1
|
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; 20: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.
Collapse
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
| |
Collapse
|
2
|
Li L, Antony RP, Santos CS, Limani N, Dieckhöfer S, Schuhmann W. Anodic H 2O 2 Generation in Carbonate-Based Electrolytes-Mechanistic Insight from Scanning Electrochemical Microscopy. Angew Chem Int Ed Engl 2024:e202406543. [PMID: 38923335 DOI: 10.1002/anie.202406543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 05/29/2024] [Accepted: 06/11/2024] [Indexed: 06/28/2024]
Abstract
For the anodic H2O2 generation, it has been shown that the electrolyte composition can steer the reaction pathway toward increased H2O2 generation. Previous efforts made on composition optimization found that the impact of the molar fraction of carbonate species varies for different anodes, and therefore, controversies remain concerning the reaction pathways as well as the species involved in H2O2 formation. Considering that water oxidation results in the liberation of protons within the anode microenvironment, the corresponding acidification would cause an equilibrium shift between carbonate species, which in turn may modulate the reaction pathway. We determined the changes in the fraction of carbonate species in the vicinity of an anode by performing local pH measurements using a Au nanoelectrode positioned in close proximity to an operating anode by shear-force scanning electrochemical microscopy (SECM). It could be confirmed that the main anionic species at the interface is HCO3 -, at potentials where H2O2 is preferentially formed, regardless of the pH value in the bulk. The simultaneous use of a Au-Pt double barrel microelectrode in generator-collector SECM measurements demonstrates that the local HCO3 - concentration is collectively determined by the oxidation current, buffer capacity, and bulk pH of the electrolyte.
Collapse
Affiliation(s)
- Lejing Li
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, D-44780, Bochum, Germany
| | - Rajini P Antony
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, D-44780, Bochum, Germany
| | - Carla Santana Santos
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, D-44780, Bochum, Germany
| | - Ndrina Limani
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, D-44780, Bochum, Germany
| | - Stefan Dieckhöfer
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, D-44780, Bochum, Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, D-44780, Bochum, Germany
| |
Collapse
|
3
|
Gunnarson A, Quast T, Dieckhöfer S, Pfänder N, Schüth F, Schuhmann W. Stability Investigations on a Pt@HGS Catalyst as a Model Material for Fuel Cell Applications: The Role of the Local pH. Angew Chem Int Ed Engl 2023; 62:e202311780. [PMID: 37846806 DOI: 10.1002/anie.202311780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 10/18/2023]
Abstract
Increasing the resistance of catalysts against electrochemical degradation is one of the key requirements for the wider use of Proton Exchange Membrane Fuel Cells (PEMFCs). Here, we study the degradation of one entity of a highly stable catalyst, Pt@HGS, on a nanoelectrode under accelerated mass transport conditions. We find that the catalyst degrades more rapidly than expected based on previous ensemble measurements. Corroborated by identical location transmission electron microscopy and catalyst layer experiments, we deduce that locally different pH values are likely the reason for this difference in stability. Ultimately, this work provides insights into the actual conditions present in a PEMFC and raises questions about the applicability of accelerated stress tests usually performed to evaluate catalyst stability, particularly when they are performed in half-cell setups under inert gas.
