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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (05): 367-373.    下一篇

研究论文

有机钌螯合物/TiO2杂化膜修饰电极上Pt纳米团簇的光电流增强效应

周环，王舜*，林娟娟，陈锡安，蔡晓庆，温海虹，蒋峰   

  1. (温州大学纳米材料与化学重点实验室 温州 325027)
  • 投稿日期:2009-08-30 修回日期:2009-11-02 发布日期:2010-03-14
  • 通讯作者: 王舜 E-mail:shunwang@wzu.edu.cn
  • 基金资助:

    国家自然科学基金(No. 20471043;No. 20843003)、浙江省自然科学基金(No.Y408177;No.Y404118)和浙江省科技计划(No. 2007C21134)资助项目.

Enhanced Photocurrent of an ITO Electrode by the Photodeposition of Pt Nanoclusters onto a Monolayer TiO2-Ru Complex Hybrid Film

Zhou Huan Wang Shun* Lin Juanjuan Chen Xi'an Cai Xiaoqing Wen Haihong Jiang Feng   

  1. (Nano-materials & Chemistry Key Laboratory, Wenzhou University, Wenzhou 325027)
  • Received:2009-08-30 Revised:2009-11-02 Published:2010-03-14
  • Contact: WANG Shun E-mail:shunwang@wzu.edu.cn

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利用LB膜技术可控制备了纳米单层和多层的二氧化钛-有机钌螯合物杂化膜, 并研究了上述无机-有机杂化膜修饰电极在Pt纳米团簇敏化后的光电流增强效应. 实验结果表明: (1)纳米单层TiO2/[Ru(phen)2(dC18bpy)]2＋(简称为TiO2-Ru)杂化膜的平均厚度为(3.6±0.5) nm; (2)在光照条件下TiO2-Ru杂化膜能有效催化还原[Pt(NH3)6]4＋形成粒径位于20～160 nm之间的Pt纳米团簇; (3) Pt纳米团簇的引入消除了金属钌螯合物中配体对电子传递的阻碍作用, 改变了电子传递途径, 从而有效减少了电子空穴对的复合, 提高了Pt纳米团簇敏化的n层杂化膜修饰电极(ITO/(TiO2-Ru)n/Pt)在支持电解质中的光电流. 与纳米单层TiO2-Ru杂化膜修饰的ITO电极(ITO/TiO2-Ru)相比, 当工作电压为900 mV时, ITO/TiO2-Ru/Pt 在0.1 mol•L－1的NaClO4电解质溶液中和光照(λ＞360 nm)条件下, 单位面积的光电流提高了约5倍; (4) ITO/(TiO2-Ru)n/Pt电极光电流的大小与杂化膜的层数密切相关, 当TiO2-Ru杂化膜的层数从一层、二层增加到四层时, 光电流呈现先升高后下降行为, 这表明ITO/(TiO2-Ru)n/Pt电极的电子传递过程直接通过非电活性的二氧化钛纳米单层进行.

关键词: LB膜法, 有机-无机杂化膜, Pt纳米团簇, 修饰电极, 光电流

An indium tin oxide (ITO) electrode modified with mono-/multilayer TiO2/[Ru(phen)2- (dC18bpy)]2＋ [phen＝1,10-phenanthroline, dC18bpy＝4,4'-dioctadecyl-2,2'-bipyridyl] hybrid film [denoted as ITO/(TiO2-Ru)n] has been prepared by a modified Langmuir-Blodgett (LB) method. The effects of Pt-photodeposition on the photocurrent of above ITO/(TiO2-Ru)n electrode were studied. Our experiments illustrated: (1) the single-layered hybrid film of TiO2/[Ru(phen)2(dC18bpy)]2＋ (denoted as TiO2-Ru) was closely packed at a surface pressure of 25 mN•m－1 and had a thickness of (3.60±0.5) nm; (2) under light irradiation (λ＞360 nm), Pt clusters with radii of 20～160 nm were authentically observed by the reduction of [Pt(NH3)6]4＋ through the TiO2-Ru hybrid film; (3) the enhanced photocurrent was achieved by depositing the Pt nanocluster onto the surface of the ITO/(TiO2-Ru)n electrodes at the applied potential above 500 mV (vs. Ag|AgCl|KCl) under light irradiation (λ＞360 nm). For example, the photocurrent of ITO/TiO2-Ru/Pt was increased about 5 times in comparison with an ITO/TiO2-Ru electrode at the applied potential 900 mV when they were both in contact with 0.1 mol•L－1 NaClO4 solution. Such a result indicates that the Pt clusters are able to hamper the combination of electron hole pairs and reduce the counterwork of insulating long alkyl chains of amphiphilic Ru(II) complexes, and thus produce the enhanced photocurrent; (4) the photocurrent was strongly dependent on the number of TiO2-Ru hybrid films. With the increase in the number of layers from one, two to four, the photocurrent intensity was found to firstly increase and then decrease, suggesting that the electron transfer be directly through the electrochemically inactive TiO2 monolayer.

Key words: Langmuir-Blodgett method, organic-inorganic hybrid film, Pt nanocluster, modified electrode, enhanced photocurrent