Incipient Hydrous Oxides—The Missing Link in Noble Metal Electrocatalysis

Burke, L.D.; Healy, Jim; O’Dwyer, Katie; O'Leary, W. A.

doi:10.1149/1.2096776

Cited by 56 publications

(63 citation statements)

References 20 publications

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“…over the range 0.3 to 0.45V. It was pointed out earlier [8] that organic oxidation proceses, involving oxygen insertion from water, usually commence on Pt at ~ 0.2 V(RHE), i.e. in the region of peak Hi where incipient hydrous oxide formation is assumed to commence on the anodic sweep.…”

Section: Resultsmentioning

confidence: 99%

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The stability of hydrous oxide films on platinum

Burke

O’Sullivan

1991

J Appl Electrochem

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The stability of hydrous oxide films grown on platinum in both acid and base was investigated as a function of holding potential in solutions of different pH. In contrast to similar films grown on gold -whose behaviour was described earlier -the stability of the bulk of the hydrous oxide deposks on platinum was not very dependent on solution pH. This was attributed to a rather facile rearrangement, in the case of platinum, of the initially anionic oxide species to a virtually neutral state. However, there was invariably a minor component in these deposits that was difficult to reduce in base; this probably involves an outer layer of oxide material (the latter being in contact 'with the aqueous phase) which retained its hyperextended, anionic form. Reduction of the bulk hydrous oxide in base showed a marked degree of inhibition in the region of 0 V(RHE); the effect seemed to be related to the presence of weakly bound hydrogen on the platinum surface. The hydrous oxide growth process on platinum showed a marked dependence on electrode history -this is a topic for further investigation.

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Section: Resultsmentioning

confidence: 99%

“…in the region of peak Hi where incipient hydrous oxide formation is assumed to commence on the anodic sweep. The region for the most marked rise in current for the oxidation of species such as N2H 4 that do not deactivate the surface is observed [8] at ~ 0.4 V(RHE), i.e. at approximately the potential of peak C~.…”

Section: Resultsmentioning

confidence: 99%

The stability of hydrous oxide films on platinum

Burke

O’Sullivan

1991

J Appl Electrochem

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“…We conclude that under our experimental conditions no anomalous heat of the magnitude reported by either trocatalysts to date has been essentially empirical (1), and the basic physical chemistry of such systems is not well understood. A novel aspect of electrocatalysis has emerged recently from work carried out in this laboratory (3)(4)(5) on noble metal electrode systems, although the same principle, i.e., involvement of hydrated surface groups in electrocatalytic processes, was applied earlier in the case of RuO2-based anodes (6). The basic idea is that many organic oxidation reactions, e.g., methanol oxidation at platinum anodes, viz.…”

Section: Discussionmentioning

confidence: 99%

Incipient Hydrous Oxide Species as Inhibitors of Reduction Processes at Noble Metal Electrode

Burke

O’Sullivan

O’Dwyer

et al. 1990

J. Electrochem. Soc.

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Evidence is presented to illustrate the important role of hydrous oxide species in noble metal electrocatalysis. It was demonstrated, for instance, that .in the case of gold in acid the onset/termination potential, under potential sweep conditions, for hydrazine oxidation and persulfate or iodate reduction occurred at the end of the hydrous oxide reduction peak (recorded for a thick film grown by potential multicycling); there was also a maximum in the faradaic ac response for gold in acid in the same region. Both gold and. platinum were investigated in acid and base electrolytes. In some cases a range of potential, rather than a discrete value, was found to be involved, different species react with (or are inhibited by) different types (or coverages) of these submonolayer species. In some, possibly electrocatalytically nondemanding, reduction reactions the hydrous oxide seemed to have little effect.The need for electrocatalysts in electrochemical technology is widely appreciated (1) as the use of these materials may lead to significant energy saving, more efficient conversion (great selectivity or faster rates of reaction with consequent saving in plant size and capital cost), and increased electrode stability. The role of electrocatalysts in fuel cell systems was reviewed recently (2), and it is evident that in some cases, e.g., the direct methanol/air fuel cell, the lack of effective electrocatalysts is the main barrier to progress. Unfortunately, the development of elec-) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 169.230.243.252 Downloaded on 2015-02-20 to IP

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“…We have also considered Reaction 6-17, which is proposed mainly by Burke, et al [97][98][99][100][101]. This reaction is reported to begin occurring at about 200 m V on the anodic scan (between the two platinum hydride oxidation peaks).…”

Section: Candidate Reactionsmentioning

confidence: 99%