Cathodic oxygen reduction on noble metal and carbon electrodes

Oxygen reduction at a manganate electrocatalyst in KOH solutions

“…2,10 In the anodic potential region also, the catalyst maintains its stability and the evolution of oxygen is observed at a potential of about 0.6 V (measurements in the potential range of 0.8 V to -0.6 V, as it is shown in Figure 1, curve a).…”

“…But in view of the present RRDE data in which one observes that the end product depends on the applied potential, it has been assumed that HO 2 -ion maintains an adsorption-desorption equilibrium and this equilibrium constant may be dependent on the potential of the electrode. The reaction model can be written as shown in Figure 6.…”

“…Os resultados do disco-anel e outros parâmetros cinéticos indicaram que, a baixas sobretensões, a redução do oxigênio ocorre por adsorção química. Para sobretensões mais elevadas foi observada a formação de peróxido de hidrogênio (HO 2 -neste caso) no eletrocatalisador. A densidade de corrente de permuta aparente, determinada para a redução do oxigênio no LCM foi de 5 × 10 -8 A cm -2 , sendo o correspondente coeficiente de Tafel de 0,115 V por década.…”

“…One of the major concerns of fuel cells research is the development of good electrocatalysts for the oxygen reduction reaction. Platinum group metal electrodes, 1,2 activated carbons, 2,3 semiconducting mixed metal oxides, 4 among others, 5,6 are a family of materials that have been shown to possess good catalytic activity for oxygen reduction at low temperature.…”

“…2,7,8 In the present paper, the electrocatalysis of the oxygen reduction reaction by lanthanum calcium manganate, La 0.5 Ca 0.5 MnO 3 (LCM) has been studied by linear sweep cyclic voltammetry (LSCV) using the rotating ring-disc electrode technique (RRDE) in KOH solutions.…”