Integrating carbon dioxide capture and electrochemical conversion using industrially relevant streams

Abstract

A method for capturing carbon dioxide and converting carbon dioxide electrochemically into fuels and chemicals is provided.

Description

INTEGRATING CARBON DIOXIDE CAPTURE AND ELECTROCHEMICAL CONVERSION USING INDUSTRIALLY RELEVANT STREAMSCROSS REFERENCES

[0001] This application is based on and claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 711,840, filed October 25, 2024, which is herein incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates to capturing carbon dioxide and its conversion.BACKGROUND

[0003] Carbon capture and utilization promises to change the paradigm of the chemical industry and decouple the need for fossil fuels to produce fuels and chemicals. Major industries, such as manufacturing and power, contribute to greater than two-thirds of global carbon dioxide (CO2) emissions. These industries produce flue gas composed of 12-20% CO2, 80-90% nitrogen (N2), 3-5% oxygen (O2), and minor compounds such as SOX, NOX, and carbon monoxide (CO). Carbon dioxide may be captured from these point-source flue and off-gas streams and converted to a diverse array of products. Conventionally, CO2 was captured using chemisorption with aqueous amine solutions, then released in a desorber / regenerator unit at temperatures as high as 150 °C. The regeneration step is typically the most energy-intensive in the CO2 capture process. Carbon conversion can be done via thermochemical or electrochemical processes, but these conventionally required pure CO2 streams, which lead to high purification and pressurization costs. Currently, capture and conversion processes are performed independently.

[0004] Reactive CO2 capture has integrated the capture and conversion of CO2 in a single process, in which energy typically applied as heat to release captured CO2 could be redirected toward direct conversion of the captured CO2 into fuels and basic chemical precursors, such as carbon monoxide (CO). Thermal reactive capture methods typically have required high temperatures or high pressures for CO2 conversion. Electrochemical approaches hold great promise because they can operate at ambient temperatures and pressures, taking advantage of renewable energy sources like wind or solar power. However, there are several challenges to electrochemical conversion of amine-CO2. For example, electrochemical approaches are performed under aqueous conditions, resulting in low CO2 capture capacities, relying onprecious metal catalysts and pure CO2 streams, and suffering from the competing hydrogen evolution reaction (“HER”).

[0005] Thus, there is a need for the integration of CO2 capture and electrochemical conversion of an amine-CCh adduct in a nonaqueous environment that provides increased CO2 uptake. Further, there is a need for capture systems and methods that produce higher faradaic efficiency (“FE”) towards CO at lower temperatures. Further, there is a need for capture systems and methods that enable the use of an earth- abundant catalyst, so as to reduce cost of production of CO.SUMMARY

[0006] The present disclosure generally relates to a method for capturing and converting carbon dioxide.

[0007] In some example embodiments, the method for capturing and converting carbon dioxide includes contacting a source of carbon dioxide with a nonaqueous electrolyte composition comprising a capture agent and an aprotic solvent, the capture agent comprising an amine, wherein the carbon dioxide reacts with the capture agent in the nonaqueous electrolyte composition to produce an amine solution comprising an amine-CCh adduct. Followed by contacting the amine solution with an electrode and applying an electric potential to the amine solution to convert the carbon dioxide to carbon monoxide upon electrochemical reduction.

[0008] In other example embodiments, a carbon dioxide conversion system is disclosed.

[0009] Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.BRIEF DESCRIPTION OF DRAWINGS

[0010] In order that the present disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings. The components in the figures are not necessarily to scale.

[0011] FIG. 1 illustrates a galvanostatic product distribution analysis over a zinc porous electrode for a solution containing 0.3 M (“MEA”) and 0.5 M CsCICh in dimethylsulfoxide (“DMSO”) under different current densities and at 40°C, the solution initially saturated with pure CO2 and purged with argon at 5 cm2during product distribution analysis, with error bars corresponding to the standard deviation of 3 samples.

[0012] FIG. 2 illustrates reaction equations demonstrating amine and CO2 speciation in DM SO and water.

[0013] FIG. 3 illustrates a bar graph plot of conductivity measurements of 0.3 M MEA aqueous and DMSO solutions saturated with each of Ar and CO2.

[0014] FIG. 4 illustrates1H NMR and13C NMR spectra providing chemical shifts for Araud13CO2-saturated solutions containing 0.3 M MEA with 0.5 M CsCl in D2O or 0.5 M CSCIO4 in C?6-DMSO, the13CO2-saturated solutions purged with Ar for the removal of soluble CO2, and identification of}H and13C provided by numbers corresponding to atoms in FIG. 2.

[0015] FIG. 5 illustrates13C NMR spectra of13CO2 saturated solutions containing 0.3 M MEA and 0.5 M CsCl in D2O before and after purging with Ar, with 0.6 mL of solution purged with13CO2at 2 standard cubic centimeters per minute (“SCCM”) for about 30 minutes during13CO2saturation and for 5 minutes with Ar at 1 SCCM during the Ar purging.

[0016] FIG. 6 illustrates13C NMR spectra of13CO2 saturated solutions containing 0.5 M CSCIO4 in r / e-DMSO before and after purging with Ar, with 0.6 mL of solution purged with13CO2at 2 SCCM for about 30 minutes during13CO2 saturation and for 5 minutes with Ar at 1 SCCM during the Ar purging.

[0017] FIG. 7 illustrates a summary of reaction equations demonstrating amine and CO2 speciation in water and DMSO.

[0018] FIG. 8 illustrates a heteronuclear single quantum coherence (“HSQC”) spectrum for Ar-saturated solution containing 0.3 M MEA and 0.5 M CsCl in water, with peak identification provided by numbers corresponding to atoms in FIG. 7.

[0019] FIG. 9 illustrates a HSQC spectrum for13CO2-saturated solution containing 0.3 M MEA and 0.5 M CsCl in water, with peak identification provided by numbers corresponding to atoms in FIG. 7.

[0020] FIG. 10 illustrates a HSQC spectrum for Ar-saturated solution containing 0.5 M CSCIO4 in DMSO, with peak identification provided by numbers corresponding to atoms in FIG. 7.

[0021] FIG. 11 illustrates a HSQC spectrum for13CO2-saturated solution containing 0.5 M CSCIO4 in DMSO, with peak identification provided by numbers corresponding to atoms in FIG. 7.

[0022] FIG. 12 illustrates a13C NMR spectrum of13CO2 saturated / Ar purged solution of 0.3 M MEA and 0.5 M CsCl in D2O, 0.6 mL of solution purged with13CO2 at 2 SCCM forabout 30 minutes during13CC>2 and for 5 minutes with Ar at 2 SCCM during the Ar purging, with peak identification provided by numbers corresponding to atoms in FIG. 7.

[0023] FIG. 13 illustrates a13C NMR spectrum of13CO2 saturated / Ar purged solution of 2 M MEA and 2 M KC1 in D2O, 0.6 mL of solution purged with13CO2 at 2 SCCM for about 30 minutes during13CO2 and for 5 minutes with Ar at 2 SCCM during the Ar purging, with peak identification provided by numbers corresponding to atoms in FIG. 7.

[0024] FIG. 14 illustrates a13C NMR spectrum of13CO2 saturated / Ar purged solution of 0.3 M MEA and 0.5 M CSCIO4 in de-DMSO, 0.6 mL of solution purged with13CO2 at 2 SCCM for about 30 minutes during13CO2 and for 5 minutes with Ar at 2 SCCM during the Ar purging, with peak identification provided by numbers corresponding to atoms in FIG. 7.

[0025] FIG. 15 illustrates a plot of13CO2 uptake per mole of amine in different electrolyte compositions prepared by integrating13C peak intensities.

[0026] FIG. 16 illustrates a linear sweep voltammogram at 50 mV / s over an Ag disk electrode for Ar- and CO2-saturated solutions containing 0.3 M MEA and 0.5 M CsCl in water, with the CO2-saturated solution (about 15 mL) purged with Ar at 5 SCCM for 10 minutes to remove dissolved CO2.

[0027] FIG. 17 illustrates a linear sweep voltammogram at 50 mV / s over an Ag disk electrode for Ar and CO2-saturated solutions containing 0.5 M CSCIO4 in DMSO, with the CO2-saturated solution (about 15 mL) purged with Ar at 5 SCCM for 10 minutes to remove dissolved CO2.

[0028] FIG. 18 illustrates a bar graph of a product distribution analysis performed using a potentiostat on an H-cell setup with Ar as a carrier gas at 5 SCCM for CO2 saturated solutions containing 0.3 M MEA and 0.5 M Cs salts in water over a Ag disk electrode, with the CO2-saturated solution (about 15 mL) purged with Ar at 5 SCCM for 10 minutes to remove dissolved CO2.

[0029] FIG. 19 illustrates a bar graph of a product distribution analysis performed using a potentiostat on an H-cell setup with Ar as a carrier gas at 5 SCCM for CO2 saturated solutions containing 0.3 M MEA and 0.5 M Cs salts in water over a Zn disk electrode, with the CO2-saturated solution (about 15 mL) purged with Ar at 5 SCCM for 10 minutes to remove dissolved CO2.

[0030] FIG. 20 illustrates a bar graph of a product distribution analysis performed using a potentiostat on an H-cell setup with Ar as a carrier gas at 5 SCCM for CO2 saturated solutions containing 0.3 M MEA and 0.5 M Cs salts in DMSO over a Zn disk electrode, with the CO2-saturated solution (about 15 mL) purged with Ar at 5 SCCM for 10 minutes to remove dissolved CO2.

[0031] FIG. 21 illustrates13C NMR spectra of solutions containing 0.5 M CsCICh and 0.3 M MEA in de-DMSO saturated with either 100%13CC>2 or 20%13CO2 / 80% Ar, normalized against the de-DMSO peak.

[0032] FIG. 22 illustrates a plot demonstrating the effect of the Ar purge (5 SCCM) on the CO2 headspace concentration during product distribution analysis with a potentiostat of a CO2-saturated solution of 0.5 M CSCIO4 and 0.3 M MEA in DMSO over an Ag electrode at 1.0 V versus RHE.

[0033] FIG. 23 illustrates an airtight cell used during CO2 displacement tests, with a cell compartment with a total volume of 15 mL, 10 mL of CO2-saturated sample stirred at 750 rpm while purged with Ar at 10 SCCM, and an ExplorIR®-M 100% CO2 Sensor (CO2meter®) used to monitor the cell headspace outlet, the cell pressure kept near 1 atm.

