Enhancement of photocatalytic activity of TiO₂ film electrode by in situ photoelectro-generating active chlorine

来源期刊：中国有色金属学报(英文版)2007年第5期

论文作者：程小芳 冷文华 皮欧阳 张昭 张鉴清 曹楚南

文章页码：1087 - 1087

Key words：TiO₂; photoelectrocatalysis; active chlorine; nitrite ion

Abstract: The photoelectrocatalytic activity of TiO2 film electrodes in the degradation of nitrite ion was greatly enhanced in the presence of chlorine ion. The influences of NaCl concentration and initial pH value on the degradation rate of and active chlorine production were studied. The results show that the decay rate of and the accumulation rate of active chlorine increase with increasing NaCl concentration. At pH＜8, both the decay of and active chlorine formation rates are enhanced with increasing NaCl concentration, while at pH＞10, they are suppressed. In addition, contrast to conventionally accepted view, in which an advantage of anatase over the rutile modification of TiO₂ is in terms of photoactivity, it is found that a thermal oxidation rutile TiO₂ electrode is more suitable for both photogenerating active chlorine and degrading in the presence of Cl^-. The correlative mechanism was also discussed in detail. Specific adsorption of Cl^- on the electrode causes its energy band edges to move towards positive value and also lower the photocurrent, thus less OH· radicals are produced. However, more active species of Cl^- that have longer lifetime are available to take part in the oxidation of, thus improving its degradation rate.

基金信息：the National Natural Science Foundation of China