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Development of Preparation Process of Fine Particles Using Reverse Micelles

反胶束微细颗粒制备工艺的开发

基本信息

批准号：
04453124
负责人：
KOMASAWA Isao
金额：
$ 3.14万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

The mechanism of formation of TiO_2 ultrafine particles in aerosol OT(AOT)/isooctane reverse micellar system by hydrolysis of titanium tetrabutoxide (TTB) was investigated. The mesurement of change in UV-vis. absorption spectra showed that the increase of TTB concentration and water content ( = [H_2O]/[AOT]), and the decrease of surfactant concentration were found to facilitate particle formation. The particle formation was controlled by TTB concentration and the number of micelles, since a certain number of hydrolyzed molecules are required to form a stable nucleus in a micell. A reaction scheme of particle formation based on the number of micelles was proposed, which successfully explained the absorption spectra and particle diameter experimentally obtained.CdS and ZnS ultrafine particles were prepared by mixing two reverse micellar solutions containing Cd(NO_3)_2 (or Zn(NO_3)_2)and Na_2S, respectively. The particles less than 5nm in diameter were successfully prepared when the water content was less than 10. In the early stage (0-20ms), the particle formation and coagulation was controlled by the collision and redispersion process of the micelles. In the later stage (20ms-), the coagulation was dominated by distribution of the particles amongst the reverse micelles.The preparation of CdS-ZnS composite particle was also investigated. Zn_XCd_<1-X>S composite ultrafine particles were prepared by simultaneous precipitation in the reverse micellar system. ZnS-coated CdS ultrafine particles were prepared by sequential precipitation of ZnS on the CdS particles in the reverse micelles. These particles showed high photocatalytic activity for hydrogen generation by water cleavage in the reversed micellar system.

研究了四丁氧基钛（TTB）水解在OT（AOT）/异辛烷反胶束气溶胶体系中形成TiO_2超微粒子的机理。紫外-可见光变化的测量。吸收光谱表明，TTB浓度和水含量（= [H_2O]/[AOT]）的增加以及表面活性剂浓度的降低有利于粒子的形成。颗粒的形成受TTB浓度和胶束数量的控制，因为需要一定数量的水解分子在胶束中形成稳定的核。用Cd（NO_3）_2（或Zn（NO_3）_2）和Na_2S两种反胶束溶液混合制备了CdS和ZnS超微粒子。当水含量小于10时，成功制备了粒径小于5 nm的纳米粒子。在初始阶段（0- 20 ms），粒子的形成和凝聚过程主要由胶束的碰撞和再分散过程控制。在凝聚后期（20 ms-1），粒子在反胶束中的分布控制了凝聚过程。采用<1-X>反胶束体系同时沉淀法制备了Zn_xCd_ S复合超微粒子.在反胶束体系中，通过顺序沉淀法制备了ZnS包覆CdS超微粒子。这些粒子在反胶束体系中表现出很高的光催化分解水制氢活性。