Durability of platinum-based fuel cell electrocatalysts: Dissolution of bulk and nanoscale platinum

Cherevko, Serhiy; Kulyk, Nadiia; Mayrhofer, Karl Johann Jakob

doi:10.1016/j.nanoen.2016.03.005

Cited by 289 publications

(333 citation statements)

References 179 publications

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“…These observations support the link between particle growth and dissolution processes. 14,26,35,70 as have the more limited data on Pt/C dissolution rates. 26,35,69 The dissolution rates shown in Fig times faster for Pt/C than for poly-Pt.…”

Section: Resultsmentioning

confidence: 99%

“…14,26,35,70 as have the more limited data on Pt/C dissolution rates. 26,35,69 The dissolution rates shown in Fig times faster for Pt/C than for poly-Pt. A factor of twenty times higher dissolution rate for Pt/C versus a polycrystalline Pt film has also been observed by Dam et al for potential holds at 1.05 V and 80…”

Section: Resultsmentioning

confidence: 99%

“…50 Postulated Pt dissolution reactions and dissolved species formed under potential cycling conditions.-As discussed above, numerous dissolution reactions have been proposed to explain the dissolution behavior of poly-Pt and Pt/C. 35,50,100,101 Proposed reactions for the anodic dissolution of Pt 0 in non-complexing perchloric acid electrolyte are a two-electron electrochemical reaction to form an aquo, hydroxy, or aquo-hydroxy-complex (reactions D-1a and D-1b), a direct fourelectron electrochemical reaction also to form aquo, hydroxy, or aquohydroxy-complex (reactions D-2a and D-2b), or further oxidation of surface adsorbed hydroxide or oxide species to form these soluble Pt complexes (reactions D-3 to D-5). The proposed cathodic reaction is the reduction of Pt oxides to form Pt 2+ (reaction D-6).…”

Section: Journal Of the Electrochemical Society 165 (6) F3178-f3190 mentioning

confidence: 99%

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Potentiostatic and Potential Cycling Dissolution of Polycrystalline Platinum and Platinum Nano-Particle Fuel Cell Catalysts

Myers

Wang

Smith

et al. 2018

J. Electrochem. Soc.

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The dissolution of Pt in aqueous electrolytes has been studied for over forty years, most recently in the context of understanding the observed loss in electrochemically-active surface area (ECA) of cathode electrocatalysts in polymer electrolyte fuel cells. Despite extensive research, there are many unresolved issues regarding the dissolution of nano-particle Pt, such as the source of the observed potential dependence of potentiostatic and potential cycling dissolution rates. To help resolve these issues, in this paper we present results of measurements of the concentration of dissolved Pt and Pt dissolution rates for carbon-supported platinum nano-particles (Pt/C) in dilute perchloric acid, as a mimic of the PEFC cathode environment, as a function of potential and upper potential limit of potential cycling. Also presented, for comparison, are results of similar studies on polycrystalline platinum. In situ Pt L III X-ray absorption spectroscopy was used to determine the extent of oxidation, the coordination environment, and loss of Pt from the Pt nano-particles to elucidate the mechanism of Pt dissolution. Based on the correlation of these studies with those presented in the literature, mechanisms for Pt dissolution under potentiostatic and potential cycling conditions are proposed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Journal Of the Electrochemical Society 165 (6) F3178-f3190 mentioning

confidence: 99%

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Potentiostatic and Potential Cycling Dissolution of Polycrystalline Platinum and Platinum Nano-Particle Fuel Cell Catalysts

Myers

Wang

Smith

et al. 2018

J. Electrochem. Soc.

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“…A crucial step in the comprehension of metal dissolution is to understand surface oxidation, a topic that has captivated interest for decades [4]. Experimental studies have found the formation of subsurface oxygen on oxidized transition metal surfaces [5][6][7][8]; yet, so far no coherent theoretical picture of the atomistic mechanism underlying these processes has emerged [4].…”

