High temperature stability study of carbon supported high surface area catalysts—Expanding the boundaries of ex-situ diagnostics

Polymeros, George; Baldizzone, Claudio; Geiger, Simon; Grote, Jan-Philip; Knossalla, Johannes; Mezzavilla, Stefano; Keeley, Gareth P.; Cherevko, Serhiy; Žeradjanin, Aleksandar R.; Mayrhofer, Karl Johann Jakob

doi:10.1016/j.electacta.2016.06.105

Cited by 39 publications

(50 citation statements)

References 61 publications

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“…39 Recently, extensive investigation of Pt nanoparticles on high surface area carbon supports, such as nitrogen doped hollow graphitic spheres (Pt/HGS), has shown that particles of sizes smaller than 5 nm exhibit excellent stability under a variety of degradation conditions. 5 The increased stability in comparison to benchmark Pt/C catalysts has been ascribed to the confinement of particles inside the mesoporous matrix of HGS. Additionally, some studies indicated that the improved stability in N-doped vs. non-doped carbons was due to a better dispersion of Pt nanoparticles which inhibited agglomeration of Pt during electrochemical testing 50,51 (and references therein).…”

Section: -21mentioning

confidence: 99%

“…For example, the stability of Pt nanoparticles and Pt alloys has been substantially increased by the addition of other noble metals. [25][26][27][28][29] Furthermore, the detrimental role of nanoparticle coalescence 5 and its circumvention by designing a microporous carbon support (exploiting the so-called confinement effect) has been reported. [30][31][32] Platinum dissolution has been extensively studied before -either in the form of a polycrystalline disk [33][34][35][36] or as a nanoparticulate catalyst.…”

Section: -21mentioning

confidence: 99%

“…2 Literature data indicate that platinum nanoparticle-based electrocatalystswhile reducing effectively the required Pt amount -are not stable under harsh operating conditions at the cathode side. [3][4][5] Recently, new strategies to study the catalyst layers have been developed. In large part, these strategies rely on a combinatorial approach where new analytical concepts have provided novel insights into the dissolution of platinum or more general catalyst layer degradation mechanisms.…”

Section: Introductionmentioning

confidence: 99%

“…In large part, these strategies rely on a combinatorial approach where new analytical concepts have provided novel insights into the dissolution of platinum or more general catalyst layer degradation mechanisms. [5][6][7][8][9][10][11][12] In situ experimental methodologies are especially insightful, where the electrochemical treatment of the catalyst layer is coupled with one or several highly sensitive analytical tools (e.g. X-ray absorption spectrometers, XRD diffractometers and mass spectrometers).…”

Section: Introductionmentioning

confidence: 99%

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Importance of non-intrinsic platinum dissolution in Pt/C composite fuel cell catalysts

Jovanovič

Petek

Hodnik

et al. 2017

Phys. Chem. Chem. Phys.

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The dissolution of different platinum-based nanoparticles deposited on a commercial high-surface area carbon (HSAC) support in thin catalyst films is investigated using a highly sensitive electrochemical flow cell (EFC) coupled to an inductively coupled plasma mass spectrometer (ICP-MS). The previously reported particle-size-dependent dissolution of Pt is confirmed on selected industrial samples with a mean Pt particle size ranging from 1 to 4.8 nm. This trend is significantly altered when a catalyst is diluted by the addition of HSAC. This indicates that the intrinsic dissolution properties are masked by local oversaturation phenomena, the so-called confinement effect. Furthermore, by replacing the standard HSAC support with a support having an order of magnitude higher specific surface area (a micro-and mesoporous nitrogen-doped high surface area carbon, HSANDC), Pt dissolution is reduced even further. This is due to the so-called non-intrinsic confinement and entrapment effects of the (large amount of) micropores and small mesopores doped with N atoms. The observed more effective Pt re-deposition is presumably induced by local Pt oversaturation and the presence of nitrogen nucleation sites. Overall, our study demonstrates the high importance and beneficial effects of porosity, loading and N doping of the carbon support on the Pt stability in the catalyst layer.

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Section: -21mentioning

confidence: 99%

Section: -21mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Importance of non-intrinsic platinum dissolution in Pt/C composite fuel cell catalysts

Jovanovič

Petek

Hodnik

et al. 2017

Phys. Chem. Chem. Phys.

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“…[4][5][6][7][8][9][10][11] Those studies have revealed that Pt electrochemical dissolution is predominantly a transient phenomenon occurring due to an interplay of Pt oxidation and reduction. The amount of dissolved platinum can be manipulated via different electrochemical treatments (scan rate, width of anodic and cathodic potential window), 1 gas atmosphere, 12 electrolyte, presence of organic molecules, 6,13 alloying metals, 8,14,15 thickness of the catalyst layer, 10,16 type of support material 16 and, last but not least, by the Pt particle size.…”

mentioning

confidence: 99%

Platinum Dissolution and Redeposition from Pt/C Fuel Cell Electrocatalyst at Potential Cycling

Pavlišič

Jovanovič

Šelih

et al. 2018

J. Electrochem. Soc.

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Extremely sensitive on-line detection of metal ions concentration was used to investigate potential-resolved platinum dissolution from commercial fuel cell electrocatalyst. The experiments were carried out in an electrochemical flow cell connected to inductively coupled plasma mass spectrometer. A variety of electrochemical treatments using different voltage scan rates confirmed the previously observed primary platinum degradation mechanism -the so-called "transient dissolution". Importantly, the redeposition of dissolved platinum is now shown to play an important role in the overall effective Pt dissolution. Pt redeposition trends exhibit a significant dependence on voltage scan rate.

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Low‐PGM and PGM‐Free Catalysts for Proton Exchange Membrane Fuel Cells: Stability Challenges and Material Solutions

et al. 2020

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Fuel cells as an attractive clean energy technology have recently regained popularity in academia, government, and industry. In a mainstream proton exchange membrane (PEM) fuel cell, platinum‐group‐metal (PGM)‐based catalysts account for ≈50% of the projected total cost for large‐scale production. To lower the cost, two materials‐based strategies have been pursued: 1) to decrease PGM catalyst usage (so‐called low‐PGM catalysts), and 2) to develop alternative PGM‐free catalysts. Grand stability challenges exist when PGM catalyst loading is decreased in a membrane electrode assembly (MEA)—the power generation unit of a PEM fuel cell—or when PGM‐free catalysts are integrated into an MEA. More importantly, there is a significant knowledge gap between materials innovation and device integration. For example, high‐performance electrocatalysts usually demonstrate undesired quick degradation in MEAs. This issue significantly limits the development of PEM fuel cells. Herein, recent progress in understanding the degradation of low‐PGM and PGM‐free catalysts in fuel cell MEAs and materials‐based solutions to address these issues are reviewed. The key factors that degrade the MEA performance are highlighted. Innovative, emerging material concepts and development of low‐PGM and PGM‐free catalysts are discussed.

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High temperature stability study of carbon supported high surface area catalysts—Expanding the boundaries of ex-situ diagnostics

Cited by 39 publications

References 61 publications

Importance of non-intrinsic platinum dissolution in Pt/C composite fuel cell catalysts

Importance of non-intrinsic platinum dissolution in Pt/C composite fuel cell catalysts

Platinum Dissolution and Redeposition from Pt/C Fuel Cell Electrocatalyst at Potential Cycling

Low‐PGM and PGM‐Free Catalysts for Proton Exchange Membrane Fuel Cells: Stability Challenges and Material Solutions

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