Highly ordered, visible light driven TiO2 nanowire arrays doped with Fe photocatalysts were grown on the surface of
functionalized graphene sheets (FGSs) using a sol-gel method with titanium isopropoxide (TIP) monomer, acetic acid
(HAc) as the polycondensation agent and iron chloride in the green solvent, supercritical carbon dioxide (scCO2). The
morphology of the synthesized materials was studied by SEM and TEM, which showed uniform formation of Fe doped
TiO2 nanofibers on the surface of graphene sheets, which acted as a template for nanowire growth through surface
-COOH functionalities. Increasing Fe content in the nanowires did not change the morphology significantly. Optical
properties of the synthesized composites were examined by UV spectroscopy which showed a significant reduction in
band gap with increasing Fe content, i.e. 2.25 eV at 0.6% Fe. The enhancement of the optical properties of synthesized
materials was confirmed by photocurrent measurement. The optimum sample containing 0.6% Fe doped TiO2 on the
graphene sheets increased the power conversation efficiency by 6-fold in comparison to TiO2 alone.
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