Laminated electrode device for electrocatalytic reduction of carbon dioxide capture liquid

Abstract

The invention belongs to the field of integration of carbon dioxide capture and electrocatalytic utilization, and particularly relates to a laminated electrode device for electrocatalytic reduction of carbon dioxide capture liquid. The electrode device comprises a cathode gas diversion layer, a cathode gas-liquid separation layer, a cathode liquid diversion layer, a cathode catalyst layer, a cation exchange membrane, an anion exchange membrane, an anode catalyst layer, an anode liquid diversion layer, an anode gas-liquid separation layer and an anode gas diversion layer which are sequentially laminated. According to the laminated electrode device provided by the invention, the independent flow guide of the cathode trapping liquid and the anode electrolyte is realized, an external flow field plate is not needed, and the reactor structure is simplified. And meanwhile, in-situ autonomous separation of cathode and anode gas products in the electrode is realized, gas retention and product crossing are avoided, and a subsequent separation unit is omitted. Besides, through the unique layered structure design, electron conduction, ion transmission and diffusion mass transfer of reactants / products are synergistically optimized, the internal resistance is reduced, and the reaction efficiency and stability are improved.

Description

Technical Field

[0001] This application belongs to the field of integrated carbon dioxide capture and electrocatalytic utilization, and more specifically, relates to a stacked electrode device for electrocatalytic reduction of carbon dioxide capture liquid. Background Technology

[0002] With increasing global pressure on carbon emissions, the efficient capture and resource utilization of carbon dioxide (CO2) from industrial flue gas and the air has become an important research direction in the energy and environment fields. Electrocatalytic reduction of carbon dioxide has attracted widespread attention because it can convert carbon dioxide into high-value-added chemicals or fuels. However, existing electrocatalytic reduction technologies mostly use gaseous carbon dioxide as raw material, requiring complex processes such as capture, desorption, and drying. The overall process has high energy consumption and many steps, affecting the economic efficiency and effectiveness of carbon dioxide resource utilization.

[0003] In recent years, direct electrolysis of carbon dioxide capture solutions has attracted research interest as an in-situ utilization method. This method enables direct electrochemical reduction within the capture solution, eliminating the need for traditional carbon dioxide desorption steps, thus significantly reducing energy consumption and improving process simplicity and overall efficiency. However, direct electrolysis of the capture solution places higher demands on the electrode devices. Traditional electrode device designs are primarily designed for gaseous carbon dioxide and are not suitable for capture solution systems with high viscosity and high water content, resulting in problems such as low mass transfer efficiency, liquid retention, and difficulty in separating reduction products.

[0004] To address the aforementioned issues, there is an urgent need in this field for an electrode device capable of simultaneously adapting to the electrolysis of liquid carbon dioxide capture solutions, achieving gas-liquid separation, and efficient catalysis. An ideal electrode should possess the following functions: firstly, it should enable efficient reduction of carbon dioxide under conditions of high conductivity and catalytic activity; secondly, through a rational layered structure design, it should achieve self-flowing electrolyte and gas-liquid separation of reduction products, eliminating the need for additional flow channel design, thereby simplifying the reactor structure and improving operational stability.

[0005] Currently, there is a lack of stacked electrode devices that can meet the above functional requirements, especially in the design of rationally stacked multilayer flow-conducting layers, catalytic layers, and ion exchange membranes. Therefore, developing a high-efficiency stacked electrode device for the direct electrolysis of carbon dioxide capture solutions has significant technological value and application prospects. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this application is to provide a stacked electrode device for the electrocatalytic reduction of carbon dioxide capture liquid. The stacked electrode device provided by this invention can effectively achieve self-guiding of the cathode carbon dioxide capture liquid and the anolyte, improving mass transfer and fluid flow, eliminating the need for a flow-channel electrolyzer. Simultaneously, it achieves self-separation of the cathode gas products and the anolyte gas products within the electrode device, eliminating the need for additional separation processes, resulting in a simpler process path and lower equipment investment costs.

[0007] To achieve the above objectives, in a first aspect, this application provides a stacked electrode device for the electrocatalytic reduction of carbon dioxide capture liquid, comprising, in sequence, a cathode gas guiding layer, a cathode gas-liquid separation layer, a cathode liquid guiding layer, a cathode catalyst layer, a cation exchange membrane, an anion exchange membrane, an anode catalyst layer, an anode liquid guiding layer, an anode gas-liquid separation layer, and an anode gas guiding layer; wherein: The cathode liquid guiding layer is provided with a vertically penetrating water-blocking channel structure, and the inner surface of the channel structure is provided with water-blocking material to provide a channel for directional flow and diffusion mass transfer of the carbon dioxide capture liquid. The cathode gas-liquid separation layer is made of a water-resistant and air-permeable material, which is used to achieve primary separation of gas and liquid on the cathode side. The cathode gas guiding layer is a porous material used to provide a diffusion channel for the gaseous reduction products generated at the cathode. The anode liquid guiding layer is provided with a vertically continuous water-blocking channel structure, and the inner surface of the channel structure is provided with a water-blocking material; it is used to provide a channel for directional flow and diffusion mass transfer of alkaline electrolyte for the anode. The anode gas-liquid separation layer is made of a water-resistant and air-permeable material, which is used to achieve primary separation of gas and liquid on the anode side; The anode gas guide layer is a porous material used to provide a diffusion channel for the gaseous oxidation products generated at the anode.

