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  本文關鍵詞： 石墨烯 鈣鈦礦 復合物 取代 電催化　出處：《燕山大學》2015年碩士論文　論文類型：學位論文

【摘要】：鈣鈦礦具有催化活性高、耐氧化、堿性溶液中穩(wěn)定、導電性高等優(yōu)點,被用來替代貴重金屬催化劑,解決限制金屬空氣電池規(guī)模生產(chǎn)和應用的問題。石墨烯是一種具有單個碳原子厚度的二維碳材料,具有極大的比表面積、優(yōu)異的導電性和化學穩(wěn)定性,是催化劑理想的支撐材料。將鈣鈦礦與石墨烯進行復合,石墨烯作為半導體納米粒子的支撐材料,不僅可以有效阻止納米粒子的團聚,而且能夠起到電子傳遞通道的作用。因此,復合后可以產(chǎn)生新的協(xié)同效應,具有廣闊的應用前景。本研究采用改進的Hummers方法制備出了氧化石墨,并通過熱剝離還原氧化石墨制得薄層石墨烯。采用溶膠-凝膠法將制得的石墨烯懸浮液與硝酸鹽溶液進行復合,成功制備了La Mn O3/石墨烯、A位不同摻雜量的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)的復合粉體。通過熱重-差熱技術分析了La Mn O3/石墨烯前驅體凝膠與焙燒后樣品的熱分解歷程。通過掃描電鏡觀察到La Mn O3與石墨烯復合形成了多孔結構;BET結果證實,La Mn O3/石墨烯的比表面積大于純La Mn O3。通過電化學表征手段確定了空氣電極的最佳工藝條件,并確定復合材料中石墨烯的最佳百分含量為10 wt%。利用X-射線衍射對A、B位摻雜樣品進行了物相分析,結果證實不同價態(tài)元素的取代沒有改變鈣鈦礦的晶體結構。通過一系列電化學行為測試對制得的改性粉體進行了電催化表征。研究結果表明,當Ca的取代量為0.4或Co的取代量為0.1時,復合粉體具有優(yōu)異的電催化效果,說明摻雜有利于提高復合材料的導電性;兩種復合粉體的電子數(shù)分別為3.60、3.87,ORR過程包括4 e-路徑與2 e-路徑,說明經(jīng)A、B摻雜的復合粉體具有極高的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.

【學位授予單位】：燕山大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TB383.3

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本文編號：1546898