Carbon dioxide electroreduction reaction device having function of direct generation of multi-phase flow

Abstract

A carbon dioxide electroreduction reaction device having the function of direct generation of a multi-phase flow. The carbon dioxide electroreduction reaction device comprises a cathode plate, a cathode electrode and a cathode flow channel plate, which are arranged in sequence. The cathode plate is provided with a cathode first feeding channel and a cathode second feeding channel. The cathode electrode is provided with a first hole connected to the cathode first feeding channel and a second hole connected to the cathode second feeding channel. The cathode flow channel plate comprises a first area provided with non-hollowed-out grooves and a hollowed-out second area, wherein the first area is arranged on the side of the cathode flow channel plate close to the cathode electrode in the direction of thickness; and both the first hole and the second hole are connected to the first area, and the first area is connected to the second area, such that a cathode first material and a cathode second material can enter the first area respectively through the cathode first feeding channel and the cathode second feeding channel, converge and mix in the first area, and then enter the second area.

Description

Carbon dioxide electroreduction reaction device with direct multiphase flow generation function

[0001] Citation of Related Applications

[0002] This application claims priority to a prior invention patent application filed in China with an application date of March 27, 2024, application number 202410359372.7, and invention name “Carbon dioxide electro-reduction reaction device with multiphase flow direct generation function”. The entire contents of the prior application are incorporated herein by reference. Technical Field

[0003] The present application relates to the field of electrochemical reduction of carbon dioxide, and in particular to a carbon dioxide electrochemical reduction reaction device with a multiphase flow direct generation function. Background Art

[0004] As global industrialization continues, carbon dioxide (CO2), the most important greenhouse gas, generated by fossil fuel consumption continues to accumulate in the atmosphere, leading to a series of serious environmental pollution and climate change issues. Among the various CO2 conversion and utilization technologies, CO2 electroreduction strategies have attracted widespread attention due to their mild reaction conditions and excellent sustainability.

[0005] In the early studies on carbon dioxide electroreduction, intermittent electrolyzers were more commonly used. Carbon dioxide gas molecules, as raw materials for heterogeneous catalytic reactions, need to first be dissolved in the electrolyte and then diffuse to the electrode surface to participate in the reaction. Due to the low solubility of carbon dioxide in aqueous solution, this greatly slows down the supply of gaseous reactants on the electrode surface, resulting in a slower reaction rate. In comparison, gas diffusion electrodes with a porous structure can directly transport carbon dioxide from the gas phase to the catalyst surface, effectively weakening the mass transfer limitations. Therefore, compared with intermittent electrolyzers, the theoretical reaction activity of carbon dioxide electroreduction in flow electrolytic cells equipped with gas diffusion electrodes can be increased by several orders of magnitude (for example, up to 10kA / m 2 ).

[0006] However, the catalyst layer of the gas diffusion electrode needs to be hydrophilic in order to form a path in direct contact with the electrolyte. During the long electrolysis process, solution infiltration and salt precipitation cause the electrolyte to penetrate and block the gas diffusion channels, ultimately reducing the opportunity for carbon dioxide gas to enter the catalyst surface, resulting in a significant decrease in reaction activity. Therefore, under actual working conditions, gas diffusion electrodes often need to enhance their overall stability through complex and high-cost structural control. Even so, the actual activity of the electrode after optimization (1-2kA / m 2 ) is still far below 10kA / m 2The theoretical activity of CO2 electroreduction is limited. Therefore, the field of CO2 electroreduction urgently needs to develop a technical route other than gas diffusion electrodes to further improve operational stability while maintaining a high reaction rate within the system.

