节点文献
钴、镍硒化物的溶剂热合成及其性质研究
Solvothermal Synthesis of Cobalt and Nickel Selenides and Their Properties
【作者】 赵京凤；
【作者基本信息】 安徽大学 ， 无机化学， 2013， 硕士
【摘要】 镍和钴的硒化物纳米材料在催化剂、传感材料、磁性材料以及电池等方面有着极其广泛的应用。开发新型的镍、钴化合物以及深入研究它们在各领域中的应用具有十分重要的意义,将有利于充分发挥这一类材料的最大潜能。本论文利用溶剂热法合成NiSe和Co0.85Se两种化合物,并研究了它们在环境保护中的应用。论文主要内容如下：1、以乙二醇为溶剂兼还原剂,利用简单的溶剂热方法合成了六方相的八面体形貌的硒化镍(NiSe)。运用X射线粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)等测试手段对产物进行了表征,并研究了反应温度、反应时间对产物的影响,找到制备八面体NiSe的最佳反应条件。将制备的这一产物用于催化降解水合肼,并与非典型合成条件下制备样品的催化效果对比,发现八面体硒化镍对水合肼具有较为明显的催化降解作用。这一性质可用于污水中水合肼的去除,从而对环境保护具有重要的意义。2、在不使用任何表面活性剂和模板的情况下,成功地合成了六方相的石墨烯状的Co0.85Se。X-射线衍射(XRD)、扫描电子显微镜(SEM)、选区电子衍射(SAED)以及透射电子显微镜(TEM)和BET的方法都被用来表征产物的结构、形态和比表面积。SEM观察结果表明,得到的Co0.85Se纳米晶体是厚度小于10纳米的石墨烯状的薄片。对制备的产品在室温下进行铁磁性测试,发现这种样品具有弱的顺磁性。并且该产品具有较高的比表面积,可以作为吸附剂用于废水处理中。3、在前部分实验的基础上,对实验方法稍微改变,采用溶剂热方法制备出石墨烯状的纳米Co0.85Se薄膜。通过进一步的实验发现这种Co0.85Se纳米材料在催化还原对硝基苯酚的过程中具有较高的活性,同时对甲基蓝具有较强的吸附能力。在硼氢化钠的存在下,Co0.85Se作为催化剂用于还原对硝基苯酚的实验中,实验结果表明,随着硼氢化钠浓度和催化剂量的增加,还原反应的动力学常数也增大。并且这种催化剂在多次使用后,利用磁铁分离收集再用于同样的体系中仍然具有很高的活性。此外,该Co0.85Se对甲基蓝具有很强的吸附能力,并考虑了pH值对其吸附能力的影响,发现在不同条件下,吸附过程在30分钟内达到平衡。
【Abstract】 Nickel and cobalt selenides are widely applied in the fields of catalyst, sensor materials, magnetic materials, cell and so on. It is important to explore novel synthesis and expand application extents of nickel and cobalt selenides. In this thesis, solvothermal routes have been chosen to synthesize Co0.85Se and NiSe nanosturctuers, and their applications in environmental protection have also been studied. The main contents are as follows:1. Nano nickel selenides with octahedral morphology were successfully synthesized via a simple mild solvothermal method. In the process, glycol was used as both solvent and reducing agent. The as-synthesized nano-sized nickel selenide was characterized by SEM, XRD, TEM, and so on. The results indicated that the formation of the octahedral NiSe was strongly dependent on the reaction temperature and reaction time. Interestingly, it was found that the as-prepared octahedral NiSe showed efficient catalytic performance for decomposition of hydrazine hydrate at room temperature.2. Hexagonal Co0.85Se with Ni0.85Se-type structure has been successfully synthesized without any surfactants by a solvothermal reduction route. X-ray diffraction (XRD), scanning electron microscopy (SEM), selected area electron diffraction pattern (SAED), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) method were used to characterize the structure, morphology and specific surface area of the Co0.85Se nanocrystals. SEM observation indicated that the obtained Co0.85Se nanocrystals were of Graphene-like morphology with thickness less than10nm. The as-prepared products have ferromagnetic at room temperature from magnetic measurement. And the products with high specific surface area could be used as adsorbent in wastewater treatment, which may be very useful for the environment.3. Uniform Graphene-like Co0.85Se nanosheets which exhibit a remarkable catalytic activity for the reduction of p-nitrophenol and a high adsorption capacity for Methyl Blue were prepared via a modified solvothermal process. The prepared nanosheets were applied to catalyze the reduction of p-nitrophenol in the presence of NaBHt, and the results indicated that the kinetic constant of the reaction increased when the concentrations of NaBH4and the amount of catalyst increased. The catalyst can be recycled a number of times after the quantitative reduction of4-nitrophenol. In addition, the adsorption efficiency for methyl blue was evaluated by the product and possible influence factors were discussed.