Electrochemical tools to disclose the electrochemical reduction mechanism of CO2 in aprotic solvents and ionic liquids

Mena, Silvia; Ribas, Esteve; Richart, Clara; Gallardo, Iluminada; Faraudo, Jordi; Shaw, Scott K.; Guirado, Gonzalo

doi:10.1016/j.jelechem.2021.115411

Cited by 7 publications

(9 citation statements)

References 51 publications

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“…8,11 However, various researchers have discussed stabilization based on other intermediate stabilization mechanisms. 27,28 One of the reasons for this is the lack of experimental detection of the intermediate.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanism of the overpotential decrease induced by imidazolium-based RTILs is still under discussion for both cases of neat RTILs used as electrolytes and dilute ones used as additives. − Although overall reaction mechanisms are different owing to the role of solvent molecules, , for both cases, it is natural to presume that the one-electron reductant CO 2 •– , , the origin of high overpotentials in conventional electrolytes, is somehow stabilized on the electrode. Various stabilization mechanisms have been thus proposed: stabilization due to ionic environment, formation of CO 2 •– –imidazolium complex through π–π interaction, , formation of a carboxylate adduct, − and stabilization through Coulombic interaction or hydrogen bonding between imidazolium cations and CO 2 •– on the electrode. , Stabilization by cations was rationalized by observation of the overpotential-decreasing tendency with respect to methylation of different parts of the imidazolium cation. , However, various researchers have discussed stabilization based on other intermediate stabilization mechanisms. , One of the reasons for this is the lack of experimental detection of the intermediate.…”

Section: Introductionmentioning

confidence: 99%

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In Situ Spectroscopic Characterization of an Intermediate of CO₂ Electroreduction on a Au Electrode in Room-Temperature Ionic Liquids

2022

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Room-temperature ionic liquids (RTILs) are fascinating electrolytes for CO 2 electroreduction owing to their low overpotentials. Although it is well accepted that the key to understanding the low overpotential is the stabilization of the intermediate, its mechanism is still under discussion. To elucidate the intermediate stabilization mechanism, RTIL/electrode interfaces under CO 2 reduction were observed using surface-enhanced infrared absorption spectroscopy (SEIRAS). This in situ interfaceselective spectroscopy allows us to detect CO 2•− that is not observed in aqueous solutions. For a negative-going potential scan, identical onsets were observed for increasing SEIRA band intensities of CO 2•− and RTIL cations and reduction current. This result indicates that RTIL cations stabilize CO 2 •− on the electrode, and this stabilizing effect can be ascribed to the origin of the low overpotentials of CO 2 electroreduction in RTILs.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

In Situ Spectroscopic Characterization of an Intermediate of CO₂ Electroreduction on a Au Electrode in Room-Temperature Ionic Liquids

2022

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“…Electrochemical reduction of CO 2 involves the adsorption of carbon (IV) oxide, solvent molecules, ions, intermediates, and end products on the cathode surface. e nature of the latter significantly affects the equilibrium processes of adsorption↔desorption due to inappropriate adsorption energies of key reaction intermediates [60]. e result is the dependence of the rate of certain electrochemical reactions and, accordingly, the product selectivities and Faradaic efficiencies of the CO 2 conversion process on the catalytic activity of the cathode surface.…”

Section: Nature and Topography Of Catalytically Activementioning

confidence: 99%

“…•CO 2 = − 2.21 V according to [68] and − 1.97 V according to [58]. Since, in such a nonaqueous medium, •CO 2 (− ) is the starting electrochemical stage of CO 2 reduction (Figure 5), the quantitative formation of conversion products begins at approximately − 2.0 V [32,33,[58][59][60]69] on electrodes of different nature. A typical F− i cathode dependence is shown in Figure 6.…”

Section: Nature and Topography Of Catalytically Activementioning

confidence: 99%

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CO2 Electroreduction in Organic Aprotic Solvents: A Mini Review