Collapse
Affiliation(s)
- Alexander Gunnarson
- Department of Heterogeneous Catalysis, Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Thomas Quast
- Analytical Chemistry-Center for Electrochemical Sciences (CES); Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Stefan Dieckhöfer
- Analytical Chemistry-Center for Electrochemical Sciences (CES); Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Norbert Pfänder
- Department of Heterogeneous Reactions, Max-Planck-Institute for Chemical Energy Conversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Ferdi Schüth
- Department of Heterogeneous Catalysis, Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry-Center for Electrochemical Sciences (CES); Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| |
Collapse
|
4
|
Dieterich E, Herrmann L, Dzhyginas O, Binnenböse L, Steimecke M, Kinkelin SJ, Bron M. Multimethod Approach to the Low-Overpotential Region of Micro- to Macro-Scale Working Electrodes of Sub-10 nm Gold Nanoparticles in the CO 2 Reduction Reaction. Anal Chem 2023; 95:16522-16530. [PMID: 37910605 DOI: 10.1021/acs.analchem.3c02338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
The electrochemical carbon dioxide reduction reaction (CO2RR) over carbon-supported gold nanoparticles (AuNP) was investigated using a broad variety of (electro)analytical methods, including linear sweep voltammetry with a rotating disk electrode (LSV-RDE), sample-generation tip-collection mode of scanning electrochemical microscopy (SG/TC-SECM), as well as full cell tests with highly sensitive online gas chromatography (GC). In contrast to most other studies, this work focuses on the low-overpotential region (0 to -0.4 V vs RHE) where initial product formation is already detected and addresses micro- to macro-sized electrodes. The sub-10 nm AuNPs supported on three different carbon supports (CNTs and carbon blacks) were pretreated in H2/Ar to remove the stabilizer used during AuNP synthesis. LSV-RDE points toward different CO2RR mechanisms at the samples, additionally confirmed by the SG/TC-SECM and full cell tests with online GC. Besides H2 and CO, the AuNP supported on carbon nanotubes showed significant evolution of H2CO in contrast to the other two samples, which was additionally confirmed by accumulating the product during chronoamperometric RDE experiments followed by mass spectroscopic analysis. Surface analysis indicated a complete removal of residual thiolate stabilizer molecules exclusively at the AuNPs supported on carbon nanotubes, which may result in a change in the adsorption geometry or reaction mechanism at this sample. The results demonstrate the effectiveness of the combination of these multiple methods to investigate the CO2RR in the low-overpotential region.
Collapse
Affiliation(s)
- Emil Dieterich
- Institut für Chemie, Technische Chemie I, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - Lukas Herrmann
- Institut für Chemie, Technische Chemie I, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - Olga Dzhyginas
- Institut für Chemie, Technische Chemie I, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - Lukas Binnenböse
- Institut für Chemie, Technische Chemie I, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - Matthias Steimecke
- Institut für Chemie, Technische Chemie I, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - Simon-Johannes Kinkelin
- Institut für Chemie, Technische Chemie I, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - Michael Bron
- Institut für Chemie, Technische Chemie I, Martin-Luther-Universität Halle-Wittenberg, Von-Danckelmann-Platz 4, 06120 Halle, Germany
| |
Collapse
|
5
|
Gong Y, He T. Gaining Deep Understanding of Electrochemical CO 2 RR with In Situ/Operando Techniques. SMALL METHODS 2023; 7:e2300702. [PMID: 37608449 DOI: 10.1002/smtd.202300702] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/09/2023] [Indexed: 08/24/2023]
Abstract
Electrocatalysis for CO2 conversion has been extensively studied to mitigate the energy shortage and environmental issues, which are gaining ever-increasing attention. However, the complicated CO2 reduction process and the dynamic evolution occurring on electrocatalyst surface make it hard to understand the catalytic mechanism. The development of advanced in situ/operando techniques intelligently coupled with electrochemical cells sheds light on the related study via capturing surface atomic rearrangement, tracing chemical state change of catalysts, monitoring the behavior of intermediates and products, and depicting microenvironment near the electrode surface. In this review, fundamentals of the state-of-the-art in situ/operando techniques are clarified first. Case studies on the in situ/operando techniques performed to probe the CO2 reduction reaction processes are then discussed in detail. Finally, conclusions and outlook on this field are presented.
Collapse
Affiliation(s)
- Yue Gong
- CAS Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| | - Tao He
- CAS Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
- University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
| |
Collapse
|
6
|
Santana Santos C, Jaato BN, Sanjuán I, Schuhmann W, Andronescu C. Operando Scanning Electrochemical Probe Microscopy during Electrocatalysis. Chem Rev 2023; 123:4972-5019. [PMID: 36972701 PMCID: PMC10168669 DOI: 10.1021/acs.chemrev.2c00766] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Scanning electrochemical probe microscopy (SEPM) techniques can disclose the local electrochemical reactivity of interfaces in single-entity and sub-entity studies. Operando SEPM measurements consist of using a SEPM tip to investigate the performance of electrocatalysts, while the reactivity of the interface is simultaneously modulated. This powerful combination can correlate electrochemical activity with changes in surface properties, e.g., topography and structure, as well as provide insight into reaction mechanisms. The focus of this review is to reveal the recent progress in local SEPM measurements of the catalytic activity of a surface toward the reduction and evolution of O2 and H2 and electrochemical conversion of CO2. The capabilities of SEPMs are showcased, and the possibility of coupling other techniques to SEPMs is presented. Emphasis is given to scanning electrochemical microscopy (SECM), scanning ion conductance microscopy (SICM), electrochemical scanning tunneling microscopy (EC-STM), and scanning electrochemical cell microscopy (SECCM).
