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Brosch S, Wiesner F, Decker A, Linkhorst J, Wessling M. Spatio-Temporal Electrowetting and Reaction Monitoring in Microfluidic Gas Diffusion Electrode Elucidates Mass Transport Limitations. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2310427. [PMID: 38386289 DOI: 10.1002/smll.202310427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 01/15/2024] [Indexed: 02/23/2024]
Abstract
The use of gas diffusion electrodes (GDEs) enables efficient electrochemical CO2 reduction and may be a viable technology in CO2 utilization after carbon capture. Understanding the spatio-temporal phenomena at the triple-phase boundary formed inside GDEs remains a challenge; yet it is critical to design and optimize industrial electrodes for gas-fed electrolyzers. Thus far, transport and reaction phenomena are not yet fully understood at the microscale, among other factors, due to a lack of experimental analysis methods for porous electrodes under operating conditions. In this work, a realistic microfluidic GDE surrogate is presented. Combined with fluorescence lifetime imaging microscopy (FLIM), the methodology allows monitoring of wetting and local pH, representing the dynamic (in)stability of the triple phase boundary in operando. Upon charging the electrode, immediate wetting leads to an initial flooding of the catalyst layer, followed by spatially oscillating pH changes. The micromodel presented gives an experimental insight into transport phenomena within porous electrodes, which is so far difficult to achieve. The methodology and proof of the spatio-temporal pH and wetting oscillations open new opportunities to further comprehend the relationship between gas diffusion electrode properties and electrical currents originating at a given surface potential.
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Affiliation(s)
- Sebastian Brosch
- RWTH Aachen University, Aachener Verfahrenstechnik - Chemical Process Engineering, Forckenbeckstr. 51, 52074, Aachen, Germany
| | - Florian Wiesner
- RWTH Aachen University, Aachener Verfahrenstechnik - Chemical Process Engineering, Forckenbeckstr. 51, 52074, Aachen, Germany
| | - Alexandra Decker
- RWTH Aachen University, Aachener Verfahrenstechnik - Chemical Process Engineering, Forckenbeckstr. 51, 52074, Aachen, Germany
| | - John Linkhorst
- RWTH Aachen University, Aachener Verfahrenstechnik - Chemical Process Engineering, Forckenbeckstr. 51, 52074, Aachen, Germany
- Verfahrenstechnik elektrochemischer Systeme, Technical University Darmstadt, Otto-Berndt-Str. 2, 64287, Darmstadt, Germany
| | - Matthias Wessling
- RWTH Aachen University, Aachener Verfahrenstechnik - Chemical Process Engineering, Forckenbeckstr. 51, 52074, Aachen, Germany
- DWI - Leibnitz Institute for Interactive Materials, Forckenbeckstr. 50, 52074, Aachen, Germany
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Tengattini A, Kardjilov N, Helfen L, Douissard PA, Lenoir N, Markötter H, Hilger A, Arlt T, Paulisch M, Turek T, Manke I. Compact and versatile neutron imaging detector with sub-4μm spatial resolution based on a single-crystal thin-film scintillator. OPTICS EXPRESS 2022; 30:14461-14477. [PMID: 35473188 DOI: 10.1364/oe.448932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
A large and increasing number of scientific domains pushes for high neutron imaging resolution achieved in reasonable times. Here we present the principle, design and performance of a detector based on infinity corrected optics combined with a crystalline Gd3Ga5O12 : Eu scintillator, which provides an isotropic sub-4 µm true resolution. The exposure times are only of a few minutes per image. This is made possible also by the uniquely intense cold neutron flux available at the imaging beamline NeXT-Grenoble. These comparatively rapid acquisitions are compatible with multiple high quality tomographic acquisitions, opening new venues for in-operando testing, as briefly exemplified here.
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Ehelebe K, Knöppel J, Bierling M, Mayerhöfer B, Böhm T, Kulyk N, Thiele S, Mayrhofer KJJ, Cherevko S. Platinum Dissolution in Realistic Fuel Cell Catalyst Layers. Angew Chem Int Ed Engl 2021; 60:8882-8888. [PMID: 33410273 PMCID: PMC8048487 DOI: 10.1002/anie.202014711] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/15/2020] [Indexed: 11/12/2022]
Abstract
Pt dissolution has already been intensively studied in aqueous model systems and many mechanistic insights have been gained. Nevertheless, transfer of new knowledge to real‐world fuel cell systems is still a significant challenge. To close this gap, we present a novel in situ method combining a gas diffusion electrode (GDE) half‐cell with inductively coupled plasma mass spectrometry (ICP‐MS). With this setup, Pt dissolution in realistic catalyst layers and the transport of dissolved Pt species through Nafion membranes were evaluated directly. We observed that 1) specific Pt dissolution increased significantly with decreasing Pt loading, 2) in comparison to experiments on aqueous model systems with flow cells, the measured dissolution in GDE experiments was considerably lower, and 3) by adding a membrane onto the catalyst layer, Pt dissolution was reduced even further. All these phenomena are attributed to the varying mass transport conditions of dissolved Pt species, influencing re‐deposition and equilibrium potential.
