be easily recycled, reused and simple post-treatment process, was widely applied to environmental field, still it was limited by some factors, such as low utilization rate for sunlight, high recombination of the photogenerated carriers. The above drawbacks can be overcome by incorporating rGO into TiO2 film so that photocatalytic efficiency can be conspicuously improved. In addition, how to solve the mutual combination between rGO film and TiO2 film and improve their quality were regard as major aspects in our research.rGO-TiO2 film and rGO-TiO2(PVP) film were prepared by dip-coating method, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy (Raman), fluorescence spectrum(PL) and Brunauer Emmett Teller (BET) surface area. The efforts of polyvinyl pyrrolidone (PVP)、number of layers and dosage of films on microstructure, surface morphology and photocatalytic efficiency of composite film were researched. The main results were summarized as follows:1. The viscosity of TiO2 precursor sol, TiO2(PVP) precursor sol and GO precursor sol was 1.95 × 10-3(N·s/m2),7.88 × 10-3(N·s/m2) and 72.68× 10-3(N·s/m2), respectively. Under the irradiation of UV lamp, the reduction time was 24h for GO.2. Citric acid, as the hydrolysis inhibitor of tetrabutyl titanate and the surfactant of GO, can not only solve the incompatible problem of rGO film and TiO2 film, but also obtain rGO-TiO2 film with mesoporous structure; the introduction of rGO can inhibit the formation of rutile TiO2, prevent the agglomeration and growth of TiO2 particles, and prolong the lifetime of photo carriers;3. The surface of rGO-TiO2(PVP) thin film,with mesoporous structure film, was smooth and uniform; incorporating PVP into TiO2 can inhibit the formation of rutile TiO2, prevent the agglomeration and growth of TiO2 particles, and prolong the lifetime of photo carriers;4. When alternate layers were 6 and the number of slices was 8 for rGO-TiO2(PVP) film, optimal photocatalytic efficiency was achieved: degradation rate for Methyl Orange reached to 92.5% after 120 min. when recycling times were 5, the degradation rate of rGO-TiO2(PVP) film for Methyl Orange reached to 85%.