Integrated system(s) and method for continuous electrochemical capture and reduction of CO2 from a dilution source

Abstract

In one aspect, the present disclosure relates to compositions and catalysts for substantially continuous CO capture and reduction from a source containing flue gas diluted CO 2 and the flux of captured CO 2 is substantially equal to the flux of CO reduction. The system may include an integrated CO 2 capture and reduction component. An exemplary system includes a composition of a catalyst and an electrolyte. The catalyst may include a supported or unsupported mesh electrode comprising Cu, a Cu-Al alloy, and / or copper oxide. In one aspect, the system includes one or more membranes that separate the anode side from the cathode side in the system, and the one or more membranes can be bipolar membranes, anion exchange membranes, or both, which can reduce or eliminate Cl 2 generation. In an exemplary embodiment, the value-added product may be selected from CO, CH 2 , C 2 H 4 , C 2 H 4 , C 2 H 5 OH, CH 3 COOH, CH 3 OH, C 3 H 6 , and / or H 2 .

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 63 / 332,644, filed on April 19, 2022, which is hereby incorporated by reference in its entirety.

[0002] This disclosure relates to systems and methods for the continuous electrochemical reduction of CO from dilution sources such as flue gas and air. More specifically, this disclosure relates to a fully integrated system for the continuous CO capture and processing from dilution sources, and the reduction of CO to value - added products and fuels. 2 2 2

Background Art

[0003] The increasing global energy demand has accelerated the consumption of fossil fuels, increased anthropogenic CO emissions, and caused serious environmental problems. Despite the continuous progress in the utilization of renewable energy sources such as sunlight, wind, and hydroelectric power to reduce fossil fuel consumption, they still satisfy only a small part of the current energy demand. 2

[0004] Recently, more attention has been focused on the development of additional CO capture technologies, including liquid absorption, solid adsorption, membrane separation, and cryogenic distillation. Currently, most of these technologies are limited to laboratory - scale implementation due to their low capture fluxes, adsorbent erosion and replenishment, and the high energy intensity of these processes. Liquid absorption with amine - based adsorbents such as monoethanolamine (MEA) is one of the few technologies facing large - scale implementation by retrofitting industrial plants that directly emit CO into the atmosphere. However, due to the strong MEA - CO binding, CO 2 2 2 2Releasing and recycling the MEA adsorbent requires high temperatures. This causes additional energy losses for making the absorption of MEA a continuous process. High-temperature recycling also causes solvent losses due to evaporation, thereby hindering the widespread implementation of CO 2 capture using MEA. Furthermore, since CO 2 is captured as carbamate, further utilization of the CO 2 captured by MEA is difficult. Carbamates have limited downstream uses, and it can be difficult to convert this CO 2 into value-added products unless this CO 2 is recovered in the gas phase. Therefore, there is a need to develop highly energy-efficient CO 2 capture technologies that exhibit high fluxes of CO 2 capture, which can also be integrated with CO 2 utilization technologies for synthesizing value-added products.

[0005] Therefore, there is an urgent need to develop sustainable alternatives for reducing the concentration of anthropogenic CO 2 in the atmosphere. The electrochemical reduction of CO 2 to value-added chemicals and fuels serves the urgently needed intermittent storage of renewable electricity and opens up a broader path for a closed carbon cycle process. Ethylene (C 2 H 4 ) is an essential product of the CO 2 reduction reaction (CO2RR), mainly due to its high volumetric and gravimetric energy density. Furthermore, C 2 H 4 has a significant global market size of $230 billion, most of which is due to its use in the polymer industry for synthesizing the most common plastics such as polystyrene, polyvinyl chloride, and polyethylene. The widespread use of C 2 H 4 has led to an annual carbon footprint of 862 Mt of CO 2 equivalent, the second largest CO 2 emissions after ammonia. Therefore, C2 H 4 The renewable synthesis of is of great interest to significantly reduce the impact on global warming.

[0006] CO 2 Considerable effort has been devoted to the design of various catalysts for the reduction of CO 2 The reduction of CH to form two-electron products such as CO or formic acid has even achieved faradaic efficiencies (FE) of over 90%. 4 High-electron C1 products such as also have a reported FE of about 90%. However, C0RR to multicarbon products remains challenging because C-C coupling must compete with the more favorable C-O and C-H bond formation in suppressing the hydrogen release reaction (HER) on the catalyst surface. Furthermore, C 2 H 4 Carbon-rich products such as C are formed uniquely only on Cu-based electrocatalysts. 2 H 4 Many strategies have been implemented to enhance the selectivity of Cu-based electrocatalysts for CORR. Hori et al. showed that the selectivity for CORR products is facet dependent, with Cu(100) being the most favorable for C 2 H 4 More recently, Zhang et al. used electrodeposited Cu on a gas diffusion layer (GDL) in a conventional H2 cell setup and demonstrated that C 2+ De Luna et al. used a combination of electrodeposition and sol-gel techniques to deposit Cu(0) and Cu(I) onto a GDL and demonstrated a C of 200:1. 2 H 4 / CH 4 Molar selectivity ratio of 160mA / cm 2 High C 2 H 4 The partial current density was obtained. The presence of a Cu gas diffusion electrode (GDE) with needle-like morphology and Cu(I) species was 2+ Dinh et al. designed the electrode-electrolyte interface using a highly concentrated 10 M KOH electrolyte and a Cu GDE. In such a concentrated electrolyte, the dissolved CO2 exists only in the first 120 nm of the catalyst layer, forming a sharp electrode-electrolyte interface, and C 2+ results in a high selectivity for the product. This configuration is different from the configuration observed in a 1 M KOH electrolyte where the reaction interface is more distributed with respect to the product and has low selectivity. Pulsed potential CO2RR is a relatively new strategy that has attracted attention for further enhancing the CO2RR selectivity for the product. Cu-based catalysts suffer from deactivation over time and are not stable for long-term operation. Pulsing the applied potential has been shown to suppress HER, improve the stability of the catalyst, and maintain the CO 2+ saturation. Recent studies by Tang et al. have suggested that vibration promotes the dynamic surface reconstruction of the catalyst that helps to enhance the selectivity and stability of the catalyst. However, more insights are needed to understand the effect of oscillating potentials that can help better control the selectivity of CO2RR products. 2+ saturation. Recent studies by Tang et al. have suggested that vibration promotes the dynamic surface reconstruction of the catalyst that helps to enhance the selectivity and stability of the catalyst. However, more insights are needed to understand the effect of oscillating potentials that can help better control the selectivity of CO2RR products. 2 saturation. Recent studies by Tang et al. have suggested that vibration promotes the dynamic surface reconstruction of the catalyst that helps to enhance the selectivity and stability of the catalyst. However, more insights are needed to understand the effect of oscillating potentials that can help better control the selectivity of CO2RR products.

[0007] Furthermore, most of the recent studies, although they can reach industrially relevant CO2RR currents, all of them implement a gas diffusion electrode (GDE) configuration of an electrochemical cell with gaseous products containing CO 2 in the product stream. Since the electrochemical process has a low single-pass conversion (less than 10%), the product stream still contains more than 90% CO 2 in it. This makes gas separation economically difficult and thus makes it difficult to implement such technologies on a larger scale. O'Brien et al. showed a conversion of about 85% for single-pass conversion but observed a decrease in C 2 H 4 selectivity and current density upon achieving high conversion. In addition, implementing multi-pass CO 2 conversion by looping or recycling the outgoing CO 2 and the product stream requires additional equipment and this process is not economically sustainable for long-term operation. Therefore, C 2 H 4 to promote high selectivity for and CO 2There is a need to develop a catalyst cell configuration having a product stream that does not contain. In addition, efficient integration of such a CO2RR system with a solar cell can provide an opportunity to sustainably synthesize green plastics. Due to the high full cell voltage of the Cu-based CO2RR system, such an integration scheme is rarely seen in the literature, and most of the reported solar-to-carbon (STC) efficiency is about 5%. According to the principles herein, the effect of oscillating potential on CO2RR using a 3D Cu mesh and a systematic investigation of integration with a triple junction solar cell are achieved.

[0008] To stabilize CO in the atmosphere, it is necessary to significantly reduce anthropogenic CO emissions. 2 emissions. 2 To efficiently suppress CO emissions, extensive attempts have been made to separately develop CO capture technology and CO utilization (or reduction) technology. However, there is no known current system that provides a rapid and economically feasible reduction of CO in the atmosphere. These and other needs are met by the present disclosure. 2 emissions 2 capture technology and CO 2 utilization (or reduction) technology have been made separately. However, there is no known current system that provides a rapid and economically feasible reduction of CO in the atmosphere. 2 in the atmosphere. These and other needs are met by the present disclosure. SUMMARY OF THE INVENTION

[0009] Exemplary systems herein may include compositions and catalysts for substantially continuous CO capture and reduction at near atmospheric pressure, and the flux of captured CO may be substantially equal to the flux of CO reduction. The system may include integrated CO capture and reduction components. Methods for maximizing efficiency in various flue gas environments in accordance with the principles herein may include steps of manufacturing a continuous CO capture and reduction system configured to produce high purity value-added products at a Faradaic efficiency in the range of up to 60% and a current density of up to 300 mA / cm2 in the liquid phase. Other reduction systems are contemplated in accordance with the principles herein, such as gas phase CO conversion. 2 capture and reduction, and the flux of captured CO 2 may be substantially equal to the flux of CO 2 reduction. The system may include integrated CO 2 capture and reduction components. Methods for maximizing efficiency in various flue gas environments in accordance with the principles herein may include steps of manufacturing a continuous CO 2 capture and reduction system configured to produce high purity value-added products at a Faradaic efficiency in the range of up to 60% and a current density of up to 300 mA / cm 2 2 in the liquid phase. Other reduction systems are contemplated in accordance with the principles herein, such as gas phase CO 2 conversion.

[0010] An exemplary system constructed in accordance with the principles of this specification may include a composition of catalyst and electrolyte for capture and reduction at a substantially atmospheric pressure of about 0.5 to 3 bar and a temperature range of about 20°C to 40°C, and the captured CO 2 may include a composition of catalyst and electrolyte for capture and reduction, and the proportion of the captured CO 2 is substantially equal to the rate of CO 2 reduction.

[0011] In some embodiments, an exemplary catalyst of the system includes a supported or unsupported mesh electrode including Cu, a Cu-Al alloy, at least one copper oxide, or any combination thereof, which is regenerated via a cycle of applied potential. In some aspects, the supported electrode has an aluminum support. In another aspect, the catalyst may include five or more mesh electrodes directly connected within the stack. The applied potential may be, for example, in the range of about 0.8V to -1.2V. In one aspect, the electrode has a mesh size of about 40 mesh to about 120 mesh.

[0012] In one aspect, the system includes a membrane that separates the anode side within the system from the cathode side, and the mesh electrode may be present on the cathode side within the system. In another aspect, the membrane may be a bipolar membrane, a cation exchange membrane, an anion exchange membrane, or a combination thereof. In any of these embodiments, the membrane can reduce or eliminate Cl 2 generation compared to a system without the same membrane at other points.

[0013] The catalyst(s) of the exemplary system has a higher Faradaic efficiency (about 50% to about 60%, or about 57%), and a current density of about 550 mA / cm 2 to about 600 mA / cm 2 and a current density of about 250 mA / cm 2 to about 300 mA / cm 2To provide a partial current density of ethylene, it may include five or more meshes directly connected within the stack. In some embodiments, the catalyst(s) includes at least one of the strained Cu layers having facets such as 111, 200, or 220 on copper oxide, Cu alloyed with Al, and mixed oxides of Cu, for CO 2 reduction.

[0014] Exemplary electrolytes may include alkali metal chlorides, bicarbonates, and hydroxides mixed in an electrolyte composition or other suitable electrolyte. The electrolyte composition may be, for example, an aqueous solution of an alkali chloride and an alkali bicarbonate (e.g., 0.75 M KCl, 0.025 M KHCO 3 ) containing dissolved CO 2 . In one aspect, the alkali chloride may be KCl, NaCl, or any combination thereof. In another aspect, the alkali bicarbonate may be KHCO 3 , NaHCO 3 , or any combination thereof. In certain aspects, the electrolyte may include from about 0.5 M to about 1 M alkali chloride and from about 0.01 M to about 0.03 M alkali bicarbonate, or about 0.75 M alkali chloride and about 0.025 M alkali bicarbonate. The system may be further defined by an integrated CO 2 capture and conversion device.

