Determination of Oxygen Sources for Oxidation of Benzene on TiO2 Photocatalysts in Aqueous Solutions Containing Molecular Oxygen
详细信息 查看全文
- 作者：Thuan Duc Bui ; Akira Kimura ; Shigeru Ikeda ; Michio Matsumura
- 刊名：Journal of the American Chemical Society
- 出版年：2010
- 出版时间：June 23, 2010
- 年：2010
- 卷：132
- 期：24
- 页码：8453-8458
- 全文大小：256K
- 年卷期：v.132,no.24(June 23, 2010)
- ISSN：1520-5126
文摘
Photocatalytic oxidation of benzene to CO2 was studied in aqueous solutions using different kinds of TiO2 powders, and isotopic oxygen tracers (H218O and 18O2) were used to investigate the oxidation process. Phenol was produced as a main intermediate in solution. When anatase powders, which showed high activity for oxidation of benzene, were used, 70−90% of oxygen introduced into phenol was from water. On the other hand, when rutile powders were used, only 20−40% of the oxygen was from water. The rest was from molecular oxygen in both cases. The rate of phenol production by using molecular oxygen was nearly the same between anatase and rutile powders. Hence, the high activity of anatase powders for oxidation of benzene to CO2 is attributed to their high activity for oxidation of benzene to phenol, which is considered to be the rate-determining step, using water as the oxygen source. The processes using water and molecular oxygen as the oxygen sources are ascribed, respectively, to oxygen transfer and hole transfer processes in the initial step of benzene oxidation.