Temperature-Dependent Dissolution of Polycrystalline Platinum in Sulfuric Acid Electrolyte

Cherevko, Serhiy; Topalov, Angel Angelov; Žeradjanin, Aleksandar R.; Keeley, Gareth P.; Mayrhofer, Karl Johann Jakob

doi:10.1007/s12678-014-0187-0

Cited by 92 publications

(133 citation statements)

References 50 publications

Supporting

Mentioning

117

Contrasting

Order By: Relevance

“…As, the scanning flow cell often has a gasket (a silicone ring) used to avoid leakage of the electrolyte, [9][10][11] we additionally performed calculations on its influence on the determination of kinetic parameters.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Simulation of an Electrochemical Flow Cell with V-Shape Channel Geometry

Kulyk

Cherevko

Auinger

et al. 2015

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

The electrolyte flow profile and reactive species concentration distribution are calculated for a Scanning Flow Cell (SFC) by means of finite element method numerical calculation using COMSOL Multiphysics software. In case of a simple one-step reaction with kinetic parameters close to those of the oxygen reduction reaction the applicability of conventional Koutecky-Levich (KL) analysis for the kinetic current calculations is proved. In addition, the influence of the cell geometry, particularly the angle between inlet and outlet tubes and the tube diameter, is investigated to guide the further optimization of the method. The applicability of the kinetic analysis is demonstrated experimentally on the example of oxygen reduction reaction.

show abstract

Section: Resultsmentioning

confidence: 99%

“…In addition, since it is a flow-type cell, it enables facile coupling with downstream analysis or even spectrometry. [8][9][10][11] The system is also highly versatile due to its modular design and coupling possibilities and can therefore easily be tailored to suit specific requirements.…”

Section: H861mentioning

confidence: 99%

Numerical Simulation of an Electrochemical Flow Cell with V-Shape Channel Geometry

Kulyk

Cherevko

Auinger

et al. 2015

J. Electrochem. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…2 indicates no loss of electrochemically active surface area of the working electrode due to platinum dissolution during potential sweeps. 30 A potential step, chronoamperometric measurement under the same conditions produces a current spike comprised of both capacitive charging and faradaic ORR (Fig. S1a) that quickly decays.…”

Section: Resultsmentioning

confidence: 99%

Time-Dependent Mass Transport for O2 Reduction at the Pt Perfluorosulfonic Acid Ionomer Interface

Novitski

Xie

Holdcroft

2014

ECS Electrochemistry Letters

View full text Add to dashboard Cite

Chronoamperometric analysis of the oxygen reduction reaction (ORR) at Pt microelectrode | perfluorosulfonic acid (PFSA) ionomer interfaces in a solid state electrochemical cell reveals an increase in both the oxygen diffusion coefficient (D b Proton exchange membrane fuel cell (PEMFC) catalyst layers typically employ an ionomer component to reduce ionic resistance and improve electrochemical kinetics.)1,2 Recent studies reveal the ionomer in the catalyst layer may be present as an ultrathin film, and ex-situ studies have indicated that such films undergo a surface morphological reconstruction from hydrophobic to hydrophilic upon exposure to liquid water. Moreover, the reconstruction is observed to have a timedependency proportional to film thickness.3 Exposure to water vapor is found not to trigger this surface reconstruction. 3 The nature of these morphological reorganizations at the surface of the ionomer film is of considerable interest for understanding electrochemical mass transport at the ionomer | Pt interface. 4 However, there is little evidence concerning the role of these reorganizations on actual faradaic electrochemical activities. Overall, the complex morphological changes at ionomer surfaces are of increasing interest, where variables such as film thickness, substrate, and film preparation result in a markedly different outcome for the resulting ionomer properties. [5][6][7][8] Previous electrochemical studies have shown that mass transport through perfluorosulfonic acid (PFSA) ionomer membranes is dependent upon oxygen solubility in the hydrophobic, fluorinated domains and its transport into, and diffusion through, aqueous domains. 9-11The relatively high rate of oxygen permeation through PFSA ionomer is attributed to the relatively high oxygen solubility and large diffusion coefficient.9,12 The oxygen mass transport through the ionomer in a cathode catalyst layer (CCL), and its role in determining fuel cell performance, is relatively unexplored but is under increasing scrutiny. Studies based on limiting current techniques indicate that as Pt catalyst loading in the CCL is reduced, oxygen mass transport resistance in, and through, the PFSA ionomer increases, ultimately reducing the available power density of a fuel cell. [13][14][15] Other studies support this contention -that oxygen mass transport resistance through the catalyst layer ionomer plays a large role in determining the power that can be extracted from a fuel cell. 16 It has also been suggested that the total mass transport resistance is exacerbated by a mass transport resistance at the gas/ionomer interface, which becomes increasingly dominant as ionomer film thickness is reduced. [17][18][19] Understanding oxygen mass transport limitations at ionomer | Pt interfaces is therefore of growing interest.Ex-situ solid state electrochemical techniques provide a means to study ORR at Pt | ionomer interfaces under conditions of specific temperature, pressure, and RH. Pioneering work by Srinivasan and * Electrochemical Society Student Member....