Section: Introductionmentioning

confidence: 99%

Atomistic Mechanism of Pt Extraction at Oxidized Surfaces: Insights from DFT

Eslamibidgoli

Eikerling

2016

Electrocatalysis

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In this article, we propose a novel mechanism for the atomic-level processes that lead to oxide formation and eventually Pt dissolution at an oxidized Pt(111) surface. The mechanism involves a Pt extraction step followed by the substitution of chemisorbed oxygen to the subsurface. The energy diagrams of these processes have been generated using density functional theory and were analyzed to determine the critical coverages of chemisorbed oxygen for the Pt extraction and O ads substitution steps. The Pt extraction process depends on two essential conditions: (1) the local coordination of a Pt surface atom by three chemisorbed oxygen atoms at nearestneighboring fcc adsorption sites; (2) the interaction of the buckled Pt atom with surface water molecules. Results are discussed in terms of surface charging effects caused by oxygen coverage, surface strain effects, as well the contribution from electronic interaction effects. The utility of the proposed mechanism for the understanding of Pt stability at bimetallic surfaces will be demonstrated by evaluating the energy diagram of a Cu ML /Pt(111) near-surface alloy.

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“…Therefore, the bulk of our understanding of Pt and transition metal dissolution from Pt and Pt alloy catalysts, including real-time resolution of the dissolution processes during potential cycling, has been obtained through aqueous studies. [5][6][7][8][9][10] For example, earlier aqueous studies have established that a) Pt oxides play a role in Pt dissolution at potentials higher than 0.9 V, 5,7,11,12 b) Pt oxides are passivating but are also susceptible to dissolution at higher potentials, 9,11,13 and c) Pt dissolution can be accelerated by potential cycling to a degree that depends on the potential wave form, including the upper and lower potential limits, scan rate in triangle waves, and hold time in square waves. 8,12,[14][15][16] Utilizing rotating ring disk electrode (RRDE) and channel-flow double-electrode (CFDE) methods, 7,10,11 dissolution of platinum during both anodic (increasing potential) and cathodic (decreasing potential) sweeps has been distinguished, albeit semi-quantitatively.…”

mentioning

confidence: 99%

Potential Dependence of Pt and Co Dissolution from Platinum-Cobalt Alloy PEFC Catalysts Using Time-Resolved Measurements

Ahluwalia

Papadias

Kariuki

et al. 2018

J. Electrochem. Soc.

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An electrochemical flow cell system with catalyst-ionomer ink deposited on glassy carbon is used to investigate the aqueous stability of commercial PtCo alloys under cyclic potentials. An on-line inductively coupled plasma-mass spectrometer, capable of real-time measurements, is used to resolve the anodic and cathodic dissolution of Pt and Co during square-wave and triangle-wave potential cycles. We observe Co dissolution at all potentials, distinct peaks in anodic and cathodic Pt dissolution rates above 0.9 V, and potential-dependent Pt and Co dissolution rates. The amount of Pt that dissolves cathodically is smaller than the amount that dissolves anodically if the upper potential limit (UPL) is lower than 0.9 V. At the highest UPL investigated, 1.0 V, the cathodic dissolution greatly exceeds the anodic dissolution. A non-ideal solid solution model indicates that the anodic dissolution can be associated with the electrochemical oxidation of Pt and PtOH to Pt 2+ , and the cathodic dissolution to electrochemical reduction of a higher Pt oxide, PtO x (x > 1), to Pt 2+ . Pt also dissolves oxidatively during the cathodic scans but in smaller amounts than due to the reductive dissolution of PtO x . The relative amounts Pt dissolving oxidatively as Pt and PtOH depend on the potential cycle and UPL.

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Durability of platinum-based fuel cell electrocatalysts: Dissolution of bulk and nanoscale platinum

Cited by 289 publications

References 179 publications

Potentiostatic and Potential Cycling Dissolution of Polycrystalline Platinum and Platinum Nano-Particle Fuel Cell Catalysts

Potentiostatic and Potential Cycling Dissolution of Polycrystalline Platinum and Platinum Nano-Particle Fuel Cell Catalysts

Atomistic Mechanism of Pt Extraction at Oxidized Surfaces: Insights from DFT

Potential Dependence of Pt and Co Dissolution from Platinum-Cobalt Alloy PEFC Catalysts Using Time-Resolved Measurements

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