Collapse
Affiliation(s)
- Carla Santana Santos
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Bright Nsolebna Jaato
- Technical Chemistry III, Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen Carl-Benz-Straße 199, 47057 Duisburg, Germany
| | - Ignacio Sanjuán
- Technical Chemistry III, Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen Carl-Benz-Straße 199, 47057 Duisburg, Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry - Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Corina Andronescu
- Technical Chemistry III, Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen Carl-Benz-Straße 199, 47057 Duisburg, Germany
| |
Collapse
|
7
|
Hursán D, Janáky C. Operando characterization of continuous flow CO 2 electrolyzers: current status and future prospects. Chem Commun (Camb) 2023; 59:1395-1414. [PMID: 36655495 PMCID: PMC9894021 DOI: 10.1039/d2cc06065e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The performance of continuous-flow CO2 electrolyzers has substantially increased in recent years, achieving current density and selectivity (particularly for CO production) meeting the industrial targets. Further improvement is, however, necessary in terms of stability and energy efficiency, as well as in high-value multicarbon product formation. Accelerating this process requires deeper understanding of the complex interplay of chemical-physical processes taking place in CO2 electrolyzer cells. Operando characterization can provide these insights under working conditions, helping to identify the reasons for performance losses. Despite this fact, only relatively few studies have taken advantage of such methods up to now, applying operando techniques to characterize practically relevant CO2 electrolyzers. These studies include X-ray absorption- and Raman spectroscopy, fluorescent microscopy, scanning probe techniques, mass spectrometry, and radiography. Their objective was to characterize the catalyst structure, its microenviroment, membrane properties, etc., and relate them to the device performance (reaction rates and product distribution). Here we review the current state-of-the-art of operando methods, associated challenges, and also their future potential. We aim to motivate researchers to perform operando characterization in continuous-flow CO2 electrolyzers, to understand the reaction mechanism and device operation under practically relevant conditions, thereby advancing the field towards industrialization.
Collapse
Affiliation(s)
- Dorottya Hursán
- University of Szeged, Department of Physical Chemistry and Materials ScienceAradi sq. 1Szeged6720Hungary
| | - Csaba Janáky
- University of Szeged, Department of Physical Chemistry and Materials ScienceAradi sq. 1Szeged6720Hungary
| |
Collapse
|
8
|
Wang L, Li X, Hao L, Hong S, Robertson AW, Sun Z. Integration of ultrafine CuO nanoparticles with two-dimensional MOFs for enhanced electrochemicgal CO2 reduction to ethylene. CHINESE JOURNAL OF CATALYSIS 2022. [DOI: 10.1016/s1872-2067(21)63947-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
9
|
He W, Zhang J, Dieckhöfer S, Varhade S, Brix AC, Lielpetere A, Seisel S, Junqueira JRC, Schuhmann W. Splicing the active phases of copper/cobalt-based catalysts achieves high-rate tandem electroreduction of nitrate to ammonia. Nat Commun 2022; 13:1129. [PMID: 35236840 PMCID: PMC8891333 DOI: 10.1038/s41467-022-28728-4] [Citation(s) in RCA: 136] [Impact Index Per Article: 68.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 02/08/2022] [Indexed: 12/21/2022] Open
Abstract
Electrocatalytic recycling of waste nitrate (NO3−) to valuable ammonia (NH3) at ambient conditions is a green and appealing alternative to the Haber−Bosch process. However, the reaction requires multi-step electron and proton transfer, making it a grand challenge to drive high-rate NH3 synthesis in an energy-efficient way. Herein, we present a design concept of tandem catalysts, which involves coupling intermediate phases of different transition metals, existing at low applied overpotentials, as cooperative active sites that enable cascade NO3−-to-NH3 conversion, in turn avoiding the generally encountered scaling relations. We implement the concept by electrochemical transformation of Cu−Co binary sulfides into potential-dependent core−shell Cu/CuOx and Co/CoO phases. Electrochemical evaluation, kinetic studies, and in−situ Raman spectra reveal that the inner Cu/CuOx phases preferentially catalyze NO3− reduction to NO2−, which is rapidly reduced to NH3 at the nearby Co/CoO shell. This unique tandem catalyst system leads to a NO3−-to-NH3 Faradaic efficiency of 93.3 ± 2.1% in a wide range of NO3− concentrations at pH 13, a high NH3 yield rate of 1.17 mmol cm−2 h−1 in 0.1 M NO3− at −0.175 V vs. RHE, and a half-cell energy efficiency of ~36%, surpassing most previous reports. Electrocatalytic recycling of waste nitrate to NH3 under ambient conditions maybe an appealing alternative to the Haber−Bosch process. Here the authors report a tandem catalyst system involving cooperative adsorption of reaction intermediate on different transition metal active sites for nitrate electroreduction with high efficiency.
