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Design and Preparation of Ultra Highly Active Semiconductor Photocatalyst

超高活性半导体光催化剂的设计与制备

基本信息

批准号：
07805077
负责人：
OHTANI Bunsho
金额：
$ 1.41万
依托单位：
HOKKAIDO UNIVERSITY (1996)Kyoto University (1995)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07805077/
关键词：
Photocatalyst Surface Area Crystallinity Recombination Hydrothermal Pyrolysis Transfer Hydrolysis Organic Solvents

项目摘要

It has been clarified that the most decisive factor controlling the photocatalytic activity of semiconductor powders is surface area and crystallinity, on the basis of the investigation on the activity of commercial and laboratory-made titanium (IV) oxide powders. The larger the surface area becomes, the more the reaction substrate molecules are adsorbed on the surface, to result in the higher activity, while the higher the crystallinity of particles, the smaller the crystal defect inducing electron-hole recombination. The thus obtained hypothesis that semiconductor particles having large surface area and being high crystallinity should exhibit high photocatalytic activity, however, a little difficult to apply on the practical preparation of photocatalyst powders, because, in the conventional method of titanium (IV) oxide preparation, titanium hydroxide (or oxihydroxide) is prepared and then calcined to remove water. The higher-temperature calcination may induces crystallization but at the same time reduce the surface area, and vice versa. We have developed the novel method of titanium (IV) oxide preparation without the use of water ; (1) Hydrothermal Crystallization of Organic Media (HyCOM), (2) Thermal Decomposition (TD), and (3) Transfer Hydrolytic Crystallization in Alcohols (THyCA). The titanium (IV) oxide powders thus prepared had large surface area and high crystallinity of anatase crystallites. As expected from these physical properties, these powders showed the photocatalytic activity, under both ceroted and deceroted conditions, which is marked higher than that of highly active commercially available titanium (IV) oxide (Degussa P-25). Thus, we have confirmed the principle for the design of ultra-highly semiconductor photocatalyst and developed the novel synthetic methods.

根据对商业和实验室制造的氧化钛（IV）粉末活性的研究，已经阐明控制半导体粉末光催化活性的最决定性因素是表面积和结晶度。表面积越大，表面吸附的反应底物分子越多，活性越高，而颗粒的结晶度越高，引起电子空穴复合的晶体缺陷越小。由此获得的假设，即具有大表面积和高结晶度的半导体颗粒应表现出高光催化活性，然而，应用于光催化剂粉末的实际制备有点困难，因为在传统的氧化钛(IV)制备方法中，制备氢氧化钛(或羟基氧化钛)，然后煅烧以除去水。较高温度的煅烧可能会引起结晶，但同时会减少表面积，反之亦然。我们开发了不使用水制备氧化钛（IV）的新方法； (1) 有机介质水热结晶 (HyCOM)，(2) 热分解 (TD)，以及 (3) 醇中转移水解结晶 (THyCA)。由此制备的氧化钛(IV)粉末具有大的表面积和高锐钛矿微晶的结晶度。正如从这些物理特性所预期的那样，这些粉末在消磁和消磁条件下都显示出光催化活性，明显高于高活性的市售氧化钛 (IV) (Degussa P-25)。由此，我们确定了超高半导体光催化剂的设计原理并开发了新的合成方法。