溶剂热法合成锐钛矿型二氧化钛纳米晶的形状演化规律

以钛酸四丁酯为前驱体,乙醇为溶剂,月桂酸和十二胺为共同稳定剂,采用溶剂热法制备了不同形状的锐钛矿型二氧化钛纳米晶。利用透射电子显微镜(TEM)、选区电子衍射(SAED)、X射线衍射(XRD)、傅里叶变换红外(FTIR)光谱和热失重-差热分析(TG-DTA)等技术对纳米晶的结构、尺寸、形貌及形状进行了系统的表征,并探讨了月桂酸与十二胺不同配比时纳米晶的形状演化规律。结果表明:用溶剂热法在不同配比情况下获得的二氧化钛均为锐钛矿相;在月桂酸与十二胺总摩尔量不变的情况下,随着十二胺含量的增加,二氧化钛纳米晶的形状由球形逐渐演化为棒状,且结晶化程度在两者摩尔比为1:1时最好;月桂酸与十二胺稳定剂与纳米晶内核之间以桥接配位体的形式结合,且稳定剂在样品中的含量约为5%。

Shape Evolution Behavior of Anatase Titania Nanocrystals via the Solvothermal Method

Anatase titania nanocrystals with different shapes were successfully prepared by a solvothermal method, using titanium butoxide as a precursor, ethanol as a solvent, and lauric acid and dodecyl amine as stabilizing agents. The structure, size, morphology, and shape of the nanocrystals were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), Fourier transmission infrared (FTIR) spectroscopy, and thermogravimetric-differential thermal analysis (TG-DTA). We discuss how the ratio of lauric acid to dodecyl amine can influence the shape of nanocrystals. XRD results indicate that the phase of titania nanocrystals synthesized under different conditions is pure anatase. The shapes of titania nanocrystals gradually evolve from spheres to rods with increasing dodecyl amine content (at constant total molar content of lauric acid and dodecyl amine). The crystallinity of anatase titania nanocrystals prepared at a molar ratio of 1:1 (lauric acid to dodecyl amine) was better than that of nanocrystals prepared at other molar ratios. The stabilizing agents and nanocrystal core were combined by a bridging coordination ligand, and the content of stabilizing agents in samples was about 5%.