形貌可控表面修饰纳米级TiO_2的合成与表征

Synthesis and Characterization of Surface-modified Nanocrystalline Anatase Titania with Different Morphologies

以Ti(OC4H9)4为前驱体,甲苯为溶剂,油胺为表面活性剂,通过在反应釜中直接封存固态干冰的简易方法来替代传统超临界CO2技术,在190℃、17MOa下通过非水解路线成功制备了形貌可控、表面修饰的锐钛矿相纳米TiO2粉末。利用XRD、TEM、FT-IR测试技术对样品的结构与形貌进行了表征。结果表明,油胺在产物表面形成修饰层使得纳米TiO2能够稳定地分散在甲苯等有机溶剂中。当体系中V(甲苯)∶V(油胺)∶V(Ti(OC4H9)4)=2∶0.4∶0.5时,TiO2为直径约2nm、平均长度约8nm的纳米棒,推测其长度方向可能为锐钛矿相c轴。对纳米TiO2的生长过程及干冰作用进行了初步探讨。

Surface-modified nanocrystalline anatase titania with different morphologies were prepared via a non-hydrolytic route through a simplified supercritical CO2 method, which deploys direct sealing of dry ice into autoclave instead of using supercritical CO2. The decomposition of Ti （OC4H9 ）4 precursor was fulfilled at 190 ℃ with the presence of oleyamine as surfactant in toluene and CO2. The pressure inside the autoclave could reach 17 MPa due to the evaporation of dry ice at elevated temperature. The morphologies and structure of the products were characterized by XRD, TEM and FT-IR. The experimental results show that the products obtained using surfactant are dispersible within organic solvents such as toluene and hexane. Nanorods of titania with dimension size of 2 -× 8 nm could be obtained when the volume ration of tolune： oleyamine： Ti （OC4H9）4 was set as 2：0. 4：0.5. The growth direction of such nanorods might be along with the C axis of anatase titania. A possible growth mechanism and function of dry ice in this system wereproposed based on experimental observations.