The Preparation Of Dye-sensitized Semiconductor/graphene Nanocomposites And Its Application In Photocatalytic Hydrogen Evolution

Energy and environmental issues at a global level are important topics. It is indispensable to construct clean energy systems in order to solve the issues. Hydrogen as a clean, efficient, high calorific value and environmentally friendly fuel has received a wide publicity. One of the important ways to sustainable energy development is to utilize renewable solar energy to realize photocatalytic hydrogen evolution.In this paper we use graphene as substrate material. A series of inorganic-organic nanocomposite functionalized graphene nanocomposites were prepared by a facile synthesized method. These nanocomposites were characterized and used as photocatalyst for water splitting. Some corresponding researches were done as follows:(1) Ru(dcbpy)3/TiO2was prepared by self-assembly method, Ru(dcbpy)3/TiO2/RGO composites were prepared by a modified one-step colloidal blending method. The structures of nanohybrid were characterized by XRD, Raman, FTIR and TEM. The results of UV-vis DRS and photocurrent enhancement of Ru(dcbpy)3/TiO2/RGO revealed that nanocomposites extend the light absorbance into visible regions and prolong the lifetime of photoinduced electron due to the present of RGO, which can accept and transfer electron effectively. Under the UV-vis light irradiation, the photocatalytic activity was enhanced effectively compared to those of TiO2, Ru(dcbpy)3/Ti02or TiO2/RGO in EDTA solution. The catalytic activity of Ru(dcbpy)3/TiO2/RGO/Pt nanocomposite was influenced by the content of Ru(dcbpy)3and pH value in system, and we also investigated the stability of catalyst. According to the experimental results, we explain the mechanism of hydrogen evolution over Ru(dcbpy)3/TiO2/RGO/Pt photocatalyst under visible light irradiation.(2) TiO2/RGO/Pt nanocomposites were prepared by one-step solvothermal method using tetrabutyl titanate and RGO/Pt as precursor. In this procedure, TiO2was forming on graphene sheets by the situ growth method. TiO2/RGO/Pt was sensitized with EY. The structure of TiO2/RGO/Pt was characterized with XRD, Raman and SEM, respectively. The results of UV-vis DRS, fluorescence quenching and photocurrent enhancement of EY/TiO2/RGO/Pt revealed that EY/TiO2/RGO/Pt possess a nice response to visible light, the good electron transfer occurred between Eosin Y and TiO2/RGO/Pt. In10vol%TEOA aqueous solution, EY/TiO2/RGO/Pt was used as photocatalyst to catalysis splitting water into hydrogen, its photocatalytic activity was enhanced obviously compared with TiO2and EY/TiO2, the catalytic activity of EY/TiO2/RGO/Pt was influenced by the concentration of Eosin Y, RGO/Pt content in TiO2/RGO/Pt and pH value of catalytic system under visible light irradiation. According to the experimental results, we explain the mechanism of hydrogen evolution over EY/TiO2/RGO/Pt nanocomposite.