TiO_x基材料的制备、表征及光电化学应用

发布时间：2018-03-14 02:23

  本文选题：多孔结构　切入点：TiO_x基材料　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：当今全球经济的快速发展,带来了环境污染和能源短缺问题。随着光电化学技术的迅速发展,光催化技术和染料敏化太阳能电池(Dye-sensitized solar cell,DSSC)以其绿色环保和节能等特点引起了广泛关注。Ti02是光电领域重要的氧化物半导体,其中金红石相(Eg:3.2eV)和锐钛矿相(Eg:3.0eV)具有较高的光活性,在光催化剂和新型太阳能电池领域得到了重要应用。然而Ti02具有较宽的带隙以及较高的电子空穴复合率,使其对太阳能的利用率不足。3DOM(Three-DimensionallyOrdered Macroporous)结构(又称opal结构)具有开放和相互连接的大孔网络,比表面积大、表面空位多,因而广泛应用于光电(化学)领域。TiOx是具有氧空位的一系列亚氧化态化合物,电导率高且在腐蚀性介质中显示化学惰性,其中Ti4O7表现出最高的电导率(1000S/cm),与石墨相当,Ti4O7以其优良的电化学稳定性在光电化学等领域中被广泛关注。SnOx由于具有天然的缺陷,带隙较窄,可以实现对太阳能的转换利用,可应用于光催化、多结光伏电池等领域。本论文首次将多孔的TiOx材料应用于DSSC光阳极和光催化氧化NOx,并首次制备出优异近红外光吸收性能的Ti407/Sn506复合材料,并应用于光催化降解亚甲基蓝溶液。详细开展了以下研究工作:1、通过无乳液聚合法合成出不同粒径的单分散PMMA(聚甲基丙烯酸甲酯)微球,分别使用离心法和恒温水浴法组装出不同粒径的胶晶模板,然后采用溶胶-凝胶法对胶晶模板进行Ti02凝胶前驱物的填充。通过改变前驱物的浸泡次数和煅烧的保温时间制备出TiOx三维有序大孔结构,并使用SEM,XRD进行材料表征。将3DOM-TiOx材料用于DSSC光阳极,使用300nm粒径的胶晶模板、前驱物浸泡次数为2次,保温时间为4h的TiOx-3DOM材料的最高光电转化效率为2.5%。2、通过氢气还原3DOM-TiOx(Ti02相含量接近100%),分别在700、800℃、900℃和1000℃下制备出多孔TiOx,并使用SEM、XRD、N2气吸脱附仪、紫外-可见吸收光谱对材料进行表征。将不同还原温度下的多孔TiOx应用于光催化降解亚甲基蓝(MB)溶液和光催化氧化NOx气体,结果表明,还原温度为700℃的多孔TiOx降解MB 2h和氧化NOx气体15min后分别达到98%的降解效率和55%的氧化效率。3、通过一步水热法制备出Ti4O7/Sn506复合物,通过调整Ti4O7和Sn5O6的摩尔比例制备出系列Ti4O7/Sn506复合物。使用SEM、XRD、TEM、XPS以及紫外-可见吸收光谱对材料进行表征。将该复合材料用于光催化降解MB溶液,当Ti407与Sn506之比为1:0.8时光催化效果最佳,在紫外-可见光照4h后达到97.5%。
[Abstract]:The rapid development of the global economy has brought about environmental pollution and energy shortage. With the rapid development of photochemical technology, Photocatalytic technology and Dye-sensitized solar cell DSSCs have attracted wide attention for their green environmental protection and energy saving. Ti02 is an important oxide semiconductor in the field of optoelectronics, in which rutile phase Eg3.2eV) and anatase phase Eg3.0eV) have high photoactivity. It has been widely used in photocatalyst and new solar cells. However, Ti02 has wide band gap and high electron hole recombination rate. The three-dimensional ordered Macroporous) structure (also known as opal structure) has an open and interconnected macroporous network with large specific surface area and plenty of surface vacancies. Therefore, it is widely used in optoelectronic (chemical) field. TiOx is a series of suboxide compounds with oxygen vacancies, which have high conductivity and show chemical inertia in corrosive media. Among them, Ti4O7 has the highest conductivity of 1000S / cm ~ (-1), and Ti _ 4O _ (7) has been widely concerned in photochemistry because of its excellent electrochemical stability. Because of its natural defects and narrow band gap, Ti4O7 can realize the conversion of solar energy. In this paper, porous TiOx materials were first used in DSSC photoanode and photocatalytic oxidation of no _ x, and Ti407/Sn506 composites with excellent near-infrared absorption properties were prepared for the first time. It was applied to photocatalytic degradation of methylene blue solution. The following research work was carried out in detail. The monodisperse PMMA (polymethyl methacrylate) microspheres with different particle sizes were synthesized by non-emulsion polymerization. The colloidal templates with different particle sizes were assembled by centrifugal method and isothermal water bath method respectively. Then the colloidal template was filled with the precursor of Ti02 gel by sol-gel method. The three-dimensional ordered macroporous structure of TiOx was prepared by changing the immersion times of the precursor and the heat preservation time of calcination. The 3DOM-TiOx material was used as DSSC photoanode, and the precursor was soaked twice with the gel crystal template of 300nm diameter. The highest photoelectric conversion efficiency of TiOx-3DOM materials with holding time of 4 h is 2.5.2. The content of 3DOM-TiOxTi02 phase is close to 100m by hydrogen reduction. Porous TiOxs are prepared at 700,800 鈩，

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