水热法制备硫化镉纳米材料及其表征

发布时间：2018-02-26 16:03

本文关键词： 水热法硫化镉形貌晶体结构光学性质　出处：《兰州理工大学》2011年硕士论文　论文类型：学位论文

【摘要】：半导体纳米材料由于具有许多优异的性质,从而引起人们极大的研究兴趣。其中的硫化镉半导体材料在光、电、磁、催化等方面具有应用潜能,发展前景广阔,已引起了人们的高度重视。因此本文将就利用水热法制备的硫化镉纳米颗粒和纳米棒进行报道。首先,利用水热法成功地制备了硫化镉纳米颗粒,并利用X射线衍射(XRD)、透射电子显微镜(TEM)和相应选区电子衍射(SAED)等测试手段对样品的晶体结构、形貌和粒度等特征进行了表征分析。实验结果表明:适当控制某些工艺参数可以改变硫化镉纳米晶的晶型。在一定温度下,硫化镉可以从低温稳定态,即立方晶相,向高温稳定态,即六角晶相转化;改变反应时间,硫化镉也可以从立方晶相向六角晶相转化,延长反应时间样品的结晶效果更好。其次,改变试验条件用水热法成功制备了硫化镉纳米棒,利用X射线衍射(XRD)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)对样品的晶体结构、形貌进行性能表征。实验结果表明,该法制备的硫化镉纳米棒为纤锌矿结构,直径为48~74 nm,沿[001]方向择优生长。同时,以自制的硫化镉为光催化剂,钨灯模拟可见光,研究了硫化镉对活性染料亚甲基蓝的的光催化降解过程。考察了光照时间、催化剂用量、污染物的初始浓度对光催化过程的影响。也对硫化镉纳米晶的形成机理进行了初步的探讨。同时,采用紫外-可见和荧光分光光度计表征了样品的光学性质,结果发现:纳米级的硫化镉,无论是颗粒还是棒状的,吸收峰相对块体材料都发生了蓝移,但是随着反应温度的升高,吸收峰会产生一定的红移。由于表面缺陷的影响,发光峰也发生了大幅度的红移。另外,利用阳极弧放电等离子体技术成功地制备了铜纳米颗粒,并利用X射线衍射(XRD)、透射电子显微镜(TEM)和相应选区电子衍射(SAED)、BET氮吸附等测试手段对样品的晶体结构、形貌、比表面积和粒度等特征进行了表征分析,并计算了其不同晶面的晶格参数。实验结果表明:铜纳米颗粒为fcc晶态结构,晶格畸变表现为晶格收缩。
[Abstract]:Semiconductor nanomaterials have attracted great interest because of their excellent properties. Among them, cadmium sulfide semiconductor materials have the potential to be applied in light, electricity, magnetism, catalysis and so on. Therefore, cadmium sulfide nanoparticles and nanorods prepared by hydrothermal method are reported in this paper. Firstly, cadmium sulfide nanoparticles were successfully prepared by hydrothermal method. The crystal structures of the samples were measured by X-ray diffraction (XRD), transmission electron microscopy (TEM) and corresponding selected area electron diffraction (SAE). The morphology and particle size of the nanocrystalline were characterized and analyzed. The experimental results show that the crystal form of cadmium sulfide nanocrystalline can be changed by controlling some technological parameters properly. At a certain temperature, cadmium sulfide can be stabilized from the low temperature state, that is, cubic crystal phase. When the reaction time is changed, cadmium sulfide can also be transformed from cubic phase to hexagonal phase, and the crystallization effect of the sample can be improved by prolonging the reaction time. Secondly, cadmium sulfide nanorods were successfully prepared by hydrothermal method under different experimental conditions. The crystal structures of the samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and high resolution transmission electron microscope (HRTEM). The morphology of the nanorods was characterized. The experimental results showed that the nanorods prepared by this method were wurtzite structure with a diameter of 480.74 nm and preferred growth along the direction of [001]. At the same time, using the self-made cadmium sulfide as the photocatalyst, the tungsten lamp was used to simulate the visible light. The photocatalytic degradation of reactive dye methylene blue by cadmium sulfide was studied. The effect of the initial concentration of pollutants on the photocatalytic process and the formation mechanism of cadmium sulfide nanocrystals were also discussed. At the same time, the optical properties of the samples were characterized by UV-Vis and fluorescence spectrophotometer. The results showed that the absorption peaks of nano-scale cadmium sulfide, whether granular or rod-like, had a blue shift in relation to bulk materials. However, with the increase of the reaction temperature, the absorption summit produces a certain red shift. Due to the influence of surface defects, the luminescence peak also has a large red shift. In addition, copper nanoparticles were successfully prepared by anodic arc discharge plasma technique. The crystal structure and morphology of the samples were measured by X-ray diffraction (XRDX), transmission electron microscopy (TEM) and nitrogen adsorption of the corresponding selected area electron diffraction (SAEDET). The characteristics of specific surface area and particle size were analyzed and the lattice parameters of different crystal planes were calculated. The experimental results show that copper nanoparticles are fcc crystal structure and lattice distortion is lattice shrinkage.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TB383.1

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