[0007] As a widely used micro-chemical technology, multiphase flow technology can enhance the mass transfer process between the gas and liquid phases, thereby increasing the rate of carbon dioxide electroreduction reaction. At present, electrolysis devices based on multiphase flow technology generally adopt a scheme of pre-mixing and then electrolysis outside the device, that is, a multiphase flow is first generated in an external pipeline, and then introduced into the electrolysis device for reaction. However, during the transportation of the multiphase flow in the external pipeline, its flow pattern often changes, which may cause the gas-liquid phase contact area to decrease, and ultimately lead to a decrease in mass transfer efficiency; at the same time, the multiphase flow generation module and supporting pipelines outside the electrolysis device occupy a large amount of space, making the reaction system complicated. The carbon dioxide electrolysis device disclosed in the patent application with publication number CN116288441A uses the above-mentioned multiphase flow technology to provide reaction raw materials for the cathode of the electrolytic cell, and it also has the above-mentioned problems worthy of attention.

[0008] Therefore, there is still room for improvement in carbon dioxide electroreduction reaction devices.

[0009] Summary of the Invention

[0010] In order to solve or alleviate at least one of the problems mentioned in the background art, the present application provides a carbon dioxide electroreduction reaction device with a multiphase flow direct generation function.

[0011] The present application provides a carbon dioxide electroreduction reaction device with a multiphase flow direct generation function, comprising:

[0012] A cathode plate, wherein a first cathode feed channel and a second cathode feed channel are provided on the cathode plate, wherein the first cathode feed channel is used to introduce a first cathode material, and the second cathode feed channel is used to introduce a second cathode material;

[0013] a cathode electrode, wherein the cathode electrode is provided with a first hole connected to the first cathode feed channel and a second hole connected to the second cathode feed channel;

[0014] A cathode flow channel plate, the cathode flow channel plate includes a first area with non-hollowed grooves and a hollowed second area, the first area is arranged on the side of the cathode flow channel plate close to the cathode electrode in the thickness direction, the first hole and the second hole are both connected to the first area, and the first area is connected to the second area, so that the cathode first material and the cathode second material can enter the first area through the cathode first feed channel and the cathode second feed channel respectively, intersect and mix in the first area, and then enter the second area.

[0015] In at least one embodiment, the flow channel where the first cathode material and the second cathode material meet is perpendicular to the flow channel where the second cathode material meets.

[0016] In at least one embodiment, the first region includes a first flow channel, the first hole and the second hole are respectively connected to the upstream and downstream of the first flow channel, and the axis direction of the second hole is perpendicular to the cathode flow channel plate.

[0017] In at least one embodiment, the axial direction of the first hole and the axial direction of the second hole are both perpendicular to the cathode flow channel plate.

[0018] In at least one embodiment, the first region includes a first flow channel and a second flow channel that are perpendicular to each other, the first hole is connected to the first flow channel, and the second hole is connected to the second flow channel.

[0019] In at least one embodiment, the first zone includes a third flow channel, and the third flow channel is located downstream of the intersection of the cathode first material and the cathode second material.

[0020] In at least one embodiment, the carbon dioxide electroreduction reaction device further includes an ion exchange membrane, an anode electrode, and an anode plate arranged in sequence, and the ion exchange membrane is attached to the cathode flow channel plate.

[0021] In at least one embodiment, the carbon dioxide electric reduction reaction device further includes an anode membrane electrode, an anode current collector, and an anode plate arranged in sequence, and the anode membrane electrode is attached to the cathode flow channel plate.

[0022] In at least one embodiment, the cathode plate further has a cathode discharge channel.

[0023] In at least one embodiment, the anode plate has an anode feed channel and an anode discharge channel. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 shows a disassembled schematic diagram of a carbon dioxide electroreduction reaction device with a multiphase flow direct generation function according to one embodiment of the present application.

[0025] FIG2 shows a schematic structural diagram of a multiphase flow generation site of a carbon dioxide electroreduction reaction device having a multiphase flow direct generation function according to one embodiment of the present application.

[0026] FIG3 shows a schematic structural diagram of a cathode plate and a cathode flow channel plate of a carbon dioxide electroreduction reaction device with a multiphase flow direct generation function according to one embodiment of the present application.

[0027] FIG4 shows a schematic structural diagram of a cathode plate and a cathode flow channel plate of a carbon dioxide electroreduction reaction device with a multiphase flow direct generation function according to another embodiment of the present application.

[0028] FIG5 shows a relationship diagram between the total current density and product selectivity of the carbon dioxide electroreduction reaction device with a multiphase flow direct generation function according to Example 1 of the present application.

