基于表面金属有机化学方法的硅胶表面氧化钛的制备及表征

Preparation and Characterization of Ti—O Units Anchored on Silica by Surface Organometallic Chemistry Method

以普通硅胶为载体,采用表面金属有机化学合成技术,通过'一锅'反应制备了硅胶表面金属有机钛化合物,然后经高温煅烧获得了硅胶表面氧化钛.采用傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)、热重分析(TG-DTA)及原子力显微镜(AFM)对硅胶表面金属有机钛化合物和表面氧化钛进行了结构表征.结果表明,高温煅烧过程中,硅胶表面金属有机钛化合物不仅脱除了有机配体,并且通氧使其表面'再生'羟基,确保了钛的四配位形式不变;氧化钛通过Si—O—Ti键锚定在硅胶表面,呈分散、孤立状态分布.高温煅烧后,硅胶的骨架结构保持完好.

Based on the surface organometallic chemistry method,four surface organtitanium complexes anchored on silica were obtained by the reaction of spacer ligand（ phenol,benzoic acid,1-naphthol and1-naphthol acid as spacer ligand,respectively）,Ti（ NMe2）4and silica in one pot reaction system. Then,the four products were calcined respectively to obtain the titanum oxide anchored on silica. The surface organtitanium complexes and surface titanum oxides were characterized by Fourier transform infrared spectrum（ FTIR）,thermogravimetry analysis（ TG-DTA）,X-ray photoelectron spectrometry（ XPS） and atomic force microscopy（ AFM）. The results showed that after calcination of surface organtitanium complexes at high temperature in O_2,not only were the organic ligands removed,but also the surface hydroxy was regenerated,which ensured that the four coordination forms of Ti were not changed. Meanwhile,titanium oxides anchored on silica surface by Si—O—Ti bonds,and existed as isolated,dispersed and ordered form. In addition,the skeleton structure of the silica was kept well after calcination of surface organtitanium complexes.