CeO2论文：纳米CeO 2复合物的制备及光电性质研究

CeO2 论文：纳米 CeO_2 复合物的制备及光电性质研究【中文摘要】YiO2 是一种优良的半导体材料,在太阳能电池、光催化、空气净化方面有着广泛的应用。稀土元素具有独特的 4f 亚层电子结构,与半导体材料复合可以改进其性能。目前报道较多的是关于稀土掺杂半导体材料的光催化性质,对于其电化学性质研究的很少。本文采用溶胶-凝胶法,制备出多种 CeO2 复合物,采用扫描电子显微镜(SEM)、-射线衍射仪(XRD)、红外光谱仪(FT-IR)、紫外-可见光谱(UV-vis)等对产物的结构和组成进行了表征,探讨了复合物的形成机理,研究了产物的电化学发光性质和光催化性质。论文主要内容如下：1. TiO2/CeO2 复合薄膜的制备及其电化学性质研究首先利用溶胶-凝胶法制备 TiO2 溶胶,然后掺杂一定量的 Ce(NO3)3·6H2O,采用浸渍提拉的方法,经过不同的煅烧温度得到 TiO2/CeO2 复合薄膜。利用 SEM、XRD、UV、FTIR 等测试手段对他们的形貌、晶型等性质进行表征。同时,通过循环伏安法(CV)对合成薄膜的电化学发光(ECL)性质进行对比研究,考察不同 pH 的电解质溶液对其 ECL 结果的影响。研究表明：TiO2/CeO2 复合薄膜的电化学发光性能相比较单纯薄膜有很大的提高,不同煅烧温度对于复合薄膜的形貌和电化学性质有较大的影响。结果显示：在 200下煅烧 1h 后,再于 450下煅烧 1h,所得样品具有较好的 ECL 性质。2. TiO2/CeO2 复合粉末的制备及其电化学性质研究以 Ce (NO3) 3·6H2O 为铈源,通过氨水沉淀法得到黄色的 CeO2 粉末。在溶胶-凝胶法制备 YiO2 溶胶时,加入一定量的 上述 CeO2 粉末,经过干燥、煅烧、研磨以得到淡黄色的 TiO2/CeO2复合粉末。利用 SEM、XRD 等现代分析测试手段对所得的产物进行表征,利用循环伏安法研究 TiO2/CeO2 复合粉末电化学发光性质。实验研究了不同的扫描范围,不同 pH 的电解质溶液,以及粘合剂 nafion对 ECL 性质的影响,结果表明：不同扫描范围、不同 pH 的电解质溶液,所得 ECL 不同,适当的 nafion 浓度可以将样品很好地固定在玻碳电极上。对于样品产生的两个峰 ECL1 与 ECL2,通过控制所加电位研究了它们的发光机理。结果表明：ECL1 为电化学发光峰,ECL2 伴随有化学发光峰。3. CeO2/GO 纳米复合物的制备及其光催化性质研究以 Ce (NO3)3·6H2O 为铈源,通过氨水沉淀法首先得到黄色的 Ce02粉末,然后通过混合法制备掺杂氧化石墨烯(GO)的 CeO2/GO 复合物。产物用扫描电镜、X 射线粉末衍射和固体紫外可见光谱进行表征。在太阳光照下测定了产物对亚甲基蓝溶液的光催化降解效果。结果表明：GO 可以大大增强 CeO2/GO 复合物对亚甲基蓝的光催化效果。【英文摘要】TiO2 is an excellent semiconductor material that has a wide applications in solar cell, photocatalysis, and air purification. As well known, rare earth element has a unique 4f sub-layer electronic structure that can improve the performance of semiconductor composites. Recently the photocatalysis of the rare earth doped semiconductor materials has mainly been studied, but their electrochemical properties have rarely been reported.In this paper, various CeO2 composites were prepared by using sol-gel method, and the structure and composition of the products were characterized by Scanning Electron Microscope (SEM), X-ray Diffraction (XRD), Infrared Spectrometer (FT-IR), and X ultraviolet-visible Spectroscopy (UV-vis). The formation mechanism of the composites was discussed, and the electrochemical luminescence property and photocatalysis of the products were studied.Our main work as follows:1. The preparation and electrochemical property of TiO2/CeO2 composite filmsFirst, the TiO2 sol-gel prepared by using the sol-gel process was doped with a certain amnount of Ce (NO3) 3·6H2O. Then, the TiO2/CeO2 composite films were prepared by dipping lifting method and calcining. The morphology and crystal structure of films as-obtained were characterized by SEM, XRD, UV and FTIR. The electrochemical luminescence (ECL) of the composite films was studied by cyclic voltammetry (CV), and the effect of the electrolyte solution with different pH on ECL was discussed. The results show that the ECL property of the TiO2/CeO2 composite films has been greatly improved, comparing to the pure films. The calcining temperature affected the morphology and electrochemical property of composite films. When calcinated at 200for 1h and then at 450for 1h, the composite film as-obtained has a excellent ECL property. 2. The preparation and electrochemical property of TiO2/CeO2 composite powderWith Ce (NO3) 3·6H2O as cerium source, the CeO2 yellow powder was first obtained through the ammonia precipitation method. Then, the TiO2 sol formed by sol-gel process was added a certain amount of the CeO2 powder. Finally, the TiO2/CeO2 composite powder was obtained by drying and calcining the sol. The products as-prepared were characterized by SEM and XRD, and their ECL property was studied by cyclic voltammetry. The effect of scanning range, the pH of electrolytic solution and adhesive nafion on ECL was discussed. The results show that the different ECL curves was obtained in different scanning range or with different pH solution. With appropriate amount nafion, the powder can be solidly fixed on the surface of glassy carbon electrode. Significantly, the ECL1 and ECL2 peaks produced by TiO2/CeO2 composite powder were studied by controlling potential exerted on the work electrode. The result shows that the ECL1 is electrochemical luminescence peak and ECL2 involves some chemiluminescence component.3. The preparation and photocatalysis of CeO2/GO composite powderWith Ce (NO3)3·6H2O as cerium source, the CeO2 yellow powder was first obtained through the ammonia precipitation method. Then, the CeO2/GO composite powder was prepared by mixing graphene oxide and CeO2 powder. The structure and composition of the products were characterized by SEM, XRD and UV-vis. The photocatalytic activity of the CeO2/GO composite power was studied by photodegradating organic methylene blue with sun light. The results show that the GO can enhance t