<i>Operando</i>characterization of continuous flow CO<sub>2</sub>electrolyzers: current status and future prospects

Hursán, Dorottya; Janáky, Csaba

doi:10.1039/d2cc06065e

Cited by 13 publications

(9 citation statements)

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“…Efforts are also needed to understand the exact reaction processes and mechanisms in MEA systems. Operando characterizations can give comprehensively mechanistic understanding of CO 2 RR, even in continuous flow electrolysers [136] . In situ XAS can provide real‐time monitoring of the chemical state, which can give a comprehensive understanding of the active sites [137] .…”

Section: Summary and Perspectivementioning

confidence: 99%

“…Operando characterizations can give comprehensively mechanistic understanding of CO 2 RR, even in continuous flow electrolysers. [136] In situ XAS can provide real-time monitoring of the chemical state, which can give a comprehensive understanding of the active sites. [137] Accurately determining the key intermediates and elementary steps of catalytic reactions can help to describe the reaction pathways for CO 2 RR on different active sites.…”

Section: Summary and Perspectivementioning

confidence: 99%

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Membrane Electrode Assembly for Electrocatalytic CO₂ Reduction: Principle and Application

et al. 2023

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Electrocatalytic CO 2 reduction reaction (CO 2 RR) in membrane electrode assembly (MEA) systems is a promising technology. Gaseous CO 2 can be directly transported to the cathode catalyst layer, leading to enhanced reaction rate. Meanwhile, there is no liquid electrolyte between the cathode and the anode, which can help to improve the energy efficiency of the whole system. The remarkable progress achieved recently points out the way to realize industrially relevant performance. In this review, we focus on the principles in MEA for CO 2 RR, focusing on gas diffusion electrodes and ion exchange membranes. Furthermore, anode processes beyond the oxidation of water are considered. Besides, the voltage distribution is scrutinized to identify the specific losses related to the individual components. We also summarize the progress on the generation of different reduced products together with the corresponding catalysts. Finally, the challenges and opportunities are highlighted for future research.

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Section: Summary and Perspectivementioning

confidence: 99%

Section: Summary and Perspectivementioning

confidence: 99%

Membrane Electrode Assembly for Electrocatalytic CO₂ Reduction: Principle and Application

et al. 2023

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“…22,26,27 The reaction system is further complicated by the evolution of gas bubbles on the electrodes, which can affect the energy efficiency by introducing overpotentials. 28,29 Experimental characterization techniques 30,31 can be used to complement these numerical studies. For example, absorption spectroscopy can determine the pH at plate cathode surfaces 32,33 or inside a bipolar membrane (BPM).…”

Section: ■ Introductionmentioning

confidence: 99%

“…Experimental characterization techniques , can be used to complement these numerical studies. For example, absorption spectroscopy can determine the pH at plate cathode surfaces , or inside a bipolar membrane (BPM) …”

Section: Introductionmentioning

confidence: 99%

Direct Imaging of Local pH Reveals Bubble-Induced Mixing in a CO₂ Electrolyzer

Baumgartner

Kahn

Hoogland

et al. 2023

ACS Sustainable Chem. Eng.

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Electrochemical CO 2 reduction poses a promising pathway to produce hydrocarbon chemicals and fuels without relying on fossil fuels. Gas diffusion electrodes allow high selectivity for desired carbon products at high current density by ensuring a sufficient CO 2 mass transfer rate to the catalyst layer. In addition to CO 2 mass transfer, the product selectivity also strongly depends on the local pH at the catalyst surface. In this work, we directly visualize for the first time the two-dimensional (2D) pH profile in the catholyte channel of a gas-fed CO 2 electrolyzer equipped with a bipolar membrane. The pH profile is imaged with operando fluorescence lifetime imaging microscopy (FLIM) using a pH-sensitive quinolinium-based dye. We demonstrate that bubble-induced mixing plays an important role in the Faradaic efficiency. Our concentration measurements show that the pH at the catalyst remains lower at −100 mA cm −2 than at −10 mA cm −2 , implying that bubble-induced advection outweighs the additional OH − flux at these current densities. We also prove that the pH buffering effect of CO 2 from the gas feed and dissolved CO 2 in the catholyte prevents the gas diffusion electrode from becoming strongly alkaline. Our findings suggest that gas-fed CO 2 electrolyzers with a bipolar membrane and a flowing catholyte are promising designs for scale-up and high-current-density operation because they are able to avoid extreme pH values in the catalyst layer.