[0015] An exemplary method for maximizing the efficiency in various dilute CO 2 feedstock environments is to produce a continuous CO 2 capture and reduction system configured to capture CO 2 at a flux higher than 1 mmol / m2 / s with an energy of less than 120 kJ / mol using an electrodialysis unit, and generating high-purity (greater than 30%) value-added products at a Faradaic efficiency in the range of up to 60% and a current density of up to 300 mA / cm 2 in a liquid-fed electrochemical reactor. In various embodiments, the fluid connections between components may be gas or liquid, or both.

[0016] Various diluted CO 2 An exemplary method for maximizing the efficiency in the environment of the raw materials may include manufacturing a continuous CO capture and reduction system configured to capture CO at a flux higher than 1 mmol / m / s with an energy of less than 120 kJ / mol using an electrodialysis unit, and generating a high-purity (more than 10%) value-added product at a Faradaic efficiency in the range of up to 60% and a current density of up to 1000 mA / cm in a gas-fed electrochemical reactor. 2 / s, and CO 2 capturing and reduction system, and generating a high-purity (more than 10%) value-added product at a Faradaic efficiency in the range of up to 60% and a current density of up to 1000 mA / cm in a gas-fed electrochemical reactor. 2 capturing and reduction system, and generating a high-purity (more than 10%) value-added product at a Faradaic efficiency in the range of up to 60% and a current density of up to 1000 mA / cm in a gas-fed electrochemical reactor. 2 capturing and reduction system, and generating a high-purity (more than 10%) value-added product at a Faradaic efficiency in the range of up to 60% and a current density of up to 1000 mA / cm in a gas-fed electrochemical reactor.

[0017] In an exemplary embodiment, one or more value-added products may be selected from CO, CH 4 , C 2 H 4 , C 2 H 5 OH, CH 3 COOH, CH 3 OH, C 3 H 6 , H 2 , or any combination thereof. In a further aspect, in the disclosed systems and methods, the value-added product is selective for ethylene such that the C 2 H 4 to CH 4 molar selectivity ratio is about 200:1 to about 1000:1, or about 200:1 to about 500:1, or about 500:1 to about 1000:1, or at least about 200:1. In another aspect, the molar amount of C 2 H 4 relative to all other gaseous products is about 30% to about 60%, or about 30% to about 45%, about 45% to about 60%, or about 40% to about 50%.

[0018] Other systems, methods, and components constructed in accordance with the principles of this specification are equally contemplated herein and will become apparent to those of ordinary skill in the art by examining the following drawings and detailed description, or will be apparent. All such additional systems, methods, features, and advantages are included within this specification, are within the scope of the present disclosure, and are intended to be protected by the appended claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the present disclosure taught herein. Further, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments, are combinable with each other and are interchangeable.

Brief Description of the Drawings

[0019] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, but rather emphasis is placed on clearly illustrating the principles of the present disclosure. Further, in the drawings, like reference numerals designate corresponding parts throughout the several views.

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[0043] Further advantages of the present invention will be described in part in the following description, will be apparent in part from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

Mode for Carrying Out the Invention

[0044] CO in the atmosphere 2 In order to provide an integrated system and method designed for the rapid and economically feasible reduction of, integrated technologies need to develop various embodiments capable of capturing in a closed carbon cycle and reducing it to value-added products and fuels. 2

[0045] According to the principles of the present disclosure, the systems and methods herein can evaluate various individual electrochemical CO capture and electrochemical CO reduction processes, and capture CO from dilute sources such as flue gas (0.16% SO, 12.39% CO, 6.96% O, 80.49% N) and simulated flue gas (10% CO, 90% N), and achieve a functional and fully integrated continuous process for further reduction of CO to value-added products and fuels. For CO capture, a mobile-assisted moisture gradient (MAMG) is integrated into the CO capture process to capture gaseous CO as HCO in a CO-binding organic liquid, transport it across an anion exchange membrane to an aqueous solution under an electric field, and HCO, CO, and CO 2 capture 2 2 2 2 2 2 2 2 capture 2 2 capture 2 2 2 3 - 3 - 2 ​3 2- By equilibration between them, in the presence of a water-rich environment, the dissolved CO 2 was converted. For CO 2 reduction, an electrochemical cell configuration for the extraction without CO 4 of reduction gas-like products such as CO, CH 2 H 4 and C 2 as well as liquid products such as ethanol, propanol, and formic acid on a Cu mesh catalyst was developed. The successful integration of these continuous CO 2 capturing and reduction processes to value-added products with a Faradaic efficiency of about 57% was achieved. 2

[0046] CO 2 utilization technologies should always complement CO 2 capturing technologies to promote a decarbonized economy. To convert CO 2 into value-added products and fuels, various thermochemical, photochemical, biochemical, and electrochemical technologies have been recently developed. The electrochemical reduction of CO 2 is desirable among other CO 2 utilization technologies due to its high reaction rate, high control over product selectivity, relatively mild operating conditions, and excellent potential for large-scale industrial applications.

[0047] Furthermore, the availability of inexpensive electrons (i.e., electricity that is not expensive and is abundant) makes the further development of the electrochemical CO 2 reduction reaction (CO2RR) even more advantageous at present. CO2RR can be used to synthesize various fuels and value-added products such as syngas, HCOOH, CH 4 , C 2+ products (C 2 H 4 , C 2 H 5 OH, etc.) as the industrial-scale implementation of this process is desirable. However, gaseous CO 2Most of these electrochemical systems with supply have low single-pass conversion (less than 10%), and the outlet of the gaseous product still contains more than 90% CO 2 . This results in additional costs for separating CO 2 from the product stream and hinders the scale-up of new technologies. Therefore, the development of the configuration of an electrocatalyst-electrochemical cell for efficient CO2RR with a product stream free of CO 2 is of utmost importance.

[0048] CO 2 capture and the integration of the CO 2 utilization (or reduction) process, the proportion of the captured CO 2 must be at least equal to the proportion of CO 2 reduction. This state is that the depletion of the concentration due to an insufficient CO 2 capture process may seriously affect the performance of the CO 2 reduction process and, as a result, may reduce the efficiency of the complete integration process. Therefore, it is necessary for the development of a high-throughput and continuous integrated CO 2 capture and reduction system.

[0049] CO 2 capture has been integrated with the CO 2 reduction process in several attempts, but most of the processes are either very energy-intensive or act in discontinuous cycles of CO 2 capture and reduction. According to the principles herein, exemplary systems and methods are described that systematically address all of the above issues regarding the capture, reduction, and integration of the two processes of CO 2 . Herein, CO 2 (from simulated flue gas, 90% N 2 , 10% CO 2 ) can be captured in a CO 2 binding organic liquid and, in the presence of an electric field, dissolved CO 2 , HCO 3 - , and CO3 2- and can be transported to an aqueous medium at neutral pH, a high-flux electrochemical CO 2 capture technology is described.

[0050] The captured CO 2 migration can occur through the interconversion of CO 2 , HCO 3 - and CO 3 2- in the presence of a water gradient between the aqueous and organic media. The CO 2 capture technology is mobile-assisted moisture gradient (MAMG) CO 2 capture. For an exemplary CO 2 capture system, controlled CO 2 removal from the aqueous medium can be emulated by injecting a fresh 0.1 M KOH solution that increases the pH of the aqueous medium by removing dissolved CO 2 and determining the flux of CO 2 capture. A CO2RR electrochemical cell can be developed using a Cu mesh electrocatalyst to extract gaseous products free of CO 2 . In this CO2RR system, controlled CO 2 addition can be emulated by spraying CO 2 onto the electrolyte at different flow rates to determine the flux of CO 2 removal. By integrating the CO 2 capture and CO 2 reduction processes, the need for auxiliary CO 2 storage facilities and associated energy losses is eliminated. Therefore, these two capture and reduction processes can be integrated and used to demonstrate a fully functional integrated CO 2 capture and reduction system.

[0051] Those skilled in the art having the benefit of the teachings presented in the foregoing description and the associated drawings will envision many modifications and other embodiments of the disclosed compositions and methods. Accordingly, it is to be understood that the disclosure is not limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Those skilled in the art will recognize many variations and adaptations of the aspects described herein. These variations and adaptations are intended to be included within the teachings of this disclosure and are intended to be encompassed by the claims of this specification.

[0052] Certain terms are used herein, but they are used only in a general and descriptive sense and not for purposes of limitation.

[0053] As will be apparent to those skilled in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein can be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the disclosure.

[0054] Any recited method can be performed in the order of the recited events or in any other order that is logically possible. That is, unless expressly stated otherwise, it is never intended that any method or aspect described herein be construed as requiring that its steps be performed in a particular order. Accordingly, method claims are never intended to imply order in any respect where the steps are not specifically described in the claims or specification as being limited to a particular order. This holds for any possible non-explicit basis for interpretation, including the arrangement of steps or operational flow, the plain meaning derived from grammatical construction or punctuation, or logical matters regarding the number or type of aspects described in the specification.

[0055] All publications mentioned in this specification are hereby incorporated by reference herein to disclose and describe the methods and / or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publications by virtue of prior invention. Further, the dates of the publications provided herein may be different from the actual publication dates, which may require independent confirmation.

[0056] Aspects of the present disclosure may be described and claimed in a specific statutory class such as a statutory class, but this is for convenience only, and one of ordinary skill in the art will understand that each aspect of the present disclosure may be described and claimed in any statutory class.

[0057] Also, it should be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed compositions and methods belong. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning that coincides with the meaning in the context of the present specification and the relevant art and are not to be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0058] Before describing various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure.

[0059] Definitions As used herein, "comprising" is to be interpreted as specifying the presence of the features, integers, steps, or components described as such, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Further, each of the terms "by", "comprising", "comprises", "comprised of", "including", "includes", "included", "involving", "involves", "involved", and "such as" is used in its open-ended non-limiting sense and can be used interchangeably. Further, the term "comprising" is intended to include examples and aspects subsumed by the terms "consisting essentially of" and "consisting of". Similarly, the term "consisting essentially of" is intended to include examples subsumed by the term "consisting of".

[0060] As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, references to "a catalyst", "copper oxide", or "an electrolyte" include mixtures or combinations of two or more such catalysts, copper oxides, or electrolytes, but are not limited thereto.

[0061] It should be noted that ratios, concentrations, amounts, and other numerical data may be expressed in range format in this specification. It will be further understood that each endpoint of a range is significant both in relation to and independent of the other endpoints. There are several values disclosed in this specification, and it is understood that each value, in addition to the value itself, is also disclosed herein as "about" that particular value. For example, if the value "10" is disclosed, "about 10" is also disclosed. In this specification, a range can be expressed as from "about" a particular value and / or to "about" another particular value. Similarly, when a value is expressed as an approximate value by use of the antecedent "about", it is to be understood that the particular value forms a further aspect. For example, if the value "about 10" is disclosed, "10" is also disclosed.

[0062] When a range is recited, further aspects include from a particular value and / or to another particular value. For example, if the recited range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure. For example, the phrase "x to y" includes the range from "x" to "y" as well as the range greater than "x" and less than "y". A range may also be expressed with an upper limit, for example, as "about x, y, z, or less", and is to be interpreted as including the specific ranges of "about x", "about y", and "about z", as well as the ranges "less than x", "less than y", and "less than z". Similarly, the phrase "about x, y, z, or more" is to be interpreted as including the specific ranges of "about x", "about y", and "about z", as well as the ranges "greater than x", "greater than y", and "greater than z". In addition, when "x" and "y" are numerical values, the phrase "about "x" to "y"" includes from about "x" to about "y".

[0063] Such a range format is used for convenience and brevity and thus should be interpreted flexibly to include not only the explicitly recited numerical values as the limits of the range, but also all individual numerical values or sub-ranges subsumed within that range as if each numerical value and sub-range were explicitly recited. By way of illustration, a numerical range of “about 0.1% to 5%” should be interpreted to include not only the explicitly recited values of about 0.1% to about 5%, but also the individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and sub-ranges (e.g., about 0.5% to about 1.1%, about 5% to about 2.4%, about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range.