[0029] FIG6 shows a relationship diagram among the device operation time, voltage and product selectivity of the carbon dioxide electroreduction reaction device with multiphase flow direct generation function according to Example 2 of the present application. DETAILED DESCRIPTION

[0030] The following describes exemplary embodiments of the present application with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all possible embodiments of the present application, nor to limit the scope of the present application.

[0031] 1 , the carbon dioxide electroreduction reaction device with a multiphase flow direct generation function provided herein (hereinafter sometimes referred to as the "carbon dioxide electroreduction reaction device") may include a cathode plate 100, a cathode electrode 200, a cathode flow channel plate 300, an ion exchange membrane 410, an anode electrode 510, and an anode plate 600, which are sequentially arranged. Furthermore, the above components may be tightly fitted together.

[0032] The cathode plate 100 may be provided with a first cathode feed channel 110 and a second cathode feed channel 120. The first cathode feed channel 110 is used to introduce a first cathode material, such as a cathode electrolyte, and the second cathode feed channel 120 is used to introduce a second cathode material, such as carbon dioxide gas.

[0033] The cathode electrode 200 may be provided with a first hole 210 connected to the first cathode feed channel 110 and a second hole 220 connected to the second cathode feed channel 120 .

[0034] 2 to 4 , the cathode flow channel plate 300 may include a first region 310 having a non-hollowed-out groove and a hollowed-out second region 320. The first region 310 is disposed on a side of the cathode flow channel plate 300 that is close to the cathode electrode 200 in the thickness direction (i.e., the groove opening of the first region 310 faces the cathode electrode 200). The first hole 210 and the second hole 220 are both connected to the first region 310, and the first region 310 is connected to the second region 320, so that the cathode first material and the cathode second material can enter the first region 310 through the cathode first feed channel 110 and the cathode second feed channel 120, respectively, and intersect and mix in the first region 310 to form a multiphase flow before entering the second region 320.

[0035] For example, referring to FIG2 , flow channels are formed in both the first region 310 and the second region 320. The cathode electrode 200 and the cathode flow channel plate 300 form the two side walls of the flow channel in the first region 310, and the cathode electrode 200 and the ion exchange membrane 410 form the two side walls of the flow channel in the second region 320. The two cathode materials can converge at the first region 310 (e.g., the point in the first region 310 corresponding to the second hole 220 shown in FIG2 ) to form a multiphase flow and flow into the flow channel in the second region 320. When power is applied, the multiphase flow will undergo a reduction reaction on the surface of the cathode electrode 200.

[0036] It can be understood that the multiphase flow provided in the present application is a two-phase mixed flow consisting of carbon dioxide gas and electrolyte. Outside the carbon dioxide electro-reduction reaction device, the carbon dioxide gas path and the electrolyte liquid path are separated from each other, and after passing through the first cathode feed channel 110 and the second cathode feed channel 120, they intersect in the first zone 310, and are in situ mixed on the surface of the cathode electrode 200 to form an electrolyte containing a large number of carbon dioxide microbubbles (the overall flow of the multiphase flow presents a bubble flow). After the multiphase flow flows to the second zone 320, it contacts the ion exchange membrane 410, and the multiphase flow undergoes a carbon dioxide electro-reduction reaction in the second zone 320.

[0037] It can be understood that the present application is based on gas-liquid multiphase flow technology and does not adopt gas diffusion electrodes, thus avoiding the corresponding disadvantages of the gas diffusion electrodes described in the background art.

[0038] In addition, the present application directly embeds the multiphase flow generation site between the cathode electrode 200 and the cathode flow channel plate 300, and directly generates a continuous multiphase flow in situ on the surface of the cathode electrode 200, so that the gas-liquid two-phase contact area is always maintained at a large level in the electro-reduction device. During the flow of the multiphase flow, the carbon dioxide gas in the bubbles will be continuously added to the electrolyte, so that the electrolyte maintains a high carbon dioxide concentration during the reaction process, further strengthening the interphase mass transfer while accelerating the dissolution of carbon dioxide gas, improving the carbon dioxide electro-reduction activity, overcoming the mass transfer limitation, and solving the problem mentioned in the background technology that the multiphase flow is generated in the external pipeline and then introduced into the electrolysis device for reaction, which will result in a reduction in the gas-liquid contact area and ultimately a decrease in mass transfer efficiency.

