Study of Photophysical Process and Photocatalytic Activity of Anchored Catalyst Prepared by thev Sol-Gel Method

溶胶-凝胶法制备锚定催化剂的光物理过程及光催化活性研究

基本信息

批准号：
02805099
负责人：
FUJII Tsuneo
金额：
$ 1.15万
依托单位：
Shinshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02805099/
关键词：
Sol-Gel Method Mixed Metal Oxides Photocatalyst Photophysics Anchored Catalyst Fluorescence Spectra Photo CVD Photoprobe 蛍光スペクトル光CVD

项目摘要

The absortion, fluorescence, and fluorescence-excitation spectra of some aromatic photoprobe molecules(l-naphthol, benzoqunolines, rhodamine VB, fluorescein, and pyrene)have been observed along with the progress of the sol-gel reaction of SI-AI and Si-Ti mixed alkoxides. The spectral changes during the sol-gel process reflected the changes of the polarity, microviscosity, and other chemical and physical properties around the photoprobes of the reaction specimes. In a case of small fraction of AI, gelation occurred relatively slow and polarity and microviscosity around the photoprobe molecules increased relatively fast. On the other hand, the reverse chemical and physical phenomena are observed in a case of large fraction of AI. In a case of acid catalyst, hydrolysis proceeded fast and the rate determing reaction is condensation step. On the other hand, in a case of basic catalyst, the condensation proceeds fast and the rate determining step is hydrolysis. Observation of the fluorescence spectra of aromatic molecules is a useful photophysical and photochemical probe for studying the sol-gel-xerogel transition of metal alkoxides on a molecular level.The thermal stability, similar to the photostability, of aromatic molecules encapsulated in xerogel state prepared by the sol-gel method is one of the important point for the utility of functional materials. We found that the encapsulated rhodamine B and fluorescein molecules have increased thermal stability than in air circumstance. This enhancement can be sttributed to the prevention of the permeation of oxygen into the pores of the prepared silica gel.Excimer-like fluorescence of pyrene during the sol-gel reaction disappeared before gelation, but the fluorescence intensity became strong in encapsulated state into pores of the Si-Ti and SI-AI. This striking phenomenon can be attributable to the adsorption of two molecules at Ti site and 1 : 1 complex formation between aromatic molecules and AI.

The absortion, fluorescence, and fluorescence-excitation spectra of some aromatic photoprobe molecules(l-naphthol, benzoqunolines, rhodamine VB, fluorescein, and pyrene)have been observed along with the progress of the sol-gel reaction of SI-AI and Si- Ti混合烷氧化物。在溶胶 - 凝胶过程中的光谱变化反映了反应斑点的光探测器周围的极性，微度和其他化学和物理特性的变化。在AI的少数情况下，凝胶化发生相对较慢，极性和光探针分子周围的微度粘度相对较快。另一方面，在大量AI的情况下，观察到反向化学和物理现象。在酸催化剂的情况下，水解进行快速进行，确定反应的速率是凝结步骤。另一方面，在基本催化剂的情况下，凝结速度很快进行，并且确定速率的步骤是水解。观察芳族分子的荧光光谱是一种有用的光学和光化学探针，用于研究金属烷氧化物在分子水平上的Sol-Gel-xerogel转变。类似于芳香凝胶分子的光稳定性，类似于光稳定性，该光稳定性由芳族分子包装在Xeromotial consapity中，由芳族凝胶固定在Xerogel coles consy中。 Sol-Gel方法是功能材料实用性的重要点之一。我们发现，与空气情况相比，封装的Rhodamine B和荧光素分子的热稳定性增加。这种增强可以被限制为预防氧气渗透到制备的硅胶孔中。在胶质反应过程中，pyrene的外观样荧光消失了，但荧光强度在封装的状态中变为强度Si-ti和Si-ai。这种引人注目的现象可以归因于在Ti位点吸附两个分子，而芳族分子和AI之间的复合形成为1：1。