| Research Abstract |
Water-soluble organics such as benzene sulfonate, glucose, etc. were potodegraded in oxygen atmosphere under UV-illumination using a semicondtuctor electrode of which TiO_2-fixed transparent conductive oxide glass was employed. The organics were mineralized to CO_2 gas via oxidation steps. During these processes, acetic and formic acids were formed. The photocurrent was flowed to an outer circuit according to the "photocurrent doubling" by the charge separation as well as the decomposition of carboxylic acids.
The photocurrent generation for the photodegradation rate and CO_2 evolution was measured in agneous NaCl electrolyte. The increase of photocurrent by applied biases was examined, which was closely related to the adsorption of the substrates on TiO_2/TCO surface. It is very important to reveal the photocatalytic and electrochemical characteristics of TiO_2 thin films. The TiO_2/TCO thin film electrode was prepared by the following procedures : (1) pulse-laser CO_2 deposition method, (2) sol-gel mnethod, (3) hybrid method combined with pasted and sol-gel techniques. In particular, the laser flash breakdown for the gas mixture of TiCl_4, H_2 and O_2 in a globular reactor was carried out to deposit TiO_2 thin film on TCO plate. The pure anatase and homogenous thin film of TiO_2 can be prepared by the pulse laser technique. The crystalline ratio of anatase and rutile is dependent upon the gas composition of TiCl_4, H_2 and O_2. When the composition of H_2 and O_2 was 1 : 1, the fine thin film having anatase crystal more than 98% and thin film width of 0.4μm was manufactured. When this anatase TCO/TiO_2 was employed as a working electrode with Pt plate as a counter electrode, benzene sulfonte was degraded to generate the maximum photocurrent of 3 mA/cm^2. The possibility of a newly wet solar cell was discussed concerning the photocurrent generation under solar exposure in the photodegradatin of aquatic pollutants.
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