show abstract

“…31,62,64,66 Merck Suprapur 96% H 2 SO 4 and 70% HClO 4 were diluted using ultrapure water (PureLab Plus system, Elga, 18 M , TOC < 3 p.p.b.) for preparation of 0.1 M acidic electrolytes.…”

Section: Methodsmentioning

confidence: 99%

A Comparative Study on Gold and Platinum Dissolution in Acidic and Alkaline Media

Cherevko

Žeradjanin

Keeley

et al. 2014

J. Electrochem. Soc.

Self Cite

267

280

View full text Add to dashboard Cite

Electrochemical dissolution of gold and platinum in 0.1 M HClO 4 , 0.1 M H 2 SO 4 , and 0.05 M NaOH is investigated. The qualitative picture of both metals' dissolution is pH-independent. Oxidation/reduction of the metal's surface leads to the transient dissolution peaks which we label A 1 and C 1 on the dissolution profiles. Commencement of the oxygen evolution reaction (OER) results in the additional dissolution peak A 2 . Quantitatively, there are important differences. The amount of gold transiently dissolved in alkaline medium is more than an order of magnitude higher in comparison to that in acidic medium. Oppositely, steady-state gold dissolution in base in the potential region of OER is hindered. The transient dissolution of platinum is by a factor of two higher in base. It is suggested that variation of the pH does not change the mechanism of the OER on platinum. Consequently, the dissolution rate of platinum is equal in acidic and alkaline electrolytes. As an explanation of the observed difference in gold dissolution, a difference in the thickness of compact oxide formed in acid and base is suggested. Growth of a thicker compact oxide in the alkaline medium explains the increased transient and the decreased steady-state dissolution of gold. Platinum and gold are perhaps the most frequently studied metals in electrochemistry. In particular, they constitute important model systems in the context of fundamental investigations of the mechanism and kinetics of the initial stages of metal oxidation. Surface processes during transition of adsorbed hydroxyl groups to, initially, compact couple of monolayers thickness and, later, relatively thick bulk phase oxides have occupied electrochemists for many decades. In the earliest works, investigations were directed toward the general problem of metal passivity, hotly debated at the beginning of the twentieth century. [1][2][3] In the 1960s and 1970s, the rapid development of fuel cells and application of platinum as a catalyst for the hydrogen oxidation and the oxygen reduction reactions (HOR and ORR) re-stimulated research efforts on noble metal oxidation. As adsorbed intermediates and other oxygenated species present on the catalyst surface were believed to have a poisoning effect on the rate of the ORR, understanding of the oxygen-platinum interaction was of substantial importance. The great progress in the development of electrochemical experimental techniques and surface analytics in these years significantly contributed to new insights of electrocatalysis at the solid-liquid interface. The understanding of noble metal oxidation is, however, not only crucial for these reactions but also the essential step in the comprehension of dissolution. Despite its importance in general and as a basis for the current work, the description of the theories and models for noble metal oxidation over the last century is beyond the scope of the present article. The interested reader is therefore referred to a comprehensive work published by Conway, and references therein. Plat...

show abstract

Temperature-Dependent Dissolution of Polycrystalline Platinum in Sulfuric Acid Electrolyte

Cited by 92 publications

References 50 publications

Numerical Simulation of an Electrochemical Flow Cell with V-Shape Channel Geometry

Numerical Simulation of an Electrochemical Flow Cell with V-Shape Channel Geometry

Time-Dependent Mass Transport for O2 Reduction at the Pt Perfluorosulfonic Acid Ionomer Interface

A Comparative Study on Gold and Platinum Dissolution in Acidic and Alkaline Media

Contact Info

Product

Resources

About