Kinetics of hydrogen underpotential deposition at polycrystalline platinum in acidic solutions

Łosiewicz, B.; Jurczakowski, Rafał; Lasia, Andrzej

doi:10.1016/j.electacta.2012.07.019

Cited by 65 publications

(67 citation statements)

References 30 publications

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“…58,60 It is important to point out that the local variation in activity visualized by SECCM would have some impact on macroscopic CV measurements of heterogeneous ET on polycrystalline platinum. Electrode kinetic measurements on polycrystalline platinum tend to implicitly assume a uniform electrode surface 45,46,56,57 and evidently, at least for the case of Fe 2+ /Fe 3+ (and perhaps other reactions), this is not always appropriate. …”

Section: Resultsmentioning

confidence: 99%

Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe²⁺/Fe³⁺ Redox Reaction

et al. 2013

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The influence of electrode surface structure on electrochemical reaction rates and mechanisms is a major theme in electrochemical research, especially as electrodes with inherent structural heterogeneities are used ubiquitously. Yet, probing local electrochemistry and surface structure at complex surfaces is challenging. In this paper, high spatial resolution scanning electrochemical cell microscopy (SECCM) complemented with electron backscatter diffraction (EBSD) is demonstrated as a means of performing ‘pseudo-single-crystal’ electrochemical measurements at individual grains of a polycrystalline platinum electrode, while also allowing grain boundaries to be probed. Using the Fe2+/3+ couple as an illustrative case, a strong correlation is found between local surface structure and electrochemical activity. Variations in electrochemical activity for individual high index grains, visualized in a weakly adsorbing perchlorate medium, show that there is higher activity on grains with a significant (101) orientation contribution, compared to those with (001) and (111) contribution, consistent with findings on single-crystal electrodes. Interestingly, for Fe2+ oxidation in a sulfate medium a different pattern of activity emerges. Here, SECCM reveals only minor variations in activity between individual grains, again consistent with single-crystal studies, with a greatly enhanced activity at grain boundaries. This suggests that these sites may contribute significantly to the overall electrochemical behavior measured on the macroscale.

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Section: Resultsmentioning

confidence: 99%

Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe²⁺/Fe³⁺ Redox Reaction

et al. 2013

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“…For CVs recorded at fast scan rates it is known that, at least for Pt, the H-UPD in acid environments is a fast process, characterized by a small charge transfer resistance. 68,69 As a result, it is possible to measure CVs at scan rates up to v = 1-10 V/s without destabilizing the H-UPD adsorption isotherm. 70 Admittedly, this has only been demonstrated on Pt 70 and Ir 71 electrodes.…”

Section: Resultsmentioning

confidence: 99%

“…70 Admittedly, this has only been demonstrated on Pt 70 and Ir 71 electrodes. For metal surfaces such as Rh or Pd, characterized by two orders of magnitudes slower H-UPD rates 72,73 than Pt, 68,69 higher scan rates than 0.1 V/s could already lead to lower H-UPD coverages reached during CVs, and ultimately to underestimated H-UPD charge densities. Regarding now the use of diluted hydrogen in the anode compartment, 5 vol.% H 2 in N 2 induces a fixed thermodynamical shift of the anode potential by ca.…”

Section: Resultsmentioning

confidence: 99%

“…69,70 The same charge density is probed in the two environments, leading to similar ECSA CO-stripping values of 120 m The latter ECSA CO-stripping value determined in fuel cell will be used to normalize in the following HOR/HER currents.…”

Section: Resultsmentioning

confidence: 99%

“…to Pt (2 orders of magnitude difference in the H-UPD charge transfer resistance between these metals). 69,84 The low H-UPD rate on Pd electrodes might have as a consequence that a low scan rate is required for the H-UPD process to become reversible, and reach higher H-UPD coverages during CVs.…”

Section: Resultsmentioning

confidence: 99%

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Hydrogen Oxidation and Evolution Reaction Kinetics on Carbon Supported Pt, Ir, Rh, and Pd Electrocatalysts in Acidic Media