[0064] As used herein, the terms “about,” “approximately,” “substantially,” and “essentially” mean that the quantity or value in question could be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, quantities, sizes, formulations, parameters, and other quantities and features are not exact and need not be exact, but may be approximations that reflect tolerances, conversion factors, rounding, measurement errors, and other factors known to those of skill in the art, and / or may be greater or less, as desired, such that equivalent results or effects are obtained. In some situations, the value providing equivalent results or effects cannot be reasonably determined. In such cases, “about” and “substantially” are generally understood to mean a nominal value indicating a variation of ±10% unless otherwise indicated or implied. Generally, a quantity, size, formulation, parameter, or other quantity or feature is “about,” “approximately,” or “substantially” whether or not so expressly described. When “about,” “approximately,” or “substantially” is used before a quantitative value, the parameter is also understood to include the specific quantitative value itself unless otherwise specifically described.

[0065] As used herein, the terms "optional" or "optionally" mean that the subsequent recited event or circumstance may or may not occur, and that both an example in which the event or circumstance occurs and an example in which it does not occur are included herein.

[0066] Unless otherwise indicated, the temperatures referred to herein are based on atmospheric pressure (i.e., 1 atmosphere).

[0067] Although aspects of the present disclosure have been described herein, generally, the following examples describe some additional aspects of the present disclosure. The aspects of the present disclosure are described in connection with the following examples and corresponding text and figures, but there is no intention to limit the aspects of the present disclosure to this specification. On the contrary, the intention is to cover all alternatives, modifications, and equivalents that are within the spirit and scope of the present disclosure.

Example

[0068] The following examples are set forth to provide those skilled in the art with a complete disclosure and description of how the compounds, compositions, articles, devices, and / or methods claimed herein are made and evaluated, and are intended purely as examples of the present disclosure and are not intended to limit the scope of what the inventors regard as their disclosure. Although efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperatures, etc.), some error and deviation should be accounted for. Unless otherwise specified, parts are parts by weight, temperature is in °C or at ambient temperature, and pressure is at or near atmospheric pressure.

[0069] Example 1: Mobile-Assisted Moisture Gradient (MAMG) CO 2 Process Outline of Capture Experimental Method As shown in Figure 1A, the MAMG experiment was carried out on a custom 3D printed electrochemical cell. The electrochemical cell contained a 2×2 cm Cu-coated Al mesh (#120 mesh, FindProLabs, Zhejiang) as the cathode and carbon paper (190 μ Toray 060, Fuel Cell Store) as the anode. On the organic side, ethylene glycol (EG) and choline hydroxide (ChOH) or choline chloride (ChCl) in a 1:0.05 (V / V) EG:ChOH ratio acting as a combined organic liquid (CO2BOL), consisting of a 1.25 M KOH saturated solution. ChOH is a 45 wt% solution of ChOH in methanol. A simulated flue gas of 10% CO 2 and 90% N 2 was sprayed into the CO2BOL reservoir. On the aqueous side, it consisted of a 25% 0.1 M KHCO 2 and 75% 1 M KCl (V / V%) electrolyte pre-equilibrated with CO 2 at a pH of 7.4. SnowPure Excellion A200 AEM separated the aqueous side and the organic side. The solutions on the aqueous side and the organic side were recirculated using a ColeParmer MasterFlex multi-drive peristaltic pump. The MAMG experiment was started by applying a constant current using an Eventek 32V / 10A DC power supply. The concentration of dissolved CO 3 moving from the organic side to the aqueous side was monitored as a function of the pH of the aqueous electrolyte using a Thermo Orion Star Versa Star Pro. 2 Controlled CO

[0070] removal 2 experiments were conducted to determine the CO removal flux (and as a result, the CO 2 capture rate). When the pH on the aqueous side reached maximum CO 2 saturation in the steady state, a fresh supply of 0.1 M KOH (pH = 13) was injected into the aqueous reservoir at different flow rates from 20 to 160 μL / min to remove CO 2 from the aqueous solution. 2 When the pH on the aqueous side reached maximum CO 2Emulate the removal. Remove the electrolyte in the aqueous reservoir at the same flow rate as fresh KOH enters to prevent accumulation in the aqueous reservoir. Continuously stir the aqueous reservoir using magnetic stirring to ensure sufficient mixing of the solution. Monitor the increase in pH using a pH probe in the aqueous reservoir until a new steady state is reached at a higher pH. At this pH, the rate of CO 2 capture from the MAMG experiment must be equal to the rate of CO 2 removal from the controlled removal experiment.

[0071] Electrochemical CO2RR The CO2RR experiments were carried out in an exemplary custom 3D printed electrochemical cell as seen in Figure 1B. A 1×1 cm Cu-coated Al mesh (99.9% Cu coating, FindProLabs, Zhejiang) was used as the working electrode together with an Ag / AgCl micro reference electrode (Innovative instruments inc.), and Pt (99.99% ACI alloy) was used as the counter electrode. The working and counter compartments of the electrochemical cell were separated by an ion exchange separator, e.g., SnowPure Excellion A200 AEM. The exemplary electrolyte used in the CO2RR experiments was the same as the aqueous electrolyte in the MAMG experiments to enable seamless integration between the two processes. The electrochemical experiments were carried out using a BioLogic SP300 potentiostat at various reduction currents in the range of 10 - 700 mA / cm 2 . Each experiment was run for 1 hour, and Ar was used as the sweep gas in the headspace of the working compartment to entrain the CO2RR product gas, which was quantified at 15-minute intervals by an SRI 8610C MG#5 gas chromatograph (GC). At the end of each experiment, 1 ml of the electrolyte was sampled into a vial, and the liquid CO2RR products were quantified using an Agilent 1260 Infinity II high-pressure liquid chromatography (HPLC).

[0072] Controlled CO 2 addition Controlled CO2 Performed addition experiments to CO 2 Determined the addition flux (and as a result, CO 2 removal). First, the electrolyte was sprayed with pure CO at a high flow rate of 100 sccm to saturate the dissolved concentration of CO in the electrolyte ([CO 2 =33 mM, pH ~ 6.19). Then, the CO 2 spray flow rate was reduced to 10 - 30 sccm. Next, CO2RR experiments were performed at various reduction currents. For CO2RR on a Cu-based catalyst, at such a low CO 2 spray flow rate, the CO 2 concentration depletes faster, which is monitored by observing the change in pH of the electrolyte reservoir. At steady state, the pH stabilizes and the flux of CO2RR is equal to the flux of CO 2 addition. 2 concentration depletion, which is monitored by observing the change in the pH of the electrolyte reservoir. At steady state, the pH stabilizes and the flux of CO2RR is equal to the flux of CO 2 addition.

[0073] Integrated CO 2 Capture and Reduction Integrated CO 2 Performed capture and reduction experiments to demonstrate the feasibility of seamless integration between the MAMG CO 2 capture technology and electrochemical CO2RR. The custom 3D printed setup from MAMG CO 2 capture and CO2RR, as seen in Figure 1C, was arranged such that both the CO 2 capture and CO2RR units shared the aqueous electrolyte. The MAMG unit was maintained at a constant mobile current of 75 mA, and the CO2RR unit was operated at a constant reduction current density of 25 mA / cm 2 . The pH of the aqueous electrolyte was monitored using a pH probe, and once steady state was reached, the product distribution of CO2RR was measured using GC and HPLC.

[0074] CO2RR and Controlled CO 2 Addition Experiments The CO2RR experiments were carried out in an electrochemical cell as shown in Fig. 1B. The reduction was carried out for 1 hour at a constant current, and the gaseous products generated were monitored at 15-minute intervals using a GC, and the liquid products were measured at the end of each experiment using an HPLC. First, the CO2RR efficiency at different CO 2 concentrations was evaluated. This is done theoretically because CO2RR is most efficient in a CO 2 -saturated electrolyte. However, if the CO2RR unit is integrated with a CO 2 capture unit, it has to operate using the CO 2 concentration determined by the CO 2 capture unit. Since the CO2RR unit has to be part of the integration process, it is important to evaluate the CO2RR efficiency at different concentrations of dissolved CO 2 .

[0075] Figs. 4A - 4C show the product distribution as a function of pH at different reduction current densities. Since the solubility of CO in an aqueous medium depends on its partial pressure according to Henry's law, CO was sparged into the aqueous electrolyte at different partial pressures of 100 sccm to keep the pH constant. Figs. 4A - 4C show that CO2RR functions best at a low pH of 6.2 where the electrolyte is saturated with CO 2 . Since extensive investigations have been carried out on similar CO2RR systems containing a CO 2 -saturated electrolyte, these results are comparable to some of the results reported in the literature. CO2RR shows a Faradaic efficiency (FE) of 66.4% for C 2 H 2 , CO, and CH4 for all three current densities at pH 6.2 and a hydrogen evolution reaction (HER) of 33.6%. As the pH increases, less CO 2 H 4 is produced. As the pH increases, less CO 2becomes available for CO2RR, the CO2RR FE decreases and HER becomes more dominant. Above pH 9.2, the CO2RR FE is almost negligible (<5%) and the electrochemical cell shows almost exclusively HER above 95%. The FE of CO2RR at various reduction current densities and pHs is a measure of the rate of consumption of CO from the aqueous electrolyte and can be calculated as follows: 2 is a measure of the rate of consumption of CO2 from the aqueous electrolyte and can be calculated as follows: [Number] where R CO2 consumption (mmol / s) is the rate of consumption of CO from CO2RR, I 2 is the partial current density of the i-th CO2RR product, A = 1 cm i 2 is the area of the electrode, n 2 is the number of electrons transferred per mole of CO2 consumed for the CO2RR product. Understanding the integration of this CO2RR system with the CO 2 capture unit was the next step in developing a fully integrated setup. This was done by using a pseudo-integrated system for CO2RR with controlled addition of CO i . Controlled addition of CO 2 was carried out by sparging pure CO 2 at different flow rates in the aqueous electrolyte. By sparging pure CO 2 , it is ensured that given sufficient time, the solution reaches CO

[0076] saturation without CO 2 consumption. In such experiments, the solubility is not limited by the partial pressure of CO 2 , but the rate of addition of CO 2 depends on mass transfer at the gas-liquid interface. Thus, at higher CO 2 sparging flow rates, as seen in Figure 5A, the pH of the electrolyte is affected by enhanced mass transfer and CO 2 2 2 2 2 ​​​​The increased availability results in a faster decline and a more rapid saturation. When the pH is high, the pH decline is relatively rapid, and the CO 2 concentration begins to plateau as it reaches saturation in the aqueous electrolyte. This indicates that the rate of CO 2 addition is not constant and changes over time. The rate of CO 2 addition (R CO2 addition ) can be determined as follows:

Equation

[0077] Starting from a CO 2 saturated electrolyte at pH 6.2, these pseudo-integration experiments were performed by varying the rate of CO 2 sparging at different CO2RR current densities. Figures 5B - 5D show the effect of flow rate on the steady-state pH at different CO2RR current densities. When the rate of CO 2 sparging is low, the steady-state pH is high because the rate of initial CO 2 consumption is higher than the rate of CO 2 addition. Since CO 2 consumption also depends on pH, the rate of CO 2 consumption decreases as the pH increases, and a plateau is reached at the steady state. At higher CO 2 sparging flow rates, the steady-state pH is close to saturation. As the CO2RR current density increases, the partial current density of all CO2RR products formed increases, so the CO 2 consumption flux also increases. This is seen in Figures 5C - 5D at higher CO2RR current densities for a given CO 2Results in an increase in the steady-state pH with respect to the sparging flow rate. The net CO removed from this pseudo-integrated setup 2 can be determined as follows.

Equation

[0078] The results of CO2RR with controlled addition are better understood from the perspective of operating lines similar to those created for the MAMG CO 2 capture process with controlled CO 2 removal. These operating lines are shown in Fig. 5E. Since the rate of CO 2 consumption is lower, at a low CO2RR current density of 25 mA / cm 2 the operating line extends to a lower pH range. The pH is near saturation at a high CO 2 sparging flow rate of 20 sccm and increases to a higher value at a CO 2 sparging flow rate of 5 sccm. A similar trend is seen in the operating lines at 50 and 75 mA / cm 2 . These operating lines complement the operating lines generated for MAMG CO 2 capture with controlled CO 2 removal.