[0039] Furthermore, the present application does not require the installation of an additional multiphase flow generation module and supporting pipelines outside the electro-reduction reaction device, thereby simplifying the system flow path, making operation more convenient, and further reducing operation and maintenance costs.

[0040] Therefore, the carbon dioxide electric reduction reaction device provided in the present application is superior to the carbon dioxide electric reduction reaction device based on gas diffusion type electrodes and the carbon dioxide electric reduction reaction device with external multiphase flow.

[0041] In one embodiment of the present application, referring to FIG2 , the first cathode material and the second cathode material intersect in a first region 310 through their respective flow channels, and at the intersection, the flow channel for the first cathode material is perpendicular to the flow channel for the second cathode material. It will be appreciated that the perpendicular flow channels at the intersection of the two materials facilitate the mutual cutting of the two materials to form a multiphase flow. The flow channel at the intersection of the two materials can be formed into a T-shape.

[0042] For example, referring to Figure 3, the first zone 310 includes a first flow channel 311. The first hole 210 and the second hole 220 are respectively connected to the upstream and downstream of the first flow channel 311. Also, referring to Figure 2, the second hole 220 connected to the downstream of the first flow channel 311 is perpendicular to the cathode flow channel plate 300, so that the first flow channel 311 is perpendicular to the axial direction of the second hole 220, thereby realizing the vertical intersection of the two fluids. Of course, the cathode second feed channel 120 can also be perpendicular to the cathode flow channel plate 300, and the axial direction of the first hole 210 and the cathode first feed channel 110 can also be perpendicular to the cathode flow channel plate 300. This application refers to the T-shaped structure of the flow channel at the intersection in this embodiment as a vertical T-shape.

[0043] Alternatively, referring to Figure 4, the first zone 310 may include a first flow channel 311 and a second flow channel 312 that are perpendicular to each other, the first hole 210 is connected to the first flow channel 311, and the second hole 220 is connected to the second flow channel 312. That is, by making the first flow channel 311 and the second flow channel 312 where the two materials are located before they intersect perpendicular, the two fluids intersect vertically. Of course, in this embodiment, the axial direction of the first hole 210, the axial direction of the cathode first feed channel 110, the axial direction of the second hole 220 and the cathode second feed channel 120 can also be perpendicular to the cathode flow channel plate 300. This application refers to the T-shaped structure of the flow channel at the intersection in this embodiment as a horizontal T-shape.

[0044] Furthermore, the first zone 310 may also include a third flow channel 313, which is located downstream of the intersection of the cathode first material and the cathode second material. Specifically, in FIG3 , the third flow channel 313 is located downstream of the first flow channel 311. In FIG4 , the third flow channel 313 is located downstream of the intersection of the first flow channel 311 and the second flow channel 312. It will be appreciated that after the multiphase flow is generated at the intersection (junction), it will continue to flow for a distance along the unrecessed third flow channel 313 to ensure the stability of the multiphase flow pattern.

[0045] In one embodiment of the present application, referring to FIG1 , the cathode plate 100 may further include a cathode discharge channel 130 , which is used to discharge products and related materials. For example, liquid products dissolve in the electrolyte, and gaseous products form bubbles that are ultimately discharged from the cathode discharge channel 130 .

[0046] 3 and 4 , the cathode plate 100 can act as a current collector, and a cathode current collecting joint 140 can be provided on the cathode plate 100 for connecting to an external circuit. The cathode current collecting joint 140 can be a threaded joint. The cathode plate 100 can also act as a fixed plate, and the carbon dioxide electric reduction reaction device can include a sealing ring 700, and a sealing groove 150 for accommodating the sealing ring 700 can be provided on the cathode plate 100. The first area 310 and the second area 320 can be arranged on the inner side of the sealing groove 150. The sealing ring 700 can enhance the sealing performance and prevent the multiphase flow from flowing out from the side of the carbon dioxide electric reduction reaction device. The material of the cathode plate 100 can be a metal or alloy material serving as a current collector, such as copper, titanium, silver, iron, nickel, aluminum and their alloys.

