Oxygen reduction at a manganate electrocatalyst in KOH solutions

Journal of the Brazilian Chemical Society

César A. C. Sequeira²  Diogo M. F. Santos²  Walmar Baptista¹ 

[1] ,Instituto Superior TécnicoLisboa,Portugal

关键词: fuel cell;    metal-air battery;    lanthanum calcium manganate;    oxygen reduction;    HO2- disproportionation;   

DOI  :  10.1590/S0103-50532006000500014

来源: SciELO

【 摘 要 】

The electrocatalysis of the oxygen reduction reaction by lanthanum calcium manganate, (La0.5Ca0.5MnO3) (LCM) has been studied by cyclic voltammetry using the rotating ring-disc electrode technique (RRDE) in alkaline medium. From the ring-disc data and other kinetic parameters it has been assumed that the oxygen reduction occurs by dissociative chemisorption at low overpotentials. At higher overpotentials, the formation of hydrogen peroxide (HO2- in this case) has been observed on this electrocatalyst. The apparent exchange current density value for oxygen reduction on LCM has been found to be 5 ´ 10-8 A cm-2, while the corresponding Tafel slope is 0.115 V per decade. The possible reaction mechanism for electroreduction of oxygen on this oxide catalyst has been discussed.

【 授权许可】

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