[0079] Integrated CO 2 capture and reduction The MAMG CO 2 capture process system is integrated with the CO2RR unit, as seen in Fig. 1C, and both the capture system and the reduction system share an aqueous electrolyte. The simulated flue gas sparged on the organic side of the capture unit is converted to HCO 3 - and transported across the AEM / BPM to the aqueous side as dissolved CO 2 , HCO 3 - , and CO 3 2- . The CO2RR unit then utilizes the dissolved CO 2 to convert CO 2 to CO, HCOOH, CH4 , C 2 H 4 , C 2 H 5 OH, and C 3 H 7 OH and other value-added products and fuels. To continuously implement the integrated CO 2 capture and reduction process properly, the CO 2 capture flux from the capture unit and the CO 2 consumption flux from the reduction unit need to be matched. The operating lines obtained from the individual CO 2 capture (Figure 3D) and CO2RR processes (Figure 5E) provide this information and are merged in Figure 6A. The intersection of any of these curves indicates that at a given transfer current for CO 2 capture and the current density of CO2RR, the rate of CO 2 capture is equal to the rate of CO 2 consumption. Also, the pH of the aqueous electrolyte that defines the product selectivity of CO2RR is determined. CO2RR functions best at a pH close to 6.2. Therefore, the integrated CO 2 capture and reduction process needs to operate near a pH of 6.2. This can be achieved by operating the CO 2 capture process at a high transfer current and the CO2RR process at a low reduction current density. The integrated CO 2 capture and reduction process must be noted to operate in a range where the rate of CO 2 capture is greater than or equal to the rate of CO 2 consumption. If the rate of CO 2 consumption is higher than the rate of CO 2 capture and the electrochemical CO2RR process operates, the concentration of CO 2 in the common aqueous reservoir will always be low, showing a dominant hydrogen evolution reaction (HER). When the integrated setup operates at a rate of CO 2 capture higher than the rate of CO 2 consumption, the electrochemical CO2RR process is the maximum CO 2will be utilized. Within the experimental domain, the MAMG CO operating with a mobile current of 75 mA 2 capture and CO2RR with a reduction current density of 25 mA / cm 2 intersection occurs at a pH of approximately 6.75. The fully integrated CO 2 capture and reduction system operates under these conditions and the pH change was observed over time. From Figure 6B, it can be seen that the pH increases from 6.2 and approaches stability at pH 6.71 after the system reaches a steady state. The steady state pH of the fully integrated experiment is close to the pH predicted by the operating line. This similarity further clarifies the importance and reliability of the process operating line for the CO 2 capture and reduction processes.

[0080] This more realistic implementation of the integrated CO 2 capture and reduction process can be seen by understanding the influence of impurities typically present in flue gas emissions from coal-fired power plants such as O 2 and SO x . The influence of impurities on the MAMG CO 2 capture unit is responsible for maintaining a stable concentration of CO for the CO2RR unit, it is essential to observe the performance of the MAMG CO 2 capture process using realistic flue gas. The influence of impurities on MAMG CO 2 capture can be seen in Figure 6C. Realistic flue gas contains an approximate composition of 70% N 2 , 19% O 2 , 10% CO 2 , and less than 1% SO 2 . It can be seen that the performance of MAMG in the presence of impurities is approximately the same as that of the impurities. The MAMG CO x capture process enables the selective capture of CO 2 and HCO 2 3 - ​Due to the high affinity of the organic phase for that conversion, it is a robust technology in the presence of contaminants. The CO2RR product distribution as a function of time for this fully integrated experiment can be seen in Figure 6D. First, the pH is nearly saturated as seen in Figure 6B, and thus it has the highest concentration of CO 2 It has. The CO2RR efficiency is up to about 64% FE for CO2RR. According to the steady state predicted from the operating line, the pH must stabilize at about 6.75. As the system approaches the steady state, the pH increases. At 20 minutes, the pH of the solution approaches 6.5 and the CO2RR FE decreases to about 57%. As time passes, the pH further plateaus around 6.71, and thus there are no significant changes in FE observed at 40 minutes and 80 minutes. The CO2RR efficiency at steady state is 57.75%.

[0081] According to the principles of this specification, a systematic protocol for underrating and establishing a fully integrated CO 2 capture and reduction system is described. The Moving Assisted Moisture Gradient (MAMG) CO 2 capture process is benchmarked, and CO 2 from simulated flue gas is chemically adsorbed as HCO 2 in a CO 3 - -binding organic liquid of KOH-saturated ethylene glycol and choline hydroxide. This HCO 3 - is transported to the aqueous side across an anion exchange membrane, where it is converted to dissolved CO 3 - in the presence of a water-rich environment by the equilibrium interconversion between CO 2 and CO 3 2- . The concentration of dissolved CO 2 was determined by monitoring the pH of the aqueous electrolyte. A pseudo-integrated process with controlled CO 2 removal was incorporated by injecting a fresh feed of KOH at various flow rates, and the MAMG CO 2 2 ​Process operating lines for capture were generated. These operating lines showed the rate of CO removal at various moving currents. Second, the electrochemical CO2RR process was benchmarked by evaluating the CO2RR efficiency for different electrolyte pHs. A pseudo-integration process with controlled CO addition was incorporated by spraying pure CO into the electrolyte at various flow rates to generate operating lines for CO2RR. These operating lines showed the net CO removal rate from the CO2RR process at various CO reduction current densities. Finally, for the success and continuous integration of the MAMG CO capture and the electrochemical CO2RR process, the operating point must be at or near the intersection of the operating lines from both processes. This hypothesis was tested by performing a fully integrated experiment at a moving current of 75 mA for the MAMG CO capture unit and a reduction current density of 25 mA / cm2 for the CO2RR unit. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Removal rates were shown for different moving currents. Second, the electrochemical CO2RR process was benchmarked by evaluating the CO2RR efficiency for different electrolyte pHs. A pseudo-integration process with controlled CO addition was incorporated by spraying pure CO into the electrolyte at various flow rates to generate operating lines for CO2RR. These operating lines showed the net CO removal rate from the CO2RR process at various CO reduction current densities. Finally, for the success and continuous integration of the MAMG CO capture and the electrochemical CO2RR process, the operating point must be at or near the intersection of the operating lines from both processes. This hypothesis was tested by performing a fully integrated experiment at a moving current of 75 mA for the MAMG CO capture unit and a reduction current density of 25 mA / cm2 for the CO2RR unit. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Addition was incorporated by spraying pure CO into the electrolyte at various flow rates to generate operating lines for CO2RR. These operating lines showed the net CO removal rate from the CO2RR process at various CO reduction current densities. Finally, for the success and continuous integration of the MAMG CO capture and the electrochemical CO2RR process, the operating point must be at or near the intersection of the operating lines from both processes. This hypothesis was tested by performing a fully integrated experiment at a moving current of 75 mA for the MAMG CO capture unit and a reduction current density of 25 mA / cm2 for the CO2RR unit. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Was sprayed into the electrolyte at various flow rates to generate operating lines for CO2RR. These operating lines showed the net CO removal rate from the CO2RR process at various CO reduction current densities. Finally, for the success and continuous integration of the MAMG CO capture and the electrochemical CO2RR process, the operating point must be at or near the intersection of the operating lines from both processes. This hypothesis was tested by performing a fully integrated experiment at a moving current of 75 mA for the MAMG CO capture unit and a reduction current density of 25 mA / cm2 for the CO2RR unit. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Reduction current density showed the net CO removal rate from the CO2RR process. Finally, for the success and continuous integration of the MAMG CO capture and the electrochemical CO2RR process, the operating point must be at or near the intersection of the operating lines from both processes. This hypothesis was tested by performing a fully integrated experiment at a moving current of 75 mA for the MAMG CO capture unit and a reduction current density of 25 mA / cm2 for the CO2RR unit. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Removal rate from the CO2RR process. Finally, for the success and continuous integration of the MAMG CO capture and the electrochemical CO2RR process, the operating point must be at or near the intersection of the operating lines from both processes. This hypothesis was tested by performing a fully integrated experiment at a moving current of 75 mA for the MAMG CO capture unit and a reduction current density of 25 mA / cm2 for the CO2RR unit. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Capture and the success and continuous integration of the electrochemical CO2RR process, the operating point must be at or near the intersection of the operating lines from both processes. This hypothesis was tested by performing a fully integrated experiment at a moving current of 75 mA for the MAMG CO capture unit and a reduction current density of 25 mA / cm2 for the CO2RR unit. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Capture unit was 75 mA of moving current, and for the CO2RR unit was 25 mA / cm2 of reduction current density, by performing a fully integrated experiment. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Of reduction current density, by performing a fully integrated experiment. The pH at the intersection from the operating lines was about 6.75, but the actual steady-state pH from the experiment was 6.71. Since the actual pH was close to the pH predicted by the intersection of the operating lines, the initial hypothesis was supported. Furthermore, integration experiments were performed using a more realistic flue gas containing impurities such as O and SO. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 And SO x Such as impurities were used to perform integration experiments. The MAMG CO capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Capture process showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Affinity showed the same performance regardless of the presence of impurities due to the high CO affinity of the organic phase. The fully integrated CO capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Capture and reduction showed a steady-state CO2RR FE of about 57%. Such systematic and individual evaluation of the integration and scale-up of the CO capture and CO reduction processes. 2 Capture and CO 2 Reduction process such systematic and individual evaluation of the integration and scale-up.

[0082] Example 2: Experimental Method The following exemplary details of the materials and chemicals used to obtain the results herein, exemplary CO2 3D printing and fabrication of an electrochemical cell used in both the capture and reduction processes, and CO 2 Exemplary GC and HPLC methods for quantifying the reduction products.

[0083] Materials Table 1 shows CO 2 A list of all exemplary consumables used in the capture and reduction experiments, their purities, and sources. [Table 1]

[0084] Fabrication of the device Exemplary MAMG CO 2 3D models of the different parts of the exemplary MAMG CO capture setup and the exemplary CO2RR setup were designed in SolidWorks® (2018, Dassault Systems) and then 3D printed using a stereolithography (SLA) 3D printer (Form 2, Formlabs Inc., USA). An optically transparent microfluidic device with a lateral resolution of 150 μm and an axial resolution of 25 μm was 3D printed using a transparent FLGPCL02 resin activated by a 405 nm laser. The transparent resin was chemically resistant to a wide range of solvents over a pH range of 0 - 14. The printed parts were washed in an isopropyl alcohol (IPA) (90%, Sigma-Aldrich) bath in Form Wash (Formlabs Inc., USA) for 20 minutes to remove resin residues from the outer surface. The 3D printed device after washing was finished by removing the support and curing it in Form Cure for 20 minutes. (Formlabs Inc., USA). The light transparency of the 3D printed ED device was improved by wet sanding using 400 - 12000 grit pads followed by spray painting of the resin.

[0085] Product distribution analysis for CO2RR CO2RR products were quantified using chromatography techniques. H 2, CO, CH 4 and C 2 H 4 Gaseous products generated from CO2RR such as HCOOH, C 2 H 5 OH, and liquid products such as C 3 H 7 OH were quantified using high performance liquid chromatography (HPLC).

[0086] GC: Gaseous products were quantified using an SRI 8610C GC MG#5. Gaseous products generated were detected by passing the outlet from the electrochemical cell to the GC through argon as the carrier gas at 15 - minute intervals, and product detection was carried out via a thermal conductivity detector (TCD) and a flame ionization detector (FID). The product gas in the GC was passed through two size - exclusion columns, Mol - sieve 8A and HaySep D. HaySep D efficiently separates larger molecules such as C 2 H 4 . Smaller molecules such as H 2 (from HER), CO, and CH 4 were separated through Mol - sieve 8A. Hydrocarbons were detected using FID, and non - hydrocarbon products were detected using TCD.

[0087] HPLC: Quantification of the liquid products of CO 2 reduction was carried out on an Agilent Infinity 1260 II HPLC using a 300 mm × 7.5 mm Agilent Hi - plex - H column and a refractive index detector (RID). Isocratic elution of the mobile phase with 1 mM H 2 SO 4 was established at 0.6 mL / min. The column temperature was set at 60 °C and the RID temperature was set at 35 °C. For each sample analysis with a total run time of 30 minutes, 10 μL of the sample was injected into the system via an autosampler. This operating method ensures that none of the peaks overlap with each other at the shortest run time, for the retention time of the electrolyte and possible CO2 Reduction products: HCOOH, HCHO, CH 3 OH, CH 3 COCH 3 , CH 3 COOH, C 2 H 5 OH, and C 2 H 2 O 4 was developed by observing.

