锌钴氧体系的制备及其电化学性能研究

发布时间：2018-03-18 17:00

本文选题：钴酸锌　切入点：尖晶石　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：尖晶石结构金属氧化物以低廉的价格、优秀的导电性能和活泼的电化学性能成为能源领域研究的热点。本文主要研究了尖晶石结构锌钴氧体系氧化物的电容和氧催化还原性能。通过尿素水热合成的方法成功制备出钴酸锌,利用X射线衍射技术确定其尖晶石结构,场发射扫描电镜观测发现其粒径约在100~300nm范围内。通过电化学测试,发现制备的电极在1、2、5和10A g~(-1)的电流密度下,电容分别为705.4、647.0、561.2和550.0F g~(-1),循环3000次后电容值下降到80.6%。通过线性扫描技术计算发现钴酸锌电极为二电子催化过程,放电20000s后,电流密度降为起始电流密度的70.5%。为了观察镍取代锌对钴酸锌性能的影响,在制备过程中控制锌和镍的比例,分别制备出Zn_(1-x)Ni_xCo_2O_4(x=0、0.2、0.4、0.6、0.8和1)粉体,实验结果表明:掺杂镍后的材料仍然为尖晶石结构,但是表面形貌都发生了细微变化。随着镍含量的增加,在1 A g~(-1)的电流密度下,比电容由705.4 F g~(-1)(x=0)下降到685.8 F g~(-1)(x=0.2),随后又上升到1165.0 F g~(-1)(x=1),电极稳定性逐渐减小。各电极都表现出对氧催化还原的活性。采用NiCo_2O_4为催化材料时,氧气直接通过四电子反应步骤还原,而其他材料表现出二电子与四电子混合步骤。采用相似的方法研究掺杂锰对钴酸锌性能的影响,制备出Zn1-xMnxCo_2O_4(x=0、0.2、0.4、0.6、0.8和1)粉体,实验结果表明:掺杂锰后的材料仍然为尖晶石结构,表面形貌也发生了变化,随着锰原子分数的增大,电容性能呈现先增大后减小的趋势,电极稳定性逐渐降低。在氧催化还原方面,Zn1-xMnxCo_2O_4各电极都表现出明显的催化活性,掺杂后的材料电极同时具有二电子和四电子反应步骤。
[Abstract]:Spinel structure metal oxides at low prices, Excellent electrical conductivity and active electrochemical performance have become a hot topic in the field of energy. In this paper, the capacitance and oxygen catalytic reduction properties of spinel zinc-cobalt oxide system have been studied. Zinc Cobalt was successfully prepared by the method. The spinel structure was determined by X-ray diffraction technique. The particle size of the spinel was found to be in the range of about 100 ~ 300nm by field emission scanning electron microscopy. The electrochemical measurements showed that the prepared electrode was at the current density of 1 ~ 2G ~ (5) and 10 A ~ (-1). The capacitance of the electrode was 705.4U 647.0N 561.2 and 550.0F g ~ (-1), respectively, and the capacitance value decreased to 80.6 after 3000 cycles. It was found by linear scanning technique that the electrode was a two-electron catalytic process, and that it was 20 000 s after discharge. In order to observe the effect of zinc substituted by nickel on the properties of zinc cobalate, the ratio of zinc and nickel was controlled during the preparation process, and the ZnH1-xNixCo2O00.20.40.4n0.60.8-0.60.and 1) powders were prepared, respectively, in order to observe the effect of the current density drop to the initial current density of 70.5% of the initial current density, and to control the ratio of zinc and nickel during the preparation process, respectively. The experimental results show that the nickel doped material is still spinel structure, but the surface morphology changes slightly. With the increase of nickel content, at the current density of 1 A g ~ (-1), The specific capacitance decreased from 705.4 F / g ~ (-1) to 685.8 F / g ~ (-1) ~ 0.2g ~ (-1), and then increased to 1165.0 F / g ~ (-1) G ~ (-1) ~ (1) ~ (1) ~ (1) ~ (1) ~ (1) ~ (1) ~ (1) ~ 1 ~ (-1) F ~ (-1) F ~ (-1) G ~ (-1), and the stability of the electrode decreased gradually. All the electrodes showed the activity of catalytic reduction of oxygen. When NiCo_2O_4 was used as the catalytic material, oxygen was reduced directly by four-electron reaction. The other materials showed two-electron and four-electron mixing steps. The effect of doped manganese on the properties of zinc cobalt was studied in a similar way. Zn1-xMnxCo2O4xCo2O4xCO2O0. 2 and 1) powders were prepared. The experimental results show that the doped manganese is still spinel structure. The surface morphology also changed. With the increase of mn atom fraction, the capacitance performance increased first and then decreased, and the electrode stability gradually decreased. In the oxygen catalytic reduction, the electrode showed obvious catalytic activity at all electrodes, such as Zn1-xMnxCo2O4, Zn1-xMnxCo2O4. The doped electrode has both two electron and four electron reaction steps.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ132.41;TM53

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