for the reduction of O2 by a conductance band electron was ca. 40–50 times smaller than that for the reduction of methyl orange by e–. Corrosion studies indicated that photoreduction of methyl orange to a hydrazine derivative (D3–) sensitised by CdS, was accompanied by anodic corrosion of the semiconductor even in the presence of EDTA. In this work the role of EDTA (at pH 4.4) appeared to be as a mediator
硫化
镉(CdS)粉末分散体已被用于在
水溶液中pH <7的条件下敏化甲基橙(D –)的光还原。添加了许多电子供体(PVA,TEOA,硝酸盐,酒石酸盐,半胱氨酸,柠檬酸盐,乙酸盐和EDTA),但在pH 4.4时,仅EDTA显着提高了甲基橙的光还原速率。建立了稳态方程,该方程成功地描述了观察到的甲基橙光还原初始速率随甲基橙,光子,EDTA和O 2浓度(如果存在)的变化。从这项工作已表明对于孔(H速率常数+)通过清除EDTA是CA。比h +之间的重组反应大19000倍和一个电导带电子(e –)。此外,用于降低的O的速率常数2由导带电子是CA。比通过e –还原甲基橙要小40–50倍。腐蚀研究表明,即使在有EDTA的情况下,甲基橙也会被CdS敏化为CdS敏化的肼衍生物(D 3–),并伴随着半导体的阳极腐蚀。在这项工作中,
EDTA(在pH为4.4时)的作用似乎是反应的媒介(省略了图示),而不是“理想的”牺牲电子供体。讨论了其原因。