364910 Hydrothermal Synthesis of Graphene/Fe3+-Doped TiO2 Nanowire Composites with Enhanced Photocatalytic Activity Under Visible Light Irradiation
TiO2 is one of the most widely investigated semiconducting metal oxides that exhibits photocatalytic activity and is used in a wide range of applications. However, with its 3.2 eV electronic band gap, TiO2 is only sensitive to the light wavelengths below ∼380 nm which belong to the UV range. Besides, the photogenerated electron−hole pairs, which are mainly responsible for the photocatalytic activity, have faster recombination rates than the rate of chemical interaction between TiO2 and adsorbed pollutants, reducing the photocatalytic efficiency. To enhance photocatalytic activity of TiO2, many methods have been employed, such as ion doping, graphene incorporating and so on.
In this study, the hydrothermal method was employed to synthesize Fe3+ −doped TiO2 nanowires (FeNW) and then fabricate graphene/Fe3+−Doped TiO2 nanowire nanocomposite (GFeNW). Graphene oxide (GO) reduction to graphene and hybridization between FeNWs and graphene by forming chemical bonding was achieved in a one-step hydrothermal process. Graphene/TiO2 nanoparticle nanocomposite (GNP) and graphene/ TiO2 nanowire nanocomposite (GNW) were also synthesized as controls. Photocatalytic performance and related properties of TiO2 nanoparticle (NP), TiO2 nanowires (NW), FeNW, GNP, GNW and GFeNW were comparatively studied. It was found that by incorporation of graphene, GNP, GNW and GFeNW have higher performance than their counterparts. It was also found that FeNWs and NWs, in comparison with NPs, have more uniform dispersion on graphene with less agglomeration, resulting in more direct contact between TiO2 and graphene, and hence further improve electron−hole pair separation and transportation. The diffuse reflectance spectra and photocurrent properties of these composites indicated that Fe3+ doping could improve the response of TiO2 nanowire under visible-light irradiation. The result reveals that the relative photocatalytic activity of GFeNW is highest of all.
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