[0034] FIG. 24 illustrates a plot of the results of a CO2 displacement test performed on the airtight cell illustrated in FIG. 23, the test of DMSO solutions saturated with 100% CO2, Ar at 10 SCCM was used as carrier gas.

[0035] FIG. 25 illustrates linear sweep voltammograms performed over an Ag electrode at 5 mV / s of DMSO CO2-saturated solutions containing either 0.5 M CsC104 saturated with 100% CO2 or 0.5 M CsC104 and 0.3 M MEA saturated with 20% CO2 / 80% Ar.

[0036] FIG. 26 illustrates an X-ray diffraction pattern of the Ag electrode before and after 10 minutes of electrolysis of CO2-saturated solutions containing 0.3 M MEA and CSCIO4.

[0037] FIG. 27 illustrates an X-ray diffraction pattern of the Zn electrode before and after 10 minutes of electrolysis of CO2-saturated solutions containing 0.3 M MEA and CSCIO4.

[0038] FIG. 28 illustrates a free energy diagram for the amine-CO2 reduction over Ag(l 11) and Zn (101) catalysts in the presence and absence of Cs+, the pathway starting with carbamate adsorption over an Ag (111) facet represented in dashed lines.

[0039] FIG. 29 illustrates a plot of double-layer capacitance and current density values averaged over 1 minute during electrochemical impedance spectroscopy experiments over a Ag disk catalyst of CO2 saturated solution containing 0.3 M MEA with and without 0.5 M CSCIO4.

[0040] FIG. 30 illustrates a galvanostatic production distribution analysis performed with a potentiostat over an Ag disk electrode at -3 mA / cm2for CO2-saturated DMSO solutionscontaining 0.3 M MEA and different CsCICh concentrations, solutions initially purged with Ar at 10 SCCM for 10 minutes for removal of dissolved CO2, Ar at 10 SCCM used as carrier gas.

[0041] FIG. 31 illustrates a bar graph providing binding energies for potential proton donors for HER and carbon sources for CO formation over Ag (111) and Zn (101) facets in the presence of Cs+, with R referring to HOCH2CH2NH-.

[0042] FIG.32 illustrates a free energy diagram for the ammonium reduction over Ag (111) facet with and without Cs+.

[0043] FIG.33 illustrates a free energy diagram for the ammonium reduction over Zn (101) facet with and without Cs+.

[0044] FIG. 34 illustrates a free energy diagram for the proton reduction over Ag (111) facet with and without Cs+.

[0045] FIG. 35 illustrates a free energy diagram for the proton reduction over Zn (101) facet with and without Cs+.

[0046] FIG. 36 illustrates the Eevelized Total Operating Cost (“ETOC”) and Eevelized Total Variable Operation and Maintenance (“ETVOM”) for CO production in water and DMSO over Ag catalysts under electrochemical conditions present in FIGs. 18 and 37.

[0047] FIG. 37 illustrates a bar graph of a product distribution analysis performed using a potentiostat on an H-cell setup with Ar as a carrier gas at 5 SCCM for CO2 saturated solutions containing 0.3 M MEA and 0.5 M Cs salts in DMSO over a Ag disk electrode, with the CO2-saturated solution (about 15 mF) purged with Ar at 5 SCCM for 10 minutes to remove dissolved CO2.

[0048] FIG. 38 illustrates a bar graph providing a CO production cost breakdown over Ag catalyst in water under electrochemical conditions used for the analysis illustrated in FIG. 18, potentials in the legend reported either against the IR-compensated RHE scale (labeled as cathode) or overall cell potential (cell).

[0049] FIG. 39 illustrates a bar graph providing a CO production cost breakdown over Ag catalyst in DMSO under electrochemical conditions used for the analysis illustrated in FIG. 37, potentials in the legend reported either against the IR-compensated RHE scale (labeled as cathode) or overall cell potential (cell).

[0050] FIG. 40 illustrates a bar graph providing a CO production cost breakdown over Zn catalyst in DMSO under electrochemical conditions used for the analysis illustrated in FIG. 20, potentials in the legend reported either against the IR-compensated RHE scale (labeled as cathode) or overall cell potential (cell).

[0051] FIG. 41 illustrates a bar graph providing a CO production cost breakdown over Ag and Zn catalysts in DMSO under electrochemical conditions presented in FIGs. 37 and 20 at -1.5 V.

[0052] FIG.42 illustrates a heatmap of CO production costs in terms of current density and CO FE, ranging from 5 to 1000 mA / cm2in a realistic scenario with a Pt anode.

[0053] FIG. 43 illustrates a plot of apparent pH of solutions containing 0.3 M MEA and 0.5 M of CsC104 in de-DMSO fed with different CO2 / Ar compositions at 10 SCCM.

[0054] FIG. 44 illustrates1H NMR spectra of13CO2-saturated solutions of 0.5 M CsC104 and 0.3 M MEA in r / e-DMSO before and after 35 minutes of Ar purging, an increase in the population of ammonium ions (peaks 3 and 4) in comparison to the carbamic acid (peaks 1 and 2) after purging indicating the displacement of CO2.

[0055] FIG. 45 illustrates a galvanostatic product distribution analysis performed with a potentiostat for different CO2 stream compositions as carrier gas at 20 SCCM for solutiosn containing 0.3 M MEA and 0.5 M CSCIO4 in DMSO over a Zn electrode at -10 mA / cm2, flue gas containing 16% CO2, 3% O2, and 81% N2.

[0056] FIG. 46 illustrates a galvanostatic product distribution analysis performed with a potentiostat for 0.3 M MEA and 0.5 M CSCIO4 in DMSO over a Zn electrode at -10 mA / cm2over 24 h under constant flue gas flow of simulated flue gas at 20 SCCM.

[0057] FIG. 47 illustrates1H NMR spectra of the catholyte solution saturated with flue gas and containing 0.5 M CSCIO4 and 0.3 M MEA in DMSO over 24 hours electrolysis, the anolyte solution fully refreshed every 6 hours.

[0058] FIG. 48 illustrates a product distribution analysis, performed with a potentiostat, of 0.5 M CSCIO4 and 0.3 M MEA in DMSO saturated with simulated flue gas over a Zn electrode at -10 mA / cm2, without the flow of a carrier gas, for 6 hours, no argon gas flow during the experiment to eliminate speciation changes occurring due to the flow of argon, the CO and H2 sampled form the H-Cell headspace.

[0059] FIG. 49 illustrates a scanning electron microscopy image of electrodeposited Zn particles over a stainless- steel cloth.

[0060] FIG. 50 illustrates linear sweep voltammograms at 50 mV / s over a Zn cloth (6 mm2-electrode of DMSO solution containing 0.3 M MEA and 0.5 M CsC104 saturated with high-oxygen content flue gas (“HOC-FG”) at different temperatures in a H-Cell configuration, a platinum wire (surface area of 4 cm2) used as a counter electrode.

[0061] FIG. 51 illustrates a galvanostatic product distribution analysis performed with a potentiostat for the solution analyzed in the voltammograms illustrated in FIG. 50 under different current densities and temperatures, HOC-FG at 20 SCCM used as a carrier gas.

[0062] FIG. 52 illustrates a galvanostatic product distribution analysis performed with a potentiostat over a Zn porous electrode for a solution containing 0.3 M MEA and 0.5 M CsClO4 in DMSO under different current densities and at 40°C, the solution initially saturated with pure CO2 and purged with Ar at 5 SCCM during the analysis (30 minutes total).

[0063] FIG. 53 illustrates a schematic of an H-cell used for product distribution analysis, coupled with a CO2 sensor and gas chromatography.

[0064] FIG. 54 illustrates a plot of a galvanostatic test at 100 mA / cm2and 40°C in a three-electrode H-cell setup for solutions analyzed in the voltammograms illustrated in FIG. 50, the anolyte purged with either H2 or air at 20 SCCM and about 1.5 C / mL was passed during the test, and a porous palladium membrane was used as a counter electrode and Zn cloth was used as a working electrode.

[0065] FIG. 55 illustrates a GC-MS analysis of the anolyte solutions for which the galvanostatic test results are provided in FIG. 50.

[0066] FIG. 56 illustrates a bar graph plot of accelerated recycling performance of the 0.3 M MEA and 0.5 m CSCIO4 electrolyte at a constant applied current of 100 mA / cm2over Zn cloth at 40°C in a H-cell configuration, and H2 at 20 SCCM purged in the anolyte, each cycle including a step for catholyte saturation with HOC-FG, followed by purging with synthetic air (20% O2, 80% N2) at 10 SCCM.

[0067] FIG. 57 illustrates a plot of comparative performance of different reactive capture systems using MEA at room temperature, simulated high-oxygen content flue gas (HOC-FG) including 17% CO2, 17% O2, and 66% N2.

[0068] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.DETAILED DESCRIPTION

[0069] Definitions

[0070] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meanings as those generally understood by those skilled in the art to which the present disclosure pertains. Such terms as those defined in a generally used dictionary are to be interpreted as having meanings equal to the contextual meanings in the relevant field of art.

[0071] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0072] In describing elements of the present disclosure, the terms “1st,” “2nd,” “first,” “second,” “A,” “B,” “(a),” “(b),” and the like may be used herein. These terms are only used to distinguish one element from another element, but do not limit the corresponding elements irrespective of the nature or order of the corresponding elements.

[0073] Numerical values, including endpoints of ranges, may be expressed herein as approximations preceded by the term “about,” “approximately,” or the like. In such cases, other examples include the particular numerical values. Regardless of whether a numerical value is expressed as an approximation, two examples are included in this disclosure: one expressed as an approximation, and another not expressed as an approximation. It will be further understood that an endpoint of each range is significant both in relation to another endpoint, and independently of another endpoint. It will be further understood by one skilled in the art, for any and all purposes, all ranges recited herein also encompass any and all possible sub-ranges and combinations of sub-ranges thereof, as well as the individual values making up the range, particularly integer values. It is therefore understood that each unit between particular units is also disclosed. For example, if “10 to 15” is disclosed, then 11, 12, 13, and 14 are also disclosed, individually, and as part of a range. A recited range (for example, weight percentages or carbon groups) includes each specific value, integer, decimal, or identity within the range. Any listed range may be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, or tenths. As will also be understood by one skilled in the art, all language such as “up to,” “at least,” “greater than,” “less than,” “more than,” “or more,” and the like, include the number recited and such terms refer to ranges that may be subsequently broken down into sub-ranges. In the same manner, all ratios recited herein also include all sub-ratios falling within the broader ratio. Accordingly, specific values recited for radicals, substituents, and ranges are for illustration only; the specific values do not exclude other defined values or other values within defined ranges for radicals and substituents. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0074] One skilled in the art will also readily recognize that where members are grouped together in a common manner, such as in a Markush group, the invention encompasses not only the entire group listed as a whole, but each member of the group individually and all possiblesubgroups of the main group. Additionally, for all purposes, the invention encompasses not only the main group, but also the main group absent one or more of the group members. The invention therefore envisages the explicit exclusion of any one or more of members of a recited group. Accordingly, provisos may apply to any of the disclosed categories or examples whereby any one or more of the recited elements, species, or examples may be excluded from such categories or examples, for example, for use in an explicit negative limitation.

