Direct carbonate electrolysis into pure syngas

Xiao, Yurou Celine; Gabardo, Christine M.; Liu, Shijie; Lee, Geonhui; Zhao, Yong; O’Brien, Colin P.; Miao, Rui Kai; Xu, Yi; Edwards, Jonathan P.; Fan, Mengyang; Huang, Jianan Erick; Li, Jun; Papangelakis, Panagiotis; Alkayyali, Tartela; Rasouli, Armin Sedighian; Zhang, Jinqiang; Sargent, Edward H.; Sinton, David

doi:10.1039/d2ey00046f

Cited by 29 publications

(42 citation statements)

References 51 publications

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“…The CO 2 concentration in outlet stream, which experimentally quantifies unreacted CO 2 in the outlet stream by GC, is a crucial parameter for assessing carbon loss and downstream separation costs (Figure b). , The detection of an extremely low CO 2 concentration in the outlet stream is a noteworthy aspect, indicating that this system has the potential to significantly reduce the need for CO 2 removal. This is particularly advantageous, considering CO 2 removal is recognized as the most energy-intensive step in downstream separation processes .…”

Section: Resultsmentioning

confidence: 99%

Ethylene Production from Carbonate Using a Bipolar Membrane Electrolysis System

Song,

Fernández,

Venkataraman

et al. 2024

ACS Appl. Energy Mater.

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Electrochemical CO 2 reduction has attracted significant interest as a pathway for achieving a carbon-neutral society. However, conventional gas-phase CO 2 electrolysis cell configurations often face challenges like low CO 2 utilization efficiency due to carbonate crossover, and costly integration with carbon capture systems. The membrane electrode assembly (MEA) electrolysis cell configuration involving a bipolar membrane (BPM) has been recently spotlighted as this system can directly release CO 2 stored in carbonate solutions using a pH swing process driven by water dissociation within the BPM. Here, we assess the reactor's capacity to liberate CO 2 and facilitate its conversion into ethylene (C 2 H 4 ), using Cu−Ag catalysts and carbon capture solutions such as potassium carbonate (K 2 CO 3 ). Bench-top flow cell system testing using an optimized Cu−Ag electrocatalyst demonstrates that the conversion of CO 2 to C 2 H 4 reaches 10% Faradaic efficiency, corresponding to a partial current density of 10 mA/cm 2 . During all tests, the BPM-MEA electrolysis cell also maintained approximately 0% CO 2 concentration in the outlet over 24 h. Operating at elevated temperatures, such as 50 °C, has shown promising results in our exploration, demonstrating improved C 2 H 4 Faradaic efficiency and current densities. Lastly, we examine the feasibility of this combined CO 2 generation and conversion reactor architecture and estimate the potential energy and process efficiencies achievable using the BPM-MEA system. While the BPM-MEA system offers innovative solutions for carbon capture and conversion, continued research and optimization are imperative to fully harness its potential for a sustainable future.

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Section: Resultsmentioning

confidence: 99%

Ethylene Production from Carbonate Using a Bipolar Membrane Electrolysis System

Song,

Fernández,

Venkataraman

et al. 2024

ACS Appl. Energy Mater.

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“…Carbonate electroreduction in a BPM-based electrolyzer was studied by Li et al 94 Using a silver catalyst, these authors produced syngas with a H 2 /CO ratio of 3:1 at a CD of 150 mA/cm 2 and 3.8 V. The carbonate-to-syngas system was shown to be stable for a continuous run of 145 h. No CO 2 was detected in the syngas product, because all the in situ generated CO 2 , from the reaction of carbonates with the protons of the BPM, was consumed by the CO2RR. Recently, Xiao et al 95 studied the conversion of carbonate to pure syngas using a CEM-based flow cell and a CO 2 diffusion layer (CDL) inserted between the CEM and the cathode. These authors obtained a H 2 /CO ratio of 1.2, corresponding to a CO FE of 46%, at 200 mA/cm 2 and ∼3.7 V. Long-term stability tests at 100 mA/cm 2 and ∼3.4 V showed stable operation and syngas production with a H 2 /CO ratio of 2:1 for 23 h of experiments.…”

Section: Electrolysis Of Reactive Carbon Solutionsmentioning

confidence: 99%

Carbonation in Low-Temperature CO₂ Electrolyzers: Causes, Consequences, and Solutions

Ramdin

Moultos

Broeke

et al. 2023

Ind. Eng. Chem. Res.