[0047] In one embodiment of the present application, cathode electrode 200 may be a metal foil electrode or a supported conductive foil electrode. The metal foil electrode may be made of metals and alloys including, but not limited to, tin, silver, copper, gold, bismuth, zinc, lead, and others, which exhibit carbon dioxide electroreduction activity. The supported conductive foil electrode may be made by loading a catalyst onto a conductive substrate, which may be a metal-based or carbon-based material.

[0048] In one embodiment of the present application, the material of the cathode flow channel plate 300 can be an insulating inert polymer material, such as polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), polyetheretherketone (PEEK), and polymethyl methacrylate (PMMA). The flow channel in the cathode flow channel plate 300 can be a serpentine flow channel to maximize the time the multiphase flow flows in the second zone 320. In order to avoid an increase in resistance due to an excessive thickness of the cathode flow channel plate 300, the thickness of the cathode flow channel plate 300 (the thickness of the area not hollowed out and not provided with grooves) can be set to less than 3 mm.

[0049] In one embodiment of the present application, the ion exchange membrane 410 may be an anion exchange membrane or a cation exchange membrane. The cation exchange membrane 410 may be Nafion 115 membrane, Nafion 117 membrane, Nafion XL membrane, and Nafion N324 membrane produced by DuPont.

[0050] In one embodiment of the present application, referring to FIG1 , an anode plate 600 may be provided with an anode feed channel 610 and an anode discharge channel 620. An anode plate groove 630 may be provided in the anode plate 600, and an anode plate flow channel 640 may be provided in the anode plate groove 630. The anode electrode 510 may be embedded in the anode plate groove 630 and cover the anode plate flow channel 640. The anode plate flow channel 640 may be formed as a serpentine flow channel.

[0051] The anode material (for example, the anode electrolyte) can enter the anode plate 600 from the anode feed channel 610 and flow along the anode plate flow channel 640. When energized, the anode electrolyte undergoes an oxidation reaction and is then discharged from the anode discharge channel 620. The anode plate 600 can serve as a current collector, and a current collecting joint is provided thereon to connect to an external circuit, and the joint can be a threaded joint. Referring to Figure 1, the anode plate 600 can serve as a fixed plate, and a sealing groove 650 for accommodating a sealing ring 700 can also be provided thereon. The material of the anode plate 600 can be a metal or alloy material that can serve as a current collector, such as copper, titanium, silver, iron, nickel, aluminum and alloys thereof.

[0052] The anode electrode 510 can be a fiber felt or porous foam metal loaded with a catalyst, and its base material can be a metal or metal oxide, such as titanium, nickel, copper, silver, aluminum and their oxides. The anode electrode 510 can play a certain supporting role for the ion exchange membrane 410 while catalyzing the oxidation reaction on the anode side. The anode catalyst loaded by the anode electrode 510 needs to be active for the water oxidation reaction. The anode catalyst can be a metal or metal oxide, such as iridium, platinum, palladium, ruthenium, rhodium, iron, cobalt, nickel, titanium and their oxides, and the loading amount can be 0.5 to 2 mg / cm 2 .

[0053] In one embodiment of the present application, the ion exchange membrane 410 and the anode electrode 510 can be replaced by an anode membrane electrode and an anode current collector. The anode membrane electrode can be an ion exchange membrane loaded with an anode catalyst. The anode catalyst can be evenly loaded on one side of the ion exchange membrane using an ultrasonic spraying process, and the side with the anode catalyst is close to the anode current collector, and the other side is close to the cathode flow channel plate 300. The ion exchange membrane 410 in the anode membrane electrode can be an anion exchange membrane or a cation exchange membrane, wherein the cation exchange membrane can use Nafion 115 membrane, Nafion 117 membrane, Nafion XL membrane and Nafion N324 membrane produced by DuPont. The loaded anode catalyst needs to be active in the water oxidation reaction. The anode catalyst can be a metal or a metal oxide, such as iridium, platinum, palladium, ruthenium, rhodium, iron, cobalt, nickel, titanium and its oxides, and the loading amount can be 0.5 to 2 mg / cm 2 .