[0008] Preferably, the main material of the cathode liquid guiding layer and the anode liquid guiding layer is hydrophilic foam metal. More preferably, the foam metal is made of any one or a combination of at least two of nickel foam, copper foam, silver foam, gold foam, platinum foam, or titanium foam.

[0009] More preferably, the porosity of the foamed metal is 0.85 to 0.95; the pore size of the foamed metal is 20 micrometers to 60 micrometers; and the depth of the water-blocking channel structure is 75 micrometers to 800 micrometers, and the width is 2 millimeters to 5 millimeters.

[0010] Preferably, the water-blocking material disposed on the inner surface of the flow channel structure is any one or a combination of at least two of polyetheretherketone, polyaryletherketone, polyetherimide, polyarylethersulfone, polyphenylene sulfide, or polyaryletherimide.

[0011] More preferably, the water-blocking material is applied to the inner surface of the flow channel structure by inkjet printing, injection, or spraying to block water, thereby allowing the carbon dioxide capture liquid to flow directionally within the flow channel structure.

[0012] Preferably, the water-resistant and air-permeable material used in the cathode gas-liquid separation layer and the anode gas-liquid separation layer is a water-resistant and air-permeable polymer membrane.

[0013] More preferably, the material of the water-resistant and breathable polymer membrane is any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyurethane, and polyethersulfone.

[0014] More preferably, the porosity of the water-resistant and breathable polymer membrane is 0.30 to 0.70; the hydrostatic pressure of the water-resistant and breathable polymer membrane is greater than or equal to 1,000 mm H2O; the CO permeability of the water-resistant and breathable polymer membrane is 50 to 5,000 Barrer; and the water contact angle of the water-resistant and breathable polymer membrane is greater than or equal to 120°.

[0015] Preferably, the porous materials used in the cathode gas guiding layer and the anode gas guiding layer are hydrophobically treated carbon paper or porous layers composed of metal foam.

[0016] Preferably, the porous material is a carbon layer of doped polytetrafluoroethylene with a mesoporous structure.

[0017] More preferably, the mesoporous structure has a pore size ranging from 50 to 250 nanometers; the mesoporous structure has a porosity ranging from 0.60 to 0.80; and the polytetrafluoroethylene doping amount is 20-80 wt.%.

[0018] More preferably, the carbon layer is made of any one or a combination of at least two of the following: graphite, graphene, graphynylene, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon aerogel, and carbon fiber.

[0019] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art: (1) The stacked electrode device for electrocatalytic reduction of carbon dioxide capture liquid in this invention integrates the four major functions of flow guiding, catalysis, mass transfer and separation into one stacked electrode device. This invention completely eliminates the complex flow field plate and external gas-liquid separation unit in traditional electrolyzers. This makes the structure of the entire electrolysis reactor extremely compact and simple, and greatly reduces the material cost, manufacturing difficulty and assembly complexity of the system.

[0020] (2) This invention bypasses the thermal desorption step, which has the highest energy consumption in traditional technology, and directly electrolyzes the collected liquid, thus eliminating the biggest energy consumption bottleneck at the source. The functionalized stacked structure design, the application of a highly conductive current-carrying layer, and the optimized ion transport path together significantly reduce the internal resistance and cell voltage of the electrolytic cell, thereby directly reducing power consumption and improving energy efficiency.

[0021] (3) The present invention employs a unique gas-liquid separation design (independent liquid guide layer and gas guide layer) to fundamentally avoid the "bubble shielding effect" caused by the retention of gaseous products in the channels, ensuring that the reactants (CO2 absorbent) can be continuously and stably transported to the catalytic active sites. The in-situ gas-liquid separation mechanism prevents the physical erosion of the catalyst layer and pore blockage by the gas, maintains the long-term stability of the catalyst active sites, and extends the device life.

[0022] (4) In this invention, the gaseous products of the cathode and anode are physically isolated and separated inside the device after generation, and are discharged through their respective gas guide layers. This design avoids cross-mixing of cathode products (such as CO and ethylene) and anode products (oxygen) from the source, and can directly obtain high-purity gaseous products, greatly reducing the burden and cost of downstream product separation and purification.

[0023] (5) The stacked electrode device design in this invention has good compatibility with various absorbents (such as alkaline absorbents and amine absorbents) and can be adapted to different cathode catalysts to flexibly adjust the reduction products (such as formic acid, carbon monoxide, ethylene, etc.), providing a universal core hardware solution for the integration of carbon capture and in-situ electrochemical conversion. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the stacked electrode device for electrocatalytic reduction of carbon dioxide capture liquid in this application; Figure 2 This is a top view of the cathode liquid guiding layer structure in the stacked electrode device for electrocatalytic reduction of carbon dioxide capture liquid in this application; Figure 3 This is a top view of the anolyte liquid flow guide layer structure in the stacked electrode device for electrocatalytic reduction of carbon dioxide capture liquid in this application; Figure 4This is a schematic diagram of the mass transfer process of reactants and products in the cathode portion of the stacked electrode device for electrocatalytic reduction of carbon dioxide capture liquid in this application; Figure 5 This is a schematic diagram of the mass transfer process between reactants and products in the anode portion of the stacked electrode device for the electrocatalytic reduction of carbon dioxide capture liquid in this application.

