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采用溶胶-凝胶法不添加任何表面活性剂和胶体模板制备具有旋节相分离结构的TiO_2薄膜。首先,在TiO_2前驱体溶胶中引入可聚合的有机单体丙烯酰胺,利用浸渍法制备TiO_2胶体薄膜。然后将该薄膜在紫外光下照射一段时间。紫外光照可以诱发单体聚合,这样导致薄膜中出现相分离。在200和600℃分别热处理10 min后,可以得到具有相互连接的旋节相分离结构的TiO_2薄膜。该旋节相分离结构非常适于光催化反应,因为它具有连续的TiO_2骨架、较少的晶界位阻使载流子传输容易以及较大的比表面积。采用XRD,SEM,AFM,TG等技术对样品进行表征。结果表明,薄膜的微区尺寸可以通过改变反应参数进行调控,600℃℃的煅烧可以将体系中绝大部分的有机物除去。光催化降解亚甲基蓝溶液实验结果表明,具有旋节相分离结构的TiO_2薄膜比致密薄膜具有较好的光催化性能。
A TiO 2 thin film with spinodal phase separation structure was prepared by sol-gel method without adding any surfactant and colloidal template. First, the polymerizable organic monomer acrylamide was introduced into the TiO 2 precursor sol and the TiO 2 colloidal film was prepared by impregnation method. The film is then irradiated under UV light for a period of time. UV light can induce the polymerization of monomers, which leads to phase separation in the film. After heat treatment at 200 and 600 ℃ for 10 min respectively, TiO 2 films with interconnected spinodal phase separation structures can be obtained. The spinodal phase separation structure is very suitable for photocatalytic reaction because it has a continuous TiO 2 framework, less grain boundary hindered carrier transport easier and larger specific surface area. The samples were characterized by XRD, SEM, AFM and TG. The results show that the micro-size of the film can be controlled by changing the reaction parameters. The calcination at 600 ℃ can remove most of the organic matter in the system. The results of photocatalytic degradation of methylene blue solution show that TiO_2 films with spinodal phase separation structure have better photocatalytic activity than compact films.