Formation and reduction of hydrous oxide films on platinum in aqueous solution at 273 K

Burke, L.D.; Buckley, D. H.

doi:10.1007/bf00241585

Cited by 7 publications

(16 citation statements)

References 27 publications

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“…The main contributions to the CV for Pt in PBS are double-layer capacitance and the redox chemistry of metal oxide formation and reduction [73,74]. The shape of the CV for Pt wires in PBS was essentially the same as that for Pt (1.6 mm disks) reported previously [56].…”

Section: Resultsmentioning

confidence: 67%

“…First, some of the electrochemical characteristics of the background current, recorded in PBS only, were quantified (see Figure 1 inset, and Table 1 ). The main contributions to the CV for Pt in PBS are double-layer capacitance and the redox chemistry of metal oxide formation and reduction [ 73 , 74 ]. The shape of the CV for Pt wires in PBS was essentially the same as that for Pt (1.6 mm disks) reported previously [ 56 ].…”

Section: Resultsmentioning

confidence: 99%

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Modifications of Poly(o-phenylenediamine) Permselective Layer on Pt-Ir for Biosensor Application in Neurochemical Monitoring

Kirwan

Rocchitta

McMahon

et al. 2007

Sensors

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Abstract:Reports that globular proteins could enhance the interference blocking ability of the PPD (poly(o-phenylenediamine) layer used as a permselective barrier in biosensor design, prompted this study where a variety of modifying agents were incorporated into PPD during its electrosynthesis on Pt-Ir electrodes. Trapped molecules, including fibrous proteins and β-cyclodextrin, altered the polymer/modifier composite selectivity by affecting the sensitivity to both H 2 O 2 (signal molecule in many enzyme-based biosensors) and the archetypal interference species, ascorbic acid. A comparison of electrochemical properties of Pt and a Pt-Ir alloy suggests that the benefits of the latter, more rigid, metal can be exploited in PPD-based biosensor design without significant loss of backward compatibility with studies involving pure Pt.

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Section: Resultsmentioning

confidence: 67%

Section: Resultsmentioning

confidence: 99%

Modifications of Poly(o-phenylenediamine) Permselective Layer on Pt-Ir for Biosensor Application in Neurochemical Monitoring

Kirwan

Rocchitta

McMahon

et al. 2007

Sensors

View full text Add to dashboard Cite

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“…34 The β-oxide is envisioned to go below the surface Pt atoms due to placeexchange. [35][36][37][38] The position of this second peak shifts toward lower potentials with the number of consecutive TWs with decreased intensity. Additionally, the profile of the H ads features is altered with increased consecutive TWs region (ii).…”

Section: 29mentioning

confidence: 97%

Platinum Dissolution in Fuel Cell Electrodes: Enhanced Degradation from Surface Area Assessment in Automotive Accelerated Stress Tests

Rice

Urchaga

Pistono

et al. 2015

J. Electrochem. Soc.

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Automotive fuel cells are plagued by high platinum-based cathode catalyst costs exacerbated by high catalyst loadings to circumvent performance losses induced by typical urban drive cycles. Accelerated durability tests are commonly used to evaluate the impact of nano-structure and/or operating conditions on cathode catalyst loss rates. To map out loss rates the electrochemical surface area (ECSA) of the catalyst is periodically monitored. Herein the accelerated stress testing was performed 25,000 times by imposing perturbations from 0.9 V to 0.6 V in a triangular wave profile while the ECSA was measured by assessing the hydrogen adsorption/desorption region with a lower potential limit of 0.025 V at intermittent points during the triangular wave perturbations. The ECSA loss observed during the 25,000 triangle wave cycles is 7% when measured only 2 times, but 26.3% when measured 250 times. The exacerbated losses during frequent low potential ECSA measurements suggest a restructuring of the catalyst surface due to the formation of a protective β-oxide, as seen by alterations in the cyclic voltammtric profile and particle size distribution. The increasing price of fossil fuel stimulated by an impending near future accessible supply depletion combined with the increased awareness of the adverse contributions of the Internal Combustion Engines (ICEs) on global warming has driven an international research thrust toward alternative energy production for personal automotive transportation from alternative energy technologies. Proton Exchange Membrane Fuel Cells (PEMFCs) currently appear as one of the potential alternatives to ICEs for automotive applications due to their higher efficiency and the fact that they use hydrogen and air (21% oxygen) as fuel and oxidant, respectively, with water as the only by-product. Furthermore, depending on the production method, hydrogen can be considered as a renewable source of energy if generated in ways such as electrolysis from either wind turbines or solar energy.The commercialization and massive production of automotive PEMFC technologies is still a challenge due to durability and cost limitations.1 The PEMFC type is the most suitable fuel cell technology to replace ICEs for vehicle propulsion because of the solid electrolyte permitting comparable travel distances, available power for frequent fast idle-to-peak transients to support typically sized personal vehicles and fast startup/shutdown. However, the relatively low working temperature of PEMFCs (typically below 100• C, due to membrane limitations) requires the use of Pt based catalysts for both the anode and the cathode catalyst layers thereby significantly increasing their price. Utilization of finely dispersed catalyst nanoparticles onto a high surface electrically conducting substrates (typically high surface carbon supports) and optimization of catalytic layers have yet allowed a drastic decrease of the catalytic layer cost by lowering the Pt loading by a factor of 10 (reaching 0.4 mg. cm −2 total loading) in the past 30 ...