Collapse
Affiliation(s)
- Wenhui He
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Jian Zhang
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Stefan Dieckhöfer
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Swapnil Varhade
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Ann Cathrin Brix
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Anna Lielpetere
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Sabine Seisel
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - João R C Junqueira
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany.
| |
Collapse
|
10
|
Junqueira JRC, O'Mara PB, Wilde P, Dieckhöfer S, Benedetti TM, Andronescu C, Tilley RD, Gooding JJ, Schuhmann W. Combining Nanoconfinement in Ag Core/Porous Cu Shell Nanoparticles with Gas Diffusion Electrodes for Improved Electrocatalytic Carbon Dioxide Reduction. ChemElectroChem 2021; 8:4848-4853. [PMID: 35909946 PMCID: PMC9303450 DOI: 10.1002/celc.202100906] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 11/18/2021] [Indexed: 11/25/2022]
Abstract
Bimetallic silver-copper electrocatalysts are promising materials for electrochemical CO2 reduction reaction (CO2RR) to fuels and multi-carbon molecules. Here, we combine Ag core/porous Cu shell particles, which entrap reaction intermediates and thus facilitate the formation of C2+ products at low overpotentials, with gas diffusion electrodes (GDE). Mass transport plays a crucial role in the product selectivity in CO2RR. Conventional H-cell configurations suffer from limited CO2 diffusion to the reaction zone, thus decreasing the rate of the CO2RR. In contrast, in the case of GDE-based cells, the CO2RR takes place under enhanced mass transport conditions. Hence, investigation of the Ag core/porous Cu shell particles at the same potentials under different mass transport regimes reveals: (i) a variation of product distribution including C3 products, and (ii) a significant change in the local OH- activity under operation.
Collapse
Affiliation(s)
- João R. C. Junqueira
- Analytical Chemistry – Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr-Universität BochumUniversitätsstraße 150D-44780BochumGermany
| | - Peter B. O'Mara
- School of Chemistry and Australian Centre for NanoMedicineUniversity of New South WalesSydney2052Australia
| | - Patrick Wilde
- Analytical Chemistry – Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr-Universität BochumUniversitätsstraße 150D-44780BochumGermany
| | - Stefan Dieckhöfer
- Analytical Chemistry – Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr-Universität BochumUniversitätsstraße 150D-44780BochumGermany
| | - Tania M. Benedetti
- School of Chemistry and Australian Centre for NanoMedicineUniversity of New South WalesSydney2052Australia
| | - Corina Andronescu
- Chemical Technology IIIFaculty of Chemistry and CENIDECenter for NanointegrationUniversity Duisburg EssenCarl-Benz-Straße 199D-47057DuisburgGermany
| | - Richard D. Tilley
- School of Chemistry and Australian Centre for NanoMedicineUniversity of New South WalesSydney2052Australia
- Electron Microscope UnitMark Wainwright Analytical CentreUniversity of New South WalesSydney2052Australia
| | - J. Justin Gooding
- School of Chemistry and Australian Centre for NanoMedicineUniversity of New South WalesSydney2052Australia
| | - Wolfgang Schuhmann
- Analytical Chemistry – Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr-Universität BochumUniversitätsstraße 150D-44780BochumGermany
| |
Collapse
|
11
|
Monteiro MCO, Dieckhöfer S, Bobrowski T, Quast T, Pavesi D, Koper MTM, Schuhmann W. Probing the local activity of CO 2 reduction on gold gas diffusion electrodes: effect of the catalyst loading and CO 2 pressure. Chem Sci 2021; 12:15682-15690. [PMID: 35003599 PMCID: PMC8654039 DOI: 10.1039/d1sc05519d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/09/2021] [Indexed: 01/14/2023] Open
Abstract
Large scale CO2 electrolysis can be achieved using gas diffusion electrodes (GDEs), and is an essential step towards broader implementation of carbon capture and utilization strategies. Different variables are known to affect the performance of GDEs. Especially regarding the catalyst loading, there are diverging trends reported in terms of activity and selectivity, e.g. for CO2 reduction to CO. We have used shear-force based Au nanoelectrode positioning and scanning electrochemical microscopy (SECM) in the surface-generation tip collection mode to evaluate the activity of Au GDEs for CO2 reduction as a function of catalyst loading and CO2 back pressure. Using a Au nanoelectrode, we have locally measured the amount of CO produced along a catalyst loading gradient under operando conditions. We observed that an optimum local loading of catalyst is necessary to achieve high activities. However, this optimum is directly dependent on the CO2 back pressure. Our work does not only present a tool to evaluate the activity of GDEs locally, it also allows drawing a more precise picture regarding the effect of catalyst loading and CO2 back pressure on their performance.
