CO 2 capture and electrochemical conversion

Machado, Ana S. Reis; Ponte, Manuel Nunes da

doi:10.1016/j.cogsc.2018.05.009

Cited by 45 publications

(31 citation statements)

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“…This work also shows the potential for process intensification, in terms of productivities and of further integration with CO 2 capture, since relatively low concentrations of IL were used. This can in principle be achieved as ionic liquid are also being used as CO 2 capture agents at pilot scale [43]. Taking advantage of the tunable properties of ionic liquids, there is large room for designing ionic liquids optimized simultaneously as electrolytes and co-catalysts for syngas production, contributing to significant improvements in the energy efficiency of the process.…”

Section: Discussionmentioning

confidence: 99%

Electrochemical production of syngas from CO₂at pressures up to 30 bar in electrolytes containing ionic liquid

et al. 2019

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Section: Discussionmentioning

confidence: 99%

Electrochemical production of syngas from CO₂at pressures up to 30 bar in electrolytes containing ionic liquid

et al. 2019

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“…The activity of a nitrogen-free catalyst (graphite) under similar experimental conditions showed negligible activity for CO 2 ER. This electrolyte was chosen due to the high CO 2 absorption capacity of some ionic liquids [51]. The N-doped CNFs were synthesized by pyrolysis of electrospun nanofiber mats of heteroatomic polyacrylonitrile (PAN) polymer.…”

Section: Carbon Fibersmentioning

confidence: 99%

“…Liquid phase electrolysis needs further breakthroughs in terms of materials for electrodes, membranes and electrolytes that will allow the higher mass transfer limitations to be overcome, when compared with gas-phase electrolysis. However, this operation mode presents important advantages namely allowing the integration of CO 2 capture and conversion [51] and achieving higher conversions avoiding the costs of separating unreacted CO 2 from gaseous electrolysis products [95,96]. The development of cost-effective 3D materials with pore engineered structures that can be used directly as electrodes is an important nascent R&D avenue.…”

Section: Conclusion and Future Prospectsmentioning

confidence: 99%

Carbon Materials as Cathode Constituents for Electrochemical CO2 Reduction—A Review

Messias

Ponte

Machado

2019

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This work reviews the latest developments of cathodes for electrochemical CO 2 reduction, with carbon black, mesoporous carbons, carbon nanofibers, graphene, its derivatives and/or carbon nanotubes as constituents. Electrochemical CO 2 reduction into fuels and chemicals powered by renewable energy is a technology that can contribute to climate change mitigation. Strategies used in this fast-evolving field are discussed, having in mind a commercial application. Electrochemical performance of several materials is analyzed, using in some cases the findings of theoretical computational studies, which show the enormous potential of these materials. Considerable challenges still lie ahead to bring this technology into industrial deployment. However, the significant progress achieved so far shows that further R&D efforts might pay off.C 2019, 5, 83 2 of 26 considering the findings of theoretical computational studies, are in some cases analyzed, when this type of study is available. Knowledge gaps and new promising R&D trends of nanocarbon-based materials development for this application are highlighted. Carbon BlackCarbon black is produced by the incomplete combustion of petroleum heavy fractions. It is a form of para-crystalline carbon of high surface area. Although activated carbon has a more favorable surface area to volume ratio (>1000 m 2 /g) than carbon black, its low electrical conductivity makes it unsuitable as electrode material. Commercial carbon blacks, such as Vulcan or Ketjen black have been most frequently used as support to ensure large electrochemical reaction surfaces and to reduce noble metal loading. Metal and Metal-Derived Particles Supported on Carbon BlackCO 2 ER can be carried out in gas phase, where gaseous CO 2 is fed to the cathode through gas diffusion electrodes (GDE), or in liquid phase, where CO 2 dissolved in the liquid electrolyte contacts the electrode. Figure 1 presents a schematic diagram of two possible configurations of both operation modes.C 2019, 5, x FOR PEER REVIEW 2 of 25 discussed, having in mind a commercial application. Electrochemical performances of several materials, considering the findings of theoretical computational studies, are in some cases analyzed, when this type of study is available. Knowledge gaps and new promising R&D trends of nanocarbonbased materials development for this application are highlighted. Carbon BlackCarbon black is produced by the incomplete combustion of petroleum heavy fractions. It is a form of para-crystalline carbon of high surface area. Although activated carbon has a more favorable surface area to volume ratio (>1000 m 2 /g) than carbon black, its low electrical conductivity makes it unsuitable as electrode material. Commercial carbon blacks, such as Vulcan or Ketjen black have been most frequently used as support to ensure large electrochemical reaction surfaces and to reduce noble metal loading. Metal and Metal-Derived Particles Supported on Carbon BlackCO2ER can be carried out in gas phase, where gaseous CO2 is fed to the cathode thro...