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Affiliation(s)
- Konrad Ehelebe
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany.,Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Julius Knöppel
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany.,Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Markus Bierling
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany.,Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Britta Mayerhöfer
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany.,Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Thomas Böhm
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany.,Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Nadiia Kulyk
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany
| | - Simon Thiele
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany.,Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Karl J J Mayrhofer
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany.,Department of Chemical and Biological Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Egerlandstr. 3, 91058, Erlangen, Germany
| | - Serhiy Cherevko
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11), Forschungszentrum Jülich GmbH, 91058, Erlangen, Germany
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Ehelebe K, Knöppel J, Bierling M, Mayerhöfer B, Böhm T, Kulyk N, Thiele S, Mayrhofer KJJ, Cherevko S. Platinum Dissolution in Realistic Fuel Cell Catalyst Layers. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014711] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Konrad Ehelebe
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
- Department of Chemical and Biological Engineering Friedrich-Alexander University Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Julius Knöppel
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
- Department of Chemical and Biological Engineering Friedrich-Alexander University Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Markus Bierling
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
- Department of Chemical and Biological Engineering Friedrich-Alexander University Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Britta Mayerhöfer
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
- Department of Chemical and Biological Engineering Friedrich-Alexander University Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Thomas Böhm
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
- Department of Chemical and Biological Engineering Friedrich-Alexander University Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Nadiia Kulyk
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
| | - Simon Thiele
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
- Department of Chemical and Biological Engineering Friedrich-Alexander University Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Karl J. J. Mayrhofer
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
- Department of Chemical and Biological Engineering Friedrich-Alexander University Erlangen-Nürnberg Egerlandstr. 3 91058 Erlangen Germany
| | - Serhiy Cherevko
- Helmholtz-Institute Erlangen-Nürnberg for Renewable Energy, (IEK-11) Forschungszentrum Jülich GmbH 91058 Erlangen Germany
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Gebhard M, Tichter T, Franzen D, Paulisch MC, Schutjajew K, Turek T, Manke I, Roth C. Improvement of Oxygen‐Depolarized Cathodes in Highly Alkaline Media by Electrospinning of Poly(vinylidene fluoride) Barrier Layers. ChemElectroChem 2020. [DOI: 10.1002/celc.201902115] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Marcus Gebhard
- Electrochemical Process EngineeringUniversity of Bayreuth Universitätsstraße 30 95447 Bayreuth Germany
| | - Tim Tichter
- Institute of Chemistry and BiochemistryFreie Universität Berlin Takustraße 3 14195 Berlin Germany
| | - David Franzen
- Institute of Chemical and Electrochemical Process EngineeringClausthal University of Technology Leibnizstrasse 17 38678 Clausthal-Zellerfeld Germany
| | - Melanie C. Paulisch
- Institute of Applied MaterialsHelmholtz-Zentrum Berlin für Materialien und Energie GmbH Hahn-Meitner-Platz 1 Berlin 14109 Germany
| | - Konstantin Schutjajew
- Institute of ChemistryUniversity of Potsdam Karl-Liebknecht-Str. 24–25 14476 Potsdam Germany
| | - Thomas Turek
- Institute of Chemical and Electrochemical Process EngineeringClausthal University of Technology Leibnizstrasse 17 38678 Clausthal-Zellerfeld Germany
| | - Ingo Manke
- Institute of Applied MaterialsHelmholtz-Zentrum Berlin für Materialien und Energie GmbH Hahn-Meitner-Platz 1 Berlin 14109 Germany
| | - Christina Roth
- Electrochemical Process EngineeringUniversity of Bayreuth Universitätsstraße 30 95447 Bayreuth Germany
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Operando Laboratory X-Ray Imaging of Silver-Based Gas Diffusion Electrodes during Oxygen Reduction Reaction in Highly Alkaline Media. MATERIALS 2019; 12:ma12172686. [PMID: 31443453 PMCID: PMC6747613 DOI: 10.3390/ma12172686] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 11/27/2022]
Abstract
Operando laboratory X-ray radiographies were carried out for imaging of two different silver-based gas diffusion electrodes containing an electroconductive Ni mesh structure, one gas diffusion electrode composed of 95 wt.% Ag and 5 wt.% polytetrafluoroethylene and one composed of 97 wt.% Ag and 3 wt.% polytetrafluoroethylene, under different operating parameters. Thereby, correlations of their electrochemical behavior and the transport of the 30 wt.% NaOH electrolyte through the gas diffusion electrodes were revealed. The work was divided into two parts. In the first step, the microstructure of the gas diffusion electrodes was analyzed ex situ by a combination of focused ion beam technology and synchrotron as well as laboratory X-ray tomography and radiography. In the second step, operando laboratory X-ray radiographies were performed during chronoamperometric measurements at different potentials. The combination of the ex situ microstructural analyses and the operando measurements reveals the impact of the microstructure on the electrolyte transport through the gas diffusion electrodes. Hence, an impact of the Ni mesh structure within the gas diffusion electrode on the droplet formation could be shown. Moreover, it could be observed that increasing overpotentials cause increasing electrolyte transport velocities and faster droplet formation due to electrowetting. In general, higher electrolyte transport velocities were found for the gas diffusion electrode with 97 wt.% Ag in contrast to that with 95 wt.% Ag.
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