Durst

Simon

Hasché

et al. 2014

J. Electrochem. Soc.

455

459

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The hydrogen oxidation and evolution reaction (HOR/HER) behavior of carbon supported metal (Pt, Ir, Rh, Pd) nanoparticle electrocatalysts is studied using the H 2 pump approach, in a proton exchange membrane fuel cell (PEMFC) setup. After describing the best method for normalizing the net faradaic currents to the active surface area of the electrodes, we measure the HOR/HER kinetic parameters (exchange current densities and transfer coefficients) in a temperature range from 313 K to 353 K and calculate the activation energy for the HOR/HER process. We compare the measured kinetic parameters with those extracted from different mass-transport limitation free setups in literature, to evaluate the hydrogen electrocatalysis on these most active surfaces. The HOR/HER activity scales with the following: Pt > Ir Rh > Pd. The anodic and cathodic transfer coefficients are similar for all metals (ca. 0.5), leading to Tafel In the current view of energy conversion based on the use of fuel cells and electrolyzers, the hydrogen electrocatalysis plays a central role. H 2 is used as a fuel in proton exchange membrane fuel cells (PEMFCs), where it is electrochemically oxidized at the anode electrode according to:In PEMFC anode electrode, only small amounts of Pt (ca. 0.05 mg Pt /cm 2 geo ) are required to catalyze the hydrogen oxidation, without contributing to any efficiency loss of the overall fuel cell performance.1 The same would hold true for the hydrogen evolution reaction -HER -at the cathode side of water electrolyzer systems. Moreover, except when considering contamination issues e.g. due to the presence of CO in reformate hydrogen, or stability issues e.g. due to hydrogen starvation events mode, a replacement of the current carbon supported platinum (Pt/C) based electrode technology is not contemplated in PEMFC. 2 The drawback of both PEM-based fuel cells and electrolyzer systems arise from the large amounts of noble metal (ca. ≈0.4 mg metal /cm 2 geo ) required to catalyze at acceptable rates the sluggish oxygen reduction reaction (ORR) in fuel cell cathodes, and the oxygen evolution reaction (OER) in electrolyzer anodes. [3][4][5] Contrary to the acidic PEM-based technologies, anion exchange membrane (AEM) based devices, [6][7][8] which are operating at high pH, offer the use of cost-effective non-noble metal electrodes to catalyze the ORR 9,10 and OER 11-13 at almost similar rates than on noble metal electrodes in acidic electrolytes. As a result, a replacement of PEMbased devices by AEM ones will be advantageous 14 if and only if AEM conductivities will be further increased to the level of PEM, 15,16 and their sensitivity to CO 2 significantly reduced. 17 However, getting rid of the noble metal contents in AEM-device electrodes would be feasible only in the case of similar hydrogen oxidation and evolution reaction (HOR/HER) rates in AEMs versus PEM-based conversion devices. Unfortunately, recent studies have shown that the HOR/HER rates of noble metal electrodes in the alkaline environment are much slower than in ...

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The Hydrogen Electrode Reaction

2019

Fundamentals of Electrocatalyst Materials and Interfacial Characterization

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Kinetics of hydrogen underpotential deposition at polycrystalline platinum in acidic solutions

Cited by 65 publications

References 30 publications

Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe²⁺/Fe³⁺ Redox Reaction

Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe²⁺/Fe³⁺ Redox Reaction

Hydrogen Oxidation and Evolution Reaction Kinetics on Carbon Supported Pt, Ir, Rh, and Pd Electrocatalysts in Acidic Media

The Hydrogen Electrode Reaction

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Kinetics of hydrogen underpotential deposition at polycrystalline platinum in acidic solutions

Cited by 65 publications

References 30 publications

Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe2+/Fe3+ Redox Reaction

Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe2+/Fe3+ Redox Reaction

Hydrogen Oxidation and Evolution Reaction Kinetics on Carbon Supported Pt, Ir, Rh, and Pd Electrocatalysts in Acidic Media

The Hydrogen Electrode Reaction

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Product

Resources

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Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe²⁺/Fe³⁺ Redox Reaction

Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe²⁺/Fe³⁺ Redox Reaction