[0025] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1. Cathode gas guide layer; 2. Cathode gas-liquid separation layer; 3. Cathode liquid guide layer; 31. Cathode liquid guide layer partition structure; 32. Cathode liquid guide layer liquid flow channel; 33. Cathode liquid guide layer electrolyte inlet; 34. Cathode liquid guide layer electrolyte outlet; 4. Cathode catalyst layer; 5. Cation exchange membrane; 6. Anion exchange membrane; 7. Anode catalyst layer; 8. Anode liquid guide layer; 81. Anode liquid guide layer partition structure; 82. Anode liquid guide layer liquid flow channel; 83. Anode liquid guide layer electrolyte inlet; 84. Anode liquid guide layer electrolyte outlet; 9. Anode gas-liquid separation layer; 10. Anode gas guide layer. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0027] This invention provides a stacked electrode device for the electrocatalytic reduction of carbon dioxide capture liquid, comprising, in sequence, a cathode gas guiding layer, a cathode gas-liquid separation layer, a cathode liquid guiding layer, a cathode catalyst layer, a cation exchange membrane, an anion exchange membrane, an anode catalyst layer, an anode liquid guiding layer, an anode gas-liquid separation layer, and an anode gas guiding layer; wherein: The cathode liquid guiding layer is provided with a vertically continuous water-blocking channel structure, and the inner surface of the channel structure (the surface in contact with the fluid) is provided with a water-blocking material to provide a channel for directional flow and diffusion mass transfer of the carbon dioxide capture liquid. The cathode gas-liquid separation layer is made of a water-resistant and air-permeable material, which is used to achieve primary separation of gas and liquid on the cathode side. The cathode gas guide layer is a porous material that provides a diffusion channel for the gaseous reduction products (such as CO, C2H4, etc.) generated at the cathode. The anode liquid guiding layer is provided with a vertically continuous water-blocking channel structure, and the inner surface of the channel structure (the surface in contact with the fluid) is provided with a water-blocking material to provide a channel for directional flow and diffusion mass transfer of the alkaline electrolyte (such as KOH solution) for the anode. The anode gas-liquid separation layer is made of a water-resistant and air-permeable material, which is used to achieve primary separation of gas and liquid on the anode side; The anode gas guide layer is a porous material that provides a diffusion channel for the gas oxidation products (such as oxygen) generated by the anode.

[0028] In a preferred embodiment, the main material used in the cathode liquid guiding layer and the anode liquid guiding layer is hydrophilic foam metal. The water-blocking channel structure is actually formed by creating a vertically continuous serpentine channel inside the hydrophilic foam metal main material. This liquid guiding layer, together with the upper gas-liquid separation layer and the lower catalyst layer, is then pressed together to form the water-blocking channel structure. Because the inner surface of the channel is provided with water-blocking material, after liquid is injected into the liquid guiding layer, the liquid flows forward along the serpentine channel and is distributed throughout the entire guiding layer. At the same time, because the channel is a vertically continuous structure, the liquid also enters the catalyst layer and undergoes mass transfer with the ion exchange membrane to carry out corresponding oxidation or reduction reactions.

[0029] The foam metal is made of any one or a combination of at least two of nickel foam, copper foam, silver foam, gold foam, platinum foam, or titanium foam; the water-blocking material is mainly a strongly hydrophobic polymer. The water-blocking material is any one or a combination of at least two of polyetheretherketone, polyaryletherketone, polyetherimide, polyarylsulfone, polyphenylene sulfide, or polyaryletherimide; the high electronic conductivity of the foam metal ensures the effective distribution of cathode and anodic currents. The thickness of the cathode liquid guiding layer and the anodic liquid guiding layer is 75 micrometers to 800 micrometers.

[0030] In some embodiments, the water-blocking channel structure within the cathode liquid guiding layer and the anode liquid guiding layer can be prepared as follows: First, the foam metal used as the main material for the cathode liquid guiding layer and the anode liquid guiding layer is pretreated by sequentially cleaning with acetone, ethanol, and deionized water. Then, photoresist is applied, dried, and exposed using a mask with a water-blocking channel structure pattern. After development, drying, wet etching, and photoresist removal, the water-blocking channel structure is obtained. Finally, the water-blocking material is placed within the channel structure by inkjet printing, injection, or spraying to act as a water barrier, allowing the carbon dioxide trapping liquid or anode electrolyte to flow directionally within the channel structure.

[0031] Taking a nickel foam substrate as an example, the fabrication of the water-blocking channel structure includes the following steps: Cleaning with acetone, ethanol, and deionized water; then spin-coating with SU-8 photoresist, drying, and exposing using a mask with the water-blocking channel structure pattern. Next, developing with SU-8 Developer developer, drying, and then wet etching with 5% ferric chloride etchant for 10-20 seconds, followed by rinsing for 10-20 seconds, repeated 3-5 times. Finally, removing the photoresist with Remover PG remover yields the water-blocking channel structure.