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Electrochemical reduction of carbon dioxide (CO2) to useful products is an emerging power-to-X concept, which aims to produce chemicals and fuels with renewable electricity instead of fossil fuels. Depending on the catalyst, a range of chemicals can be produced from CO2 electrolysis at industrial-scale current densities, high Faraday efficiencies, and relatively low cell voltages. One of the main challenges for up-scaling the process is related to (bi)carbonate formation (carbonation), which is a consequence of performing the reaction in alkaline media to suppress the competing hydrogen evolution reaction. The parasitic reactions of CO2 with the alkaline electrolytes result in (bi)carbonate precipitation and flooding in gas diffusion electrodes, CO2 crossover to the anode, low carbon utilization efficiencies, electrolyte carbonation, pH-drift in time, and additional cost for CO2 and electrolyte recycling. We present a critical review of the causes, consequences, and possible solutions for the carbonation effect in CO2 electrolyzers. The mechanism of (bi)carbonate crossover in different cell configurations, its effect on the overall process design, and the economics of CO2 and electrolyte recovery are presented. The aim is to provide a better understanding of the (bi)carbonate problem and guide research directions to overcome the challenges related to low-temperature CO2 electrolysis in alkaline media.

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“…This voltage creep implies incomplete ion neutralization and CO 2 transport in the control system due to a lack of full contact between the AEM and CEM. This instability could also indicate gas entrapment between the AEM and CEM in the control system …”

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confidence: 99%

“…This instability could also indicate gas entrapment between the AEM and CEM in the control system. 39 We investigated the effect of cell temperature on the CO 2 electrolysis performance. Applying higher cell temperatures (40 and 60 °C) reduced the operating full-cell potential (Figure S25), which is enabled by the higher ionic conductivity achieved with higher temperatures.…”

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confidence: 99%

Direct Membrane Deposition for CO₂ Electrolysis

Alkayyali,

Zeraati,

Mar

et al. 2023

ACS Energy Lett.

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The use of forward-bias bipolar membranes (f-BPM) in CO2 electrolyzers offers the advantage of avoiding costly CO2 reactant loss. However, current f-BPM-based electrolyzers require a high voltage and produce H2 at the expense of CO2 reduction products. In this work, we develop a direct membrane deposition (DMD) approach that combines anion and cation exchange membranes (AEM and CEM, respectively) to increase transport and facilitate CO2 regeneration. The DMD approach provides flexibility to tune the properties of the composite and optimize the AEM:CEM ratio for low resistance and low H2 evolution. Compared to a standard f-BPM, the DMD approach reduced the H2 Faradaic efficiency by 2-fold (25% vs 12%, respectively), reduced mass transport resistance by over 50%, decreased full-cell potential by 0.84 V, increased the selectivity toward multicarbon products by over 2-fold (29% vs 65%, respectively), and achieved >17% in multicarbon product energy efficiency at 300 mA cm–2.

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Direct carbonate electrolysis into pure syngas

Abstract: In a direct carbonate electrolysis system, a CO2 diffusion layer enabled the production of CO-rich syngas.

Cited by 29 publications

References 51 publications

Ethylene Production from Carbonate Using a Bipolar Membrane Electrolysis System

Ethylene Production from Carbonate Using a Bipolar Membrane Electrolysis System

Carbonation in Low-Temperature CO₂ Electrolyzers: Causes, Consequences, and Solutions

Direct Membrane Deposition for CO₂ Electrolysis

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Direct carbonate electrolysis into pure syngas

Abstract: In a direct carbonate electrolysis system, a CO2 diffusion layer enabled the production of CO-rich syngas.

Cited by 29 publications

References 51 publications

Ethylene Production from Carbonate Using a Bipolar Membrane Electrolysis System

Ethylene Production from Carbonate Using a Bipolar Membrane Electrolysis System

Carbonation in Low-Temperature CO2 Electrolyzers: Causes, Consequences, and Solutions

Direct Membrane Deposition for CO2 Electrolysis

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Product

Resources

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Carbonation in Low-Temperature CO₂ Electrolyzers: Causes, Consequences, and Solutions

Direct Membrane Deposition for CO₂ Electrolysis