[0088] Mobile support moisture gradient CO 2 Principle of operation of the capture process Figure 7 shows a detailed schematic of the overall process. CO 2 is sprayed on the organic side, where it is chemically absorbed by the 1.2 M KOH solution in CO2BOL to form HCO 3 - . The anion exchange membrane (AEM) separates the organic side from the aqueous phase and initially contains 0.1 M KOH. The separation of the organic side and the aqueous side generates a moisture gradient across the AEM, which drives the initial diffusion of HCO 3 - across the AEM. In other embodiments, a bipolar membrane (BPM) can be used instead of the AEM. The bipolar membrane can be configured to maintain or preserve chloride ions on both sides of the membrane.

[0089] On the aqueous side, the diffused HCO 3 - is converted to CO 2 and CO 3 2- , thereby reducing the pH of the alkaline aqueous medium. This moisture gradient promotes the movement of HCO 3 - and is accelerated by establishing an electric field across the device. The carbon paper cathode on the organic side is supplied with humidified N 2 and acts as a gas diffusion electrode for reducing water to H 2 and functions as a steady source for generating OH - , thereby increasing CO 2 uptake. The aqueous side is the anode, and HCO 3 -Attract ions and further increase the transfer rate of HCO and CO release on the aqueous side. 3 - and CO 2 release.

[0090] MAMG CO 2 Evaluation of mass transfer limitations in the capture process The MAMG process has the following four consecutive processes - i) Absorption of CO: Mass transfer of CO from bubbles into the organic solution, ii) Formation of HCO: Reaction of the absorbed CO with OH to generate HCO, and iii) Transfer of HCO: Transfer of HCO from the organic matter to the aqueous solution, and iv) Hydrolysis of HCO: Reaction of HCO and H O to release CO. Acid-base reactions such as the formation and hydrolysis of HCO (processes ii and iv) are usually very fast. Here, the limiting process can be either the absorption of CO or the transfer of HCO. To identify the limiting process, the inventors compared the rate of CO absorption in the organic solution (i.e., process i) with the rate of CO transfer (i.e., process iii). The rate of CO absorption in the MAMG process was obtained from previously published data. Data on the rate of CO removal (or transfer) are already provided in Figure 6A. From Figure 9, it is observed that the rate of CO absorption is much higher than the rate of CO removal from the organic solution. That is, CO 2 Absorption: CO 2 from bubbles into the organic solution, ii) Formation of HCO: HCO 3 - formation: HCO 3 - formed by the reaction of the absorbed CO 2 with OH - and iii) Transfer of HCO: HCO 3 - transfer from the organic matter to the aqueous solution, and iv) Hydrolysis of HCO: HCO 3 - transfer and iv) Hydrolysis of HCO: HCO 3 - hydrolysis: CO 2 released by the reaction of HCO 3 - and H 2 O. Acid-base reactions such as the formation and hydrolysis of HCO (processes ii and iv) are usually very fast. Here, the limiting process can be either the absorption of CO or the transfer of HCO. To identify the limiting process, the inventors compared the rate of CO absorption in the organic solution (i.e., process i) with the rate of CO transfer (i.e., process iii). The rate of CO absorption in the MAMG process was obtained from previously published data. Data on the rate of CO removal (or transfer) are already provided in Figure 6A. From Figure 9, it is observed that the rate of CO absorption is much higher than the rate of CO removal from the organic solution. That is, CO 3 - formation and hydrolysis (processes ii and iv) and other acid-base reactions are usually very fast. Here, the limiting process can be either the absorption of CO or the transfer of HCO. To identify the limiting process, the inventors compared the rate of CO absorption in the organic solution (i.e., process i) with the rate of CO transfer (i.e., process iii). The rate of CO absorption in the MAMG process was obtained from previously published data. Data on the rate of CO removal (or transfer) are already provided in Figure 6A. From Figure 9, it is observed that the rate of CO absorption is much higher than the rate of CO removal from the organic solution. That is, CO 2 absorption or HCO 3 - transfer. To identify the limiting process, the inventors compared the rate of CO absorption in the organic solution (i.e., process i) with the rate of CO transfer (i.e., process iii). The rate of CO absorption in the MAMG process was obtained from previously published data. Data on the rate of CO removal (or transfer) are already provided in Figure 6A. From Figure 9, it is observed that the rate of CO absorption is much higher than the rate of CO removal from the organic solution. That is, CO 2 absorption rate (i.e., process i) with the CO 2 transfer rate (i.e., process iii). The rate of CO absorption in the MAMG process was obtained from previously published data. Data on the rate of CO removal (or transfer) are already provided in Figure 6A. From Figure 9, it is observed that the rate of CO absorption is much higher than the rate of CO removal from the organic solution. That is, CO 2 absorption rate in the MAMG process was obtained from previously published data. The rate of CO 2 removal (or transfer) data are already provided in Figure 6A. From Figure 9, it is observed that the rate of CO absorption is much higher than the rate of CO removal from the organic solution. That is, CO 2 absorption rate is much higher than the rate of CO removal from the organic solution. That is, CO 2 absorption rate is much higher than the rate of CO removal from the organic solution. That is, CO 2The proportion that moves in the form of bicarbonate ions remains lower than the proportion of CO 2 absorption. This indicates that the MAMG CO 2 capture process is not limited by mass transfer for CO 2 absorption.

[0091] Dissolved CO 2 , gaseous CO 2 , and calculation of the total carbon balance Dissolved CO 2 : The MAMG CO 2 capture performance was measured by observing the decrease in pH on the aqueous side due to the movement of HCO 3 - , and its conversion to CO 2 and CO 3 2- . Using the well-established water balance relationships for these species, the CO 2 concentration was calculated using pH as follows.

[0092] The equilibrium constants are obtained from these aqueous reactions. CO + OH - ⇔ HCO 3 - (K 1,aq = 10 7.63 L / mol) CO 2 + H 2 O + CO 3 2- ⇔ 2HCO 3 - (K 2,aq = 10 3.88 )

[0093] Using the above relationships, the concentrations of HCO 3 - and CO 3 2- can be expressed in terms of CO 2 as follows. [HCO 3 - = K 1,aq × [CO 2 [OH - [Number]

[0094] When electrical neutrality is imposed on the aqueous side, the total ion balance can be described as follows: Σ i z i C i = 0 where z i is the charge of the ionic species and C i is the concentration of the species. The electrical neutrality equation can be expressed as follows for the ionic species on the aqueous side. [K + + [H + - [OH - - [Cl - - [HCO 3 - - 2[CO 3 2- = 0 [Number]

[0095] Since [K + = 0.775 M and [Cl - = 0.75 M, [H + = 10 -pH M, and [OH - = 10 pH-14 M are spectator ions that do not participate in the equilibrium reaction, the only unknown is [CO 2 .

[0096] The concentration of gaseous CO 2 The concentration of gaseous CO 2 was determined by Ar that sweeps the headspace of the aqueous reservoir of the MAMG CO 2 capture system into the GC. When the aqueous solution reaches the saturation pH, HCO 3 - moving from the organic side to the aqueous side can no longer be retained as dissolved CO 2 , and thus gaseous CO 2Bubbles are generated. The primary charge carrier anion on the organic side is HCO 3 - When it is, the total HCO 3 - moved can be given as follows, [Number]

[0097] In the formula, [C] is the total carbon moved from the organic side to the aqueous side, and I m (mA) is the moving current, t is the duration of the MAMG CO 2 capture experiment, and F = 96485 C / mol is the Faraday constant. Theoretically, the generated gas CO 2 can be obtained as follows, [CO 2(g) =[C] - ([CO 2(aq) +[HCO 3 - +[CO 3 2- ) In the formula, [C] is obtained from the above formula, and [CO 2(aq) , [HCO 3 - , and [CO 3 2- are obtained from the above pH. Figure 8 shows the comparison of the theoretical and experimental gas CO 2 generated during the MAMG CO 2 capture process. It is obvious that the experimental values closely follow the theoretical values, and thus occupy all the carbon moving from the organic side to the aqueous side. This further supports the assumption that the decrease in pH in the aqueous solution is due only to the movement of HCO 3 - and its conversion to dissolved CO 2 .

[0098] CO 2 The pH of the electrolyte at various partial pressures of The equilibrium pH of the electrolyte is based on Henry's law for CO 2It depends on the partial pressure. Therefore, the influence of pH on the CO2RR experiment was studied by changing the partial pressure of CO for a total gas sparging of 100 sccm into the electrolyte solution. 2 The equilibrium concentration of CO is related to its partial pressure as follows: 2 The equilibrium concentration of CO is related to its partial pressure as follows: [CO 2 =H×P CO2 where H = 33 mM / atm is the Henry's constant and P CO2 is the partial pressure of CO. The total flow rate of the sparged gas was maintained at 100 sccm, and the fraction of CO was equilibrated with Ar at different pH values. Table 2 shows how the change in the partial pressure of CO affects the pH. 2 The total flow rate of the sparged gas was maintained at 100 sccm, and the fraction of CO was equilibrated with Ar at different pH values. Table 2 shows how the change in the partial pressure of CO affects the pH. 2 The total flow rate of the sparged gas was maintained at 100 sccm, and the fraction of CO was equilibrated with Ar at different pH values. Table 2 shows how the change in the partial pressure of CO affects the pH. 2 The total flow rate of the sparged gas was maintained at 100 sccm, and the fraction of CO was equilibrated with Ar at different pH values. Table 2 shows how the change in the partial pressure of CO affects the pH.

Table 2

[0099] Ratio of CO2 addition as a function of pH While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO 2 While studying the pseudo-integration process of CO2RR and the controlled addition of CO, it was identified that sparging pure CO into the electrolyte at various flow rates affects the rate at which CO dissolves in the solution. The pH saturation at higher flow rates, such as 20 sccm, is faster compared to slower flow rates, such as 5 sccm. The rate of CO addition also depends on the pH of the electrolyte as it approaches saturation. Initially, when the concentration of CO in the electrolyte is negligibly small, the rate of CO addition is constant and substantially independent of pH. However, the slope of the rate changes as the saturation pH is approached. It is important to visualize this behavior to show the rate at which CO is added to solutions near the saturation pH for various flow rates. Subsequently, this information is also useful for calculating the net rate of CO removal from the pseudo-integrated CO2RR with a controlled CO addition process. Figure 9 shows the controlled CO2 In the addition experiment, CO from the data obtained for pH versus time and CO 2 addition ratio versus time is shown in this cross-plot visualization of the addition ratio and pH. 2 This cross-plot visualization of the addition ratio and pH is shown.

[0100] Example 3: CO on 3D Cu mesh with efficiency from 4% sunlight to ethylene 2 from the electrolytic reduction of CO 2 High-purity ethylene without CO C 2 H 4 is a hydrocarbon of broad social, environmental, and industrial importance. Thus, the sustainable synthesis of C 2 via the electrochemical CO 2 H 4 reduction reaction (CO2RR) is an attractive field to explore. Despite many existing CO2RR systems reaching industrially relevant current densities, almost all use electrochemical systems of gas diffusion electrode (GDE) type with single-pass conversions of less than 10%. This results in a reduced concentration of C 2 in the gaseous product stream containing mainly CO 2 H 4 which is a significant cause of the cost of separation after CO2RR of the product and renders even processes with high CO2RR current densities unsuitable for scale-up. Here, an aqueous flow-through electrochemical cell was developed to enhance the activity and selectivity of C 2 H 4 on a 3D Cu mesh electrode by applying a square-wave oscillating potential. The oxidation phase of the square-wave oscillating potential for in-situ generation of active Cu(OH) 2 flakes on the mesh can be controlled, which helps to enhance the selectivity of CO2RR for C 2 H 4 in the reduction phase. A high C 2 H 4 Faradaic efficiency (FE) of about 58%, a record C 2 current density of 306 mA / cm 2 H 4 in the aqueous cell, and CO in the product stream2 Approximately 28 mol% of gas C without 2 H 4 purity is obtained. Integrating the 3D Cu mesh catalyst into a PV electrolyzer results in an approximately 4% efficiency from sunlight to C 2 H 4 to an efficiency of approximately 10% from sunlight to carbon (STC), nearly twice that of current state-of-the-art sunlight-driven CO2RR systems. The new electrochemical cell and catalyst provide several breakthroughs necessary for the sustainable production of C 2 H 4 .