Collapse
Affiliation(s)
- Mariana C O Monteiro
- Leiden Institute of Chemistry, Leiden University Einsteinweg 55 2333CC Leiden The Netherlands
| | - Stefan Dieckhöfer
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum Universitätsstr. 150 D-44780 Bochum Germany
| | - Tim Bobrowski
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum Universitätsstr. 150 D-44780 Bochum Germany
| | - Thomas Quast
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum Universitätsstr. 150 D-44780 Bochum Germany
| | - Davide Pavesi
- Leiden Institute of Chemistry, Leiden University Einsteinweg 55 2333CC Leiden The Netherlands
| | - Marc T M Koper
- Leiden Institute of Chemistry, Leiden University Einsteinweg 55 2333CC Leiden The Netherlands
| | - Wolfgang Schuhmann
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum Universitätsstr. 150 D-44780 Bochum Germany
| |
Collapse
|
12
|
Monteiro MO, Mirabal A, Jacobse L, Doblhoff-Dier K, Barton SC, Koper MTM. Time-Resolved Local pH Measurements during CO 2 Reduction Using Scanning Electrochemical Microscopy: Buffering and Tip Effects. JACS AU 2021; 1:1915-1924. [PMID: 34849509 PMCID: PMC8611793 DOI: 10.1021/jacsau.1c00289] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Indexed: 06/13/2023]
Abstract
The electrochemical reduction of CO2 is widely studied as a sustainable alternative for the production of fuels and chemicals. The electrolyte's bulk pH and composition play an important role in the reaction activity and selectivity and can affect the extent of the buildup of pH gradients between the electrode surface and the bulk of the electrolyte. Quantifying the local pH and how it is affected by the solution species is desirable to gain a better understanding of the CO2 reduction reaction. Local pH measurements can be realized using Scanning Electrochemical Microscopy (SECM); however, finding a pH probe that is stable and selective under CO2 reduction reaction conditions is challenging. Here, we have used our recently developed voltammetric pH sensor to perform pH measurements in the diffusion layer during CO2 reduction using SECM, with high time resolution. Using a 4-hydroxylaminothiophenol (4-HATP)/4-nitrosothiophenol (4-NSTP) functionalized gold ultramicroelectrode, we compare the local pH developed above a gold substrate in an argon atmosphere, when only hydrogen evolution is taking place, to the pH developed in a CO2 atmosphere. The pH is monitored at a fixed distance from the surface, and the sample potential is varied in time. In argon, we observe a gradual increase of pH, while a plateau region is present in CO2 atmosphere due to the formation of HCO3 - buffering the reaction interface. By analyzing the diffusion layer dynamics once the sample reaction is turned "off", we gain insightful information on the time scale of the homogeneous reactions happening in solution and on the time required for the diffusion layer to fully recover to the initial bulk concentration of species. In order to account for the effect of the presence of the SECM tip on the measured pH, we performed finite element method simulations of the fluid and reaction dynamics. The results show the significant localized diffusion hindrance caused by the tip, so that in its absence, the pH values are more acidic than when the tip is present. Nonetheless, through the simulation, we can account for this effect and estimate the real local pH values across the diffusion layer.
