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Investigation on the photodegradation of organic contaminants by a semiconductor thin film electrod

半导体薄膜电极光降解有机污染物的研究

基本信息

批准号：
10640569
负责人：
HIDAKA Hisao
金额：
$ 2.05万
依托单位：
Meisei University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

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.

在紫外光照射下，以TiO_2固定的透明导电氧化物玻璃为电极，在氧气气氛中光降解苯磺酸盐、葡萄糖等水溶性有机物。有机物通过氧化反应被矿化为CO_2气体。在这些过程中，形成了乙酸和甲酸。根据电荷分离和羧酸分解产生的“光电流倍增”效应，将光电流到外电路中，测量了在镁盐电解质中光降解速率和CO_2释放的光电流产生情况。研究了外加偏压对光电流的影响，发现偏压对光电流的影响与衬底在TiO_2/TCO表面的吸附密切相关。研究TiO_2薄膜的光催化和电化学特性具有重要意义。采用脉冲激光CO_2沉积法、溶胶-凝胶法和混合法制备了TiO_2/TCO薄膜电极。特别是在球形反应器中对TiCl_4、H_2和O_2的混合气体进行了激光闪光击穿，在TCO板上沉积了存款TiO_2薄膜。用脉冲激光技术可以制备出纯的、均匀的TiO_2薄膜。金红石和金红石的结晶比取决于TiCl_4、H_2和O_2的气体组成。当H_2和O_2的组成为1：1时，制得的薄膜晶粒度大于98%，膜宽为0.4μm。以该复合TCO/TiO_2为工作电极，Pt板为对电极，苯磺酸盐的光电流最大可达3 mA/cm^2。探讨了新型湿式太阳能电池在水体污染物光降解过程中太阳光照射下产生光电流的可能性。