[0075] The uses of the terms “a” and “an” and “the” and similar referents in the context of describing the present disclosure (especially in the context of following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. All methods described herein may be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

[0076] As used herein, the terms “comprise(s),” “include(s),” “having,” “has,” “can,” “contain(s),” and variants thereof, are intended to be open-ended transitional phrases, terms, or words that do not preclude the possibility of additional acts, structures, elements, or components. The present description also contemplates other embodiments “comprising,” “consisting of,” and “consisting essentially of’ the examples or elements presented herein, whether explicitly set forth or not.

[0077] As used herein, the term “about,” when used in the context of a numerical value or range set forth means a variation of ±15%, or less, of the numerical value. For example, a value differing by ±15%, ±14%, ±10%, or ±5%, among others, would satisfy the definition of “about,” unless more narrowly defined in particular instances.

[0078] The term “alkyl,” by itself or as part of another substituent, refers, unless otherwise stated, to a straight, branched, or cyclic chain aliphatic hydrocarbon (“cycloalkyl”) monovalent radical having the number of carbon atoms designated (in other words, “C1-C20” means one to twenty carbons, and includes C2, C3, C4, C5, Ce, C7, Cs, C9, C10, C11, C12, C13, C14, C15, Ci6, C17, Cis, and C19). Examples include methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, sec-butyl, tert-butyl, cyclobutyl, methylcyclopropyl, cyclopropylmethyl, pentyl, neopentyl, hexyl, and cyclohexyl.

[0079] The term “aromatic” generally refers to a carbocycle or heterocycle having one or more polyunsaturated rings having aromatic character (in other words, having (4n+2) delocalized n (pi) electrons where n is an integer).

[0080] The term “aryl,” by itself or in combination with another substituent, refers, unless otherwise stated, to a carbocyclic aromatic system substituent containing one or more rings(typically one, two, or three rings), wherein such rings may be attached together in a pendant manner, such as biphenyl, or may be fused, such as naphthalene. Examples may include phenyl, benzyl, anthracyl, and naphthyl. Preferred are phenyl, benzyl, and naphthyl; most preferred are phenyl and benzyl.

[0081] The terms “heterocyclic,” “heterocycle,” and “heterocyclyl,” by themselves or in combination with another substituent, refer, unless otherwise stated, to a stable mono- or multi-cyclic ring system that consists of carbon atoms and at least one heteroatom independently selected from N, O, Si, and S, wherein each nitrogen and sulfur heteroatom may be optionally oxidized, each nitrogen heteroatom may be optionally quatemized or substituted, and each silicon heteroatom may be optionally substituted. The heterocyclic system may be attached, unless otherwise stated, at any heteroatom or carbon atom that affords a stable structure. Nonlimiting examples of monocyclic heterocyclic groups include: aziridine, oxirane, thiirane, azetidine, oxetane, thietane, pyrrolidine, pyrroline, imidazoline, pyrazolidine, dioxolane, sulfolane, 2,3-dihydrofuran, 2,5-dihydrofuran, tetrahydrofuran, thiophane, piperidine, 1 ,2,3,6-tetrahydropyridine, piperazine, N-methylpiperazine, morpholine, thiomorpholine, pyran, 2,3-dihydropyran, tetrahydropyran, 1,4-dioxane, 1,3-dioxane, homopiperazine, homopiperidine, 1,3-dioxepane, 4,7-dihydro-l,3-dioxepin, and hexamethyleneoxidine.

[0082] The term “amino” refers to a -NH2 group. The term “amine” refers to organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. Amines are classified into three types: primary (1°), secondary (2°), and tertiary amines (3°). Primary amines (1°) contain one alkyl or aryl substituent and have the general formula RNH2. Examples may include methylamine and aniline. Secondary amines (2°) have two alkyl or aryl groups attached to the nitrogen atom, with the general formula R2NH. Examples may include dimethylamine and diphenylamine. Tertiary amines (3°) contain three substituent groups bonded to the nitrogen atom and are represented by the formula R3N. Examples may include trimethylamine and ethylenediaminetetraacetic acid.

[0083] As used herein, “carbamate” is a category of organic compounds with the general formula R2NC(O)OR and structure >N-C(=O)-O-, which are formally derived from carbamic acid (NH2COOH).

[0084] Introduction

[0085] Electrochemical approaches to integrated capture and conversion are conventionally done under aqueous conditions, where CO2 reacts with primary and secondaryamines to form an amine-CCh adduct in the form of carbamates (Equation 1). This adduct then acts as a continuous source of CO2 that can be electrochemically upgraded to fuels and chemicals. Nevertheless, the CO2 capture capacity in water is impaired by the formation of ammonium and carbonate ions. These competing side reactions consume both amine and CO2, preventing their incorporation into the amine-CCh adduct. Another key challenge in integrating CO2 capture and conversion in water is the dominance of the hydrogen evolution reaction (HER). Water, bicarbonate, and particularly ammonium ions can act as proton sources for HER, reducing selectivity towards carbon-containing products.

[0086] Aqueous mediumCO2 + 2 R-NH2R-NHCO2’ + R-NH3+( 1 )

[0087] During electrochemical reduction, ammonium ions populate the surface of the negatively biased working electrode, suppressing CO formation. Using alkali salts to tailor the electrochemical double layer with inert cations (e.g. K+and Cs+), enabling the reduction of R-NHCO2-present in the outer Helmholtz plane. Using a silver (Ag) catalyst, an increase in CO faradaic efficiency (FE) from 5% to nearly 35% at room temperature when 2 M KC1 is added to a 2 M monoethanolamine (MEA) solution was observed. Further, when Ag is used as a catalyst with a pure CO2 stream (no amine present), CO faradaic efficiencies of at least 60% have been reported. Therefore, the ambient integrated approach leads to lower CO FE. To increase CO FE, elevated temperatures (~60 °C) were needed, likely facilitating the dissociation of the amine-CO2 adduct and enhancing the local CO2 concentration.

[0088] Past studies have focused on probing whether the carbon in CO originates from residual CO2 or the carbamate (amine-CO2 adduct). By changing CO2 partial pressure and solution pH, it has been demonstrated that the reduction of amine-CO2 presents comparable selectivity and kinetics to direct CO2 reduction (CO2R) in amine-free bicarbonate solutions. There are also studies using combination of first-principles modeling and electrochemical techniques to draw a universal correlation between CO2 partial pressure and CO partial current density. It has been found that dissolved CO2 is the main source of CO formation; with carbamate acting as CO2 storage. Regardless of the carbon source, these studies revealed that streams with high CO2 loading and noble metal catalysts are needed for CO formation. For industrially relevant CO2 compositions (10-20% CO2), FE values for CO of 10%, with H2 as the predominant product was observed. Moreover, none of these approaches to integrated CO2 capture and conversion have considered the presence of O2, whose concentrations can range from 1% to 5% in industrial flue gas streams. These systems are also highly sensitive to oxygen.During CO2 reduction, the presence of O2 can lead up to current losses of 99% due to the competing oxygen reduction reaction (“ORR”). These challenges have called into question whether reactive capture in an aqueous medium is truly promising.

[0089] The use of nonaqueous medium that includes aprotic solvents offers a viable strategy to increase CO2 solubility while lowering water, proton, and O2 activities towards undesired HER and ORR. More importantly, it provides an opportunity to control the amine-CO2 speciation. The use of a nonaqueous medium can deploy a new approach for integrated CO2 capture / conversion via carbamic acid as an amine-CO2 adduct. Carbamic acid is formed in polar nonaqueous solvents such as dimethyl sulfoxide (DMSO), present either as free or in equilibrium with its zwitterionic analog (Equation 2).

[0090] Nonaqueous mediumCO2 + R-NH2R-NHCO2H R-NH2+CO2“ (2)

[0091] More importantly, the formation of carbamic acid only requires one amine per CO2 molecule instead of the two needed for the carbamate / ammonium ion pair (Eq. 1). In short, the advantages of using an aprotic solvent as the electrolyte will (1) induce carbamic acid speciation (instead of carbamate) to double the theoretical capacity for CO2 uptake (1 mol amine / 1 mol CO2) when compared to an aqueous medium, (2) decrease the propensity for HER and ORR, (3) increase CO formation at lower CO2 partial pressures, and (4) enable earth-abundant catalysts beyond precious metals, such as silver (Ag).

[0092] In this disclosure, an example method for capturing and converting CO2 in a nonaqueous medium is described. The method includes contacting a source of CO2 with a nonaqueous electrolyte composition. The nonaqueous electrolyte composition includes a capture agent; and an aprotic solvent. The capture agent described herein may be an amine selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), l,5-diamino-3-oxapentane (DAOP), aniline (AN), piperazine (PZ), aminoacetonitrile (AAN), 3,3'-iminodipropionitrile (IDPN), 1,1 -dimethylguanidine (DMG), 2 -ethoxy ethylamine (EEA), 2-amino-2-methyl-l -propanol (AMP), 2-amino-2-methyl-l,3-propanediol (AMPD), 2-(2-aminoethoxy)ethanol (AEEA), ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), N-(2-hydroxyethyl)piperazine, morpholine, piperidine, mono- and di-Ci-Ce alkylamines (including methylamine, ethylamine, isopropylamine, dimethylamine, diethylamine, and dipropylamine), and combinations or salts thereof. The CO2 reacts with the capture agent in the nonaqueous electrolyte composition to produce an amine solution comprising an amine-CCh adduct. Theamine-C02 adduct is predominantly in the form of, but not limited to, a carbamic acid. Then, contacting the amine solution with an electrode (i.e., a conducting material). Followed by applying an electric potential to the amine solution to convert the carbon dioxide to carbon monoxide (CO) upon electrochemical reduction. CO is highly desired because it is a component of synthesis gas (syngas) that can be converted to further reduced products. The capture and the conversion of CO2 may be done in a single process.