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“…Significant progress has been made in developing electrode materials, [1] electrolyzer configurations, [2] and various electrolytes [3] to electrochemically convert CO 2 to commodity chemicals. However, the initial electron transfer to activate CO 2 that is otherwise linear and stable remains a critical challenge.…”

Section: Introductionmentioning

confidence: 99%

Tailoring Electrochemical CO₂ Reduction on Copper by Reactive Ionic Liquid and Native Hydrogen Bond Donors

Coskun,

Dongare,

Doherty

et al. 2023

Angew Chem Int Ed

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Electrochemical CO2 reduction (CO2RR) on copper (Cu) shows promise for higher‐value products beyond CO. However, challenges such as the limited CO2 solubility, high overpotentials, and the competing hydrogen evolution reaction (HER) in aqueous electrolytes hinder the practical realization. We propose a functionalized ionic liquid (IL) which generates ion‐CO2 adducts and a hydrogen bond donor (HBD) upon CO2 absorption to modulate CO2RR on Cu in a non‐aqueous electrolyte. As revealed by transient voltammetry, electrochemical impedance spectroscopy (EIS), and in‐situ surface‐enhanced Raman spectroscopy (SERS) complemented with image charge augmented quantum‐mechanical/molecular mechanics (IC‐QM/MM) computations, a unique microenvironment is constructed. In this microenvironment, the catalytic activity is primarily governed by the IL and HBD concentrations; former controlling the double layer thickness and the latter modulating the local proton availability. This translates to ample CO2 availability, reduced overpotential, and suppressed HER where C4 products are obtained. This study deepens the understanding of electrolyte effects in CO2RR and the role of IL ions towards electrocatalytic microenvironment design.

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Operandocharacterization of continuous flow CO₂electrolyzers: current status and future prospects

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...

Cited by 13 publications

References 160 publications

Membrane Electrode Assembly for Electrocatalytic CO₂ Reduction: Principle and Application

Membrane Electrode Assembly for Electrocatalytic CO₂ Reduction: Principle and Application

Direct Imaging of Local pH Reveals Bubble-Induced Mixing in a CO₂ Electrolyzer

Tailoring Electrochemical CO₂ Reduction on Copper by Reactive Ionic Liquid and Native Hydrogen Bond Donors

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Operandocharacterization of continuous flow CO2electrolyzers: current status and future prospects

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...

Cited by 13 publications

References 160 publications

Membrane Electrode Assembly for Electrocatalytic CO2 Reduction: Principle and Application

Membrane Electrode Assembly for Electrocatalytic CO2 Reduction: Principle and Application

Direct Imaging of Local pH Reveals Bubble-Induced Mixing in a CO2 Electrolyzer

Tailoring Electrochemical CO2 Reduction on Copper by Reactive Ionic Liquid and Native Hydrogen Bond Donors

Contact Info

Product

Resources

About

Operandocharacterization of continuous flow CO₂electrolyzers: current status and future prospects

Membrane Electrode Assembly for Electrocatalytic CO₂ Reduction: Principle and Application

Membrane Electrode Assembly for Electrocatalytic CO₂ Reduction: Principle and Application

Direct Imaging of Local pH Reveals Bubble-Induced Mixing in a CO₂ Electrolyzer

Tailoring Electrochemical CO₂ Reduction on Copper by Reactive Ionic Liquid and Native Hydrogen Bond Donors