[0032] In some embodiments, the depth of the water-blocking channel structure is 75 to 800 micrometers, and the width is 2 to 5 millimeters. Since the channel structure is vertically continuous, its depth is the same as the thickness of the liquid guiding layer. Preferably, the thickness of the liquid guiding layer is 75 to 300 micrometers, and the width is 2 to 5 millimeters. The porosity of the foam metal is 0.85 to 0.95; the pore size of the foam metal is 20 to 60 micrometers. The foam metal has a large-pore structure, resulting in less resistance to fluid flow. The water-blocking material within the channel structure is primarily composed of strongly hydrophobic polymers. This strong hydrophobicity aims to prevent fluid flow. The water-blocking material prevents fluid diffusion in the horizontal direction, ensuring that the cathode carbon dioxide capture solution or anolyte can flow along the channel and distribute throughout the entire liquid guiding layer. However, in the vertical direction (layering direction), it allows fluid diffusion and contact with the catalyst layer. Furthermore, the large-pore structure of the foam metal also ensures that gaseous products can be discharged.

[0033] In this invention, the cathode liquid guiding layer is located between the cathode gas-liquid separation layer and the cathode catalyst layer. The main structure is a hydrophilic foam metal with a water-blocking flow channel structure. Its function is to provide a directional flow channel and the pores required for diffusion mass transfer for the relatively high viscosity cathode collecting liquid (the viscosity of water is 0.89 mpa·s, while the viscosity of the collecting liquid can reach 6-10 mpa·s). At the same time, its high electronic conductivity ensures the effective distribution of cathode current.

[0034] In this invention, the anolyte liquid guiding layer has the same material and function as the cathode liquid guiding layer, providing a guiding and mass transfer channel for the anolyte (such as KOH solution).

[0035] In a preferred embodiment, the cathode gas-liquid separation layer and the anode gas-liquid separation layer of the present invention use a water-resistant and air-permeable polymer membrane as the water-resistant and air-permeable material. The thickness of the cathode gas-liquid separation layer and the anode gas-liquid separation layer, i.e., the water-resistant and air-permeable polymer membrane, can be between 4 micrometers and 650 micrometers, more preferably between 25 micrometers and 120 micrometers.

[0036] The cathode gas-liquid separation layer of this invention is located between the cathode gas guiding layer and the cathode liquid guiding layer. It is a selectively permeable layer composed of a polytetrafluoroethylene film or a polymer plastic composite film with a micro-nano porous structure, allowing gas to pass through while blocking liquid, thus achieving primary gas-liquid separation on the cathode side. In this invention, the anode gas-liquid separation layer corresponds to the cathode gas-liquid separation layer in terms of material and function, and is used to separate and remove oxygen generated at the anode.

[0037] In some embodiments, the water-resistant and breathable polymer membrane is made of any one or a combination of at least two of polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyurethane, and polyethersulfone; the porosity of the water-resistant and breathable polymer membrane is 0.30 to 0.70; the hydrostatic pressure of the water-resistant and breathable polymer membrane is greater than or equal to 1,000 mm H2O; the CO permeability of the water-resistant and breathable polymer membrane is 50 to 5,000 Barrer; and the water contact angle of the water-resistant and breathable polymer membrane is greater than or equal to 120°. This water-resistant and breathable polymer membrane can be commercially available or synthesized in a laboratory.

[0038] In a preferred embodiment, the porous material used for both the cathode gas guiding layer and the anode gas guiding layer is a hydrophobically treated carbon layer or a porous layer composed of metal foam. Preferably, it is a carbon layer doped with polytetrafluoroethylene with a mesoporous structure, and the carbon layer can be carbon paper, carbon cloth, or carbon fiber.

[0039] In some embodiments, the mesoporous structure has a pore size ranging from 50 to 250 nanometers; the mesoporous structure has a porosity ranging from 0.60 to 0.80; and the polytetrafluoroethylene (PTFE) doping amount is 20-80 wt.%. Doped PTFE can be prepared by spraying a PTFE emulsion onto the surface of a carbon layer. The PTFE emulsion is obtained by mixing PTFE monomers with a hydrated surfactant CTAB (hexadecyltrimethylammonium bromide).

[0040] More preferably, the carbon layer is made of any one or a combination of at least two of graphite, graphene, graphynylene, single-walled carbon nanotubes, multi-walled carbon nanotubes, carbon aerogels, and carbon fibers.

[0041] In this invention, the anode gas guiding layer corresponds in material and function to the cathode gas guiding layer, and is used to extract oxygen. The thickness of both the cathode gas guiding layer and the anode gas guiding layer can be between 75 micrometers and 800 micrometers.

[0042] In some embodiments, the cathode catalyst layer is directly coated or transferred onto the cathode-side surface of the cation exchange membrane, and is made of a mixture of an electrocatalyst (such as any one or a combination of at least two of silver, gold, copper, and cobalt nanoparticles), a conductive agent (such as carbon black), and an ionomer (such as an anionic ionomer); preferably, the cathode catalyst loading is 0.1. 5 mg / cm 2 The cathode catalyst has a particle size of 5-200 nanometers.