[0101] Methods and materials Electrochemical measurements: An Al mesh (#120) (FindProLabs, Zhejiang) coated with 99.9% Cu of 1×1×0.12 cm was electrochemically polished in a well-stirred electrochemical cell containing 85% H 3 PO 4 as the electrolyte and carbon paper as the counter electrode. After polishing, the catalyst was rinsed with DI water and then dried with argon and used as in all CO2RR experiments. The electrolyte used was a mixture of 0.1 M KHCO 3 and 1 M KCl (25:75 V / V%). Electrochemical measurements were performed using a Biologic SP300 potentiostat in a custom 3D printed electrochemical cell as shown in Figure 1B. CO 2It was sprayed into an external electrolyte reservoir, where the electrolyte was recycled via a peristaltic pump. A microelectrode (LF-1-50, Innovative Instruments Inc.) of Ag|AgCl, 3.4 M KCl without leakage was used as the reference electrode, and mechanically polished Pt (99.99%, ACI Alloys) or Ni-foam was used as the counter electrode. The working compartment and the counter compartment were separated by a SnowPure Excellion I200 anion exchange membrane (AEM). The gaseous products in the headspace of the working compartment were swept into a gas chromatograph (GC, SRI 8610C) using Ar to quantify the gaseous products at 15-minute intervals. Both static and oscillatory potential CO2RR experiments were carried out over a duration of 1 hour. At the end of each CO2RR experiment, 0.5 ml of electrolyte was extracted for liquid product quantification using high-performance liquid chromatography (HPLC, Agilent 1260 II Infinity).

[0102] Characterization The 3D Cu mesh was characterized before and after CO2RR by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). SEM and EDS were carried out using a Hitachi SU8030 Field-Emission SEM, XPS was carried out using a Thermo Scientific ESCALAB 250XI microprobe with an Al Kα source, FTIR was carried out on a Bruker Invenio S in attenuated total reflection (ATR) mode using a Pike VeeMax II variable angle accessory and a 60o Ge ATR crystal, and XRD was carried out on a Bruker D8 Advance using a Cu Kα radiation source.

[0103] Solar-driven CO2RR An electrochemical cell without a custom 3D-printed membrane was used for the sunlight-driven CO2RR experiment. To maintain a constant applied potential and to reduce the total cell voltage for the photoabsorber, a membrane-free electrochemical cell setup was employed for the sunlight-driven CO2RR experiment. Two triple junctions (GaInP / GaAs / Ge, Spectrolab Inc.) were connected in series with a negative terminal connected to a 3D Cu mesh and a positive terminal connected to a Ni foam. The solar cell was irradiated using an Oriel LCS-100 solar simulator to simulate AM 1.5 with a total irradiation area of 16 cm 2 The potential oscillations were implemented in the sunlight-driven CO2RR experiment using an Arduino Uno board equipped with a relay circuit attachment.

[0104] Results and Discussion Static potential: To benchmark the catalytic activity towards CO2RR against previously reported Cu-based catalysts in an H-cell type configuration, static potential experiments were conducted in the range of -0.8 to -1.4 V vs the reversible hydrogen electrode (RHE). The applied potential was measured as follows, E(V vs RHE)=E(V vs Ag|AgCl)+0.059×pH+E ref where E(V vs Ag|AgCl) is the potential applied to the reference electrode using a potentiostat, and E ref==0.205V is the standard reduction potential of the reference electrode with a 3.4 M KCl electrolyte.

[0105] Figure 10A shows the product distribution of CO2RR at various applied static potentials. H 2 , CO, CH 4 , and C 2 H 4 Four gaseous products, as well as three liquid products of HCOOH, C 2 H 5 OH, and C 3 H 7 OH (1-propanol) were detected. While quantifying the gaseous products, CO 2was not detected. The product distribution is consistent with various existing reports in the literature. As the applied potential increases, the selectivity of C 2 H 4 increases, but at potentials higher than -1.2 V vs. RHE, HER and CH 4 formation become more dominant due to the activation of the high overpotential pathway for CH 4 formation, which promotes the complete reduction of CO 2 across enhanced C-C coupling. Both the high overpotential pathway and the low overpotential pathway pass through lower electron products such as CO and HCOOH as intermediates. This is the reason why the FE of such lower electron products is not significantly affected in the range of applied potentials shown in the exemplary embodiments herein. However, at larger overpotentials, HER becomes more dominant, leading to a reduction in the FE of CO2RR, and as a result, a reduction in the FE of lower electron products as seen from the product distribution at -1.4 V vs. RHE. The highest FE of 33% for C2H4 is seen at -1.2 V vs. RHE. Since product purity is an important metric to consider when scaling up the CO2RR system, a higher purity of the desired CO2RR product can be of significant economic benefit by preventing high separation costs after CO2RR. The purity of the gaseous product is defined as the molar selectivity of the gaseous product of CO2RR. Obtaining a pure product is difficult, especially in Cu-based CO2RR systems because multiple products can be formed. The results herein focus on the purity of C 2 H 4 produced from the electrochemical cell. Since only the CO2RR products are included at the gas outlet, the product purity is calculated as follows,

Equation

Equation

[0106] where i j is the partial current of the gaseous product j, and n j is the number of electrons transferred to form the gaseous product j, and F = 96485 C / mol is the Faraday constant. Low-electron products such as H 2 and CO are more advantageous than higher-electron products such as CH 4 and C 2 H 4 . H 2 is a dominant product with a product purity of over 65% over a range of applied potentials as it is only a two-electron product, whereas C 2 H 4 is a 12-electron product that requires six times higher energy per electron as it is equal to the flux of H 2 generation. At an applied static potential of -1.2 V vs. RHE, a maximum product purity of 10% is obtained. To further increase the purity of C 2 H 4 , CO2RR was carried out using a square-wave oscillating potential to suppress HER and promote the formation of C 2+ products. These oscillations incorporated the application of a reduction potential (V bottom or V b ) as the bottom of the square wave and an oxidation potential (V top or V t ) as the top of the square wave. The switching time between the oxidation potential and the reduction potential was kept the same. This applied potential was selected as the bottom potential for implementing the oscillations as C 2 H 4 has the highest FE and purity.

[0107] Oscillating potential Figure 11A shows C at a switching time of 1 second2 H 4 Shows the effects of various Vt of the oscillating potential on FE. V t varies from +0.2 to +0.8 V with respect to RHE, and even at lower V t the selectivity for C 2 H 4 can be seen to be higher than the maximum selectivity seen in the static potential experiment. C 2 H 4 The selectivity for C t increases until V 2 H 4 reaches 0.6 V, and a sharp decrease in C 2 H 4 is observed at 0.8 V. As can be seen from Fig. 11B, in the square wave oscillation experiment, while maintaining 0.6 V as the upper (oxidation) voltage, the switching time was varied. The switching time of the oscillation varied from 0.5 s to 5 s, and initially, as the switching time increased, until the maximum FE of 59 ± 5% was reached at a switching time of 2 s, C 2 H 4 the selectivity for C

[0108] Figs. 11C - 11D respectively show the maximum C 2 H 4SEM micrographs of the catalyst before and after CO2RR under the optimal conditions for FE are shown. From Figure 11C, it can be seen that before CO2RR, the mesh has a uniform and smoother texture, indicating that the surface is mainly composed of Cu. EDS elemental mapping also shows the presence of Al as Cu is coated on the Al mesh. The SEM micrograph after CO2RR from Figure 11D shows a rough texture of the mesh, indicating a change in the surface structure due to vibration. Furthermore, EDS elemental mapping suggests that the density of oxides and Al on the mapped area is also more prominent than that of the mesh before CO2RR. A quantitative analysis of the elemental composition of the catalyst before and after CO2RR can be seen in Table 3. From these micrographs, it can also be seen that there are some sharp and flaky coatings around the mesh of the Cu mesh. Repeated oxidation and reduction on the mesh by the oscillating potential may have peeled off Cu from the mesh and redeposited it as Cu(OH) 2 around the weave. This redeposited Cu(OH) 2 could be the cause of the improved selectivity towards C 2 H 4 .

[0109] The oxidation state of the Cu mesh elements is further confirmed by the XPS in Figures 2.3F and 2.3G. It should be noted that the raw data obtained from the XPS are scattered due to the mesh characteristics of the catalyst. Since the beam diameter is too large and is focused almost equally on the hollow part and the catalyst part of the mesh, increasing the noise of the spectrum, it is difficult to extract a sufficient signal-to-noise ratio from the acquisition. Therefore, most of the conclusions made based on the XPS spectra are qualitative. The XPS spectrum before CO2RR shows the elemental form of Cu with peaks at approximately 931 and 950 eV. The splitting of the 2p peak of the XPS also indicates the presence of Cu(I) species, which is also confirmed by the presence of 5% oxygen in the catalyst before CO2RR from the EDS quantitative analysis. The spectrum also shows elemental Al peaks at approximately 70 and 71 eV. It is found that these intensities are much lower, indicating that only a small amount of Al is present near the surface. After CO2RR, the XPS spectrum shows a mixed oxidation state of Cu in the elemental, Cu(I) and Cu(II) states, with the Cu(II) satellite peak at approximately 940 eV. Similarly, Al is also in the Al(III) state, and the binding energy is shifted higher at 76 eV, indicating electrons withdrawn from elemental Al. As seen in Figure 11E, CU(OH) 2 To confirm the presence of, ATR FTIR spectroscopy was performed on the 2.3D Cu mesh sample before and after CO2RR. The Cu mesh before CO2RR does not show vibrational modes in the range of 800 - 4000 cm -1 , indicating that the catalyst is IR-inactive in the scanning region. However, the Cu mesh sample after CO2RR shows fingerprint peaks of the Cu-OH vibrational mode at 1360 and 844 cm -1 , confirming the presence of Cu(OH) 2 . The XRD patterns from Figures 11H - 11I confirm that the Cu(100) facet is dominant in the sample before CO2RR, and then new phases of Al(111) and Al(220) appear after CO2RR. This specific determination indicates that Cu dealloyed from the initial Cu-Al structure forms Cu(OH) on the oxidation cycle 2By forming, it is suggested that it undergoes a change in surface composition. This sharply flaky Cu(OH) redeposited around the mesh of the Cu mesh 2 is C 2 H 4 contributes to the increased selectivity for formation. This phenomenon has also been observed by De Luna et al., and the Cu catalyst changes the morphology of Cu crystals by dissolution and electrodeposition of oxidized Cu species, thereby 2 H 4 / CH 4 increasing the selectivity ratio. Furthermore, Zhong et al. showed that Cu-Al provides multiple surface orientations and active sites with enhanced *CO bonds favorable for CO2RR. They also showed that dealloying of Cu from Al enables a favorable cooperative environment for Cu that enhances C-C coupling. These findings support the high selectivity of the 3D Cu mesh catalyst for 2 H 4 formation. The optimal oxidation potential of 0.6 V is sufficient to strip the surface Cu and not overly expose the CO2RR-inactive Al phase of the catalyst. The switching time of 2 s was optimal because longer switching times prevent the redeposition of Cu(OH) 2 and expose more CO2RR-inactive Al catalyst sites, resulting in a reduction in selectivity for 2 H 4 production, and exposing the Cu mesh for a longer oxidation period.

[0110] Figure 12A shows the partial current density of all CO2RR products for the optimized square wave applied potential for the high 2 H 4 selectivity obtained from Figure 11A. At a switching time of 2 s, a high 2 C 2 H 4 current density of 306.3 mA / cm 2 H 4The flow containing C in the exit stream of the CO2RR system is one of the most reported values ​​in the current literature. 2 H 4 A comparison of purity versus half-cell applied potential is shown in FIG. 12C. The current design achieves a remarkable 28.7% C compared to a system with a similar half-cell potential of −1.2 V vs. RHE. 2 H 4 It also provides nearly double the product purity compared to electrochemical systems with lower overpotentials. 2 H 4 Another comparison of the partial current density and its FE can be seen in Figure 12D. This comparison was made specifically for a non-GDE based electrochemical system, given the investigation carried out here, and was performed using CO 2 The focus of this study is on the production of gaseous products that are free of C. 2+ This is one of the highest FEs reported for product synthesis. Furthermore, the Cu-mesh catalyst exhibits a significantly higher FE than existing reports in the recent literature using electrochemical cells of similar architecture. 2 H 4 The higher partial current density of production is shown.

