Methanol oxidation electrocatalysis

W. Chrzanowski, A. Wieckowski, Surface structure effects in platinum/ruthenium methanol oxidation electrocatalysis. Langmuir 1998, 14, 1967-1970. 

MacElonald JP, Gualtimi B, Rnnga N, Teliz E, Zinola CF (2008) Modification of platinum surfaces by spontaneous deposition methanol oxidation electrocatalysis. Int J Hydrogmi Energ 33 7048-7061... 

Lin, C. L., Rodriguez-Lopez, J., Bard, A. J. Micropipet delivery-substrate collection mode of scanning electrochemical microscopy for the imaging of electrochemical reactions and the screening of methanol oxidation electrocatalysis. Anal. Chem. 2009, 81, 8868-8877. 

Chrzanowski, W., Wieckowski, A. (1998) Surface strucmre effects in platinum/ruthe-nium methanol oxidation electrocatalysis. Langmuir, 14, 1967-1670. 

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. 

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

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. 

Radicals, 1139, 1147, 1193, 1416 adsorbed, in electrocatalysis, 1275 determination by rotating disk electrode, 1140 intermediate, in methanol oxidation, 1270 Radiation... 

Rate determining step (cont.) electrocatalysis and, 1276 methanol oxidation, 1270 in multistep reactions, 1180 overpotential and, 1175 places where it can occur, 1260 pseudo-equilibrium, 1260 quasi equilibrium and, 1176 reaction mechanism and, 1260 steady state and, 1176 surface chemical reactions and, 1261 Real impedance, 1128, 1135 Reciprocal relation, the, 1250 Recombination reaction, 1168 Receiver states, 1494 Reddy, 1163... 

The conclusion here is therefore that activity in methanol oxidation on platinum is limited to the 111 plane. The other planes are blocked with a radical, probably adsorbed CO or -C-OH. It is not known at present what fraction of the electrode corresponds to each plane, but it is clear that greatly improved electrocatalysis of CH3, OH to C02 would be observed if electrodes containing only the 111 plane were available. 

This chapter presents the design and application of a two-stage combinatorial and high-throughput screening electrochemical workflow for the development of new fuel cell electrocatalysts. First, a brief description of combinatorial methodologies in electrocatalysis is presented. Then, the primary and secondary electrochemical workflows are described in detail. Finally, a case study on ternary methanol oxidation catalysts for DMFC anodes illustrates the application of the workflow to fuel cell research. 

Since platinum in its pure state, and either alloyed or in mixtures with other metals/metal oxides, (which act as promoters), is among the most active materials for methanol oxidation, much attention has been devoted to the nature of, and mechanism involved in, the methanol oxidation reaction on platinum. As such, platinum has served as a useful model system illustrating the general features of metal electro-oxidation in an aqueous environment. There are many postulated mechanisms for the oxidation of methanol, and detailed descriptions of the same can be found in the literature [55-59] and will not be discussed in the present work, except from the point of view of contributions of IR and STM toward the understanding of the overall picture of electrocatalysis at model electrodes. 

The specific catalytic properties of polyciystalline and single crystal surfaces have prompted extensive research on their oxidation in electrochemical- and gas- pliase environments. Recent developments in fuel cell technology have renewed efforts to improve Pt-Ru electrocatalysis for both reformate hydrogen- and methanol-oxidation. In the following Section, we discuss the oxidation of single crystal surfaces in both UHV- and electro-chcmical-cnvi ronments. 

The study of a sublayer or a monolayer of ruthenium or osmium on platinum allows for an understanding of the role of the surface composition in the electrocatalysis of organic fuels, such as methanol oxidation. Interesting papers about ruthenium and osmium deposition on platinum single crystals and pc surfaces have been published [26,124—126],... 

Three decades ago, Bockris et al. reported enhancement of the efficiency of methanol oxidation with a platinum-ruftienium alloy electrocatalyst. Two decades ago, another promising approach to electrocatalysis of methanol oxidation was presented. That was the platinum-ruthenium oxide electrocatalyst proposed by Watanabe and Motoo [24]. 

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