[0093] The aprotic solvent described herein may be a polar, aprotic solvent selected from the group consisting of acetonitrile, propylene carbonate, tetrahydro furan, acetone, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), sulfolane, y-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), and combinations thereof or similar polar aprotic solvents. It was observed that a threefold increase in CO2 uptake by the capture agent in the form of amine-CO2 adduct when moving from water to an aprotic solvent as a result of shifting the amine-CO2 speciation from carbamate to carbamic acid. In a specific example, DMSO was chosen as the solvent due to its low toxicity and ability to induce carbamic acid speciation. In some examples, about 84% faradaic efficiency (FE) for CO2 conversion to CO in DMSO near room temperature was achieved at 100 mA / cm2over 24 hours, when compared to a maximum of 10% FE for CO in water using a silver catalyst for a same cell setup.

[0094] The nonaqueous electrolyte composition may further include a salt that includes an alkyl metal ion or organic cations. The presence of inert cations has been shown to suppress HER during amine-CO2 reduction. The alkali metal ion is formed from an alkali metal selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and francium. The anion component may be selected from perchlorate (CIO4 ), tetrafluoroborate (BF4"), hexafluorophosphate (PFe"), bis(trifhioromethanesulfonyl)imide (TFSI ), triflate (CF3SO3 ), chloride (Cl"), nitrate (NCh"), or combinations thereof. Representative salts include, but are not limited to, lithium perchlorate (LiCICh), lithium tetrafluoroborate (LiBEt), sodium chloride (NaCl), potassium chloride (KC1), cesium chloride (CsCl), and cesium perchlorate (CsCICh). In other embodiments, the salt may include an organic ammonium or phosphonium cation, such as tetramethylammonium (TMA+), tetraethylammonium (TEA+), tetrabutylammonium (TBA+), tetrahexylammonium (THA+), or tetrabutylphosphonium (TBP+), combined with any of the foregoing anions.

[0095] The concentration of capture agent present in the electrolyte composition may be in the range from about 0.10 M to about 3.0 M. The amount of the salt present in the electrolyte composition may be in the range from about 0.10 M to about its solubility limit in the organicsolvent (e.g., about 1.0 M and beyond). The rest of the electrolyte composition is made up of the aprotic solvent. The molar ratio of the capture agent to CO2 molecule is about 1 to 1.

[0096] The method described herein significantly enhanced CO2 reduction activity and selectivity, enabling the use of non-precious metal catalysts. The metal species described herein may be a metal selected from the group consisting of zinc (Zn), nickel (Ni), lead (Pb), silver (Ag), gold (Au), and tin (Sn). The metal species acts as a catalyst. In the present disclosure, density functional theory (“DFT”) calculations and electrochemical analysis indicate a further boost in CO2 activity and CO formation with the transition from using a precious metal catalyst such as a silver catalyst to a non-precious base metal, such as a zinc catalyst. Further, the superior electrochemical performance observed in DMSO over a zinc catalyst offsets the higher solvent costs associated with water-based systems, leading to about 94 to 98% decrease in CO production costs for the same cell configuration.

[0097] In one example, the CO2 is from a simulated flue gas composition where the flue gas composition contains a high oxygen content between about 3% to about 17% and CO2 content below about 20%. Despite the presence of high oxygen impurities and lower CO2 partial pressures, the faradaic efficiency (FE) values for CO2 conversion to CO were achieved between about 30% to about 40% at 100 mA / cm2over 24 hours. In some examples, the faradaic efficiency FE values for CO2 conversion to CO was at least about 43%, over 24 hours over multiple capturing-conversion cycles. Overall, the present method of capturing and converting CO2 in a nonaqueous medium described herein significantly improves CO2 capture capacity, enhances CO2 loading efficiency, and achieves higher faradaic efficiency of CO production at lower temperatures and in the presence of oxygen.

[0098] An example carbon dioxide conversion system is also described below. The system includes a gas absorber containing a nonaqueous electrolyte composition as described above. The nonaqueous electrolyte composition includes a capture agent, a dissolved salt, and an aprotic solvent as described above for producing and depositing an enriched composition in a vessel. A source of carbon dioxide fluidically connected to the gas absorber. The system also includes a metal species as described above in contact with the enriched composition and a source of an electric potential in contact with the metal species. The enriched composition contains the nonaqueous electrolyte composition and carbon dioxide free in the solution and in the form of an amine-CCb adduct.

