铜氧化物纳米薄膜的制备及光电化学性能的研究

发布时间：2018-01-21 18:26

  本文关键词： Cu_2O Cu_2O/SnO_2 CuO 纳米薄膜 可见光 光电流　出处：《浙江师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：铜氧化物半导体材料具有自然资源丰富、价格低廉、无毒且禁带宽度窄等特点。Cu20是一种直接带隙半导体材料,禁带宽度约为2.0 eV, CuO的禁带宽度为1.2 eV。它们对可见光具有优良的吸收,在光催化、太阳能电池和光电化学电池(PEC)方面拥有广泛的应用前景。纳米结构的金属氧化物具有较大的比表面积,且由于尺寸效应使其拥有优良的物理和化学性质,己被广泛用于气体传感器、锂离子电池、太阳能电池以及催化等领域。本文在导电玻璃FTO基底上,分别制备了纳米岛状Cu20、多孔Cu2O/SnO2和类球状纳米CuO薄膜。利用X射线粉末衍射(XRD)、激光拉曼光谱(Raman)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和紫外-可见漫反射光谱(UV-Vis)对样品的结构、组成、表面形貌和光谱性能进行表征,通过光电流响应图谱对薄膜的光电化学性能进行分析。主要研究内容和结果如以下几个方面：1-以0.05 mol-L-1 Cu(NO3)2+1.5 mol·L-1乳酸为基本镀液,通过两步恒电流法在FTO基底上沉积花状Cu膜,然后经空气气氛下氧化处理获得纳米岛状Cu20薄膜。考察了电沉积-热氧化的条件对薄膜形貌、结构、成分及可见光光电性能的影响。SEM、XRD和Raman分析结果表明,FTO在镀液中先经25 mA-cm-2的电流密度阴极极化10 s,再经7.5 mA-cm-2的电流密度阴极极化90 s,最后于175℃恒温加热2 h,制备的纳米岛状Cu2O薄膜显示出良好的可见光光电活性和稳定性。在0.2 mol-L-1Na2SO4溶液和零偏压条件下,光电流密度为-0.25 μA·cm-2。2.将电沉积的花状Cu膜浸渍到预先制备的SnO2溶胶中,然后低温煅烧获得SnO2修饰的多孔Cu2O薄膜(Cu2O/SnO2)。研究了SnO2修饰后对薄膜结构、组成、形貌、光学性质以及光电性能的影响。XRD、Raman、XPS和SEM结果表明,SnO2修饰于Cu2O薄膜表面,形成多孔Cu2O/SnO2复合薄膜。与单相Cu2O相比,Cu2O/SnO2薄膜在可见光区的吸收强度显著增强,具有更优异的光电流响应活性和稳定性,最佳修饰条件下的光电流密度大小增加了3倍。3.将电沉积的花状Cu膜经空气气氛下于300℃恒温氧化2 h,获得纳米类球状CuO薄膜。分析了薄膜的结构、形貌、光学性质及光电化学活性。在0.2 mol·L-1 Na2SO4电解液中,CuO薄膜在零偏压和可见光照射下表现出优良的光电化学性能,光电流密度为-3.2 μA·cm-2;SnO2修饰后薄膜的光电流密度略微降低,但样品的稳定性得到了提高。
[Abstract]:Cu20 is a direct bandgap semiconductor material with rich natural resources, low price, nontoxic and narrow band gap. The bandgap width of Cu20 is about 2.0 EV. The band gap of CuO is 1. 2 EV. They have excellent absorption of visible light and are photocatalytic. Solar cells and photochemical cells (PECs) have a wide range of applications. Nanostructured metal oxides have a large specific surface area. Because of its excellent physical and chemical properties, it has been widely used in gas sensors, lithium ion batteries, solar cells, catalysis and other fields. This paper is on the conductive glass FTO substrate. Nanocrystalline island Cu20, porous Cu2O/SnO2 and spheroid nanocrystalline CuO thin films were prepared by X-ray powder diffraction (XRD) and laser Raman spectroscopy (LRS). X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and UV-Vis-UV diffuse reflectance spectroscopy (UV-Vis) were used to characterize the structure, composition, surface morphology and spectral properties of the samples. The photochemical properties of the films were analyzed by photocurrent response atlas. The main research contents and results are as follows: 1-0. 05 mol-L-1 Cunno 3). 21.5 mol 路L -1 lactic acid as the basic bath. The flower-like Cu films were deposited on FTO substrates by two-step constant current method, and then oxidized in air atmosphere to obtain nano-island Cu20 films. The morphology and structure of the films were investigated under the conditions of electrodeposition and thermal oxidation. The effect of composition and visible light on photoelectricity. The results of Raman and XRD show that the current density cathodic polarization is 25 mA-cm-2 for 10 s. The current density cathodic polarization is 90 s at 7.5 mA-cm-2, and then heated at 175 鈩，

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