Hydrogen adsorption and oxide formation on platinum single crystal electrodes

Yamamoto, Kazuo; Kolb, Dieter M.; Kötz, R.; Lehmpfuhl, G.

doi:10.1016/s0022-0728(79)80380-0

Cited by 198 publications

(80 citation statements)

References 13 publications

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“…1 with 6. Note also the dramatic decrease in capacitance 2 around 0.4 V at pH 9-10 relative to pH=2, i.e., from 100 ~F/cm to 2 30 ~F/cm , the latter being the smallest capacitance we have ever observed on any Pt electrode. Therefore, it does not seem probable that the same anion could adsorb· in the pH = 9-10 electrolytes as in the pH = 1-2 electrolytes.…”

Section: Anion Adsorptionmentioning

confidence: 74%

“…Early studies of hydrogen and oxygen electrosorption on UHV cleaned and annealed single crystals [1][2][3][4] produced few surprises relative to prior experience with electrochemicallycleaned polycrystalline and single-crystal Pt electrodes [5]. In many of these studies impurities picked up during transfer required the use of electrochemical cleaning before voltammetry was recorded [1,3], use of a non-inert backfill gas [4] and/or Ar+-sputtering of the surface to allow post-electrochemical surface analysis [3].…”

Section: Introductionmentioning

confidence: 99%

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Long-range structural effects in the anomalous voltammetry on ultra-high vacuum prepared Pt (111)

Wagner¹,

Ross²

1988

Journal of Electroanalytical Chemistry and Interfacial Electroc

154

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Section: Anion Adsorptionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Long-range structural effects in the anomalous voltammetry on ultra-high vacuum prepared Pt (111)

Wagner¹,

Ross²

1988

Journal of Electroanalytical Chemistry and Interfacial Electroc

154

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“…Coverages are reported as a fraction of the saturated CO ads adlayer produced under identical conditions. The coverage of the saturated CO ads adlayer relative to the H upd layer was calculated to be 0.676 with a 50 standard deviation of 1.2% over 5 experiments; assuming a charge density of 210 C cm -2 for a monolayer of adsorbed hydrogen 34 . This is in good agreement with similar experiments in the literature for Pt(111) electrodes, for which the maximum coverage in CO-free 0.1 mol dm -3 H 2 SO 4 was 55 shown to be 0.68 42 .…”

Section: Methodsmentioning

confidence: 99%

The role of adsorbed hydroxyl species in the electrocatalytic carbon monoxide oxidation reaction on platinum

Kucernak

Offer

2008

Phys. Chem. Chem. Phys.

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The assumption that "OH ads " or other oxygen containing species is formed on polycrystalline or nanoparticulate platinum through a fast and reversible process at relatively low potentials is often made. In this paper we discuss the implications of this assumption and the difficulty in reconciling it with experimental phenomena. We show how presenting chrono-amperometric transients as log-10 log plots for potentials steps in the presence and absence of an adlayer of carbon monoxide o n polycrystalline platinum is particularly useful in understanding the time evolution of the CO oxidation reaction. When using log-log plots a clear power law decay can be observed in the transients both in the presence and absence of an adlayer of carbon monoxide. We explain this as an extension of current theory, such that the rate determining step in both cases is the formation of 15 a hydrogen bonded water-OH ads network, strongly influenced by anions, and that CO ads oxidation occurs, at least in part by the diffusion of OH ads through this network. We hypothesize that, at low potentials the formation of OH ads at active sites is fast and reversible but that transport of OH ads away from those sites may be rate limiting. The assumption that overall OH ads formation on platinum is fast and reversible is therefore highly dependent upon the platinum surface and th e 20 experimental conditions and it may not be appropriate for polycrystalline surfaces in sulphuric acid. Therefore, although the formation of OH ads on platinum in the absence of strongly adsorbing anions on 'ideal' surfaces is almost certainly fast and reversible, on realistic fuel cell relevant surfaces under non-ideal conditions this assumption cannot be made, and instead the formation of an OH ads adlayer may be somewhat slow and is associated with the formation of hydrogen bonded 25 water-OH ads networks on the surface. We expect this to be a more realistic description for what occurs during CO ads oxidation on fuel cell relevant catalysts which are highly heterogeneous and which have a highly defective surface. IntroductionThe formation of oxides on platinum surfaces at high potentials is relatively well studied yet contentious. The role of the species typically called "OH ads " in the surface catalysis of platinum catalysts is crucial in understanding a large 5 number of reactions, of which the most common example is the carbon monoxide oxidation reaction (COOR). The nature of this species is somewhat controversial, although Anderson has recently shown through theoretical ab initio charge selfconsistent methods that OH ads should form on a Pt surface at a 10 potential of about 0.6 V. Several investigators claim that OH ads is the species responsible for reacting with adsorbed CO ads , and that this is a chemical Langmuir-Hinshelwood (L-H) reaction [1][2][3][4][5][6][7] . The lowest potentials at which the COOR has been reported is 150 mV for carbon supported platinum 8 , 200 15 mV for a porous platinum electrode 9 and for polycrystalline platinum 10 , and ...

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“…The peak at B0.13 V vs. RHE corresponds to the adsorption-desorption processes on the (110) Pt faces, while the peak at B0.23 V vs. RHE corresponds to the processes on the (100) Pt faces. 26,27 In the case of the prepared catalysts that consist of Pt deposited on the supports carbonized at 1000 1C (e.g. Pt/GGCo-1000 and Pt/GGFe-1000), the voltammetric profile shows more clearly defined peaks.…”

Section: Structural Properties and Electrocatalytic Activity Of Pt/gcnsmentioning

confidence: 99%

Solid-phase synthesis of graphitic carbon nanostructures from iron and cobalt gluconates and their utilization as electrocatalyst supports

Sevilla

Lecea

Valdés-Solı́s

et al. 2008

Phys. Chem. Chem. Phys.

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We present a novel and facile synthesis methodology for obtaining graphitic carbon structures from Fe(II) and Co(II) gluconates. The formation of graphitic carbon can be carried out in only one step by means of heat treatment of these organic salts at a temperature of 900 1C or 1000 1C under inert atmosphere. This process consists of the following steps: (a) pyrolysis of the organic gluconate and its transformation to amorphous carbon, (b)

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Hydrogen adsorption and oxide formation on platinum single crystal electrodes

Cited by 198 publications

References 13 publications

Long-range structural effects in the anomalous voltammetry on ultra-high vacuum prepared Pt (111)

Long-range structural effects in the anomalous voltammetry on ultra-high vacuum prepared Pt (111)

The role of adsorbed hydroxyl species in the electrocatalytic carbon monoxide oxidation reaction on platinum

Solid-phase synthesis of graphitic carbon nanostructures from iron and cobalt gluconates and their utilization as electrocatalyst supports

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