Collapse
Affiliation(s)
- Mariana
C. O. Monteiro
- Leiden
Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Alex Mirabal
- Department
of Chemical & Materials Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Leon Jacobse
- Centre
for X-ray and Nano Science CXNS, Deutsches
Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg, Germany
| | - Katharina Doblhoff-Dier
- Leiden
Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Scott Calabrese Barton
- Department
of Chemical & Materials Engineering, Michigan State University, East Lansing, Michigan 48824, United States
| | - Marc T. M. Koper
- Leiden
Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| |
Collapse
|
13
|
Monteiro MCO, Liu X, Hagedoorn BJL, Snabilié DD, Koper MTM. Interfacial pH Measurements Using a Rotating Ring‐Disc Electrode with a Voltammetric pH Sensor. ChemElectroChem 2021. [DOI: 10.1002/celc.202101223] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Mariana C. O. Monteiro
- Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333CC Leiden The Netherlands
| | - Xuan Liu
- Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333CC Leiden The Netherlands
| | | | - Demi D. Snabilié
- Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333CC Leiden The Netherlands
| | - Marc T. M. Koper
- Leiden Institute of Chemistry Leiden University Einsteinweg 55 2333CC Leiden The Netherlands
| |
Collapse
|
14
|
Sikdar N, Junqueira JRC, Dieckhöfer S, Quast T, Braun M, Song Y, Aiyappa HB, Seisel S, Weidner J, Öhl D, Andronescu C, Schuhmann W. A Metal-Organic Framework derived Cu x O y C z Catalyst for Electrochemical CO 2 Reduction and Impact of Local pH Change. Angew Chem Int Ed Engl 2021; 60:23427-23434. [PMID: 34355835 PMCID: PMC8597168 DOI: 10.1002/anie.202108313] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Indexed: 01/12/2023]
Abstract
Developing highly efficient and selective electrocatalysts for the CO2 reduction reaction to produce value-added chemicals has been intensively pursued. We report a series of Cux Oy Cz nanostructured electrocatalysts derived from a Cu-based MOF as porous self-sacrificial template. Blending catalysts with polytetrafluoroethylene (PTFE) on gas diffusion electrodes (GDEs) suppressed the competitive hydrogen evolution reaction. 25 to 50 wt % teflonized GDEs exhibited a Faradaic efficiency of ≈54 % for C2+ products at -80 mA cm-2 . The local OH- ions activity of PTFE-modified GDEs was assessed by means of closely positioning a Pt-nanoelectrode. A substantial increase in the OH- /H2 O activity ratio due to the locally generated OH- ions at increasing current densities was determined irrespective of the PTFE amount.
Collapse
Affiliation(s)
- Nivedita Sikdar
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| | - João R. C. Junqueira
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| | - Stefan Dieckhöfer
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| | - Thomas Quast
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| | - Michael Braun
- Chemical Technology III; Faculty of Chemistry and CENIDE Center for NanointegrationUniversity Duisburg-EssenCarl-Benz Straße 19947057DuisburgGermany
| | - Yanfang Song
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
- CAS Key Laboratory of Low-Carbon Conversion Science and EngineeringShanghai Advanced Research InstituteChinese Academy of Sciences99 Haike RoadShanghai201203People's Republic of China
| | - Harshitha B. Aiyappa
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| | - Sabine Seisel
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| | - Jonas Weidner
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| | - Denis Öhl
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| | - Corina Andronescu
- Chemical Technology III; Faculty of Chemistry and CENIDE Center for NanointegrationUniversity Duisburg-EssenCarl-Benz Straße 19947057DuisburgGermany
| | - Wolfgang Schuhmann
- Analytical Chemistry—Center for Electrochemical Sciences (CES)Faculty of Chemistry and BiochemistryRuhr University BochumUniversitätsstr. 15044780BochumGermany
| |
Collapse
|
15
|
Sikdar N, Junqueira JRC, Dieckhöfer S, Quast T, Braun M, Song Y, Aiyappa HB, Seisel S, Weidner J, Öhl D, Andronescu C, Schuhmann W. Ein MOF‐basierter Cu
x
O
y
C
z
‐Katalysator für die elektrochemische CO
2
‐Reduktion und die Auswirkungen der lokalen pH‐Änderung. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Nivedita Sikdar
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| | - João R. C. Junqueira
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| | - Stefan Dieckhöfer
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| | - Thomas Quast
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| | - Michael Braun
- Chemical Technology III Faculty of Chemistry and CENIDE Center for Nanointegration University Duisburg-Essen Carl-Benz Straße 199 47057 Duisburg Deutschland
