A STUDY ON PHOTOACTIVATION OF FUEL CELLS

光合作用被定义为从光子到化学势的能量转换，这些能量通过类囊体膜积累。在本研究项目中，我们尝试制备具有光活性的超薄薄膜，用于构建“人工类囊体膜”。研究分为两部分：作为模型系统，将二氧化钛粉末浸渍在固态聚合物电解质Nafion薄膜表面。铂网附着在Nafion薄膜的两个表面，在双氢气的存在下构建燃料电池。当电池被紫外光照射时，甲醇水溶液可以用作燃料。光电流可达2ma /cm^2。该光电流归因于二氧化钛的光活化。甲醇的光催化氧化在膜表面释放出二氢，从而实现了燃料电池的光活化。光电流的一部分可归因于从二氧化钛导带到电极的直接电子流。通过在水面上显影聚合物溶液，制备了一种新型的超薄聚合物薄膜。聚氯乙烯在四氢呋喃-甲苯混合溶剂中选择性浸渍两亲钌-三联吡啶配合物，得到了厚度为25 nm的最佳薄膜。通过观察薄膜表面的二次谐波（SHG），证实了薄膜的非对称性质。此外，还验证了膜表面的钌配合物在水溶液中具有光氧化还原催化剂的作用。

Photosynthesis is defined as an energy conversion from photon into chemical potentials, which are accumulated across thylakoid membrane. In this research project, attempts have been made to prepare photoactive, ultrathin films for construction of "artificial thylakoid membrane" . The study was consisted of two parts :As a model system, titanium dioxide powder was impregnated on the surface of Nafion film (solid polymer electrolyte). Platinum meshes were attached to both surfaces of the Nafion film to construct a fuel cell in the presence of dihydrogen gas. Aqueous methanol solutions could be used as a fuel, when the cell was illuminated with ultraviolet light. The photocurrent reached upto 2 mA/cm^2. The photocurrent was ascribed to photoactivation of titanium dioxide. Photocatalytic oxidation of methanol liberated dihydrogen at the film surface so that photoactivation of fuel cell was achieved. A part of the photocurrents could be ascribed to direct electron-flow from conduction band of the titanium dioxide to the electrode.A novel, ultrathin polymer film was prepared by developing polymer solutions on water surface. Polyvinylchloride in THF-toluene mixed solvent afforded the best thin film (25 nm in thickness), which was selectively impregnated with amphiphylic ruthenium trisbipyridine complexes at one surface. Asymmetric property of the film was confirmed by observation of optical second harmonic generation (SHG) at the surface. In addition, the ruthenium complexes at the membrane surface were verified to act as photoredox catalyst in aqueous solutions.