Кuntyi

Zozulya

Shepida

2022

Journal of Chemistry

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An annual increase of CO2 concentrations in the atmosphere causes global environmental problems, addressed by systematic research to develop effective technologies for capturing and utilizing carbon dioxide. Electrochemical catalytic reduction is one of the effective directions of CO2 conversion into valuable chemicals and fuels. The electrochemical conversion of CO2 at catalytically active electrodes in aqueous solutions is the most studied. However, the problems of low selectivity for target products and hydrogen evolution are unresolved. Literature sources on CO2 reduction at catalytically active cathodes in nonaqueous mediums, particularly in organic aprotic solvents, are analyzed in this article. Two directions of cathodic reduction of CO2 are considered—nonaqueous organic aprotic solvents and organic aprotic solvents containing water. The current interpretation of the cathodic conversion mechanism of carbon (IV) oxide into CO and organic products and the main factors influencing the rate of CO2 reduction, Faradaic efficiency of conversion products, and the ratio of direct cathodic reduction of CO2 are given. The influence of the nature of organic aprotic solvent is analyzed, including the topography of the catalytically active cathode, values of cathode potential, and temperature. Emphasis is placed on the role of water impurities in reducing CO2 electroreduction overpotentials and the formation of new CO2 conversion products, including formate and H2.

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Aprotic phosphonium‐based ionic liquid as electrolyte for high CO₂electroreduction to oxalate

Jiang

Zeng

et al. 2022

AIChE Journal

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In this study, a new CO 2 electroreduction electrolyte system consisting of tetrabutylphosphonium 4-(methoxycarbonyl) phenol ([P 4444 ][4-MF-PhO]) ionic liquid (IL) and acetonitrile (AcN) was designed to produce oxalate, and the electroreduction mechanism was studied. The results show that using the new IL-based electrolyte, the electroreduction system exhibits 93.8% Faradaic efficiency and 12.6 mA cm À2 partial current density of oxalate at À2.6 V. The formation rate of oxalate is 234.4 μmol cm À2 h À1 , which is better than those reported in the literature. The mechanism study using density functional theory (DFT) calculations reveals that [P 4444 ][4-MF-PhO] can effectively activate CO 2 molecule through ester and phenoxy double active sites. In addition, in the phosphonium-based ionic environment, the potential barriers of the key intermediates *CO 2 À and *C 2 O 4 2À are reduced by the induced electric field, which greatly facilitates the activation and conversion of CO 2 molecule to oxalate.

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Electrochemical tools to disclose the electrochemical reduction mechanism of CO2 in aprotic solvents and ionic liquids

Cited by 7 publications

References 51 publications

In Situ Spectroscopic Characterization of an Intermediate of CO₂ Electroreduction on a Au Electrode in Room-Temperature Ionic Liquids

In Situ Spectroscopic Characterization of an Intermediate of CO₂ Electroreduction on a Au Electrode in Room-Temperature Ionic Liquids

CO2 Electroreduction in Organic Aprotic Solvents: A Mini Review

Aprotic phosphonium‐based ionic liquid as electrolyte for high CO₂electroreduction to oxalate

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Electrochemical tools to disclose the electrochemical reduction mechanism of CO2 in aprotic solvents and ionic liquids

Cited by 7 publications

References 51 publications

In Situ Spectroscopic Characterization of an Intermediate of CO2 Electroreduction on a Au Electrode in Room-Temperature Ionic Liquids

In Situ Spectroscopic Characterization of an Intermediate of CO2 Electroreduction on a Au Electrode in Room-Temperature Ionic Liquids

CO2 Electroreduction in Organic Aprotic Solvents: A Mini Review

Aprotic phosphonium‐based ionic liquid as electrolyte for high CO2electroreduction to oxalate

Contact Info

Product

Resources

About

In Situ Spectroscopic Characterization of an Intermediate of CO₂ Electroreduction on a Au Electrode in Room-Temperature Ionic Liquids

In Situ Spectroscopic Characterization of an Intermediate of CO₂ Electroreduction on a Au Electrode in Room-Temperature Ionic Liquids

Aprotic phosphonium‐based ionic liquid as electrolyte for high CO₂electroreduction to oxalate