Hydrogen, electro-oxidation

Santos E, Schmickler W. 2008. Electronic interactions decreasing the activation harrier for the hydrogen electro-oxidation reaction. Electrochim Acta 53 6149-6156. 

Igarashi H, Fujino T, Watanabe M. 1993. Hydrogen electro-oxidation on platinum catalysts in the presence of trace carbon monoxide. J Electroanal Chem 391 119-123. 

Equation (8) gives the limiting, potential-independent current density predicted for complete control of sequence (5b) -h (5c) by the dissociative chemisorption of H2 (process (5b)) at a catalyst surface with a small number of CO-free sites (see 18a). Such a limiting rate of hydrogen electro-oxidation at low anodic overpotentials has been observed recently in RDE experiments with H2/CO mixtures, performed with platinum and PtRu RDEs [18d,e]. This limiting current density (Eq. (8)) explains the PEFC characteristic observed with low CO levels in the fuel feed stream, depicted in Fig. 13. Under such conditions, the fuel cell will exhibit ordinary anode losses up to the current density defined by Eq. (8), but higher current demands would require a... 

There is clear evidence that adsorbate and alloyed metal atoms on platinum surface promote CO electro-oxidation. The reduced overpotential is primarily a result of the promotion of the activation of water. The subsequent kinetics are determined by the details of a Langmuir-Hinshelwood reaction between the adsorbed oxidant (OH) and adsorbed CO. Evidence is also presented that relates this promotion (or poisoning) of CO electro-oxidation to tolerate CO in hydrogen feeds in the hydrogen electro-oxidation reaction. An alternative mechanism that may operate at low potentials [79,113] may be that the reduction in CO adsorption energy on platinum induced by Ru [86,113,114] results in a higher equilibrium concentration of nonpoisoned sites. The relative importance of these mechanisms is a function... 

Kunimatsu, K., Uchida, H., Osawa, M. and Watanabe, M. (2006) In situ infrared spectroscopic and electrochemical study of hydrogen electro-oxidation on Pt electrode in sulfuric acid. Journal... 

Jambunathan, K., Shah, B.C., Hillier, A.C. Scanning electrochemical microscopy of hydrogen electro-oxidation. Rate constant measurements and carbon monoxide poisoning on platinum. J. Electroanal. Chem. 2001, 500, 279-289. 

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