[0054] The anode current collector can be an unloaded fiber felt or porous metal foam. It can be made of metals or metal oxides, such as titanium, nickel, copper, silver, aluminum, and their oxides. The anode current collector can be embedded in the anode plate groove 630, with one side covering the anode plate flow channel 640 and the other side in close contact with the catalyst side of the anode membrane electrode.

[0055] In one embodiment of the present application, the cathode electrolyte may be pressurized to further increase the carbon dioxide concentration in the electrolyte, thereby enabling the device to support a higher reaction current density.

[0056] In one embodiment of the present application, the sealing ring 700 may be made of fluororubber, which can achieve effective sealing of the device under normal pressure and pressurized conditions.

[0057] In one embodiment of the present application, the carbon dioxide electroreduction reaction device may further include a gas flow control device and a pump assembly to enable the addition of carbon dioxide and electrolyte to the cathode side. The carbon dioxide electroreduction reaction device may further include a pressure control device such as a back pressure valve, and the cathode discharge channel 130 and the anode discharge channel 620 may be connected to the back pressure valve to control the pressure of the fluid within the device.

[0058] For example, the flow rates of the cathode electrolyte and the anolyte can be controlled to 20 to 200 mL / min (milliliters per minute) by a pump assembly. The flow rate of the carbon dioxide gas is controlled to 20 to 1000 sccm (standard milliliters per minute) by a gas flow control device. If the device is operated under pressurized conditions, the pressure of the multiphase flow can be controlled by a back pressure valve, and the adjustable pressure range is 1 to 40 bar (bar). The pressure in the anode chamber and the cathode chamber can be kept consistent to balance the pressure difference on both sides of the ion exchange membrane 410 or the anode membrane electrode.

[0059] The reaction occurring on the cathode side of the carbon dioxide electroreduction device is carbon dioxide electroreduction, and the products may be formic acid, formate, carbon monoxide, etc.; the reaction occurring on the anode side is water oxidation to release oxygen. The anolyte and catholyte may be the same or different. The catholyte may be an aqueous solution of a first electrolyte, and the anolyte may be an aqueous solution of water, an acid, or a second electrolyte. The first and second electrolytes may be the same or different and each independently be a soluble salt or a base. The soluble salt may be selected from at least one of bicarbonate, carbonate, format, phosphate, hydrogenphosphate, hydrochloride, acetate, perchlorate, and sulfate. The cation in the soluble salt may be a metal ion, such as potassium, sodium, lithium, or cesium. The base may be selected from alkali metal hydroxides and / or ammonia water, such as sodium hydroxide, potassium hydroxide, or lithium hydroxide. The acid may be at least one of aqueous sulfuric acid, aqueous perchloric acid, and hydrochloric acid. In the catholyte and the anolyte, the concentration of the solute may be 0.1 to 10 mol / L (mole / liter).

[0060] Below, this application also provides several specific embodiments.

[0061] Example 1:

