Photo-Anodic Polymerization of Pyrrole on Nanoclustered Tio 2 from Hydrothermal One-Step on Pure Ti

Nanoclustered TiO₂ networks were synthesized hydrothermally one-step in 0.45 M tetramethylammonium hydroxide (TMAOH) aqueous solution directly on pure polished Ti substrate for 12-hour growth. Polypyrrole (PPy) nanofilm was subsequently electropolymerized with galvanostatic photo-anodization on the nanostructured TiO₂ sheet as the working electrode. Tafel polarization curve was employed to determine galvanostatic condition. Investigations of SEM, cyclic voltametry, potential-time growing curves, photo-response currents, UV-vis spectroscopy and Fourier Transform Infra-red (FTIR) spectroscopy revealed that photo-anodic polymerized pyrrole film could thoroughly change properties of nanoclustered TiO₂ electrode. The networks of nanoclustered TiO₂ was covered with homogeneous PPy nanofilm, the cyclic voltammetry revealed two reduction peaks, suggesting a compact and a porous layer of PPy. Moreover, PPy could enhance the photo-response by over 100 times compared with that of bare TiO₂ nanonetworks. Optical absorbance visualized the full spectral absorptive feature of PPy, and FTIR further confirmed the vibrations of chemical bonds from PPy. This demonstrated that PPy infiltration in TiO₂ nanonetworks could be successfully achieved via photo-anodic polymerization, and TiO₂ nanonetworks/photo-anodic polymerized PPy are promising in applications of polymer-inorganic solar cell.