Oxygen reduction at a manganate electrocatalyst in KOH solutions

Journal of the Brazilian Chemical Society

Centro de Pesquisas e Desenvolvimento, Rio de Janeiro, Brazil¹  Santos, Diogo M. F.¹  Baptista, Walmar¹  Instituto Superior Técnico, Lisboa, Portugal¹  Sequeira, César A. C.¹ 

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

DOI  :  10.1590/S0103-50532006000500014

学科分类：化学（综合）

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】

Unknown