[0099] Specifically, the carbon dioxide reacts with the capture agent in the enriched composition to produce an amine solution comprising the amine-CCb adduct, wherein thecarbon dioxide is converted to carbon monoxide upon electrochemical reduction. The amine-CO2 adduct is predominantly in the form of, but not limited to, a carbamic acid. The molar ratio of the capture agent to CO2 molecule is about 1 to 1.[000100] The materials used for the gas absorber and vessel can be any standard materials used in the art.[000101] The compositions and processes described above may be better understood in connection with the following Examples. In addition, the following non-limiting examples are an illustration. The illustrated methods are applicable to other examples of the present disclosure. The procedures described as general methods describe what is believed will be typically effective to prepare the compositions and systems indicated, and perform the methods indicated. However, the person skilled in the art will appreciate that it may be necessary to vary the procedures for any given example of the present disclosure, for example, vary the order or steps and / or the chemical reagents used.EXAMPLES[000102] I. Materials and Methods.[000103] A. Materials[000104] Dimethylsulfoxide (DMSO) (anhydrous, 99.9%), monoethanolamine (99%), and cesium chloride (99.9%) were purchased from Sigma-Aldrich, while cesium perchlorate (99.5%) was purchased from Thermo Fisher Scientific. All other reagents were used as received, if not stated otherwise. After dissolution of salts, all electrolytes presented water content lower than 500 ppm determined through Karl-Fischer coulometric titration. All glassware used was cleaned by first rinsing with soap, and subsequently three times with each of the following solvents: ethanol (Fisher, 70%), isopropanol (StatEab, 99%), and Mili-Q water (resistivity 18.2 MQ-cm at 25°C). Then the glassware was rested in a fresh acid bath containing 10% (v / v) HNO3 solution (Fisher Chemical, TraceMetal™ Grade) for 24 h, rinsed again three times with Mili-Q water, and dried at 80°C for at least 6 hours before use.[000105] B. Characterizations[000106] 1. NMR Spectroscopy[000107] Deuterated DMSO and D2O were purchased from Cambridge Isotope Eaboratories (99.8%). 10 mA / tetramethylsilane (Sigma-Aldrich, 99%) was added to all samples and used as a1H NMR internal reference as 0 ppm. All1H NMR and13C NMR spectra were collected using a Broker Ascend 9.4 T / 400 MHz. For the speciation studies,13C-labeled carbon dioxide (MilliporeSigma, 99 atom %13C and 99.93 atom %16O) was purged for 30 minutes at 1 SCCMinto 0.5 mL of sample. Then argon (Air Gas, 99.9995%) was purged at 1 SCCM was for 5 minutes to eliminate any dissolved CO2. Relaxation time (Tl) was set to 40 seconds for the collection of13C NMR spectra.[000108] 2. Conductivity and pH Measurements[000109] Conductivity measurements were taken in a Vernier platinum-cell conductivity probe with an epoxy body. pH measurements were taken with a Mettler-Toledo SevenCompact pH meter with a pH probe Sensor InLab® Smart Pro-ISM with Xerolyt polymer as a reference electrolyte and has an open junction to prevent clogging and contamination with the nonaqueous electrolytes. pH measurements taken in a nonaqueous medium are reported as apparent pH (“pHapp”).[000110] 3. Electrochemical Measurements[000111] Electrochemical data were acquired using a Biologic VSP potentiostat. Working electrodes were made by inserting a silver rod (Thermo Scientific, 3.18 mm dia., 99.9% metals basis) and zinc rod (Thermo Scientific, 99.994% metal basis) inside a PEEK tubing. Platinum wire (Thermo Scientific, 0.25 mm dia., 99.9% metals basis) was used as the counter electrode. Before each experiment, all working and counter electrodes were polished with alumina slurry (eDAQ) and rinsed with ethanol, isopropanol, and Mili-Q water. High-pressure N2 (Airgas, Ultra High Purity Grade) was used to remove any excess alumina slurry from the electrode surface. Electrodes were then dried at 80 °C. Platinum electrodes were stored in 10% HNO3 (v / v) TraceMetals grade solution when not in use. Ag / AgCl leakless electrode (eDAQ, PEEK tube) was used as a pseudo-reference electrode calibrated against leakless hydrogen reference electrode Mini-HydroFlex (Gaskatel), which was used to reference the cell potential against H2 / H+.[000112] The leakless hydrogen reference electrode Mini-HydroFlex consisted of an H2 cell generator in contact with a palladium-platinum gas diffusion electrode under H2 at nearly atmospheric pressure (1 - 2 mbar). The electrode open circuit potential using a hydrogen electrode stabilized after 45 minutes when in contact with the DMSO electrolyte. Stabilization was required before each electrochemical experiment. The conversion to RHE scale may be done by subtracting the potential measured against Ag / Ag+electrode with the open circuit potential measured after 1 hour. When using the hydrogen electrode as a working electrode and the leakless Ag / Ag+as a reference electrode, the conversion to RHE scale could be done according to ERHE = EAg / Ag+ - Eocv. The Ag / Ag+electrode was calibrated against the H2 / H+electrodes after each experiment. After each experiment, the uncompensated resistance (Ru)was acquired at -1.5 vs. Ag / AgCl at the high-frequency regime (100 kHz) of the electrochemical impedance spectra. All potentials were reported after 100% manual after- the-scan IR compensation using the average Ruvalue for each electrolyte.[000113] 4. Product Distribution Analysis[000114] Product distribution analysis was performed using a Biologic VSP potentiostat with a glass H-cell illustrated in FIG. 1. Platinum wire was used as a counter electrode, a leakless Ag / AgCl as a reference electrode, and Ag and Zn disks as working electrodes. Both catholyte and anolyte chambers were filled with the same solutions, which were separated by a Nafion-N117 (Alfa-Aesar) proton exchange membrane. A stirbar at 750 rpm was kept in the catholyte chamber. Three gas flow controllers (Allicat Scientific) were connected in parallel to a gas mixer and then lined to the H-cell. CO2 (99.9995%), N2 (99.9995%), air (20% O2 and 80% N2, 99.999%), and Ar (99.9995%) were all purchased from Airgas. Products in the gas phase were analyzed in-line using a CO2 sensor (CCbMeter, SprintIR®-W 100%) and Shimadzu GC-2014 gas chromatograph with both a flame ionization detector (“FID”) and a thermal conductive detector (“TCD”). Products in the liquid phase were analyzed using 'H-NMR in a Broker Ascend 9.4 T / 400 MHz instrument. The reference electrode calibration against the hydrogen electrode and IR correction were performed as previously described in the Electrochemical Measurements section. For the long-term electrolysis, anolyte was refreshed every 6 hours.[000115] 5. Density Functional Theory (DFT) Calculations[000116] DFT calculations with periodic boundaries were carried out using a plane-wave-based Vienna ab initio Simulation Package (“VASP”). The projector augmented wave (“PAW”) method was used to describe the ionic cores; the generalized gradient approximation (“GGA”) PBE functional was used to account for the exchange-correlation effects in the Kohn-Sham framework. The bulk structure of Ag and Zn were optimized using 520 eV cutoff energy and 8 x 8 x 8 k-point mesh based on the Monkhorst-Pack scheme. The Ag (111) and Zn (100) and (101) facets were cleaved from the optimized bulk.[000117] 6. Techno-economic Analysis (“TEA”)[000118] The TEA was based on the process for integrated carbon capture and electrochemical conversion. The process model included a physics-based, 0-D model of the electrochemical cell to model CO reduction, and a flash column to model the vapor-liquid phase equilibrium to account for solvent and amine loss into the vapor-phase stream. The outlet stream from capture unit (including solvent, amine, salt, and captured CO2) constituted the feed stream into the electrochemical cell. Product recovery was by phase separation, because noliquid products were formed, and the regenerated amine stream was recycled back into the capture unit. Amine makeup was included to account for amine loss. Model inputs included economic data such as material and electricity costs, and experimental data such as amine CO2 uptake, Faradaic efficiency, and total current density measured at different potentials, corresponding component molar fractions in the liquid and vapor phase of electrochemical cell outlet stream, and carbonate loss. Key model outputs included energy and conversion efficiency, overpotentials, overall reaction rates, outlet / product stream compositions and molar flow rates, energy demand, system size, material quantities, capital costs (for example, anode, cathode, membrane, and cell material costs), and operating costs (for example, electricity, maintenance, and makeup costs).[000119] II. Results and Discussion.[000120] Prior attempts to employ aprotic organic electrolytes have not been successful. The reduction of different amine-CCh adducts in aprotic solvents such as acetonitrile and propylene carbonate using glassy carbon and Pb was previously explored. However, no CO was observed. CO is highly desired because it is a component of synthesis gas (syngas) that can be converted to further reduced products. Instead, formic acid was the primary product. Furthermore, supporting electrolytes were utilized to induce carbamate speciation, instead of carbamic acid. Similarly, Li+salts were used to induce carbamate speciation with 2-ethoxyethylamine (EEA) in dimethyl sulfoxide (DMSO), only Li2COs was observed as the final product. It was hypothesized that, as a neutral molecule, carbamic acid should not suffer from the electrostatic repulsion from the negatively biased electrode during reduction. Therefore, higher FE towards CO was expected when compared to that observed during CO2R in aqueous medium. Moreover, by limiting the availability of R-NHC and thereby the competing HER, nonaqueous electrolytes may enable the use of a non-noble metal catalyst, as well as operation at industrially relevant CO2 partial pressures.[000121] The effect of the amine-CO2 adduct speciation in both CO2 uptake and CO formation was systematically studied. Monoethanolamine (MEA) as it is state-of-the-art for CO2 capture from industrial streams was chosen. DMSO was chosen as a solvent due to its low toxicity and ability to induce carbamic acid speciation. The results show a threefold increase in CO2 uptake in the form of amine-CO2 adduct when moving from water to DMSO. Moreover, 84% faradaic efficiency (FE) towards CO in DMSO at room temperature was achieved, when compared to a maximum of 10% in water using a silver catalyst. The transition to a nonaqueous electrolyte also enables the use of an earth-abundant zinc catalyst, which surprisingly presentshigher activity towards CO than silver. Using density functional theory (DFT) calculations, a decrease in the limiting potential for CO formation when moving from Ag to a Zn catalyst was shown. According to the techno-economic analysis (TEA), the use of an earth- abundant catalyst in this nonaqueous system promotes a 94% decrease in CO production costs compared to an aqueous approach using silver. Finally, the integrated CO2 capture and conversion under simulated flue gas composition (17% CO2, 3% O2, 80% N2) was investigated, showing that one can achieve at least 43% CO FE over 24 h when tailoring the electrolyte composition despite the presence of oxygen. For high oxygen content streams (17% CO2, 17% O2, 66% N2), it can obtain up to 35% CO FE over multiple capture / conversion cycles. This approach leads to increased CO2 capture capacity, use of earth- abundant catalysts, high CO FE, low H2 FE, even use of industrially relevant flue gas compositions with oxygen impurities, and potential scale-up and commercial viability.[000122] A. Amine-CO2 Speciation Studies[000123] The influence of solvent on modulating amine-CO2 adduct speciation was investigated. As illustrated in FIG. 2, under aqueous conditions, CO2 was expected to react with two mono-ethanolamine (“MEA”) molecules (2 mol amine / mol CO2) to yield carbamate and ammonium. MEA may also behave as a base, reacting with water to form ammonium and hydroxide ions. The hydroxide ions could subsequently react with CO2 to generate bicarbonate species. By contrast, amine reaction with CO2 in DMSO was expected to yield mostly neutral carbamic acid molecules (1 mol amine / mol CO2). Thus, the amine-CCb speciation in different solvents was easily evaluated by comparing the solution conductivity before and after addition of CO2. As illustrated in FIG. 3, the conductivity of 0.3 M MEA aqueous solution increased by nearly 20 mS / cm upon the introduction of CO2. By contrast, the conductivity increase in DMSO was merely 0.3 mS / cm, indicating lack of substantial amounts of ionic species, such as R-NH3+and HCO3“.[000124] Based on the suppression of HER during amine-CO2 reduction by inert cations, the influence of supporting electrolytes on amine-CO2 speciation in both water and DMSO was investigated. Because large alkali cations may enable speciation of carbamic acid in DMSO, cesium salts were chosen. FIG. 4 illustrates the 'H NMR spectra of Ar and13CO2 saturated solutions of MEA in D2O and deuterated DMSO (‘Tfc-DMSO”) in the presence of 0.5 M Cesium (Cs) salts. The13CO2 saturated solutions were purged with argon to remove soluble CO2, as illustrated in FIGs. 5 and 6. From the 'H NMR spectra illustrated in FIG. 4, only 2 triplets were observed, around 3.5 and 2.6 ppm for Ar-saturated solutions in both D2O and d -DMSO, which can be assigned to MEA. Upon addition of CO2, four new peaks emerged in D2O, assigned to the protons present in the carbamate and ammonium ions. For cfo-DMSO, two new peaks at 3.4 and 3.0 ppm were assigned to -C-H present in the carbamic acid, while broad bands at 6.5 and 5.6 ppm arose from the fast exchange between the protons from the amide groups (6.5 ppm) and ammonium and hydroxyl from carbamic acid (5.6 ppm). Peaks 3 and 4 in de-DMSO were assigned to ammonium ions, which are present in lesser amounts.[000125]13C NMR was performed to investigate products other than those visible in 'H NMR. From the spectra illustrated in FIG. 4, we assigned carbon peaks associated with each -C-H bond present in MEA and its related compounds in water and DMSO. The peaks were assigned based on two-dimensional heteronuclear NMR spectroscopy, illustrated in FIGs. 7-11. Distinct peaks were observed that were assigned to carbamate (165 ppm) and the fast exchange between bicarbonate and carbonate in water (158 ppm). By integrating the13C peak intensities, as illustrated in FIGs. 12-14, the CO2 load relative to the total moles of amine present in the medium could be estimated. As illustrated in FIG. 15, only 15% of the amine was converted to carbamate in water. As the amine and salt concentrations were increased to 2 M, an increase in carbamate conversion to 31% was observed. Substantial amounts of bicarbonate / carbonate, around 64% and 28%, were observed for MEA concentrations of 0.3 M and 2 M in water, respectively. These carbonate species were “a waste” of CO2 feedstock, because the carbonate species could not be directly reduced to CO. By contrast, nearly 87% of the initial MEA was converted to carbamic acid in DMSO, with merely 1% bicarbonate / carbonate formation, indicating a CO2 uptake (per mole of amine) in the form of amine-CO2 adduct nearly three times greater in DMSO than in water, and with minimal carbonate waste.