UTILIZATION OF SUNLIGHT USING STRATIFIED PHOTOCATALYSTS

使用分层光催化剂利用阳光

基本信息

批准号：
11450393
负责人：
TOHJI Kazuyuki
金额：
$ 9.41万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2001
项目状态：
已结题

项目摘要

The application of photocatalytic reaction to generate hydrogen as a source of energy is being given higher priority in photochemical research. However, the prevention of re-association of the excited electron and the hole within the catalyst has been considered difficult and considerable researches are in progress. We had succeeded to synthesize the ZnS photocatalyst with high-efficiency of hydrogen generation under UV-light irradiation. The stratified-ZnS is synthesized by a novel wet-reaction process from ZnO or Zn(OH)_2 as starting materials and has the "stratified" structure composed by nano-crystals.In this project, we had researched the relationship between the stratified structure and the photocatalytic activity. It was found that the stratified-ZnS formed capsule with a thin layer by ultra fine particles and maintained a potential gradient within this layer, from the results of the morphology observation by transmission electron microscope and the analysis of elemental distribution in the semiconductor particle by energy dispersive x-ray spectroscopy. We can consider that the effective separation of the photoexcited electron and the hole was due to the potential gradient created by the stratified structure.We also applied the synthesis process of stratified material to other compound semiconductor materials considered they can use visible region of sunlight. As the results of experiments, we found the stratified-CdS was able to synthesize from CdO or Cd(OH)_2 as starting materials by the same process in ZnS with optimized conditions. These stratified-CdS particles have photoactivity toward visible light less than 510 nm in wavelength and can generate about 7 litters/hour to 1 m^2 of sunlight irradiation. As the next step for practical application of the hydrogen generation system using the sunlight, we will carry out a research about a sulfur-recycle process by using biochemical or hydrothermal reaction, and so on.

应用光催化反应产生氢气作为能源在光化学研究中受到高度重视。然而，防止催化剂内激发的电子和空穴的重新结合被认为是困难的，并且大量的研究正在进行中。我们成功合成了在紫外光照射下高效产氢的ZnS光催化剂。层状ZnS是以ZnO或Zn(OH)_2为起始原料，采用新型湿法反应工艺合成的，具有由纳米晶组成的“层状”结构。本项目研究了层状结构与层状结构之间的关系。和光催化活性。从透射电子显微镜形貌观察和能量分析半导体颗粒中元素分布的结果发现，分层ZnS由超细颗粒形成了一个薄层的胶囊，并且在该层内保持了电位梯度。色散 X 射线光谱。我们可以认为，光生电子和空穴的有效分离是由于层状结构产生的电势梯度。我们还将层状材料的合成过程应用到其他化合物半导体材料中，考虑到它们可以利用太阳光的可见光区域。实验结果表明，以CdO或Cd(OH)_2为起始原料，采用与ZnS相同的工艺，在优化条件下可以合成层状CdS。这些分层 CdS 颗粒对波长小于 510 nm 的可见光具有光活性，可产生约 7 升/小时的 1 m^2 阳光照射。作为利用太阳光制氢系统的实际应用的下一步，我们将开展利用生化或水热反应等的硫回收工艺的研究。