液相合成超薄TiO_2纳米片微结构影响因素研究  

Influence Factors on the Microstructure of Ultrathin TiO_2 Nanosheets Synthesized by Liquid Phase Method

作　　者：楚婉怡 唐笑 李振 林景诚 钱觉时[1] Chu Wanyi;Tang Xiao;Li Zhen;Lin Jingcheng;Qian Jueshi(College of Materials Science and Engineering,Chongqing University,Chongqing 400045;School of Science,Chongqing University of Posts and Telecommunications,Chongqing 400065,China)

机构地区：[1]重庆大学材料科学与工程学院,重庆400045 [2]重庆邮电大学理学院,重庆400065

出　　处：《化学学报》2018年第7期549-555,共7页Acta Chimica Sinica

基　　金：国家自然科学基金(No.51472037)资助项目~~

摘　　要：二维纳米结构二氧化钛由于表面活性位点剧增可带来光催化活性的显著提高.本文通过液相法在低温条件下合成大尺寸TiO_2纳米片,重点研究溶液中硝酸浓度、熟化温度和反应物浓度对其二维结构形成过程的影响.采用透射电子显微镜(TEM)表征样品的微观形态,并结合紫外-可见吸收光谱、X射线衍射谱(XRD)、X射线光电子能谱(XPS)和傅立叶变换红外光谱分析样品的微结构性质.采用光催化还原Cr(VI)作为指示反应,评估各制备参数对二氧化钛光催化性能的影响.结果表明,硝酸浓度为0.0217~0.0721 mol·L^(-1)的样品在0~4℃条件下胶溶及熟化时可得到具有显著量子尺寸效应的超薄锐钛矿型TiO_2纳米片;硝酸浓度过高引起样品晶型和形态的转变,过低导致胶溶时间延长;熟化温度超过4℃会破坏二维结构的形成;提高反应物中乙醇的用量有助于分散水解产物,促进胶溶和二维结构的形成进程.Synthesis of large scale ultrathin 2D structural TiO2 is challenging and meaningful in many fields of science and technology, because of their larger surface area and higher electron-hole pairs separation efficiency. In this work, a ＂bottomup＂ method is used to synthesize the large-size ultrathin TiO2 nanosheets at low temperature by liquid-phase. The mixture of tetrabutyl titanate and ethanol could hydrolyze in a dilute nitric acid solution with an ice-water bath and the obtained hydrolysates could peptize. After peptized, the hydrolysis products become to be very small TiO2 nanoclusters and they form a two-dimensional network structure via the orientation bonding formed by hydrogen bond. Continue to be aged at low temperature, the crystallization degree of samples will increase, and the networks eventually turn into TiO2 nanosheets. Effects of the concentration of nitric acid, ambient temperature and reactant concentration on the formation of two-dimensional structure TiO2 are studied in this work. The transmission electron microscope（TEM）, ultraviolet-visible（UV-Vis） absorbance spectra, X-ray diffractometer（XRD）, X-ray photoelectron spectroscopy（XPS） and Fourier Transform infrared spectroscopy（FTIR） are used to analyze the morphology, microstructure and properties of the samples, and the experiment of photocatalytic reduction of Cr（VI） is conducted to observe the photocatalytic activity of samples as well as to verify the effects of system parameters on the microstructure of TiO2 nanosheets. The results show that when the concentration of nitric acid is during 0.0217~0.0721 mol·L^-1, the anatase TiO_2 nanosheets that thinner than 1 nm could be obtained by peptizing and aging at 0~4 ℃. Excess nitric acid leads to crystalline and morphology transformation of TiO2, but lower concentration of nitric acid could prolong the peptizing time; increasing the ambient temperature will undermine the formation of two-dimensional structure; improving the amount of ethanol in the reactant will b

关 键 词：TiO2团簇 TiO2纳米片 低温合成 影响因素 光催化活性 

分 类 号：TB383.1[一般工业技术—材料科学与工程] TQ134.11[化学工程—无机化工]