[000126] B. Solvent Effect on Amine-CO2 Reduction[000127] The role of amine-CO2 adduct speciation in modulating electrochemical selectivity was investigated. A constant cesium / amine molar ratio was maintained across different electrolytes. FIGs. 16 and 17 illustrate voltammograms obtained from the water and DMSO electrolytes before and after saturation with CO2, respectively. The cathodic potential in the nonaqueous medium was also referenced against the reversible hydrogen electrode (“RHE”). The electrolyte solutions were purged with argon gas to eliminate any dissolved CO2, as illustrated in FIGs. 5 and 6. In water, only a single cathodic feature was observed at -0.45 V vs. RHE for both Ar- and CO2-saturated solutions. For Ar-saturated solution in DMSO, a cathodic feature was observed at -1.2 V vs. RHE, which was ascribed to amine reduction orelectrolyte degradation. However, with CO2, a second cathodic feature was observed at -0.5 V, which remained diffusion-limited around -10 mA / cm2until electrolyte reduction / degradation took place.[000128] A product distribution analysis was performed at different potentials in water and DMSO to understand the interplay between amine-CCb speciation and the electrochemical activity and selectivity of the speciation over a silver catalyst. The captured stream was composed of pure CO2, while the carrier gas was Ar. As illustrated in FIG. 18, a maximum faradaic efficiency of 12% for CO was observed in water at -0.45 V, with CO partial current density ( / co) not exceeding 2 mA / cm2for potentials as negative as -0.82 V. Similar CO FE values between 9% and 19% were previously observed using similar amine composition, silver catalyst, and cell setup. In DMSO, a maximum of 88% CO FE was observed at -0.75 V, with jco reaching a maximum of 8 mA / cm2at -0.9 V. The heightened CO selectivity may be due to the decreased availability of proton sources for HER, such as H2O, HCOs’, and RNHs+, which are present in substantial amounts in an aqueous environment, but not in DMSO (~15 % based on the total amount of amine). DMSO may form strong hydrogen bond networks, which decreases both proton and water activity toward HER. The elevated CO2 load in DMSO may have contributed to the higher jco values relative to an aqueous environment.[000129] Silver catalysts are expensive, and therefore hard to scale for reactive capture in aqueous electrolytes. Because the increase in CO activity and selectivity was influenced by the electrolyte composition, comparable outcomes were thought to be possible using alternative catalysts. Product distribution analyses were conducted in both water and DMSO using an earth- abundant zinc electrode. Polycrystalline zinc was known to yield mostly CO during CO2R in both aqueous and nonaqueous media. As illustrated in FIG. 19, Zn performed poorly in water, with CO FE and partial current density values not exceeding 5% and 1 mA / cm2, respectively. By contrast, FIG. 20 illustrated CO Fe values around 83% in DMSO at -1.5 V, with a jco reaching 14.1 mA / cm2at more negative potentials. The results demonstrated a stark increase in both CO activity and selectivity for amine-CO2 reduction over non-noble metal catalysts at room temperature when shifting from water to DMSO electrolyte.[000130] C. Role of Amine-CO2 Adduct[000131] The role of monoethanolamine (MEA) and CO2 partial pressure in CO2 was investigated in order to elucidate the role of amine-CO2 adduct during CO formation in DMSO. The13C NMR spectra illustrated in FIG. 21 show a single peak at 125 ppm in the absence of MEA, corresponding to dissolved CO2. Upon addition of MEA, most of the CO2 was convertedto carbamic acid. As the CO2 partial pressure decreased to 20%, the carbamic acid peak intensity diminished, and no appreciable amount of dissolved CO2 is detected. A CO2 partial pressure of 20% was selected as a representative condition for the product distribution analysis illustrated in FIG. 22. The observations indicated that carbamic acid served as a reservoir, dynamically releasing CO2 as the carbamic acid is consumed during electrochemical reduction or displaced during purging with an inert gas.[000132] To verify whether the amine-CCb adduct (rather than dissolved CO2) serves as the primary CO2 reservoir, a displacement test was conducted to quantify the total CO2 loading with and without MEA. A CO2- saturated solution was purged with Ar in an airtight cell, while the CO2 content in the exhaust was monitored, as illustrated in FIG. 23. As illustrated in FIG.24, the CO2 loading in DMSO without amine was 130+1 mmol / E, consistent with reported literature values. In the presence of MEA, the CO2 loading increased significantly to 287 mmol / E, closely aligning with the initial amine concentration (300 mAf). The findings corroborated the13C NMR results, confirming that CO2 is predominantly present as an amine-CO2 adduct and is released upon purging the system with an inert gas.[000133] Whether an electrochemical process could drive CO2 release and subsequent reduction by comparing solutions’ linear sweep voltammograms (“LSVs”) in the presence and absence of MEA was analyzed. Solutions containing MEA were equilibrated for 1 hour with a mixture of 20% CO2 / 80% Ar to minimize the amount of dissolved CO2 in the solution. In the absence of amine, as illustrated in FIG.25, CO2 reduction took place around -1.25 V versus reversible hydrogen electrode (“RHE”) in DMSO. The electrode becomes inactive at more negative potentials due to the formation of poorly soluble cesium bi / carbonates. By contrast, when MEA was added, the onset potential for amine-CO2 reduction remained nearly the same, but electrode inactivation was mitigated. The findings suggested that CO2 was the active species for CO formation, consistent with prior studies in aqueous systems. However, the reaction was mediated by the formation of the amine-CO2 adduct, the equilibrium with CO2 (equation 3) of which outcompeted the formation of insoluble bicarbonates (equation 4). The bicarbonates would otherwise inactivate the electrode by blocking the electrode’s active sites.CO2 + 2 R-NH2R-NHCO2H (3)CO2+ OH’ HCO3- (4)[000134] D. Amine-CO2 Reduction Activity[000135] DFT simulations were carried out to further investigate the amine-CO2 reduction activity and selectivity. Calculations were performed over Ag(l 11) and Zn(101), which werethe dominant electrode facets before and after electrolysis, as illustrated in FIGs. 26 and 27, respectively. Results over the Ag(lll) are illustrated in FIG. 28, demonstrating that the carbamic acid formation in the liquid phase presented more negative free energy values than carbamate adsorption (dashed blue line) by -0.9 eV. Carbamic acid more likely acts as the amine-CO2 shuttle than the carbamate form.[000136] From the free energy diagrams, the release of CO2 presented -0.77 eV over the Ag electrode, indicating that CO2 was most likely the active species for the amine-CO2 reduction. The proton-coupled electron transfer reaction that led to the formation of COOH* was uphill by 0.99 eV. The step was followed by thermodynamically favored CO* formation and CO desorption steps. The presence of Cs+strengthened the binding interaction with carbamic acid by -0.45 eV while lowering the formation energy of COOH* by 0.55 eV, facilitating the amine-CO2 reduction. To investigate the effect of Cs+salts in the CO formation process in DMSO, the electrochemical double-layer capacitance (Cai) in the presence and absence of the supporting electrolyte. The two nonaqueous systems were compared against the internal standard decamethylferrocene (MeioFc). FIG. 29 illustrated an increase in Cai values to approximately 16 pF / cm2in the presence of Cs+as the amine-CO2 reduction, as the amine-CO2 reduction takes place between -1.8 and -2.2 V vs. MeioFc. By contrast, values between 2 and 6 pF / cm2were observed for the system without salt, suggesting that the addition of Cs+enhanced the dielectric constant near the electrode surface, likely inducing specific interactions that led to a more compact double layer and activity towards CO. In the absence of supporting ions, zwitterionic species (R-NH2+CO2 ) and ammonium ions are likely the predominant ions in the system, resulting in a thicker electrochemical double-layer and lower CO selectivity (CO FE values for different Cs+concentrations in FIG. 30).[000137] Similar trends were observed for the Zn(101) facet. The lower reaction energetics over Zn surfaces indicated higher reactivity towards CO2 reduction compared with Ag surfaces. Based on the free energy diagrams, the limiting potential for *COOH formation estimated for Zn(101) was 0.24 eV, significantly lower than the 0.61 eV estimated for Ag. The results were consistent with the higher CO activity observed experimentally for Zn when compared to Ag electrodes. The superior Zn activity towards CO in nonaqueous medium for direct CO2 reduction has been reported; for aqueous environments, Zn demonstrated slightly lower activity than Ag.[000138] The DFT calculations were further extended to possible proton donors for HER to investigate the high CO selectivity observed in DMSO. FIG. 31 compared the binding densityof H+and ammonium (R-NHs+) with the carbon shuttle (carbamic acid) and active species (CO2) for the formation of CO. In the absence of water, H+and ammonium could likely be formed by the ionization of carbamic acid, and the ammonium could likely be formed by the reaction of carbamic acid with unconverted amine. The full energy diagram for H2 formation from H+and ammonium, as well as the effect of Cs+cations, are illustrated in FIGs. 32-35.FIG. 31 illustrated that both carbamic acid and CO2 had greater affinity for either Zn or Ag electrodes than R-NH3 and H+. The results indicated that by properly speciating the amine-CO2 adduct high selectivity toward CO formation could be achieved. In an aqueous medium, larger amounts of R-NHs+(approximately 70% per mole of amine, as illustrated in FIGs. 7-11), water, and HCO3 resulted in enhanced activity toward HER, which was not captured by DFT calculations.[000139] E. Amine-CO2 Reduction Economic Feasibility[000140] A TEA model was implanted to assess the competitiveness of amine-CO2 reduction in a non-aqueous medium compared to water-based processes. Levelized Total Operating Cost (“LTOC”) included costs for anode, cathode, membrane, and cell materials, including plastic and casing materials; Levelized Total Variable Operation and Maintenance (“LTVOM”) included maintenance, electricity, and makeup costs. FIG. 36 illustrates the LTOC and LTVOM per ton of CO in water and DMSO over a silver electrode under the electrochemical conditions illustrated in FIG. 18 and 37, respectively. The TEA analysis revealed that using DMSO as a solvent significantly improved the economics of CO production compared to the more commonly used aqueous electrolytes. A cost reduction of nearly 89% for CO2 reduction over silver catalyst when operating the cell in DMSO at -1.5 V, compared to water at -0.99 V. The major contributors to the cost reduction were the higher CO partial current density ( co) and Faradaic efficiency in DMSO. The CO partial current density reached values around 7.3 mA / cm2at -1.5 V, which was 10 times greater than in water, and the difference was particularly evident at more negative potentials, where the jco in water was nearly zero, as illustrated in FIGs. 38-40, making the costs prohibitive. Similar trends were observed for FE and translated to significantly lower costs in DMSO compared to water, depending on the cathodic potential. For example, at -0.57 V, jco values in DMSO dropped to value saround 2 mA / cm2. Thus, selection of operating conditions is critical in order to balance the trade-off between CO FE, current density, and cell potential. DMSO improved CO FE, current density, reduced solvent loss, and improved CO2 uptake compared to an aqueous electrolyte, as illustrated in FIG. 41.[000141] Notwithstanding the economic gains of switching from aqueous- to DMSO-based electrolytes, the TEA was expanded to explore the potential benefits of transitioning from silver to a non-noble metal catalyst. FIG. 41 illustrated a detailed cost breakdown for the same electrochemical conditions illustrated in FIGs. 37 (Ag at -1.5 V) and 20 (Zn at -1.5 V) in DMSO. The adoption of the non-noble zinc catalyst resulted in about 90% reduction in CO production costs compared to silver in DMSO. Fewer material costs ($576 per m2for zinc plate compared to $26351.4 per m2for silver plate) accounted for about 50% of the reduction. Decreased maintenance expenses, which included replacement costs for anode, cathode, membrane, and cell materials, resulted in an additional 50% cost savings. Fewer electricity costs, solvent make-up, cell materials, anode, and membrane costs accounted for the remaining cost reduction, which was driven by enhanced CO activity observed with zinc (jeo of 11.3 mA / cm2) compared to a silver (jeo of 7.3 mA / cm2) catalyst. Detailed cost breakdown was illustrated in FIGs. 38-40. Overall, a 98% reduction in CO production costs was observed when switching from an aqueous medium using a silver catalyst to a DMSO-based system using a zinc catalyst. Further, switching to the less volatile DMSO also reduced solvent loss and improved CO2 uptake compared to an aqueous electrolyte.[000142] A parametric sweep analysis was performed to gain economic insights under industrially relevant operation conditions. Because current density and Faradaic efficiency were the major contributors to economic performance, a two-dimensional sweep using the TEA model was used to predict CO production cost for values of CO Faradaic efficiency in the range from 10% to 100%, and jeo from 5 mA / cm2to 1000 mA / cm2, as illustrated in FIG. 42. For the Zn-DMSO-MEA system, increasing CO Faradaic efficiency and current density significantly reduced production costs by up to 98% from the bottom left (low CO FE and low current density) to the top right (high CO FE and high current density) regions of FIG. 42. Beyond 200 mA / cm2, current density did not significantly affect costs. At lower CO FE (approaching 10%), production costs became very sensitive to FE.[000143] F. Conversion Under Industrially Relevant Stream Compositions[000144] The effect of CO2 stream composition on amine-CO2 speciation and electrochemical reduction was investigated. FIG. 43 illustrates the apparent pH (pHapp) evolution of MEA solutions in DMSO when purged with different CO2 / Ar mole fractions. A pH plateau at more acidic values was observed with the increase in the CO2 content in the gas stream, which is what would be expected from a reversible reaction, in which the partial pressure of the reagents (such as CO2) substantially effects the extent of product conversion.The1H-NMR peaks of the solutions were integrated after the gas purging to estimate the MEA conversion in carbamic acid concentration with CO2 content. A product distribution analysis over the best-performing Zn catalyst at high current densities (10 mA / cm2) was conducted to understand the effect of the CO2 gas composition on CO formation in DMSO. CO2 / Ar mixtures were employed as the carrier gas, because purging the solution with an inert gas induced CO2 release and altered speciation, as illustrated in FIG. 44. FIG. 45 illustrates substantial CO formation even for CO2 content as low as 20% and 10%, corresponding to CO FE of 54% and 18%, respectively.