Methanol electrocatalysis

Sriramulu S, Jarvi TD, Stuve EM. 1998. A kinetic analysis of distinct reaction pathways in methanol electrocatalysis on Pt(lll). Electrochim Acta 44 1127-1134. 

The first paper on methanol electrocatalysis under UHV conditions was published by Attard et al. [139] on the most active surface, Pt(110). Similar results to those on Pt(l 11) were found, that is, carbon monoxide and molecular hydrogen, but with a slightly larger methanol surface coverage of 9 = 0.10. It was the first time that methoxy species were proposed as intermediates and were different from the carbon monoxide or formyl species proposed earlier by Bagotskii et al. [140], However, traces of the formyl species were also detected on reconstructed Pt(l 10) using vibrational spectroscopy, which was able to co-adsorb this species with atomic oxygen [117]. 

Here, we will restrict ourselves to pointing out that ad-atoms, such as Pb and Bi, which are strong promoters for formic acid electrocatalysis, only slightly increase the activity of Pt for methanol oxidation [83-86]. The most successful promoter for methanol electrocatalysis is Ru and perhaps Sn, albeit not as ad-atoms. 

These conclusions from the infrared reflectance spectra recorded with Pt and Pt-Ru bulk alloys were confirmed in electrocatalysis studies on small bimetallic particles dispersed on high surface area carbon powders.Concerning the structure of bimetallic Pt-Ru particles, in situ Extended X-Ray Absorption Fine Structure (EXAFS>XANES experiments showed that the particle is a true alloy. For practical application, it is very important to determine the optimum composition of the R-Ru alloys. Even if there are still some discrepancies, several recent studies have concluded that an optimum composition about 15 to 20 at.% in ruthenium gives the best results for the oxidation of methanol. This composition is different from that for the oxidation of dissolved CO (about 50 at.% Ru), confirming a different spatial distribution of the adsorbed species. 

A period of high research activity in electrocatalysis began after it had been shown in 1963 that fundamentally, an electrochemical oxidation of hydrocarbon fuel can be realized at temperatures below 150°C. This work produced a number of important advances. They include the discovery of synergistic effects in platinum-ruthenium catalysts used for the electrochemical oxidation of methanol. 

Chang SC, Leung LWH, Weaver MJ. 1990. Metal crystallinity effects in electrocatalysis as prohed hy real-time ETIR spectroscopy electrooxidation of formic acid, methanol, and ethanol on ordered low-index platinum surfaces. J Phys Chem 94 6013-6021. 

Chang SC, Ho Y, Weaver MJ. 1992. Applications of real-time infrared spectroscopy to electrocatalysis at bimetallic surfaces. I. Electrooxidation of formic acid and methanol on bismuth-modified platinum (111) and platinum (100). Surf Sci 265 81-94. 

Vielstich W. 2003. CO, formic acid, and methanol oxidation in acid electrol3ftes—mechanisms and electrocatalysis. In Bard AJ, Stratmann M, Calvo EJ, eds. Encyclopedia of Electrochemistry. Volume 2. New York Wiley, p 466-511. 

Jarvi TD, Stuve EM. 1998. Fundamental aspects of vacuum and electrocatalytic reactions of methanol and formic acid on platinum surfaces. In Lipkowski J, Ross PN, eds. Electrocatalysis. New York Wiley-VCH. pp. 75-153. 

Watanabe M, Motoo S. 1975b. Electrocatalysis by ad-atoms. Part I. Enhancement of the oxidation of methanol on platinum and palladium by gold ad-atoms. J Electroanal Chem 60 259-266. 

Dinh FIN, Ren X, Garzon FTF, Zelenay P, Gottesfeld S. 2000. Electrocatalysis in direct methanol fuel cells in-situ probing of FTRu anode catalyst surfaces. J Electroanal Chem 491 ... 

Iwasita T. 2002. Electrocatalysis of methanol oxidation. Electrochim Acta 47 3663-3674. 

Iwasita T. 2003. Methanol and CO electrooxidation. In Vielstich W, Lamm A, Gasteiger HA, eds. Handbook of Euel Cells. Volume 2 Electrocatalysis. Chichester Wiley, pp. 603-624. 

Shibata M, Furuya N, Watanabe M. 1987. Electrocatalysis by ad-atoms. Part XXL Catal3ftic effects on the elementary steps in methanol oxidation by non-oxygen-adsorbing ad-atoms. J Electroanal Chem 229 385-394. 

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