[0043] In some embodiments, the anode catalyst layer is directly coated or transferred onto the anode-side surface of the anion exchange membrane, and is made of an oxygen evolution reaction electrocatalyst (such as any one or a combination of at least two of supported platinum, platinum-carbon, ethyl, ethyl oxide, and nickel) and an ionomer. Preferably, the anode catalyst loading is 0.1. 5 mg / cm 2 The anode catalyst has a particle size of 5-200 nanometers.

[0044] In this invention, the cation exchange membrane is used for selectively conducting cations (such as H+). + K + Na + The anion exchange membrane and the cation exchange membrane are directly bonded face-to-face. This dual-membrane structure design effectively prevents direct mixing between the cathode absorbent and the anolyte, and synergistically optimizes the transport paths of different ions.

[0045] The thickness of the cathode catalyst layer and the anode catalyst layer can be set between 1 micrometer and 50 micrometers as needed, the thickness of the anion exchange membrane can be between 15 micrometers and 430 micrometers, and the thickness of the cation exchange membrane can be set between 5 micrometers and 1500 micrometers as needed.

[0046] The stacked electrode device of the present invention can be formed by precise hot pressing between layers to form a zero-gap stacked structure.

[0047] In the stacked device of the present invention, the cathode catalyst layer is directly loaded on the cation exchange membrane, and the anode catalyst layer is directly loaded on the anion exchange membrane. The cation exchange membrane and the anion exchange membrane are directly bonded together to form a zero-gap stacked structure, which can provide faster electron, proton and molecule transport speed. On the other hand, it can also reduce the internal resistance of the electrodes.

[0048] The embodiments of the present invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The process parameters in the following embodiments that do not specify specific conditions are generally in accordance with conventional conditions.

[0049] The carbon dioxide capture solution applicable to the stacked electrode device of the present invention can be an alkaline capture solution obtained by capturing carbon dioxide using KOH or KHCO3 solution, or an alkaline capture solution obtained by capturing carbon dioxide using amine solution. The amine substance includes, but is not limited to, monoethanolamine (MEA), diethanolamine (DEA), piperazine (PZ), methyldiethanolamine (MDEA), 2-amino-methyl-1-propanol, etc., and the typical concentration range of KOH or KHCO3 solution or amine solution is 0.05-5 mol / L.

[0050] In some embodiments, the carbon dioxide capture solution is a fresh or partially recycled alkaline capture solution containing bicarbonate or carbamate ions that are directly absorbed by industrial flue gas or air. This capture solution is introduced from the inlet of the cathode liquid guide layer, where carbon dioxide is bound in a state such as bicarbonate (HCO3-). - , carbamate RNHCOO - Existing in the form of [agent], through local interface pH adjustment and the synergistic effect of the electrocatalyst, it can be released in situ and reduced to products such as carbon monoxide, formic acid, or ethylene. This process avoids the high-energy-consuming thermal desorption steps required for traditional amine liquid regeneration. Simultaneously, the anolyte enters from the inlet of the anolyte liquid guide layer. The anolyte, such as an aqueous solution of KHCO3 or KOH, continuously flows on the anolyte catalyst layer, serving two purposes: firstly, as an electrolyte to conduct ions, and secondly, to provide raw materials for the reaction. Water molecules or hydroxide ions in the electrolyte undergo electrochemical in-situ oxidation at the catalytic site, ultimately precipitating as oxygen bubbles.

[0051] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0052] The process parameters in the following examples, unless otherwise specified, are generally performed under conventional conditions.

[0053] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following detailed description, in conjunction with the accompanying drawings and embodiments, provides a multilayer electrode device for the electrocatalytic reduction of carbon dioxide capture liquid provided by this invention. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of protection of this invention.

[0054] Example 1 like Figure 1As shown, the present invention provides a stacked electrode device for electrocatalytic reduction of carbon dioxide capture liquid, which includes, from cathode to anode, the following layers in sequence: cathode gas guiding layer 1, cathode gas-liquid separation layer 2, cathode liquid guiding layer 3, cathode catalyst layer 4, cation exchange membrane 5, anion exchange membrane 6, anode catalyst layer 7, anode liquid guiding layer 8, anode gas-liquid separation layer 9, and anode gas guiding layer 10.

[0055] In this embodiment: The cathode gas guiding layer 1 is a carbon layer (made of carbon fiber) doped with polytetrafluoroethylene (PTFE), with a pore size of 50-250 nanometers, a porosity of 0.76, and a doping amount of 50 wt%. This layer provides a diffusion channel for the gaseous products generated at the cathode (such as CO and C2H4), and has a thickness of 315 micrometers.

[0056] The cathode gas-liquid separation layer 2 is made of a water-resistant and air-permeable polymer membrane PTFE, with a water contact angle greater than 120°, hydrostatic pressure ≥1000 mmH2O, porosity of 0.5, and CO permeability of 2,000 Barrer. It can effectively prevent electrolyte permeation while allowing gas molecules to pass through, thus achieving primary gas-liquid separation. The thickness is 50 micrometers.

