石墨烯基纳米钙钛矿复合粉体的制备及电催化性能研究

发布时间：2018-02-28 10:23

本文关键词： 石墨烯钙钛矿复合物取代电催化　出处：《燕山大学》2015年硕士论文　论文类型：学位论文

【摘要】：钙钛矿具有催化活性高、耐氧化、碱性溶液中稳定、导电性高等优点,被用来替代贵重金属催化剂,解决限制金属空气电池规模生产和应用的问题。石墨烯是一种具有单个碳原子厚度的二维碳材料,具有极大的比表面积、优异的导电性和化学稳定性,是催化剂理想的支撑材料。将钙钛矿与石墨烯进行复合,石墨烯作为半导体纳米粒子的支撑材料,不仅可以有效阻止纳米粒子的团聚,而且能够起到电子传递通道的作用。因此,复合后可以产生新的协同效应,具有广阔的应用前景。本研究采用改进的Hummers方法制备出了氧化石墨,并通过热剥离还原氧化石墨制得薄层石墨烯。采用溶胶-凝胶法将制得的石墨烯悬浮液与硝酸盐溶液进行复合,成功制备了La Mn O3/石墨烯、A位不同掺杂量的La1-xCaxMn O3/石墨烯(x=0.1、0.2、0.3、0.4、0.5)和La Mn1-xCoxO3/石墨烯(x=0.05、0.10、0.15)的复合粉体。通过热重-差热技术分析了La Mn O3/石墨烯前驱体凝胶与焙烧后样品的热分解历程。通过扫描电镜观察到La Mn O3与石墨烯复合形成了多孔结构;BET结果证实,La Mn O3/石墨烯的比表面积大于纯La Mn O3。通过电化学表征手段确定了空气电极的最佳工艺条件,并确定复合材料中石墨烯的最佳百分含量为10 wt%。利用X-射线衍射对A、B位掺杂样品进行了物相分析,结果证实不同价态元素的取代没有改变钙钛矿的晶体结构。通过一系列电化学行为测试对制得的改性粉体进行了电催化表征。研究结果表明,当Ca的取代量为0.4或Co的取代量为0.1时,复合粉体具有优异的电催化效果,说明掺杂有利于提高复合材料的导电性;两种复合粉体的电子数分别为3.60、3.87,ORR过程包括4 e-路径与2 e-路径,说明经A、B掺杂的复合粉体具有极高的ORR催化活性。
[Abstract]:Perovskite has high catalytic activity, high oxidation stability in alkaline solution, the conductivity is high, can be used as a substitute for precious metal catalyst, solve the problem of metal air battery scale production and application problems. Graphene is a two-dimensional carbon material with a single carbon atom thickness, great specific surface area, excellent conductivity and chemical stability, is the ideal catalyst support material. The perovskite and graphene composite graphene as the support material of semiconductor nanoparticles, can effectively prevent the agglomeration of the nanoparticles, and can play the role of electronic delivery channels. Therefore, the composite can produce new synergies, and has broad application prospects this research adopts the improved Hummers method was prepared by thermal exfoliation of graphite oxide, and the reduction of graphite oxide prepared thin layer of graphene. By sol-gel method The prepared graphene suspension and nitrate solution compound, La Mn O3/ graphene was successfully prepared, different A doped La1-xCaxMn O3/ graphene (x=0.1,0.2,0.3,0.4,0.5) and La (x=0.05,0.10,0.15) Mn1-xCoxO3/ graphene composite powder. Through thermogravimetric analysis technique La Mn O3/ graphite ene precursor gel and calcined samples. The thermal decomposition process observed through scanning electron microscope La Mn O3 composite with graphene formed a porous structure; the results of BET showed that the La Mn O3/ graphene surface area is larger than that of pure La Mn O3. the optimum conditions of air electrode was determined by electrochemical method, and determine the best percentage of graphene in the composites was 10 wt%. by X- ray diffraction of A, B doped samples were analyzed by phase analysis, results show that replacing the elements of different valence does not change the crystal structure through a perovskite. The electrocatalytic characterization of modified powder prepared by a series of electrochemical behavior test. The results of the study show that, when the substitution amount of substitution amount of Ca was 0.4 or 0.1 Co, the composite powder has excellent electrocatalytic activity, that doping is beneficial to improve the conductivity of composites; electron number two composite the powder was 3.60,3.87, ORR process including 4 e- and 2 e- path path, by A, ORR catalytic activity of B composite powder doped with high.

【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.3

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