| | - Yanfang Song
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
- CAS Key Laboratory of Low-Carbon Conversion Science and Engineering Shanghai Advanced Research Institute Chinese Academy of Sciences 99 Haike Road Shanghai 201203 People's Republic of China
| | - Harshitha B. Aiyappa
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| | - Sabine Seisel
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| | - Jonas Weidner
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| | - Denis Öhl
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| | - Corina Andronescu
- Chemical Technology III Faculty of Chemistry and CENIDE Center for Nanointegration University Duisburg-Essen Carl-Benz Straße 199 47057 Duisburg Deutschland
| | - Wolfgang Schuhmann
- Analytical Chemistry – Center for Electrochemical Sciences (CES) Faculty of Chemistry and Biochemistry Ruhr University Bochum Universitätsstr. 150 44780 Bochum Deutschland
| |
Collapse
|
16
|
Efficiency and selectivity of CO 2 reduction to CO on gold gas diffusion electrodes in acidic media. Nat Commun 2021; 12:4943. [PMID: 34400626 PMCID: PMC8368099 DOI: 10.1038/s41467-021-24936-6] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 07/06/2021] [Indexed: 11/08/2022] Open
Abstract
The electrochemical reduction of CO2 to CO is a promising technology for replacing production processes employing fossil fuels. Still, low energy efficiencies hinder the production of CO at commercial scale. CO2 electrolysis has mainly been performed in neutral or alkaline media, but recent fundamental work shows that high selectivities for CO can also be achieved in acidic media. Therefore, we investigate the feasibility of CO2 electrolysis at pH 2–4 at indrustrially relevant conditions, using 10 cm2 gold gas diffusion electrodes. Operating at current densities up to 200 mA cm−2, we obtain CO faradaic efficiencies between 80–90% in sulfate electrolyte, with a 30% improvement of the overall process energy efficiency, in comparison with neutral media. Additionally, we find that weakly hydrated cations are crucial for accomplishing high reaction rates and enabling CO2 electrolysis in acidic media. This study represents a step towards the application of acidic electrolyzers for CO2 electroreduction. Large scale CO2 electrolysis to produce CO has mainly been performed in neutral and alkaline media. Here, we show that it can also be realized in acidic media, with faradaic efficiencies of 80–90%, and 30% better energy efficiency than obtained in neutral media.
Collapse
|
17
|
Dieckhöfer S, Öhl D, Junqueira JRC, Quast T, Turek T, Schuhmann W. Probing the Local Reaction Environment During High Turnover Carbon Dioxide Reduction with Ag-Based Gas Diffusion Electrodes. Chemistry 2021; 27:5906-5912. [PMID: 33527522 PMCID: PMC8048634 DOI: 10.1002/chem.202100387] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Indexed: 01/03/2023]
Abstract
Discerning the influence of electrochemical reactions on the electrode microenvironment is an unavoidable topic for electrochemical reactions that involve the production of OH− and the consumption of water. That is particularly true for the carbon dioxide reduction reaction (CO2RR), which together with the competing hydrogen evolution reaction (HER) exert changes in the local OH− and H2O activity that in turn can possibly affect activity, stability, and selectivity of the CO2RR. We determine the local OH− and H2O activity in close proximity to a CO2‐converting Ag‐based gas diffusion electrode (GDE) with product analysis using gas chromatography. A Pt nanosensor is positioned in the vicinity of the working GDE using shear‐force‐based scanning electrochemical microscopy (SECM) approach curves, which allows monitoring changes invoked by reactions proceeding within an otherwise inaccessible porous GDE by potentiodynamic measurements at the Pt‐tip nanosensor. We show that high turnover HER/CO2RR at a GDE lead to modulations of the alkalinity of the local electrolyte, that resemble a 16 m KOH solution, variations that are in turn linked to the reaction selectivity.
Collapse
Affiliation(s)
- Stefan Dieckhöfer
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Denis Öhl
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - João R C Junqueira
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Thomas Quast
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| | - Thomas Turek
- Institute of Chemical and Electrochemical Process Engineering, Clausthal University of Technology, Leibnizstr 17, 38678, Clausthal-Zellerfeld, Germany
| | - Wolfgang Schuhmann
- Analytical Chemistry-Center for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Universitätsstr. 150, 44780, Bochum, Germany
| |
Collapse
|