[0057] Top view of cathode liquid guide layer 3 as shown Figure 2As shown, its main body is nickel foam material with a porosity of 0.90 and a pore size of 20 to 60 micrometers, and its surface is treated with hydrophilicity. A serpentine flow channel is formed inside this nickel foam material, running vertically through it. The cathode liquid guiding layer 3, together with the upper cathode gas-liquid separation layer 2 and the lower cathode catalyst layer 4, are compositely pressed to form this water-blocking flow channel structure, including a cathode liquid guiding layer electrolyte inlet 33, a cathode liquid guiding layer liquid flow channel 32, a cathode liquid guiding layer partition structure 31, and a cathode liquid guiding layer electrolyte outlet 34. The cathode liquid guiding layer electrolyte inlet 33 and the cathode liquid guiding layer electrolyte outlet 34 are used for the input and output of the capture liquid, respectively, enabling the carbon dioxide capture liquid to flow directionally and be evenly distributed to the cathode catalyst layer. The water-blocking channel structure on the surface of the nickel foam material was prepared by the following method: First, the substrate foam metal was pretreated by sequentially cleaning with acetone, ethanol, and deionized water. Then, SU-8 photoresist was spin-coated, dried, and exposed using a mask with a serpentine water-blocking channel pattern. Next, SU-8 Developer was used for development, followed by drying. Wet etching was performed using 5% ferric chloride etchant for 15 seconds, followed by rinsing for 15 seconds, repeated 5 times. Finally, Remover PG remover was used to remove the photoresist. Finally, polyetheretherketone (PEEK) water-blocking material was applied to the inner surface of the serpentine channel structure using inkjet printing to act as a water barrier, allowing the carbon dioxide trapping liquid to flow directionally within the channel structure. The cathode liquid guiding layer has a thickness of 100 micrometers, meaning the water-blocking channel structure is 100 micrometers thick and 2 millimeters wide.

[0058] The cathode catalyst layer 4 is directly supported on the surface of the cation exchange membrane 5, and the catalyst used is silver nanoparticles with a loading of 0.5 mg / cm³. 2 The particle size is approximately 50 nanometers. This layer also contains carbon black conductive agent and anionic ionomers, ensuring electron and ion transport channels.

[0059] The cation exchange membrane 5 and the anion exchange membrane 6 are bonded together to form a zero-gap structure. This dual-membrane structure not only ensures that the electrolytes at the anode and cathode do not cross-contaminate, but also optimizes the migration paths of protons and anions, significantly reducing internal resistance. The cation exchange membrane is made of perfluorosulfonic acid and has a thickness of 183 micrometers, while the anion exchange membrane is made of fluorocarbonate resin and has a thickness of 50 micrometers.

[0060] Anode catalyst layer 7 Figure 1 As shown, the IrO2 catalyst is directly supported on the anion exchange membrane 6. In this embodiment, nickel foam is used to support the IrO2 catalyst with a loading of 0.3 mg / cm² and a particle size of about 100 nanometers, which is used for the efficient oxygen evolution reaction.

[0061] Anode liquid guide layer 8 Figure 3As shown, the anode liquid guiding layer includes a liquid flow channel 82, an anode liquid guiding layer partition structure 81, an anode liquid guiding layer electrolyte inlet 83, and an anode liquid guiding layer electrolyte outlet 84. Its main body is titanium foam with a porosity of 0.95 and a pore size of 20 to 60 micrometers. Its preparation method is the same as that of the cathode liquid guiding layer 3. The anode liquid guiding layer electrolyte inlet 83 and the anode liquid guiding layer electrolyte outlet 84 are used for the input and output of alkaline electrolyte (such as 1 mol / L KOH), respectively.

[0062] The anode gas-liquid separation layer 9 has a similar structure to the cathode gas-liquid separation layer 2, and uses the same water-resistant and air-permeable polymer membrane to ensure that oxygen can be quickly discharged and separated from the electrolyte.

[0063] The anode gas guide layer 10 and the cathode gas guide layer are made of the same material and have the same structural parameters as the cathode gas guide layer 1. They are used to extract high-purity oxygen.

[0064] according to Figure 1 The above layers are stacked in sequence and then hot-pressed at 120°C and 8 MPa for 60 seconds on a hot press to obtain a stacked electrode device.

[0065] like Figure 4 As shown, after saturating a 0.1 mol / L aqueous solution of 2-amino-methyl-1-propanol with CO2 in a CO2 absorption tower (while maintaining a constant pH), the resulting carbon dioxide capture solution enters the cathode liquid guide layer 3 at a rate of 200 mL / min through the electrolyte inlet 33. It then flows directionally through the liquid flow channel 32, distributing throughout the liquid guide layer. Simultaneously, in the vertical direction (in the stacked direction), the fluid diffuses and contacts the cathode catalyst layer 4, ensuring uniform distribution and transport to the cathode catalyst layer 4. During electrolysis at 25 degrees Celsius, under the action of a nano-silver catalyst, the flow rate is 10 mA / cm². 2 Electrochemical reduction at a specific current density produces syngas composed of carbon monoxide (89.1%) and hydrogen (10.9%). The generated gaseous products preferentially pass through the cathode gas-liquid separation layer 2 and are then discharged through the gas guide layer 1. The generated syngas, including CO, is collected in a gas storage tank. The 0.01 mol / L 2-amino-methyl-1-propanol solution after electrolysis is recycled to a CO2 absorption tower to absorb CO2 before being electrolyzed again to produce syngas.