[0111] Solar-powered CO2RR Solar-powered CO2RR was carried out by using two Spectrolab XTJ (GaInP / GaAs / Ge) triple-junction solar cells in parallel with a membrane-less electrochemical cell, as seen in Figure 13 A. The measured power efficiency of a single solar cell was 16 cm illuminated under AM 1.5G using a Newport Oriel LCS-100 solar simulator. 2 The irradiation area was 46.83%.

[0112] The CO2RR experiments were carried out using a two - electrode setup with a counter - electrode that acts as both a counter - electrode and a reference electrode, and a 3D Cu mesh as the working electrode. The curve in Figure 13B shows the current - voltage (JV) curve of the photo - absorber setup with a short - circuit current of about 235 mA and an open - circuit voltage of 4.97 V. The curve shows the total current of the electrochemical cell at different total cell potentials. The intersection of these two curves indicates the operating point of the sunlight - driven setup with a current of about 195 mA and a total cell voltage of 4.68 V. Since the sunlight - driven experiment is limited when applying an oscillating potential, the system relaxes to the open - circuit mode and then returns to the operating point with a switching time of 2 seconds using an Arduino microcontroller equipped with a relay circuit. This limitation may prevent the catalyst from functioning at its optimal level, but there is still a significant amount of CO2RR observed in Figure 13C. From the sunlight - driven CO2RR, a total STF efficiency of 16.21% and a total STC efficiency of 9.72% were obtained, with an efficiency of 3.71% from sunlight to C 2 H 4 . The total STC efficiency and 9.72% total STC efficiency were obtained, with an efficiency of 3.71% from sunlight to C. Figure 13D shows a comparison of the STC of sunlight - driven CO2RR systems in recent literature. The 3D Cu mesh shows a very high STC efficiency among Cu - based sunlight - driven CO2RR systems.

[0113] In accordance with the principles of this specification, an exemplary system was developed and implemented in a liquid - flow - through electrochemical CO2RR system using a 3D mesh electrode to enhance mass transfer and achieve a higher CO2RR current, rather in a liquid - phase system than in a conventional GDE system. This system was designed to collect gaseous CO2RR products that do not contain a CO2 stream. In a standard static - potential experiment, a maximum FE of 33% for C2H4 was obtained at - 1.2 V vs. RHE. This applied potential was used as the bottom potential to systematically study the effect of a square - wave oscillating potential on the selectivity of CO2RR for C 2 H 4 . The catalyst was studied for C with an oscillating potential 2 H 4showed high selectivity. The vibration was optimized by fixing the bottom voltage Vb at -1.2 V vs. RHE, varying the top voltage Vt from 0.2 to 0.8 V vs. RHE, and varying the switching time between the oxidized and reduced phases from 0.5 to 5 s. The maximum FE of 59 ± 5% for C2H4 was obtained at V b = -1.2 V, V t = 0.6 V with a switching time = 2 s. Characterization of the 3D Cu mesh before and after CO2RR revealed trace amounts of Al on the surface and beneath the Cu. The surface Cu redeposited by vibration was identified as flaky and needle-like Cu(OH) 2 around the mesh weave. The detachment of surface Cu also revealed more Al sites. The combination of the presence of Cu(OH) 2 flakes and Cu-Al coordination helped enhance the selectivity towards C 2 H 4 in CO2RR. Due to the nature of the electrochemical cell setup, high-purity C 2 containing no about 28% CO 2 H 4 was obtained in the outlet product stream. Furthermore, the sunlight-driven CO2RR with 3D Cu mesh showed a very high STF efficiency of about 17% and an STC efficiency of about 10%. The efficiency from about 4% sunlight to C2H4 is nearly twice that of state-of-the-art CO2RR systems. The excellent selectivity and activity of the 3D Cu mesh for C 2 H 4 production under oscillating potential can serve as a starting point for synthesizing green plastics. The availability of gaseous products without CO 2 saves an additional gas separation step for removing CO 2 in the product stream and further enhances the economic viability of this electrochemical system.

[0114] Example 3: Experimental information on high-purity ethylene without CO 2 from the electrolytic reduction of CO 2 on 3D Cu mesh with 4% sunlight-to-ethylene efficiency Electrochemical measurements The electrochemical cell was designed in SOLIDWORKS and printed using PMMA transparent resin on a FormLabs Form 2 3D printer. The printed parts were then washed with isopropyl alcohol for 30 minutes and cured by UV for 3 hours. All experiments were carried out with this 3D printed cell. The resin used is resistant to harsh chemical environments. 0.1 M KHCO with a 25:75 V / V ratio 3 and 1 M KCl were used as electrolytes for all experiments. The cell consists of a working compartment and a counter compartment separated by a SnowPure Excellion I200 anion exchange membrane (AEM) with a dry film thickness of 0.33 - 0.35 mm. The AEM is a quaternary ammonium-based membrane and is supplied in the Cl- form, which is ideal for the electrolytes used in the CO2RR experiments in this specification, with a polymer backbone. A Pt strip or Ni foam was used as the counter electrode in the counter compartment. An Ag / AgCl micro reference electrode was inserted into the working compartment. The overall applied potential to the working electrode was determined as follows. V actual =V applied +0.205 + 0.059×pH (V実際 ) (V印加 )

[0115] Electrochemical experiments were performed using a Biologic SP300 potentiostat. Square wave oscillations were implemented by using the loop mode of the potentiostat, which sets two separate chronoamperometry techniques and the potentiostat loops through the techniques for a desired length of time. First, chronoamperometry for the reduction potential V b was performed for time t. Immediately after its completion, another chronoamperometry for the oxidation potential V t was performed for the same time t. This seamless integration of the two chronoamperometry techniques simulated square wave potential oscillations for various V t and t. A schematic diagram of the sample square wave potential can be seen in Figure 14. The solid line represents the oscillating potential, the upper dashed line is V top (oxidation potential), and the lower dashed line is V bottom(Reduction potential). The shaded zone indicates the switching time. In the case of a square wave, both the lower and upper switching times are of equal duration. In various embodiments, the voltage can include a range from 0.8 V to -1.2 V, or any other suitable voltage for a particular fluid flow.

[0116] In the electrochemical cell, the upper headspace of the working compartment was where Ar was swept to collect the gaseous products and transport them to a gas chromatograph (GC) for quantification. The liquid products were quantified by high performance liquid chromatography (HPLC).

[0117] Gas chromatography The gaseous products were quantified using an SRI 8610C GC MG#5. At 15-minute intervals, the generated gaseous products were detected by passing argon as a carrier gas from the electrochemical cell through the outlet to the GC, and product detection was performed via a thermal conductivity detector (TCD) and a flame ionization detector (FID). The product gas in the GC was passed through two size exclusion columns, Mol-sieve 8A and HaySep D. HaySep D efficiently separates larger molecules such as C2H4. 2 (from HER), CO, and CH 4 Smaller molecules such as were separated through Mol-sieve 8A. Hydrocarbons were detected using an FID, and non-hydrocarbon products were detected using a TCD. The GC operates continuously during the electrochemical experiment. Thus, the concentration of the products obtained during the oscillating potential experiment represents the average concentration of the products generated because no products are formed during the oxidation cycle of the experiment. The actual flux of the products is calculated by considering only the time spent in the reduction cycle.

[0118] High performance liquid chromatography CO 2Quantification of the liquid products of reduction was carried out using high-performance liquid chromatography (HPLC) on an Agilent Infinity 1260 II HPLC with a 300 mm × 7.5 mm Agilent Hi-plex-H column and a refractive index detector (RID). The isocratic elution of the mobile phase was established at 0.6 mL / min. The column temperature was set at 60 °C and the RID temperature was set at 35 °C. For each sample analysis with a total run time of 30 minutes, 10 μL of the sample was injected into the system via an autosampler. This operating method was developed by observing that none of the peaks overlapped with each other at the shortest run time, the retention times of the electrolytes and the possible CO 2 SO 4 reduction products: HCOOH, HCHO, CH 2 OH, CH 3 OH, CH 3 COCH 3 OH, CH 3 COOH, C 2 H 5 OH, and C 2 H 2 O 4 The flux of the liquid products was calculated in the same way as that of the gaseous products by considering only the time spent in the reduction cycle of the oscillating potential experiment.

[0119] Characterization Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS): SEM and EDS were performed on the 3D mesh catalyst before and after CO2RR using a Hitachi SU8030 field emission SEM. Image scanning was performed at an acceleration voltage of 5 kV and a emission current of 10 μA at various magnifications. EDS elemental mapping and identification were performed at an acceleration voltage of 20 kV, enabling maximum signal collection from signals from both the upper and lower detectors.

[0120] Figures 15A - 15C show SEM images and EDS elemental mappings of the 3D mesh catalyst before CO2RR. The square on the micrograph in Figure 15A is the area selected for EDS elemental mapping. EDS revealed that the 3D Cu mesh catalyst has trace amounts of Al.

[0121] Figures 15B - 15C show elemental maps of Cu and Al that are confirmed to be in the elemental (zero) state as seen from the collected XPS data.

[0122] Figures 16A - 16D show SEM images and EDS elemental mappings of the 3D mesh catalyst after CO2RR. Figure 16A shows a rough texture and sharper gradients on the surface of the mesh, indicating that the catalyst has experienced some structural changes. The square on the micrograph in Figure 16A is the area selected for EDS elemental mapping. Elemental mapping revealed a reduction in the presence of Cu and an increase in the presence of Al compared to the 3D mesh before CO2RR, as seen in Figures 16B - 16C. Furthermore, Figure 16D also shows the presence of O. This could be due to the formation of both Cu(OH) 2 and Al(II) oxides, as confirmed by the collected FTIR and XPS data.

[0123] Figures 17A - 17B show SEM micrographs of the 3D mesh catalyst before and after CO2RR for switching times exceeding 2 seconds. Both images were taken at the same magnification. Figure 17A shows the smooth texture of the catalyst before CO2RR, as seen in the SEM micrograph of Figure 2.3. Figure 17C shares some similar features with the catalyst after CO2RR, but despite having a rough texture on the surface, no sharp flaky Cu(OH) 2 deposits can be seen around the mesh weave. Longer switching times also mean that the oxidation phase is longer in the square wave oscillating potential experiment. This enhances surface exfoliation but prevents the formation and redeposition of Cu(OH) 2 and thus C 2 H 4A reduction in CO2RR activity and selectivity can be observed. Further quantification by EDS can be seen in Table 3. Here, the atomic % of carbon detected during acquisition of the EDS spectrum was considered an impurity and was thus ignored from the total atomic % calculation of the catalyst. The data seen in Table 3 are normalized after excluding the influence of impurities. Before CO2RR, the catalyst consisted of only Cu and Al with a Cu:Al ratio of 4.42:1. If both Cu and Al were uniformly distributed on the catalyst surface, the Cu:Al ratio would likely remain constant as both may undergo structural changes under oscillating potentials. However, after CO2RR, the Cu:Al ratio changed to 2.39:1, indicating that Cu and Al were not uniformly distributed on the catalyst surface. The catalyst underwent exfoliation due to the repeated oscillating potential.

Table 3

[0124] X-ray photoelectron spectroscopy (XPS) XPS for the pre-electrocatalyst before and after CO2RR was performed using a Thermo Scientific ESCALAB 250XI microprobe with an Al Kα source. The beam diameter was set to an optimal value of 500. Each analysis consisted of a survey scan to check for impurities and an elemental scan to access the chemical state of the catalyst. All XPS spectra were corrected for charge shift using C 1s at 284.8 eV as a reference. For the maximum signal-to-noise ratio, at least 10 spectra were acquired for the survey scan and 20 were acquired for the individual elemental scans for Cu and Al.

