过渡金属氧化物作为金属空气电池氧电极双功能催化剂的性能研究

发布时间：2018-03-26 08:08

本文选题：金属空气电池　切入点：复合材料　出处：《山西师范大学》2017年硕士论文

【摘要】：全球范围内能源需求的逐步增长以及生态环境的日益恶化,推动了可持续能源转换和存储技术的快速发展。金属空气电池作为一种新型的电池体系,因其高能量密度,低成本以及环境友好等优点已然引发众多科研工作者的关注。然而,氧电极缓慢的电化学反应动力学阻碍其商业化道路。因此,研究开发具备氧还原反应(ORR)和氧析出反应(OER)活性的双功能催化剂成为关键因素。基于以上问题,本文主要制备了三种以过渡金属氧化物为主的复合材料,并研究其作为金属空气电池氧电极双功能催化剂的催化活性,主要内容如下:首先,以活性碳为基底利用一步溶剂热法首次合成Ag-CoFe_2O_4/C纳米复合材料。所制备的Ag-CoFe_2O_4/C纳米复合材料在碱性溶液中表现出良好的ORR和OER催化活性。这是因为CoFe_2O_4的加入阻碍了Ag纳米颗粒的团聚,使复合材料表面暴露出更多的活性位点。与此同时,Ag与CoFe_2O_4之间产生的电子效应也促进了Ag-CoFe_2O_4/C纳米复合材料电化学性能的提升。此外,Ag-CoFe_2O_4/C催化剂表现出较好的抗甲醇能力以及稳定性。其次,采用溶剂热法制备MnO_2-CoFe_2O_4/C纳米复合材料。经过电化学测试发现,MnO_2-CoFe_2O_4/C催化剂具有比MnO_2/C、CoFe_2O_4/C以及MnO_2/C+CoFe_2O_4/C(机械混合)都要好的ORR和OER催化活性。此外,通过对不同质量比的MnO_2-CoFe_2O_4/C的催化活性进行比较,可以得出,当MnO_2与CoFe_2O_4的质量比为1:1时,其ΔE值最小,即MnO_2-CoFe_2O_4/C(1:1)具有最好的氧电极催化活性。最后,经过两步水热法合成以MnOOH纳米棒为基底的CoMn_2O_4/MnOOH纳米复合材料。其中,MnOOH不仅作为载体,还为合成CoMn_2O_4提供锰源。经测试可得,CoMn_2O_4/MnOOH具有较高的电化学活性面积(ECSA),这为氧还原反应提供更多的活性位点。同时,CoMn_2O_4与MnOOH的之间产生的协同效应也对ORR性能有促进作用。此外,CoMn_2O_4/MnOOH复合材料在碱性条件下表现出较好的OER催化性能,并且在抗甲醇能力以及稳定性方面都有出色表现。而且,较小的ΔE值说明CoMn_2O_4/MnOOH具备作为氧电极双功能催化剂的潜能。
[Abstract]:The rapid development of sustainable energy conversion and storage technology is promoted by the gradual growth of global energy demand and the worsening of ecological environment. As a new type of battery system, metal air battery has high energy density. The advantages of low cost and environmental friendliness have attracted the attention of many researchers. However, the slow electrochemical reaction kinetics of oxygen electrode hinders its commercialization. The research and development of bifunctional catalysts with the activity of oxygen reduction reaction (ORR) and oxygen precipitation reaction (ORR) have become the key factors. Based on the above problems, three kinds of composite materials with transition metal oxides (TME) were prepared. Its catalytic activity as a bifunctional catalyst for oxygen electrode of metal air battery is studied. The main contents are as follows: first of all, Ag-CoFe_2O_4/C nanocomposites were synthesized by one-step solvothermal method using activated carbon as substrate. The prepared Ag-CoFe_2O_4/C nanocomposites exhibited good catalytic activity of ORR and OER in alkaline solution. This is because the addition of CoFe_2O_4 hinders Ag. The agglomeration of nanoparticles, At the same time, the electronic effect between Ag and CoFe_2O_4 also promoted the improvement of electrochemical performance of Ag-CoFe_2O_4/C nanocomposites. In addition, Ag-CoFe2O4 / C catalyst showed better methanol resistance. Force and stability. Second, MnO_2-CoFe_2O_4/C nanocomposites were prepared by solvothermal method. Electrochemical tests showed that the catalyst MNO\ +\'s\ + _ (2) /\%\%\%\%\\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\%\. It can be concluded that when the mass ratio of MnO_2 to CoFe_2O_4 is 1:1, its 螖 E value is the smallest, that is, MNO _ 2-CoFe _ 2O _ 4 / C _ 2O _ 1: 1: 1) has the best catalytic activity on oxygen electrode. Finally, CoMn_2O_4/MnOOH nanocomposites based on MnOOH nanorods are synthesized by two-step hydrothermal method. It is found that CoMn2O4 / MnOOH has a higher electrochemical active area and this provides more active sites for the oxygen reduction reaction. At the same time, the synergistic effect between CoMn2O4 and MnOOH also promotes the performance of ORR. In addition, CoMn2O4 / MnOOH composites show better OER catalytic performance under alkaline conditions. Moreover, the small 螖 E value indicates that CoMn_2O_4/MnOOH has the potential as a bifunctional catalyst for oxygen electrode.
【学位授予单位】：山西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TM911.41

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