Ti-(纳米MCM-41)复合材料的制备与表征

Preparation and Characterization of Ti-Nanosized MCM-41 Composite Materials

采用水热合成法,溴化十六烷基三甲基铵为模板剂,正硅酸四乙酯为硅源,制备出纳米MCM-41分子筛。以钛酸四丁酯为钛源用液相移植法浸渍煅烧后的纳米MCM-41分子筛,制得了Ti-(纳米MCM-41)复合材料。采用粉末XRD,化学分析,N2吸附-解吸附技术,IR,评价了制备方法的有效性及对纳米MCM-41分子筛孔结构的影响。结果表明:钛已并入MCM-41分子筛中,MCM-41内表面上的硅羟基团是钛并入的主要位置,部分钛在分子筛孔道内。制得的材料Ti-(纳米MCM-41)保持高度有序的介孔一维结构。Ti-(纳米MCM-41)样品的紫外-可见扩散漫反射吸收光谱相对于体相TiO2发生明显蓝移,这是由于TiO2粒子组装在纳米分子筛MCM-41孔道内的结果。

Nanosized MCM-41 molecular sieve was prepared by using cetyltrimethylammonium bromide （CTMAB） and tetraethyl orthosilicate （TEOS） as the template and the silica source by means of hydrothermal method. The titanium-nano MCM-41 composite materials were prepared by impregnating the calcined nanoscale MCM-41 molecular sieve and using the tetrabutyl titanate as the titanium precusor. By means of powder X-ray diffraction, chemical analysis, nitrogen adsorption-desorption technique, infrared spectroscopy, the efficiency of the preparative method and the effect of it on the pore structure of nanometer MCM-41 molecular sieve were evaluated. The results show that titanium is incorporated into the MCM-41 molecular sieve. The silanol groups on the internal wall surfaces of MCM-41 are suggested to be the major sites for titanium incorporation. A part of titanium is in the channels of the molecular sieve. The prepared Ti-（nano MCM-41） materials keep the highly ordered mesoporous one-dimensional structure. The significant blue shift of the UV-vis diffusion reflectance absorption spectra of the Ti-（nano MCM-41） sample, compared to the spectrum of bluk TiO2, results from the encapsulation of titaniun dioxide particales in the channels of nanosized MCM-41 molecular sieve.