TiO~2修饰的介孔分子筛MCM-41的合成、表征及光 催化性研究

首次以三种不同的含钛有机物为氧化钛的前驱体，合成了三种TiO~2呈单层分散状态的TiO~2修饰的介孔分子筛MCM-41，并以XRD，FT-IR，液氮温度下N~2吸附-脱附曲线，固体UV-vis漫反射等表征手段对其结构特征和氧化钛分散状态进行了研究。TiO~2在介孔分子筛MCM-41孔道中分散，MCM-41仍能保持骨架结构，没有晶相TiO~2生成；TiO~2与MCM-41孔道表面的≡Si－OH以化学键连接，生成Si－O－Ti键；TiO~2在MCM-41内孔壁呈均匀单层分散状态；TiO~2粒子的减小使其对紫外光的吸收发生明显的蓝移现象。并以苯酚降解反应为模型检验合成的具有光催化性的TiO~2修饰的MCM-41的光催化活性。

Preparation, characterization and photocatalytic properties of titania modified monolayered mesoporous MCM-41

The titania modified inner surface of mesoporous silicate MCM - 41 was synthesized for the first time by varying titanium precursors and calcined MCM - 41. The as - synthesized samples were characterized by XRD, FT - IR, nitrogen adsorption - desorption at 77 K and solid state diffuse reflectance UV - vis spectroscopy. XRD suggested that a long - range order was still present in the hexagonal phase of the titania modified MCM - 41 and were free of crystalline TiO2. Titania cocondensed with the pendant OH groups of MCM-41 via Si-O-Ti bonds and thus modified the inner walls. The titania in the modified MCM - 41 existed as a monolayer on the inner walls according to the results of nitrogen adsorption - desorption isotherms. In solid state UV - vis spectra, the titania modified MCM - 41 had significant blue shift compared to bulk TiO2 due to the well known quantum size effect. The photocatalytic properties of the titania modified MCM - 41 were tested in the decomposition of phenol.