Bifunctional oxygen electrode

Bursell, M. Pirjamali, M. Kiros, Y. La0.6Cao 4Co03, La Cao.yMnOj and LaNiOi as bifunctional oxygen electrodes. Electrochimica Acta (2002) 47(10) 1651-1660. 

Bursell M, Pirjamali M, Kiros Y (2002) Lao.6Cao.4Co03, Lao.iCao.9Mn03 and LaNi03 as bifunctional oxygen electrodes. Electrochim Acta 47(10) 1651-1660... 

Jung, H. Y., S. Park, and B. N. Popov. 2009. Electrochemical studies of an unsupported Ptir electrocatalyst as a bifunctional oxygen electrode in a unitized regenerative fuel cell.. Power Sources 191 357-361. 

A good catalyst for the bifunctional hydrogen electrode is platinum, and for the bifunctional oxygen electrode the most promising catalyst material is a mixture of platinum and iridium oxide. The use of thin catalyst layers in the electrode helps to minimize mass transport and ohmic limitations [57]. In addition to the catalyst composition, the ionomer content, the catalyst layer thickness, and the PTFE content are varied and the influence of these variations on performance has been described [58-63]. The highest efficiency can be achieved using a catalyst with a high amount of platinum and a low amount of iridium [58, 60]. 

Song SD, Tang ZY, Pan LZ, Nan JM. Study on the electrocheinical properties of Lai. xSt Nii-yFeyOs bifunctional oxygen electrode. Huaxue Xuebao 2005 63 363-71. 

In alkaline solutions, bifunctional properties are exhibited by catalysts having the pyrochlore structure A2B2O7, where A = Pb, Bi and B = Ru, Ir (Horowitz et al., 1983), and by oxide catalysts having the perovskite structure (e.g., Lao,6Cao,4Co03) (Wu et al., 2003). The properties of bifunctional oxygen electrodes are discussed in greater detail in a paper by Jorissen (2006). 

In acid electrolytes, carbon is a poor electrocatalyst for oxygen evolution at potentials where carbon corrosion occurs. However, in alkaline electrolytes carbon is sufficiently electrocatalytically active for oxygen evolution to occur simultaneously with carbon corrosion at potentials corresponding to charge conditions for a bifunctional air electrode in metal/air batteries. In this situation, oxygen evolution is the dominant anodic reaction, thus complicating the measurement of carbon corrosion. Ross and co-workers [30] developed experimental techniques to overcome this difficulty. Their results with acetylene black in 30 wt% KOH showed that substantial amounts of CO in addition to C02 (carbonate species) and 02, are... 

The overpotentials for oxygen reduction and evolution on carbon-based bifunctional air electrodes for rechargeable Zn/air batteries are reduced by utilizing metal oxide electrocatalysts. Besides enhancing the electrochemical kinetics of the oxygen reactions, the electrocatalysts serve to reduce the overpotential to minimize... 

As the anion-exchange membrane fuel cell is the alkaline-based system, we can use non-platinum-based catalyst. This is a big advantage to lower the cost of fuel cells. Especially perovskite-type and pyrochlore-type oxides have high performance to oxygen-electrocatalysts which could be applicable to the cathode materials. Some oxides have also bifunctional activities as oxygen electrode catalyst to produce a reversible fuel cell thus, future deployment is expected. While, the big problems are stability of the base... 

Jorissen L., Bifunctional oxygen/air electrodes, J. Power Sources 155, 23 (2006). 

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