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“…Burke et al has observed the formation of an incipient hydrous oxide species on platinum at about 200 mV. [17][18][19][20][21][22] This species has been demonstrated to be active for the electro-oxidation of methanol. 21 There also is evidence of adsorbed states of water at these low potentials.…”

Section: Source Of Change In Physical Parametersmentioning

confidence: 99%

“…2,3 The chemical nature of this source of oxygen is proposed to be chemisorbed OH, [4][5][6][7][8][9][10][11][12] H 2 O, 10,[13][14][15][16] or hydrous oxides. [17][18][19][20][21][22][23][24] We recently reported results from a study on the electrooxidation of methanol at polished polycrystalline platinum using impedance spectroscopy (IS). 1 In that study we showed how information regarding the rate of the electro-oxidation of methanol at low potentials could be obtained from the impedance response of adsorbed hydrogen and reported the potential dependence of the impedance spectra for the electro-oxidation of methanol between 70 and 790 mV vs RHE.…”

Section: Introductionmentioning

confidence: 99%

Time-Dependent Impedance of the Electro-oxidation of Methanol on Polished Polycrystalline Platinum

and

Palmore

2001

J. Phys. Chem. B

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We measured the time dependence of the impedance of the electro-oxidation of methanol on polished polycrystalline platinum immersed in a solution of sulfuric acid. The impedance data were fit to a model for a reaction containing one adsorbed intermediate to obtain four physical parameters. The time dependence of these parameters illuminates how a change in the coverage of an adsorbed intermediate and the buildup of other poisons affects the kinetics and mechanism of the electro-oxidation of methanol. These results further support our conclusions based on the potential dependence of the impedance, that is, four potential regions exist between 200 and 800 mV vs RHE where a change in the mechanism for the electro-oxidation of methanol occurs (Melnick, R. E.; Palmore, G. T. R. J. Phys. Chem. B 2001, 105, 1012.). We hypothesize that changes in the mechanism are caused by the presence of four different species that contain oxygen, each belonging to a specific potential region with the more reactive species at higher potentials. We have combined impedance data from potential-dependent studies with impedance data that are time dependent to construct a qualitative model of this reaction. This model describes the rate of charge transfer for the electro-oxidation of methanol as a function of potential and coverage of adsorbed intermediate. The result is a model that predicts the behavior of this reaction at a platinum electrode, which is in agreement with that observed experimentally by impedance spectroscopy, chronoamperometry, and cyclic voltammetry.

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Formation and reduction of hydrous oxide films on platinum in aqueous solution at 273 K

Cited by 7 publications

References 27 publications

Modifications of Poly(o-phenylenediamine) Permselective Layer on Pt-Ir for Biosensor Application in Neurochemical Monitoring

Modifications of Poly(o-phenylenediamine) Permselective Layer on Pt-Ir for Biosensor Application in Neurochemical Monitoring

Platinum Dissolution in Fuel Cell Electrodes: Enhanced Degradation from Surface Area Assessment in Automotive Accelerated Stress Tests

Time-Dependent Impedance of the Electro-oxidation of Methanol on Polished Polycrystalline Platinum

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