US EPA

1037877 

Journal Article 

The dual pathway in action: decoupling parallel routes for CO(2) production during the oscillatory electro-oxidation of methanol 

Nagao, R; Cantane, DA; Lima, FH; Varela, H 

2012 

1 

Physical Chemistry Chemical Physics
ISSN: 1463-9076
EISSN: 1463-9084 

14 

23 

8294 

English 

22395562 

10.1039/c2cp00037g 

WOS:000304353600006 

http://xlink.rsc.org/?DOI=c2cp00037g
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As in the case of most small organic molecules, the electro-oxidation of methanol to CO(2) is believed to proceed through a so-called dual pathway mechanism. The direct pathway proceeds via reactive intermediates such as formaldehyde or formic acid, whereas the indirect pathway occurs in parallel, and proceeds via the formation of adsorbed carbon monoxide (CO(ad)). Despite the extensive literature on the electro-oxidation of methanol, no study to date distinguished the production of CO(2) from direct and indirect pathways. Working under, far-from-equilibrium, oscillatory conditions, we were able to decouple, for the first time, the direct and indirect pathways that lead to CO(2) during the oscillatory electro-oxidation of methanol on platinum. The CO(2) production was followed by differential electrochemical mass spectrometry and the individual contributions of parallel pathways were identified by a combination of experiments and numerical simulations. We believe that our report opens some perspectives, particularly as a methodology to be used to identify the role played by surface modifiers in the relative weight of both pathways-a key issue to the effective development of catalysts for low temperature fuel cells.