[000145] The spectroscopic and product distribution analysis indicated successful capture and selective conversion of the amine-CO2 adduct in DMSO for CO2 compositions as low as 10%. The performance of the example of a CO2 capture and conversion system was investigated under a simulated flue gas composition including 16% CO2, 3%, O2, and 81% N2. Flue gas impurities such as SOx and NOx are removable by wet scrubbing. As illustrated in FIG. 45, up to 43% CO FE for simulated flue gas composition was achieved. The reaction was carried out over 24 hours to further probe the stability of the catalyst and electrolyte after longterm exposure to O2 and CO. FIG. 46 illustrated that continuous CO formation is obtainable, with FE close to about 58% at 24 h without any substantial losses, due to the oxidation reduction reaction (“ORR”) (unaccounted FE < 5%). Further, there was no observed noticeable electrolyte degradation, and the unaccounted FE could also be attributed to CO2 reduction to formic acid, as illustrated in FIG. 47. The monotonic increase in CO FE with time was attributable to the slower formation of carbamic acid in DMSO, which may take up to 72 hours to reach equilibrium. Experiments under conditions without flow revealed larger amounts of CO when compared to H2 (about 2 moles CO per 1 mole H2) over 6 hours of electrolysis, as illustrated in FIG. 48, indicating that the CO2 was most likely supplied by the amino-CO2 adduct present in the solution as the reaction proceeded. The high CO selectivity observed absent flow of carrier gas indicated an ability to minimize potential CO2 losses associated with reversible amine-CO2 equilibrium and the purging of carrier gas.[000146] G. Enhancement of Amine-CO2 Reduction Current Density and Electrolyte Stability[000147] The electrode and the electrolyte were engineered to enhance the amine-CO2 reduction current density and improve electrolyte stability under higher oxygen content conditions. A porous Zn electrode was fabricated by electrodepositing Zn micro / nanoparticles onto a stainless-steel cloth. As illustrated in FIG. 49, the Zn deposits exhibited hexagonalshapes, offering a higher surface area compared to a flat disk architecture of the same geometric area. The electrochemical performance of the new porous electrode was evaluated in a DMSO-based electrolyte saturated with a high-oxygen-content flue gas (HOC-FG) mixture composed of 17% CO2, 17% O2, and 66% N2. Challenges associated with high oxygen content, such as the prevalence of the oxygen reduction reaction (“ORR”) under cathodic potentials and oxygen-oxygen-induced amine degradation pose significant obstacles to integrated capture and conversion. DMSO is better suited for these conditions due to its lower limiting current for oxygen reduction compared to aqueous electrolytes. Under prolonged exposure to a high-oxygen-content stream (for example, 5 days), the accelerated amine degradation test demonstrated that MEA degradation markers such as formate and nitrite could be detected in water, but not in DMSO. Less than half of evaporative mass losses in DMSO were observed when compared to water.[000148] FIG. 50 illustrated that at room temperature (for example, 20°C), the porous Zn electrode achieved a current density of 80 mA / cm2at -2.2 V versus MeioFc. The high cell voltage (6 V) limited operation at higher current densities, which may be primarily due to the low conductivity of nonaqueous electrolytes, such as DMSO and tetrahydrofuran (THF), compared to water. To decrease the cell resistance, the electrolyte temperature was increased to 40°C, aligning with the operational range of CO2 capture scrubbing columns using MEA. The adjustment resulted in current density values of 100 mA / cm2at 30°C and 120 mA / cm2at 40°C for the same cell voltage cutoff.[000149] The DMSO-based electrolyte demonstrated substantial selectivity toward CO even in high-oxygen environments. FIG. 51 illustrates stable CO FE values between 30% and 40% across different temperatures (20-40°C) and current densities (50-100 mA / cm2). If a pure CO2 stream was fed into the electrolyte instead of HOC-FG, CO FE values around 85% were observed, but with CO partial current densities up to 170 mA / cm2, as illustrated in FIG. 52.The electrochemical performance experiments were conducted in an H-cell setup illustrated in FIG. 53, in which the H-cell was coupled with a CO2 sensor and gas chromatography. The catholyte and anolyte chambers have a total capacity of 20 milliliters and 15 milliliters, respectively, and were filled with electrolytes at 80% of the volume capacities. The distances between the working and counter electrodes and the working and reference electrodes were approximately 6 centimeters and 1 centimeters, respectively. The area of the proton exchange membrane (PEM) exposed to the solution was 4 cm2. The experimental setup surprisingly and unexpectedly contributed to higher cell resistance values, suggesting that more compact cellarchitectures may significantly reduce resistance and further enhance system performance and economic viability.[000150] To improve electrolyte stability and ensure proton availability for CO formation, hydrogen oxidation reaction (HOR) was explored as an alternative reaction. Hydrogen gas (H2) was purged into the anodic chamber so the protons generated from HOR could migrate to the cathodic chamber through the proton exchang membrane. To mitigate the challenges associated with low H2 solubility, a porous palladium counter electrode was employed. Palladium exhibits superior intrinsic activity for HOR, which when combined with the large surface area of the porous architectures, may sustain high current densities of at least about 100 mA / cm2at lower cell overpotential.[000151] As illustrated in FIG. 54, the addition of H2 reduces the cell overpotential up to 1.1 V, driven by a more thermodynamically favorable HOR, without differences in the cathodic reaction. Gas chromatography coupled with mass spectrometry (GC-MS) analysis illustrated in FIG. 55 demonstrated the presence of pyrazine and dimethyl sulfone for the air purge anolyte. Pyrazine and dimethyl sulfone side products are associated with the oxidation of MEA and DMSO, respectively. The absence of any new side products in the presence of H2 suggested HOR as a sustainable anodic reaction for amine-CO2 reduction in nonaqueous media. The costs associated with supplying H2 were offset by the decrease in cell voltage for H2 prices below $3 per kilogram, indicating the economic feasibility of the use of H2 for low H2 market prices.[000152] An accelerated cycling test was performed on CO2 capture and conversion under oxygen-rich conditions to evaluate electrolyte recyclability. The solution was saturated with HOC-FC and purged with synthetic air (20% O2, 80% N2) instead of an inert gas, to accelerate the depletion of the amine-CO2 adduct. As illustrated in FIG. 56, the initial CO FE reached about 43% in the HOC-FC-saturated solution. Even as the CO2 content dropped to 3%, the system maintained a CO FE of about 20%. Some electrode restructuring was observed, with fracturing of some of the Zn nano / microparticles, which may account for reduction in peak CO FE at higher CO2 concentrations. The system demonstrated stable performance during 20 recycling tests.[000153] Overall, the use of a nonaqueous electrolyte provides a paradigm shift to integrate CO2 capture and conversion, providing substantial CO formation from industrially relevant streams. The superior performance of DMSO-based systems at ambient pressure and temperature is illustrated in FIG. 57. Compared to the current state-of-the-art water-basedelectrolyte system for reactive capture, which may achieve a CO faradaic efficiency (CO FE) of 39% over a silver catalyst and when equilibrated with pure CO2 streams, the present disclosure provides a higher CO FE of at least 35% over a Zn catalyst, under low CO2 partial pressures (17%), and in the presence of high content oxygen (17%). For industrial process that could supply pure CO2 streams, such as ethanol and ammonia product, 84% FE toward CO over an earth-abundance catalyst may be attainable.[000154] Although the present disclosure has been described with reference to examples and the accompanying drawings, the present disclosure is not limited thereto but may be variously modified and altered by those skilled in the art to which the present disclosure pertains without departing from the spirit and scope of the present disclosure.[000155] The subject-matter of the present disclosure may also relate, among others, to the following aspects:[000156] A first aspect relates to a method for capturing and converting carbon dioxide. The method includes contacting a source of carbon dioxide with a nonaqueous electrolyte composition, the nonaqueous electrolyte composition comprising a capture agent and an aprotic solvent, the capture agent comprising an amine, the carbon dioxide reacts with the capture agent in the nonaqueous electrolyte composition to produce an amine solution comprising an amine-CCE adduct; followed by contacting the amine solution with an electrode; and applying an electric potential to the amine solution to convert the carbon dioxide to carbon monoxide upon electrochemical reduction.[000157] A second aspect relates to the method of the first aspect, wherein the amine-CCE adduct is in the form of a carbamic acid.[000158] A third aspect relates to the method of the first or second aspect, wherein the capture and the conversion of CO2 are done in a single process.[000159] A fourth aspect relates to the method of any preceding aspect, wherein the capture agent is selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), l,5-diamino-3-oxapentane (DAOP), aniline (AN), piperazine (PZ), aminoacetonitrile (AAN), 3,3'-iminodipropionitrile (IDPN), 1,1-dimethylguanidine (DMG), 2-ethoxyethylamine (EEA), 2-amino-2-methyl-l -propanol (AMP), 2-amino-2-methyl-l,3-propanediol (AMPD), 2-(2-aminoethoxy)ethanol (AEEA), ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), N-(2-hydroxyethyljpiperazine, morpholine, piperidine, mono- and di-Ci-Ce alkylamines (includingmethylamine, ethylamine, isopropylamine, dimethylamine, diethylamine, and dipropylamine), and combinations or salts thereof.[000160] A fifth aspect relates to the method of any preceding aspect, wherein the aprotic solvent is selected from the group consisting of acetonitrile, propylene carbonate, tetrahydrofuran, acetone, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), sulfolane, y-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), and combinations thereof.[000161] A sixth aspect relates to the method of any preceding aspect, wherein the aprotic solvent is dimethyl sulfoxide.[000162] A seventh aspect relates to the method of any preceding aspect, wherein the nonaqueous electrolyte composition further comprises a salt, wherein the salt comprises an alkali metal ion or an organic cation, the alkali metal ion is formed from an alkali metal selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and francium.[000163] An eighth aspect relates to the method of any preceding aspect, wherein the salt is selected from lithium perchlorate (LiCICh), lithium tetrafluoroborate (LiBF4), sodium chloride (NaCl), potassium chloride (KC1), cesium chloride (CsCl), or cesium perchlorate (CsClCF).[000164] A ninth aspect relates to the method of any preceding aspect, wherein the nonaqueous electrolyte composition further comprises a metal species selected from the group consisting of zinc, nickel, lead, silver, gold, tin, and combinations thereof.[000165] A tenth aspect relates to the method of any preceding aspect, wherein the metal species is zinc.[000166] An eleventh aspect relates to the method of any preceding aspect, wherein the metal species acts as a catalyst.[000167] A twelfth aspect relates to the method of any preceding aspect, wherein the faradaic efficiency (FE) for carbon dioxide conversion to carbon monoxide is achieved at about 84% at 100 mA / cm2over 24 hours.[000168] A thirteenth aspect relates to the method of any preceding aspect, wherein the carbon dioxide is from a simulated flue gas composition comprising an oxygen content of about 3 to 17%.[000169] A fourteenth aspect relates to the method of any preceding aspect, wherein the the faradaic efficiency (FE) for carbon dioxide conversion to carbon monoxide is between about 30 to 40% at 100 mA / cm2over 24 hours.[000170] A fifteenth aspect relates to the method of any preceding aspect, wherein the molar ratio of the capture agent to CO2 molecule is about 1 to 1.[000171] A sixteenth aspect relates to a carbon dioxide conversion system. The system includes a gas absorber containing a nonaqueous electrolyte composition comprising a capture agent, a dissolved salt, and an aprotic solvent for producing and depositing an enriched composition in a vessel; a source of carbon dioxide fluidically connected to the gas absorber; a metal species in contact with the enriched composition; and a source of an electric potential in contact with the metal species, wherein the enriched composition comprises the nonaqueous electrolyte composition and the carbon dioxide.[000172] A seventeenth aspect relates to the system of the sixteenth aspect, wherein the capture agent comprises an amine a primary amine and / or a secondary amine selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), 1, 5 -diamino-3 -oxapentane (DAOP), aniline (AN), piperazine (PZ), aminoacetonitrile (AAN), 3,3 '-iminodipropionitrile (IDPN), 1,1 -dimethylguanidine (DMG), 2 -ethoxy ethylamine (EEA), 2-amino-2-methyl-l -propanol (AMP), 2-amino-2-methyl-l,3-propanediol (AMPD), 2-(2-aminoethoxy)ethanol (AEEA), ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), N-(2-hydroxyethyl)piperazine, morpholine, piperidine, mono-and di-Ci-Ce alkylamines (including methylamine, ethylamine, isopropylamine, dimethylamine, diethylamine, and dipropylamine), and combinations or salts thereof.[000173] An eighteenth aspect relates the system of the sixteenth or seventeenth aspect, wherein the aprotic solvent is selected from the group consisting of acetonitrile, propylene carbonate, tetrahydrofuran, acetone, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), sulfolane, y-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), and combinations thereof.[000174] A nineteenth aspect relates to the system of any preceding aspect, wherein the salt comprises an alkali metal ion or an organic cation, the alkali metal ion is formed from an alkali metal selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and francium.[000175] A twentieth aspect relates to the system of any preceding aspect, wherein the salt is selected from lithium perchlorate (LiCICh), lithium tetrafluoroborate (LiBF4), sodium chloride (NaCl), potassium chloride (KC1), cesium chloride (CsCl), or cesium perchlorate (CsCICh).[000176] A twenty-first aspect relates to the system of any preceding aspect, wherein the metal species acts as a catalyst.[000177] A twenty- second aspect relates to the system of any preceding aspect, wherein the metal species is selected from the group consisting of zinc, nickel, lead, silver, gold, tin, and combinations thereof.[000178] A twenty-third aspect relates to the system of any preceding aspect, wherein the molar ratio of the capture agent to CO2 molecule is about 1 to 1.[000179] A twenty-fourth aspect relates to the system of any preceding aspect, wherein the carbon dioxide reacts with the capture agent in the enriched composition nonaqueous electrolyte composition to produce an amine solution comprising an amine-CCh adduct, wherein the carbon dioxide is converted to carbon monoxide upon electrochemical reduction.[000180] In addition to the features mentioned in each of the independent aspects enumerated above, some examples may show, alone or in combination, the optional features mentioned in the dependent aspects and / or as disclosed in the description above and shown in the figures.

