Electro-reduction of Oxygen

For polymer electrolyte membrane fuel cell (PEMFC) applications, platinum and platinum-based alloy materials have been the most extensively investigated as catalysts for the electrocatalytic reduction of oxygen. A number of factors can influence the performance of Pt-based cathodic electrocatalysts in fuel cell applications, including (i) the method of Pt/C electrocatalyst preparation, (ii) R particle size, (iii) activation process, (iv) wetting of electrode structure, (v) PTFE content in the electrode, and the (vi) surface properties of the carbon support, among others.  

A number of studies have been conducted to determine the physiochemical parameters that influence the performance and life of porous 

Other approaches have focused upon using non-precious metals and their oxides as alternatives to the platinum catalysts. For example, the mixed oxide catalysts of the binary and ternary alloys of noble metals and transition metals have been investigated for the oxygen evolution reaction in solid polymer electrolyte water electrolyzers. Binary, ternary, and quaternary platinum alloys with base metals of Cu, Ni, and Co have been used as electrocatalysts in liquid acid electrolyte cells. It was also reported that a R-Cu-Cr alloy displayed better activity to oxygen reduction than R and Pt-Cr in liquid electrolyte.The enhanced electrocatalytic activity of these types of alloys has been attributed to various factors, including the decrease of the nearest neighbor distance of platinum,the formation of Raney type 

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Watanabe M, Sei H, Stonehart P. 1989. The influence of platinum crystallite size on the electro-reduction of oxygen. J Electroanal Chem 261 375-387. 

Takasu Y, Ohashi N, Zhang XG, et al. 1996. Size effects of platinum particles on the electro-reduction of oxygen. Electrochim Acta 41 2595-2600. 

However, for some electrocatalytic reactions, such as the electrooxidation of alcohols, aldehydes or acides, and also the electro reduction of oxygen, lead adatoms can exhibit a promoting effect (3-7). Moreover, lead can change the selectivity in the case of electrocatalytic reductions of nitrocompounds (8), whereas it inhibits the adsorption of hydrogen on platinum (9,10),... 

In the case of oxygen electro-reduction, the irreversibility (or polarization from the theoretical voltage) that one almost always encounters can be considered to arise primarily from the extremely high activation energy involved in breaking the very stable 0=0 bond. As a result, the electro-reduction of oxygen is typically rate limited by the reduction of an intermediate hydrogen peroxide species. The potential of this two electron reduction to the... 

Investigation of Cobalt Porphyrins for the Cathodic Electro-reduction of Oxygen... 

Investigation of the Effect of Superacid Imide Electrode Coatings Upon the Rate of Cathodic Electro-reduction of Oxygen on Pt-based Electrodes. 

Flg. 1.114 Three electrode cell design used for the electro-oxidation of hydrocarbons and the electro-reduction of oxygen using gas-diffusion-type electrodes. 

Bard et al. are using SECM in G/C mode to screen the activity of binary and ternary metallic arrays for electro-reduction of oxygen (54, 1(X), 101). They used the TG/SC described in Section 12.4.3.1 to image the activity of both multi-metaUic and wired enzyme catalyst spots deposited on single glassy carbon substrates (Figures 12.23 and 12.24). Different from the previous approach, the spots do not need to be individually connected... 

C. Leng, J. Wu, Q. Xu, G. Lai, H. Ju, F. Yan, A highly sensitive disposable immunosensor through direct electro-reduction of oxygen catalyzed by palladium nanoparticle decorated carbon nanotube label. Biosens. Bioelectron. 27 (2011) 71-76. 

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