Preparation, Modification And Photoelectrochemical Properties Of TiO₂ Nanorods Composite Materials On The FTO

Nowadays with the rapid development of economic in this world, people extract and utilize natural resources unduly, leading to the increasing of the energy and environmental crisis, which has seriously affected the harmonious development between human and nature.Therefore the scientists around the world are in an effort to explore the methods of repairing and againsting environmental pollution. The photocatalytic technology because with the green environmental protection, mild conditions, low energy consumption and cost has become the most practical method, so the key is to develop and prepare efficient photocatalyst. However, the research focus in the traditional photocatalyst is titanium dioxide. This research explores the preparation of TiO₂ nanorod arrays on FTO transparent conductive substrate, then the materials were modified for improving the performance in photoelectrochemical applications.The main parts of the thesis are as follows:1. Regular mixed phase TiO₂ nanorod arrays on the FTO transparent conductive substrate were firstly fabricated via an improved hydrothermal method at 200 °C for 8 h.The characterization confirmed that as-synthesized TiO₂ nanorods have lengths of 3 ?m and diameters range from 300-400 nm. The density, diameter, length and phase composition of TiO₂ nanorods can be readily controlled by changing reaction time, hydrothermal temperature and the ratio of reactant, finally the optimal experimental parameters for the formation of TiO₂ nanorod arrays were determined. In addition, the results of the photocatalytic activity also further verified the optimization of the structure had a significant effect on the improvement of its photocatalytic performance.2. We synthetise BiOI nanoplates on as-prepared TiO₂/FTO using SILAR method by controlling the reactant concentration, reaction time and cycle times. The results of characterization by UV-Vis, SEM, XRD, EDS show that we successfully prepared FTO/TiO₂/BiOI electrode, which has complete morphology and high crystallization degree.The photocatalytic efficiency of the composite is up to 94%⁹6%, at the same time its photocatalytic activity is relatively stable, and the degradation efficiency can still reach85%⁹0% in the continuous use of 12 h. In addition, photoelectric properties test results of the product show that BiOI/TiO₂/FTO nanocomposites have more excellent optical activity than pure TiO₂ nanorod arrays.3. Uniform Ag nanoparticles could be directionally grafted on the surface of TiO₂ nanorod arrays by a simple photo-reduction method. Then the TiO₂/Ag/Ag3PO4 composite were prepared by the sequential chemical bath deposition method. The photocatalytic efficiency of TiO₂/Ag/Ag3PO4 composites was much higher than pure TiO₂. We discovered that the decolorization efficiency of composite decreased from 94.50% to 91.30% after six cycles, which maintains 96.61% of the initial decolorization efficiency. The photocurrent density of TiO₂/Ag/Ag3PO4 composite was up to 2.50 mA·cm-2, which is about 2 times as much as 1.30 m A·cm-2 of pure TiO₂ nanorods under xenon lamp irradiation. We found that the modification of Ag/Ag3PO4 nanoparticles not only can improve the photoelectric properties of TiO₂ nanorod arrays, while enhancing its stability. Finally, we discussed the photocatalytic mechanism of the composite materials.4. TiO₂/SrTiO3 composite nanomaterials on FTO transparent conductive substrate were synthesized by two step hydrothermal method, which were assembled into the dye sensitized solar cell to test its I-V curve. Test results showed that photoelectric conversion efficiency of the DSSCs was up to 4.50%, increased by 29.30% compared with the pure TiO₂ photoanode battery.