[0125] X-ray diffraction (XRD) The crystal structure of the Cu mesh was analyzed using a Bruker D8 Discover X-ray diffractometer with Cu-Kα radiation (40 kV, 40 mA, and λ = 1.5418 Å). The diffractometer was equipped with a parallel beam optical system and a parallel slit analyzer of 0.5°. A Göbel mirror was used on the primary side, and a LYNXEYE detector with 196 channels (channel width 14.4 mm) was used on the detection side. A Ni filter was used to remove Kβ arising from Cu radiation. The detector slit was set to 1.2 mm. A 2θ scan was performed at a primary rotation absorbance value of 73.88 to obtain the offset of the beam with the sample holder in a predetermined position and perform external offset correction. A Z scan was performed at an automatic primary rotation absorbance to find the sample end, and then a rocking scan was performed at a primary rotation absorbance value of 73.88 to find the angular offset of the sample and perform flatness correction. Two combined theta / theta scans were performed at a step size of 0.02° and an automatic primary rotation absorbance of 30° to 90°. The data was processed using Diffrac Suite Eva software and background subtraction was performed. The data was matched with the crystallographic open database to identify the peaks.

[0126] Fourier transform infrared (FTIR) spectroscopy FTIR analysis (Invenio S, Bruker) was performed to confirm the structural changes between the 3D mesh catalyst before CO2RR and the 3D mesh catalyst after CO2RR. Using a crystal with an angle of the germanium 60° plane, analysis was carried out in the attenuated total reflection (ATR) mode using a Pike VeeMax III variable angle accessory. The spectrum for the catalyst was collected at a resolution of 4 cm -1 with a low sampling rate of 7.5 kHz and 64 scans per sample. The beam aperture was adjusted to 6 mm, the reflection angle was maintained at 64.5° to obtain the maximum signal from the spectrum, and the presence of CO 2 and moisture in the atmosphere was compensated for.

[0127] For spectrum acquisition, the 3D mesh catalyst before CO2RR was used as it was. After the experiment, the 3D mesh catalyst after CO2RR was taken out from the electrochemical cell, dried with Ar to remove the aqueous electrolyte, and then attached to the FTIR spectrometer for spectrum acquisition. For both samples, IR-inactive Al foil was used as the background signal. The calculations of the STF and STC efficiencies for the solar-driven CO2RR experiments were performed using a custom 3D printed cell without a membrane having an illumination area of 16 cm 2 and a Newport Oriel LCS-100 solar simulator. The general formula for calculating any STF efficiency is given by [Number] where η STF is the STF efficiency, P in or P solar is the input power which is the power irradiated by the sun on the earth's surface at AM1.5G, and P out or P EC is the output power or total power required for the electrochemical cell to produce fuel. Since the nominal power density from sunlight reaching the earth's surface is 100 mW / cm 2 , the total solar power generation for an illumination area of 16 cm 2 can be given as follows. [Number]

[0128] The power required for the electrochemical cell for a single product is as follows, P EC,j = i j × E 0,j where P EC,j (mW) is the power required for the electrochemical cell to produce fuel j, i j (mA) is the partial current of product j, and E 0,j (V) is the equilibrium potential of the cell. [Table 4]

[0129] Using the equilibrium cell potential values from Table 4 and the definition of STF from Equation (2), the STF efficiency for each product is calculated as follows:

Equation

Equation

[0130] The efficiency from total sunlight to carbon (STC) is the efficiency of the electricity consumed to produce only CO2RR products, and is an index calculated in the same way as the total STF efficiency above, using only CO2RR products and excluding the STF efficiency of HER.

[0131] State-of-the-art STC systems in the literature

Table 5

[0132]

Table 6

[0133] Selection of electrolyte The electrolyte used in this study is 25% 0.1 M KHCO 3 , 75% 1 M KCl (v / v). After varying the concentration of the electrolyte in the CO2RR system and evaluating the product distribution for each different ratio, this ratio was used. Since the selection of the electrolyte was done before implementing the oscillating potential, the performance of the CO2RR system during screening for the appropriate electrolyte ratio was carried out in static potential experiments. Figure 18 shows the C at -1.2 V vs. RHE 2 H 4Effect of different 0.1 M KHCO on FE 3 is shown. Only the 25% and 50% solutions show a high C2H4 FE exceeding 20%, and it can be seen that the electrolyte containing 25% 3 shows the highest FE at 38.7%. Therefore, a mixture of 25% 0.1 M KHCO 3 and 75% 1 M KCl was selected as the electrolyte for this study.

[0134] Stability of the CO2RR system A high proportion of C 2 H 4 To determine the stability of the 3D mesh catalyst and electrolyte for synthesis, a long-term stability test was carried out on the system. C 2 H 4 FE was monitored over time for a 6-hour long experiment. During the first hour of operation, C 2 H 4 FE was monitored every 30 minutes and then every hour. From Figure 19A, it can be seen that this system is consistently selective for generating C 2 H 4 The FE is in the range of 54 - 58%, which is consistent with the short-term 1-hour experiments reported in the manuscript. The reduction current is on the order of about 580 mA / cm 2 and the oxidation current remains at a low value of about 2 mA / cm 2 throughout the experiment. A snippet of the total cell voltage is shown in Figure 19B. During the reduction cycle, the total cell voltage was 7 - 8 V, but in the oxidation cycle, it dropped to 1 - 2 V. The average total cell voltage was 5.865 V over 1 hour of operation.

[0135] After 6 hours of operation, the FE dropped to about 43%, indicating degradation of the electrochemical system. This decomposition was further investigated by analyzing the product distribution at the anode.

[0136] Qualitative gaseous product distribution at the anode The gaseous products for the optimal oscillatory square wave potential experiments were carried out by modifying the experimental setup such that the product gas from the anode was swept from the anode compartment to the GC using Ar. The anode products were detected using the thermal conductivity detector of the GC. Figure 20 shows the chromatogram for the anode products. Oxygen is the major product at the anode, with small amounts of Cl 2 Gas generation was also detected as a result of the oxidation of Cl from the electrolyte. This is as seen in Figure 19A, where the consumption of Cl from the system affects the performance of the catalyst and the C - selectivity decreases after 6 hours of continuous operation. To prevent the migration and oxidation of Cl at the anode, a bipolar membrane can be implemented. Figure 21 shows the current (for a geometric electrode area of 1 cm - ), with or without the bipolar membrane. There is a reduction in current due to the ohmic losses of the bipolar membrane compared to the cell without the membrane. However, the generation of chlorine is significantly suppressed, and the amount of chlorine gas at the anode is at a level below ppm. 2 H 4 It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations described for the purpose of a clear understanding of the principles of the present disclosure. Many variations and modifications can be made to the above embodiments without substantially departing from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of the present disclosure and protected by the following claims. - It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations described for the purpose of a clear understanding of the principles of the present disclosure. Many variations and modifications can be made to the above embodiments without substantially departing from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of the present disclosure and protected by the following claims. 2 It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations described for the purpose of a clear understanding of the principles of the present disclosure. Many variations and modifications can be made to the above embodiments without substantially departing from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of the present disclosure and protected by the following claims.

[0137] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations described for the purpose of a clear understanding of the principles of the present disclosure. Many variations and modifications can be made to the above embodiments without substantially departing from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included herein within the scope of the present disclosure and protected by the following claims.

Claims

1. Substantially continuous CO ２ A system comprising a composition of a catalyst and an electrolyte for the capture and reduction to one or more value-added products of captured CO ２ where the proportion of is substantially equal to the proportion of CO ２ reduction.

2. The system according to claim 1, wherein the system operates at a pressure of about 0.5 bar to about 3 bar.

3. The system according to claim 1, wherein the system operates at about 20°C to about 40°C.

4. The system according to claim 1, wherein the catalyst comprises a supported or unsupported mesh electrode comprising Cu, at least one copper oxide, a Cu—Al alloy, or any combination thereof.

5. The system according to claim 4, wherein the catalyst can be regenerated via a cycle of applied potential.

6. The system according to claim 4, wherein the supported or unsupported mesh electrode has a mesh size of about 40 mesh to about 120 mesh.

7. The system according to claim 4, wherein the supported mesh electrode comprises an Al support.

8. The system according to any one of claims 1 to 6, wherein the catalyst comprises five or more mesh electrodes directly connected in the stack.

9. The system according to claim 4, further comprising a membrane that separates the anode side from the cathode side.

10. The system according to claim 9, wherein the mesh electrode is present on the cathode side within the system.

11. The system according to claim 9, wherein the membrane prevents one or more solutes from crossing from the anode side to the cathode side, from the cathode side to the anode side, or both.

12. The system according to any one of claims 9 to 11, wherein the membrane comprises a bipolar membrane, a cation exchange membrane, an anion exchange membrane, or any combination thereof.

13. The system according to claim 9, wherein the membrane reduces or eliminates Cl ２ generation as compared to a system having no membrane that is identical in other respects.

14. The system according to claim 1, wherein the system has a Faraday efficiency of about 50% to about 60%.

15. The system has a current density of about 550 mA / cm ２ to about 600 mA / cm ２ The system according to claim 1.

16. The system having a partial current density of ethylene of about 250 mA / cm ２ to about 300 mA / cm ２ The system according to claim 1.

17. The system according to claim 1, wherein the catalyst comprises at least one of the strained Cu layers having facets of 111, 200, or 220 and contains active sites for CO ２ reduction.

18. The system according to claim 1, wherein the electrolyte comprises one or more alkali metal chlorides, one or more bicarbonates, one or more hydroxides, or any combination thereof, mixed in an electrolyte composition.

19. The system according to claim 18, wherein the electrolyte composition comprises CO dissolved in a solution of an alkali chloride and an alkali bicarbonate in water. ２ ​

20. The system according to claim 19, wherein the electrolyte composition comprises about 0.5 M to about 1 M alkali chloride and about 0.01 M to about 0.03 M alkali bicarbonate.

21. The system of claim 20, wherein the electrolyte composition comprises about 0.75 M of an alkali chloride and about 0.025 M of an alkali bicarbonate.

22. The system of any one of claims 19-21, wherein the alkali chloride comprises KCl, NaCl, or any combination thereof.

23. wherein the alkali bicarbonate is KHCO ３ , NaHCO ３ , or any combination thereof, the system according to any one of claims 19 to 21.

24. Integrated CO ２ The system according to claim 1, further comprising a capture and conversion device.

25. The one or more value-added products are CO, CH ４ , C ２ H ４ , C ２ H ５ OH, CH ３ COOH, CH ３ OH, C ３ H ６ , H ２ , or any combination thereof, the system according to any one of claims 1 to 24.

26. wherein the one or more value-added products comprise C ２ H ４ and the molar selectivity ratio of C ２ H ４ to CH ４ is from about 200:1 to about 1000:1, the system of claim 25.

27. The molar amount of C ２ H ４ relative to all other gaseous products is from about 30% to about 60%, the system according to claim 25.

28. CO to one or more value-added products ２ A method for maximizing the efficiency of solar conversion of said CO ２ , said method comprising manufacturing the system according to any one of claims 1 to 27, and operating said system using an electrochemical reactor for solar power generation and a dilute CO ２ feedstock.

29. the diluted CO ２ The method according to claim 28, wherein the raw material comprises flue gas or air.

30. wherein the one or more value-added products are CO, CH ４ , C ２ H ４ , C ２ H ５ OH, CH ３ COOH, CH ３ OH, C ３ H ６ , H ２ , or any combination thereof, the method according to claim 28.

31. wherein the one or more value-added products comprise C ２ H ４ and the selectivity ratio of C ２ H ４ to CH ４ is at least about 200:1, the method according to claim 30.

32. The method of claim 28, wherein the one or more value-added products are produced with a purity greater than 10%.

33. The method of claim 32, wherein the one or more value-added products are produced with a purity greater than 30%.

34. The method of claim 28, wherein the one or more value-added products are produced with a Faradaic efficiency of up to about 60%.

35. The one or more value-added products are produced at a current density of up to about 300 mA / cm ２ in the liquid-fed electrochemical reactor, the method of claim 34.

36. The method according to claim 28, wherein the one or more value-added products are produced at a current density of up to about 1000 mA / cm in a gas-fed electrochemical reactor. ２ in the gas-fed electrochemical reactor.

37. The continuous CO ２ capture and reduction system has a flux of 1 mmol / m ２ / s or more for capturing CO ２ The method according to claim 28.

38. The continuous CO ２ The method according to claim 28, wherein the capture and reduction system operates at an energy of less than 120 kJ / mol using an electrodialysis unit.

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