Potential dependence of the saturation CO coverage of Pt electrodes: The origin of the pre-peak in CO-stripping voltammograms. Part 3: Pt(poly)

López-Cudero, Ana; Cuesta, Ángel; Gutiérrez, C.

doi:10.1016/j.jelechem.2005.10.006

Cited by 174 publications

(175 citation statements)

References 39 publications

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“…• C. Relating to literature, 43 this feature is known as the CO stripping pre-peak (or pre-oxidation wave) which only appears in the case of CO adlayers with high coverage. Therefore, we use the ECSA results at 40…”

Section: Resultsmentioning

confidence: 95%

Second Cycle Is Dead: Advanced Electrode Diagnostics for High-Temperature Polymer Electrolyte Fuel Cells

Engl

Waltar

Gubler

et al. 2014

J. Electrochem. Soc.

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In order to achieve reliable data regarding high temperature polymer electrolyte fuel cell (HT-PEFC) electrode degradation novel diagnostic techniques for the determination of the electrochemically active surface area (ECSA) were developed. Cyclovoltammetric CO-monolayer oxidation (CO stripping) charge measurements were combined with real-time CO 2 exhaust gas analysis. Different evaluating methods were developed to overcome the problem of side reactions during CO stripping. Furthermore, a calibration curve for absolute ECSA determination via CO stripping was established, eliminating the temperature dependency of CO adsorption. In addition, these methods were successfully extended and implemented to locally resolved ECSA measurements. In summary, this paper introduces novel fundamental HT-PEFC electrode diagnostics for improved understanding of degradation phenomena.

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Section: Resultsmentioning

confidence: 95%

Second Cycle Is Dead: Advanced Electrode Diagnostics for High-Temperature Polymer Electrolyte Fuel Cells

Engl

Waltar

Gubler

et al. 2014

J. Electrochem. Soc.

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show abstract

“…As aforementioned, the conditions for CO adsorption are mild, and therefore, it is possible that we have not reached the maximum coverage. Since prewaves are normally associated with compressed adlayers [47][48][49], the use of mild adsorption conditions may avoid the formation of compressed adlayers, and therefore, lead to the absence of prewaves in the oxidation profile.…”

Section: Co Oxidationmentioning

confidence: 99%

On the behavior of the Pt(100) and vicinal surfaces in alkaline media

Arán‐Ais

Figueiredo

Vidal‐Iglesias

et al. 2011

Electrochimica Acta

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Abstract:We address in this paper a voltammetric study of the charge transfer processes characteristic of Pt(100) and vicinal surfaces in alkaline media. The electrochemical behavior of a series of stepped surfaces of the type Pt(S)[n(100)×(111)] has been characterized using cyclic voltammetry at different pHs, charge displacement measurements and FTIR experiments for adsorbed CO. The results from these techniques allow assigning the different peaks appearing in the voltammogram to hydrogen and /or OH adsorption on the different sites characteristic of these surfaces, namely, terrace and step sites. Additionally, the potential of zero total charge (pztc) of the electrodes was also determined. The resulting pztc values shift to more negative values when the step density increases on the surface up to n=5. FTIR spectroscopy experiments have been used to monitor the adsorption of CO on the different surfaces as well as the consequent CO oxidation, accompanying a positive potential sweep. The oxidation of adsorbed CO on (100) terraces is catalyzed by the presence of the (111) steps. The FTIR spectra revealed that CO is mostly bonded in bridge configuration at low potentials interconverting to on-top when the electrode potential is increased.

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“…(ii) The CO is linearly bonded. Cuesta et al [17] have shown that on a polycrystalline Pt electrode CO is predominately linearly bonded, while only a small fraction is bridge bonded CO. The ratio between these two species depends on the CO adsorption potential and the quantity of latter species decreases with increasing CO adsorption potential.…”

Section: The Mechanism Of Co Strippingmentioning

confidence: 99%

“…(vi) The anion adsorption and desorption was not taken into consideration. Cuesta et al [17] have found that the influence of anion adsorption becomes significant at more positive potentials where most of the CO is already stripped from the surface and the competition between anions and OH for the adsorption sites starts to take place [17]. (vii) The surface reaction was assumed to be an irreversible reaction.…”

Section: The Mechanism Of Co Strippingmentioning

confidence: 99%

A method for rough estimation of the catalyst surface area in a fuel cell

2008

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A method for a rough estimation of the catalyst surface area in a fuel cell is developed. It is based on the deconvolution of experimental CO oxidation data by use of a mathematical model. The kinetic parameters of the model are determined by fitting the experimental curves. The experimental data are collected at different sweep rates (2-100 mV s -1 ) and at different temperatures (room -60.0°C). The model can predict the sweep rate dependence of the CO oxidation onset potential, the peak current, the peak potential and the peak broadness. The model is further used for the prediction of the baseline in the presence of CO and for calculation of the CO charge consumed up to half peak potential. It is obtained that the latter value is constant at different sweep rates and that the baseline deviates from linearity already at low sweep rates (2 mV s -1 ), but not very significantly (2.0% in comparison to 8.8% at 100 mV s -1 , based on calculated CO charge). It is suggested that lower sweep rates should be used for experimental surface area determination.Width of the X-ray diffraction peak at half height/rad B r 2hWidth of the X-ray diffraction peak at half height for a standard compound/rad c DL Me Double layer capacitance of metal surface/mF d Average particle size/nm e

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Potential dependence of the saturation CO coverage of Pt electrodes: The origin of the pre-peak in CO-stripping voltammograms. Part 3: Pt(poly)

Cited by 174 publications

References 39 publications

Second Cycle Is Dead: Advanced Electrode Diagnostics for High-Temperature Polymer Electrolyte Fuel Cells

Second Cycle Is Dead: Advanced Electrode Diagnostics for High-Temperature Polymer Electrolyte Fuel Cells

On the behavior of the Pt(100) and vicinal surfaces in alkaline media

A method for rough estimation of the catalyst surface area in a fuel cell

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