PHOTOCHEMICAL REACTION CONTROLLED BY PHOTOCHEMICAL DIODE AND ITS APPLICATION TO FIXATION OF CARBON DIOXIDE

本研究的主要结果如下：1.采用热氧化法制备了可分离的光化学二极管，该光化学二极管是以薄的Ti金属箔为光敏片，将电池完全分为两个部分。2.在电解质水溶液中，氙灯照射在光化学二极管的n-TiO_2表面，诱导Ti金属和n-TiO_2半导体上产生氢和氧，而在KHCO_3水溶液中，Ti金属上除了生成一氧化碳外，还生成甲烷、乙烯等烃类化合物。3.光照n-TiO_2/p-Si片的p-n型光化学二极管也能诱导水的分解和二氧化碳的还原。然而，量子产率与Shottky型光化学二极管的产率几乎相同。4.在电解质水溶液中，尝试电化学合成具有光催化作用的石墨层间化合物。

The results of this research are summarized as follows.1.The product-separable photochemical diode was fabricated by a thermal oxidation of thin Ti metal foil as photoactive wafers, by which the cell was completely divided into two compartments2.A Xe-lamp illumination on a n-TiO_2 surface of photochemical diode in an aqueous electrolyte solution induced the production of hydrogen and oxygen on Ti metal and n-TiO_2 semiconductor, respectively, while in an aqueous solution of KHCO_3 the production of hydrocarbons such as methane and ethylene in addition to carbon monoxide on Ti metal. The hydrocarbon production was catalyzed by Cu ad-atoms deposited onto Ti metal.3.The illumination on a p-n type photochemical diode of a n-TiO_2/p-Si wafer also induced a water decomposition and a reduction of carbon dioxide. However the quantum yield is almost the same as the yield with a Shottky-type photochemical diode.4.An attempt for synthesis of graphite intercalation compounds with photocatalytic action was made electrochemically in an aqueous electrolyte solution.