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“…Given these challenges, interest has been increasingly growing in combined capture-conversion processes that can directly utilize chemisorbed CO2 as the reactant in a subsequent electrochemical process, obviating the need to regenerate CO2 back to the gas phase. [11][12][13][14] Utilizing chemisorbed CO 2 directly, rather than post-separation CO2, invites design of new classes of electrochemical reactions by relaxing some of the key constraints of classical CO 2 electroreduction. 15 Given the high overpotentials required for the latter (e.g., > 1 V for CH 4 on Cu electrocatalysts) 16 , emphasis has largely been placed on lowering the free energy barrier of the reduction intermediate, the CO 2 anion ("CO 2 -").…”

Section: Introductionmentioning

confidence: 99%

Promoting Amine-Activated Electrochemical CO₂ Conversion with Alkali Salts

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Amine-based CO 2 chemisorption has been a longstanding motif under development for CO 2 capture applications, but large energy penalties are required to thermally cleave the N-C bond and regenerate CO 2 for subsequent storage or utilization. Instead, it is attractive to be able to directly perform electrochemical reactions on the amine solutions with loaded CO 2. We recently found that such a process is viable in dimethyl sulfoxide (DMSO) if an exogenous Li-based salt is present, leading to formation of CO 2-derived products through electrochemical N-C bond cleavage. However, the detailed influence of the salt on the electrochemical reactions was not understood. Here, we investigate the role of individual electrolyte salt constituents across multiple cations and anions in DMSO to gain improved insight into the salt's role in these complex electrolytes. While the anion appears to have minor effect, the cation is found to strongly modulate the thermochemistry of the amine-CO 2 through electrostatic interactions: 1 H NMR measurements show that post-capture, pre-reduction equilibrium proportions of the formed cation-associated carbamate vary by up to five-fold, and increase with the cation's Lewis acidity (e.g. from K + → Na + → Li +). This trend is quantitatively supported by DFT calculations of the free energy of formation of these alkali-associated adducts. Upon electrochemical reduction, however, the current densities follow an opposing trend, with enhanced reaction rates obtained with the lowest Lewis-acidity cation, K +. Meanwhile, molecular dynamics simulations indicate significant increases in desolvation and pairing kinetics that occur with K +. These findings suggest that, in addition to strongly affecting the speciation of amine-CO 2 adducts, the cation's pairing with-COOin the amine-CO 2 adduct can significantly hinder or enhance the rates of electrochemical reactions at moderate overpotentials. Consequently, designing electrolytes to promote fast cation-transfer appears important for obtaining higher current densities in future systems.

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CO 2 capture and electrochemical conversion

Cited by 45 publications

References 48 publications

Electrochemical production of syngas from CO₂at pressures up to 30 bar in electrolytes containing ionic liquid

Electrochemical production of syngas from CO₂at pressures up to 30 bar in electrolytes containing ionic liquid

Carbon Materials as Cathode Constituents for Electrochemical CO2 Reduction—A Review

Promoting Amine-Activated Electrochemical CO₂ Conversion with Alkali Salts

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CO 2 capture and electrochemical conversion

Cited by 45 publications

References 48 publications

Electrochemical production of syngas from CO2at pressures up to 30 bar in electrolytes containing ionic liquid

Electrochemical production of syngas from CO2at pressures up to 30 bar in electrolytes containing ionic liquid

Carbon Materials as Cathode Constituents for Electrochemical CO2 Reduction—A Review

Promoting Amine-Activated Electrochemical CO2 Conversion with Alkali Salts

Contact Info

Product

Resources

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Electrochemical production of syngas from CO₂at pressures up to 30 bar in electrolytes containing ionic liquid

Electrochemical production of syngas from CO₂at pressures up to 30 bar in electrolytes containing ionic liquid

Promoting Amine-Activated Electrochemical CO₂ Conversion with Alkali Salts