外场对液相合成氧化镍形貌的影响研究

发布时间：2018-05-08 20:27

  本文选题：氧化镍 + 微波　； 参考：《江西理工大学》2015年硕士论文

【摘要】：氧化镍作为一种功能性材料,因其具有良好的电化学活性与电致光性、较强的热敏性和催化性,而被广泛地应用在催化剂、超级电容器、气敏传感器、功能陶瓷材料、特种涂料以及光吸收材料等领域。为了制备形貌规则且分散性良好的氧化镍粉体,于是单一微波热合成法、有机配合物前驱体法、喷雾热解法、溶胶-凝胶法、微乳液法等逐渐被开发出来。其中对单一微波或超声波辅助合成氧化镍的研究较多,但微波与超声波协同尚未有公开报道。因此,本文采用微波与超声波协同辅助液相均匀共沉淀法制备超细氧化镍,主要的工作和相关的成果如下:本论文以Ni Cl2·6H2O为原料,CO(NH2)2和H2C2O4为沉淀剂,分别考察了加热方式、氯化镍的起始浓度、反应温度、反应时间、反应配比、陈化时间、有无添加修饰剂等的介入对氧化镍前驱体的形貌以及粒径的影响。实验结果表明,微波与超声波协同辅助液相均匀共沉淀法制备超细氧化镍前驱体要优于单一微波辐射加热和常规的水浴加热模式;以尿素和草酸为沉淀剂分别制备出类球状与块状两种形貌的氧化镍前驱体。在微波与超声波协同作用下,Ni2+的浓度为0.1 mol·L-1、CO(NH2)2的浓度为1 mol·L-1、反应温度90℃、反应时间120min、无需陈化,即可得到类球形且分散性良好的氧化镍前驱体;修饰剂pvp的添加对改善氧化镍前驱体的团聚效果并不明显;氧化镍前驱体在微波干燥箱中采用低档干燥90min形貌较好。Ni O前驱体的热分解过程,主要考察了热分解温度和保温时间对氧化镍粉体形貌以及粒径的影响。由热重-差热分析可知,在热分解温度大于300℃时,有氧化物生成;XRD和FT-IR结果显示,大于300℃时所生产的氧化物为立方晶型的Ni O粉体,且随着热分解温度的升高,Ni O颗粒晶型更完整;SEM结果表明,Ni O粉体继承了其前驱体的形貌,呈类球形,分散性良好,粒径分布在0.8~1.5μm,与前驱体的粒径分布相差不大。综合多种分析表征可知,热分解温度过低,则没有氧化镍粉体生成或分解不完全;当热分解温度过高时,粉体容易出现“烧结”;故焙烧Ni O前驱体的较优工艺:热分解温度为300~500℃,保温时间为90min。
[Abstract]:As a functional material, nickel oxide has been widely used in catalysts, supercapacitors, gas sensors and functional ceramics because of its good electrochemical activity and electroluminescence, strong thermal sensitivity and catalytic properties. Special coatings and light absorption materials and other areas. In order to prepare nickel oxide powders with regular morphology and good dispersion, single microwave thermal synthesis method, organic complex precursor method, spray pyrolysis method, sol-gel method and microemulsion method were gradually developed. There are many studies on the single microwave or ultrasonic assisted synthesis of nickel oxide, but the cooperation of microwave and ultrasonic has not been reported. Therefore, in this paper, microwave-ultrasonic assisted liquid phase homogeneous coprecipitation method is used to prepare ultrafine nickel oxide. The main work and related results are as follows: in this thesis, Ni Cl2 6H2O was used as raw materials, COG NH _ 2H _ 2 and H2C2O4 as precipitators, and the heating methods were investigated, respectively. The influence of the initial concentration of nickel chloride, reaction temperature, reaction time, reaction ratio, aging time and the addition of modifier on the morphology and particle size of nickel oxide precursor was investigated. The experimental results show that the microwave-ultrasonic assisted liquid phase homogeneous coprecipitation method is superior to single microwave radiation and conventional water bath heating mode in preparing superfine nickel oxide precursor. Using urea and oxalic acid as precipitators, the spherical and bulk nickel oxide precursors were prepared. Under the synergistic action of microwave and ultrasonic wave, the concentration of Ni _ 2 was 0.1 mol L ~ (-1), the concentration of COO _ (2) NH _ (2) was 1 mol / L ~ (-1), the reaction temperature was 90 鈩，

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