[0066] like Figure 5As shown, a 1 mol / L anolyte (KHCO3 solution) enters the anode liquid guide layer 8 from the electrolyte inlet 83 at a flow rate of 200 ml / min. It then flows directionally through the liquid flow channel 82 and is distributed throughout the entire liquid guide layer. Simultaneously, in the vertical direction (layering direction), the fluid diffuses and contacts the anode catalyst layer 7, achieving uniform distribution within the anode catalyst layer 7. Under conditions of 25 degrees Celsius and the action of the iridium oxide catalyst, the flow rate is 10 mA / cm². 2 The oxygen evolution reaction is carried out (oxygen Faraday efficiency 100%). The generated oxygen passes through the anode gas-liquid separation layer 9 and is led out by the anode gas guide layer 10, achieving physical isolation from the cathode products.

[0067] In this embodiment, the stacked electrode device does not require an external flow field plate and gas-liquid separation unit during electrolysis, making operation simple. The anode product gas (O2) has high purity, and no cathode gas products (CO, H2, etc.) cross-contaminated into the anode product gas flow are detected. The anode electrolyte can maintain stability for 50 hours, and no cathode electrolyte component (2-amino-methyl-1-propanol) was detected by NMR, resulting in a significant improvement in energy efficiency.

[0068] Example 2 The stacked electrode device in this embodiment has the same basic structure as that in embodiment 1. The difference is that the carbon dioxide capture solution input into the cathode liquid guiding layer 3 is a 0.05 mol / L monoethanolamine aqueous solution obtained after capturing and absorbing CO2 to saturation in the CO2 absorption tower (the solution pH value remains unchanged).

[0069] In this embodiment: Cathode liquid guide layer 3 (see Figure 2 The electrolyte inlet 33 of the cathode liquid guide layer is supplied with fresh or partially recycled monoethanolamine trapping solution. Guided by the liquid flow channel 32 of the cathode liquid guide layer, the liquid flows directionally and is evenly distributed to the cathode catalyst layer 4.

[0070] On the cathode catalyst layer 4, carbon dioxide exists in a bound state (such as carbamate RNHCOO). - Bicarbonate (HCO3) - It exists in the form of carbon dioxide and, through the synergistic effect of local interface pH adjustment and electrocatalyst, can be directly reduced in situ or released in situ and then (indirectly) reduced to products such as carbon monoxide, formic acid, or ethylene. This process avoids the high-energy-consuming thermal desorption steps required for the regeneration of traditional carbon dioxide-rich amine solutions (carbon dioxide capture solutions).

[0071] This embodiment specifically addresses the high viscosity of the amine-collecting solution by optimizing the material design of the cathode liquid guiding layer 3 and the cathode gas-liquid separation layer 2: The cathode liquid guiding layer 3 uses hydrophilic nickel foam with a pore size of 30 to 50 micrometers to ensure smooth flow of high-viscosity capture liquid; The cathode gas-liquid separation layer 2 is made of a water-resistant and air-permeable polymer membrane PTFE with a water contact angle ≥130° to inhibit amine liquid permeation and membrane fouling.

[0072] The liquid guide layer 8 of the anode section is fed with alkaline electrolyte (such as 1 M KOH), which is completely isolated from the cathode collecting liquid to ensure electrolytic stability.

[0073] During operation, the cathode catalyst layer 4 uses a copper-based catalyst (loading 1 mg / cm³). 2 (Particle size approximately 80 nanometers), at a current density of 100 mA / cm² 2 The reaction was conducted at a temperature of 40 ℃. The results showed that: This amine trapping solution can be used directly as an electrolysis reactant, and the system operates stably for more than 50 hours. The cathode product gases (CO, C2H4, etc.) have high purity, and no obvious amine molecules were detected crossing into the product gas stream; This method bypasses the most energy-intensive thermal desorption step in traditional technology and directly electrolyzes the collected liquid, eliminating the biggest energy bottleneck at the source. Rough calculations show that the overall energy consumption is reduced by about 20% compared to the traditional "amine liquid + thermal desorption + CO2" electrolysis route.

[0074] Example 3 The stacked electrode device in this embodiment has the same basic structure as that in embodiment 1. The difference is that the carbon dioxide capture solution input into the cathode liquid guiding layer 3 is a 2 mol / L KOH aqueous solution obtained after capturing and absorbing CO2 to saturation in the CO2 absorption tower (the solution pH value remains unchanged), and the concentration is a 2 mol / L KHCO3 aqueous solution.

[0075] Example 4 The rest is the same as in Example 1, except that the depth of the liquid flow channel is 75 micrometers and the width is 2 millimeters.

[0076] Example 5 The rest is the same as in Example 1, except that the depth of the liquid flow channel is 200 micrometers and the width is 4 millimeters.

[0077] Example 6 The rest is the same as in Example 1, except that the depth of the liquid flow channel is 800 micrometers and the width is 5 millimeters.

[0078] The stacked devices prepared in the above embodiments can all operate stably for more than 50 hours, with high purity of the anode product and no cross-contamination of cathode gas products into the anode product gas stream detected. Furthermore, the stacked electrode devices described in the above embodiments exhibit good compatibility with different types of trapping solutions, expanding the application scenarios and industrialization potential of the stacked electrode devices of this invention.

