LaSr_2Mn_2O_7 Ruddlesden-Popper manganites for oxygen reduction and electrochemical capacitors  

作　　者：Qin Li Meitian Guo Kaiyuan Wang Zhiqiang Wei Guoping Du Guoguang Zhang Nan Chen 

机构地区：[1]School of Materials Science and Engineering,Nanchang University,Nanchang 330031,China [2]School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,China

出　　处：《Journal of Rare Earths》2020年第7期763-769,I0003,共8页稀土学报（英文版）

基　　金：Project supported by National Natural Science Foundation of China (21571095,61366004)。

摘　　要：LaSr2 Mn2 O7,a Ruddlesden-Popper type bilayered perovskite,was investigated as oxygen catalyst for oxygen reduction reaction(ORR) and active electrode material for electrochemical capacitors in KOH solutions.XPS results show that Mn takes a mixed Mn2+,Mn3+and Mn4+valence state with an average valence of 3.4.As catalyst towards ORR,LaSr2 Mn2 O7 and LaSr2 Mn2 O7/acetylene black composite favor four electron pathways for ORR.LaSr2 Mn2 O7/C composite shows a comparable onset potential for ORR to that of Pt/C electrode.The improved ORR activity of LaSr2 Mn2 O7/acetylene black composite is attributed to the synergy between catalytic LaSr2 Mn2 O7 and conductive acetylene black.As electrode material for electrochemical capacitors,LaSr2 Mn2 O7 exhibits a maximum specific capacitance of 167.2 F/g with 62%faradic contribution at a scan rate of 1 mV/s in cyclic voltammetry test.

关 键 词：LaSr2Mn2O7 Oxygen reduction reaction Electrochemical capacitor Rare earths 

分 类 号：O643.36[理学—物理化学] TM53[理学—化学]