物理化学学报 >> 2007, Vol. 23 >> Issue (07): 1113-1116.doi: 10.3866/PKU.WHXB20070729

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以OTS自组装单分子膜为探针研究TiO2液相空穴氧化机理

周雪锋; 李伟; 张妍; 杨祝红; 冯新;陆小华   

  1. 南京工业大学化学化工学院, 南京 210009
  • 收稿日期:2006-12-13 修回日期:2007-01-31 发布日期:2007-07-03
  • 通讯作者: 陆小华 E-mail:xhlu@njut.edu.cn

Hole Oxidation on TiO2 Films in Aqueous Solutions Studied by Using OTS SAMs as a Probe

ZHOU Xue-Feng; LI Wei; ZHANG Yan; YANG Zhu-Hong; FENG Xin; LU Xiao-Hua   

  1. Department of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, P. R. China
  • Received:2006-12-13 Revised:2007-01-31 Published:2007-07-03
  • Contact: LU Xiao-Hua E-mail:xhlu@njut.edu.cn

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摘要： 通过引入十八烷基三氯硅烷(OTS)自组装单分子膜作为氧化反应的探针, 在排除反应物的吸附和扩散的条件下研究溶胶-凝胶制备的TiO2薄膜表面光催化空穴氧化初始过程. 研究结果表明, 在紫外光照下, 水溶液中OTS部分覆盖的TiO2表面能够很快从憎水变成亲水. 存在空穴捕获剂后, TiO2表面OTS自组装单分子膜碳链的脱除受到明显抑制, 水接触角随光照时间变化非常小; 而水中羟基自由基捕获剂或者F-的存在则对TiO2表面OTS自组装单分子膜碳链的脱除几乎无影响. 这表明, 空穴氧化在TiO2表面OTS自组装单分子膜碳链的脱除中占主要地位.

关键词: 光催化, 机理, 空穴氧化, 牺牲剂, 自组装单分子膜

Abstract: An approach was developed to investigate hole oxidation on TiO2 films in aqueous solutions by using octadecyltrichlorosilane (OTS) self-assembled monolayers (SAMs) as a probe, in which the adsorption and surface diffusion of the reactants were exculded. Under UV irradiation, the water contact angle of the OTS SAMs on TiO2 films in water decreased obviously. In the presence of hole scavengers, the decrease of water contact angle for the OTS SAMs on TiO2 films with UV irradiation was inhibited apparently, while the effect of·OH radical scavengers and fluoride on the decrease of water contact angle was very small. It indicated that direct hole oxidation played a major role in photocatalytic removal of alkyl chains on TiO2 films in aqueous solutions.

Key words: Photocatalysis, Mechanism, Hole oxidation, Scavenger, SAMs

MSC2000: 

  • O643