[0079] Comparative Example 1 The rest is the same as in Example 1, except that the depth of the water-blocking channel structure of the cathode liquid guiding layer and the anode liquid guiding layer is 850 micrometers and the width is 5 millimeters.

[0080] Comparative Example 2 The rest is the same as in Example 1, except that the thickness of the water-blocking channel structure of the cathode liquid guiding layer and the anode liquid guiding layer is 60 micrometers and the width is 5 millimeters.

[0081] The obtained stacked electrode devices were subjected to electrocatalytic reduction of carbon dioxide capture solution under the same conditions. Experiments revealed that in Comparative Example 1, the excessive thickness of the liquid guide layer (even with a width of 5 mm) resulted in significant mass transfer resistance, leading to insufficient reactant concentration at the active sites and delayed product removal, thus reducing the overall catalytic reaction rate and current density. In Comparative Example 2, the insufficient thickness of the liquid guide layer (even with a width of 5 mm) resulted in inadequate liquid storage and flow equalization capabilities, failing to continuously and stably supply reactants to the electrode surface. This easily caused excessively high local current density, uneven reaction, and even potential accumulation of gaseous products (such as CO and H2) on the electrode surface, hindering the reaction interface and leading to decreased catalytic efficiency and stability. Therefore, a suitable liquid guide layer thickness is controlled within the range of 75-800 micrometers, and the channel structure width is within the range of 2-5 mm.

[0082] In the description of this application, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0083] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A stacked electrode device for the electrocatalytic reduction of carbon dioxide capture liquid, characterized in that, It includes, in sequence, a cathode gas guiding layer, a cathode gas-liquid separation layer, a cathode liquid guiding layer, a cathode catalyst layer, a cation exchange membrane, an anion exchange membrane, an anode catalyst layer, an anode liquid guiding layer, an anode gas-liquid separation layer, and an anode gas guiding layer; wherein: The cathode liquid guiding layer is provided with a vertically penetrating water-blocking channel structure, and the inner surface of the channel structure is provided with water-blocking material to provide a channel for directional flow and diffusion mass transfer of the carbon dioxide capture liquid. The cathode gas-liquid separation layer is made of a water-resistant and air-permeable material, which is used to achieve primary separation of gas and liquid on the cathode side. The cathode gas guide layer is a porous material used to provide a diffusion channel for the gaseous reduction products generated at the cathode. The anode liquid guiding layer is provided with a vertically continuous water-blocking channel structure, and the inner surface of the channel structure is provided with a water-blocking material; it is used to provide a channel for directional flow and diffusion mass transfer of alkaline electrolyte for the anode. The anode gas-liquid separation layer is made of a water-resistant and air-permeable material, which is used to achieve primary separation of gas and liquid on the anode side; The anode gas guide layer is a porous material used to provide a diffusion channel for the gaseous oxidation products generated at the anode.

2. The stacked electrode device as described in claim 1, characterized in that, The main materials of the cathode liquid guiding layer and the anode liquid guiding layer are hydrophilic foam metal; Preferably, the porosity of the foamed metal is 0.85 to 0.95; the pore size of the foamed metal is 20 micrometers to 60 micrometers; and the depth of the water-blocking channel structure is 75 micrometers to 800 micrometers, and the width is 2 millimeters to 5 millimeters.

3. The stacked electrode device as described in claim 1, characterized in that, The water-blocking material disposed on the inner surface of the flow channel structure is any one or a combination of at least two of polyether ether ketone, polyarylether ketone, polyetherimide, polyarylether sulfone, polyphenylene sulfide, or polyarylether imide.

4. The stacked electrode device as described in claim 3, characterized in that, The water-blocking material is applied to the inner surface of the flow channel structure by inkjet printing, injection, or spraying to block water, thereby allowing the carbon dioxide capture liquid to flow directionally within the flow channel structure.

5. The stacked electrode device as described in claim 1, characterized in that, The cathode gas-liquid separation layer and the anode gas-liquid separation layer use water-resistant and air-permeable polymer membranes as the water-resistant and air-permeable material.

6. The stacked electrode device as described in claim 5, characterized in that, The water-barrier and breathable polymer membrane is made of any one or a combination of at least two of the following: polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, polyurethane, and polyethersulfone.

7. The stacked electrode device as described in claim 6, characterized in that, The porosity of the water-resistant and breathable polymer membrane is 0.30 to 0.70; the hydrostatic pressure of the water-resistant and breathable polymer membrane is greater than or equal to 1,000 mm H2O; the CO permeability of the water-resistant and breathable polymer membrane is 50 to 5,000 Barrer; and the water contact angle of the water-resistant and breathable polymer membrane is greater than or equal to 120°.

8. The stacked electrode device as described in claim 1, characterized in that, The porous materials used in the cathode gas guiding layer and the anode gas guiding layer are hydrophobically treated carbon paper or porous layers composed of metal foam.

9. The stacked electrode device as described in claim 1, characterized in that, The cathode catalyst layer is directly coated or transferred onto the cathode side surface of the cation exchange membrane; the anode catalyst layer is directly coated or transferred onto the anode side surface of the anion exchange membrane.

10. The stacked electrode device as described in claim 1, characterized in that, The cation exchange membrane is used for selective cation conduction; the anion exchange membrane is directly attached to the cation exchange membrane face to face.

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