Preparation Of TiO₂ Based Nanocomposites And Their Photocatalytic And Photoelectric Properties

Over the past decades,titanium dioxide?TiO₂?,as a semiconductor photocatalyst,has received much research interest due to its high photocatalytic activity,high physical and chemical stability,low cost and environmental friendliness.In this paper,graphene?GR?,polyaniline?PANI?and polypyrrole?PPy?were used to modify TiO₂ and TiO₂ based nanocomposites were prepared,the photocatalytic properties and photoelectric properties of the nanocomposites also were investigated.The main work is as follows:?1?The graphene?GR?modified titanium dioxide?TiO₂?nanorod array composite films which defined as GR-TiO₂ nanocomposite films was synthesized via hydrothermal method and spin-coating.The morphologies of the prepared samples were characterized by field emission scanning electron microscopy,and the structure of the samples was analyzed by X-ray diffraction and Raman spectroscopy,the results showed that GR film was loaded on the surface of the rutile TiO₂ nanorod arrays;The optical properties of the samples were studied by UV-Vis spectrophotometer,the introduction of GR expanded the range of the optical response of TiO₂;Besides,the photocatalytic properties of the prepared samples were studied under UV light and simulated sunlight,the results showed that the introduction of GR enhanced the photocatalytic properties of TiO₂;The FTO-GR-TiO₂-FTO device was assembled to study photoelectric properties of GR-TiO₂ nanocomposites,the introduction of GR not only enhanced the absorption of light by TiO₂,but also provided a way to transport the photogenerated electrons of TiO₂,which inhibited the recombination of photogenerated electron-hole pairs and enhanced the photocatalytic performance of TiO₂.?2?PANI nanowire films were deposited on the surface of GR modified TiO₂ nanorod arrays by in-situ chemical deposition method,and the FTO-PANI-GR-TiO₂-FTO device was assembled.The morphology,structure and optical properties of the samples were characterized by field emission scanning electron microscopy,Raman spectroscopy,UV-Vis spectrophotometer and fluorescence spectrometer,the results showed that PANI successfully loaded on the GR-TiO₂ nanocomposite films,and the introduction of PANI enhanced the optical absorption of TiO₂;Photoelectric properties of the composites were studied by electrochemical workstation,we found that the introduction of PANI enhanced the response of TiO₂ to UV,and further improved the photoelectric performance of the TiO₂,which would have a certain application value in UV detection and sensing fields.?3?PPy nanowire films were deposited on the surface of rutile TiO₂ nanorod arrays by in-situ chemical deposition method,PPy-TiO₂ nanocomposites with different thickness were fabricated by controlling the deposition times,and FTO-PPy-TiO₂-FTO devices were assembled.The results of field emission scanning electron microscopy and Raman spectroscopy confirmed that the rutile TiO₂ nanorod arrays were successfully covered by PPy nanowire films;The optical properties of the composites were studied by UV-Vis absorption spectra and photoluminescence spectra,which proved that the introduction of PPy could enhance the absorption of UV light by pure TiO₂,and the enhancement effect was the best when the deposition times was 3;The photoelectric properties of the composites were studied by the I-t curves and AC impedance curves,the results showed that the introduction of PPy enhanced the UV response of the device,and the photoelectric response was fastest when 3 times of deposition.