半導体光触媒ナノ構造と水素透過膜から成る二層メンブレンを用いた光誘起高純度水素生成の研究を実施した。まず, 陽極酸化TiO2ナノチューブアレイとパラジウム無電解めっき膜の二層構造を採用し, 全電気化学的手法による膜厚数μm程度の極薄メンブレンの作製条件を見出した。更にメタノールを犠牲剤とした水の光触媒分解による高純度水素生成を実証すると共に, その水素生成速度や実効的な量子収率の評価技術を新たに確立した。また, 酸化鉄ナノチューブアレイに白金を担持した試料に対し, 高真空下での気相メタノール光触媒分解の観察を行った結果, 可視光照射に伴う水素生成を検出し, 気相反応場特有の現象の観測に成功した。
Photo-induced high-purity hydrogen production was investigated by using bilayer membranes composed of nanostructured semiconductor photocatalysts and hydrogen permeable membranes. Firstly, a bilayer structure comprised by anodized TiO2 nanotube array and palladium electroless-plated film was considered, and all electrochemical fabrication of the ultrathin bilayer membranes with a thickness of a few micrometers was established. Then, high-purity hydrogen production from water photolysis with methanol as a sacrificial reagent was demonstrated as well as the establishment of evaluation methods of hydrogen production rate and apparent quantum yield in the bilayer membranes. In addition, gas-phase photocatalysis of methanol over platinum-loaded iron oxide nanotube arrays was examined in high vacuum. As a result, hydrogen production was detected under visible-light illumination, suggesting that some interesting phenomena characteristic of gas-phase photocatalysis were successfully monitored.
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