Claims

1. CLAIMS1. A method for capturing and converting carbon dioxide, the method comprising:3.contacting a source of carbon dioxide with a nonaqueous electrolyte composition, the nonaqueous electrolyte composition comprising a capture agent and an aprotic solvent, the capture agent comprising an amine, wherein the carbon dioxide reacts with the capture agent in the nonaqueous electrolyte composition to produce an amine solution comprising an amine-CO2 adduct;4.contacting the amine solution with an electrode; and5.applying an electric potential to the amine solution to convert the carbon dioxide to carbon monoxide upon electrochemical reduction.

2. The method of claim 1, wherein the amine-CCb adduct is in the form of a carbamic acid.

3. The method of claim 1, wherein the capture and the conversion of CO2 are done in a single process.

4. The method of claim 1, wherein the capture agent is selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), 1,5-diamino-3-oxapentane (DAOP), aniline (AN), piperazine (PZ), aminoacetonitrile (AAN), 3,3'-iminodipropionitrile (IDPN), 1,1 -dimethylguanidine (DMG), 2 -ethoxy ethylamine (EEA), 2-amino-2-methyl-l -propanol (AMP), 2-amino-2-methyl-l,3-propanediol (AMPD), 2-(2-aminoethoxy)ethanol (AEEA), ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), N-(2-hydroxyethyl)piperazine, morpholine, piperidine, mono-and di-Ci-Ce alkylamines (including methylamine, ethylamine, isopropylamine, dimethylamine, diethylamine, and dipropylamine), and combinations or salts thereof.

5. The method of claim 1 , wherein the aprotic solvent is selected from the group consisting of acetonitrile, propylene carbonate, tetrahydrofuran, acetone, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), sulfolane, y-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), and combinations thereof.

6. The method of claim 5, wherein the aprotic solvent is dimethyl sulfoxide.

7. The method of claim 1, wherein the nonaqueous electrolyte composition further comprises a salt, wherein the salt comprises an alkali metal ion or an organic cation, the alkali metal ion is formed from an alkali metal selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and francium.

8. The method of claim 7, wherein the salt is selected from lithium perchlorate (LiCICh), lithium tetrafluoroborate (LiBF4), sodium chloride (NaCl), potassium chloride (KC1), cesium chloride (CsCl), or cesium perchlorate (CsCICh).

9. The method of claim 1, wherein the nonaqueous electrolyte composition further comprises a metal species selected from the group consisting of zinc, nickel, lead, silver, gold, tin, and combinations thereof.

10. The method of claim 9, wherein the metal species is zinc.

11. The method of claim 9, wherein the metal species acts as a catalyst.

12. The method of claim 1, wherein the faradaic efficiency (FE) for carbon dioxide conversion to carbon monoxide is achieved at about 84% at 100 mA / cm2over 24 hours.

13. The method of claim 1, wherein the carbon dioxide is from a simulated flue gas composition comprising an oxygen content of about 3 to 17%.

14. The method of claim 13, wherein the faradaic efficiency (FE) for carbon dioxide conversion to carbon monoxide is between about 30 to 40% at 100 mA / cm2over 24 hours.

15. The method of claim 1, wherein the molar ratio of the capture agent to CO2 molecule is about 1 to 1.

16. A carbon dioxide conversion system, comprising:a gas absorber containing a nonaqueous electrolyte composition comprising a capture agent, a dissolved salt, and an aprotic solvent for producing and depositing an enriched composition in a vessel;20.a source of carbon dioxide fluidically connected to the gas absorber;21.a metal species in contact with the enriched composition; and22.a source of an electric potential in contact with the metal species,23.wherein the enriched composition comprises the nonaqueous electrolyte composition and the carbon dioxide.

17. The system of claim 16, wherein the capture agent comprises an amine selected from the group consisting of monoethanolamine (MEA), diethanolamine (DEA), diisopropanolamine (DIPA), l,5-diamino-3-oxapentane (DAOP), aniline (AN), piperazine (PZ), aminoacetonitrile (AAN), 3,3'-iminodipropionitrile (IDPN), 1,1 -dimethylguanidine (DMG), 2 -ethoxy ethylamine (EEA), 2-amino-2-methyl-l -propanol (AMP), 2-amino-2-methyl-l,3-propanediol (AMPD), 2-(2-aminoethoxy)ethanol (AEEA), ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), N-(2-hydroxyethyl)piperazine, morpholine, piperidine, mono- and di-Ci-Ce alkylamines (including methylamine, ethylamine, isopropylamine, dimethylamine, diethylamine, and dipropylamine), and combinations or salts thereof.

18. The system of claim 16, wherein the aprotic solvent is selected from the group consisting of acetonitrile, propylene carbonate, tetrahydrofuran, acetone, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), sulfolane, y-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), and combinations thereof.

19. The system of claim 16, wherein the salt comprises an alkali metal ion or an organic cation, the alkali metal ion is formed from an alkali metal selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and francium.

20. The system of claim 19, wherein the salt is selected from lithium perchlorate (LiC104), lithium tetrafluoroborate (LiBF4), sodium chloride (NaCl), potassium chloride (KC1), cesium chloride (CsCl), or cesium perchlorate (CSCIO4).

21. The system of claim 16, wherein the metal species acts as a catalyst.

22. The system of claim 16, wherein the metal species is selected from the group consisting of zinc, nickel, lead, silver, gold, tin, and combinations thereof.

23. The system of claim 16, wherein the molar ratio of the capture agent to CO2 molecule is about 1 to 1.

24. The system of claim 16, wherein the carbon dioxide reacts with the capture agent in the enriched composition to produce an amine solution comprising an amine-CCh adduct, wherein the carbon dioxide is converted to carbon monoxide upon electrochemical reduction.

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