[0062] In the carbon dioxide electroreduction reaction device, the cathode plate 100 is made of copper and has dimensions of 90 mm × 90 mm × 20 mm. The cathode electrode 200 is a metal tin sheet with dimensions of 60 mm × 60 mm × 0.1 mm. The anode membrane electrode uses a Nafion 115 cation exchange membrane with iridium oxide loaded on one side (iridium oxide loading of 2 mg / cm 2 ), and the overall area is consistent with the cathode electrode 200. The anode current collector is fiber titanium felt with a size of 50mm×50mm×0.4mm. The material of the anode plate 600 is titanium with a size of 90mm×90mm×20mm. The anode plate flow channel 640 on the anode plate 600 is a single serpentine flow channel with a flow channel width of 2mm, a depth of 1.5mm, and a flow channel length of 0.85m. The structure of the cathode flow channel plate 300 is shown in Figure 3. The flow channel at its front end (first area 310) and the channels and holes in the cathode plate 100 and the cathode electrode 200 together constitute a vertical T-shaped multiphase flow direct generation site. The material of the cathode flow channel plate 300 is CPVC, with a thickness (flow channel depth) of 1mm. It adopts a single serpentine flow channel with a flow channel length of 1.6m, a flow channel width of 1mm, and a flow channel area of ​​50mm×50mm. The cathode electrolyte is a 0.5 mol / L KHCO3 aqueous solution, the anolyte is deionized water, the cathode electrolyte flow rate is 20 mL / min, the carbon dioxide gas flow rate is 200 sccm, and the anolyte flow rate is 40 mL / min. The pressure in the device is controlled at 9 bar, and a constant current reaction is used. The total current density is set to 1 kA / m 2 (Total current 1.6A), 2kA / m 2 (Total current 3.2A), 3kA / m 2 (Total current 4.8A), 4kA / m 2 (Total current 6.4A), 5kA / m 2 (Total current 8 A). During the reaction operation, the changes in formate, carbon monoxide, and hydrogen selectivity (Faraday efficiency) with current density are shown in FIG5 .

[0063] As shown in Figure 5, in the range of 1 to 5 kA / m 2 Within the total current density range, the selectivity of the target product formate can always be maintained above 90%, showing high electroreduction activity and great application potential.

[0064] Example 2:

[0065] The carbon dioxide electroreduction reaction was carried out according to the method of Example 1, except that the constant current method was used to set the current density to 3 kA / m 2 (Total current 4.8 A) remains unchanged, and the changes in voltage and formate, carbon monoxide, and hydrogen selectivity (Faraday efficiency) with device operation time are shown in FIG6 .

[0066] As shown in Figure 6, in this embodiment, the current density is set to 3kA / m 2 Under the conditions of 120 hours of electroreduction reaction time, the device maintained a formic acid selectivity of more than 85%, and the device voltage was stable at around 4 V, indicating that the electroreduction device can operate stably for a long time at high current density.

[0067] Example 3:

[0068] In the carbon dioxide electroreduction reaction device, the anode membrane electrode is replaced with an ion exchange membrane 410, such as an unloaded Nafion 115 cation exchange membrane, and the anode current collector is replaced with an anode electrode 510, such as a fiber titanium felt loaded with iridium oxide, with an iridium oxide loading of 1 mg / cm 2 , the rest is the same as in Example 1. The cathode electrolyte is a 0.5 mol / L KHCO3 aqueous solution, and the anolyte is a 0.1 mol / L H2SO4 aqueous solution. The cathode electrolyte flow rate is 20 mL / min, the carbon dioxide gas flow rate is 200 sccm, and the anolyte flow rate is 40 mL / min. The device is not pressurized and is controlled at normal pressure. A constant current reaction is used and the current density is set to 2 kA / m 2 (Total current: 3.2 A) The changes in formate selectivity (Faraday efficiency) at different times during the reaction are shown in Table 1.

[0069] Table 1

[0070] As can be seen from Table 1, in this embodiment, the current density is set to 2kA / m 2 When the device voltage is 4.7 V, the formate selectivity can exceed 72% under normal pressure conditions (without pressurizing the cathode electrolyte, etc.).

[0071] Example 4:

[0072] In the carbon dioxide electroreduction reaction device, except that the cathode electrode 200 is adjusted to a metal sheet (the material is silver), and the structure of the cathode plate 100 and the cathode flow channel plate 300 is adjusted to be as shown in Figure 4, the rest is the same as in Example 1. The front end flow channel of the cathode flow channel plate 300, the cathode plate 100, and the cathode electrode 200 together constitute a horizontal T-type multiphase flow direct generation site. The flow channel plate is made of CPVC, the thickness (i.e., the flow channel depth) is 1mm, a single serpentine flow channel is adopted, the flow channel length is 1.45m, the flow channel width is 1mm, and the size of the area occupied by the flow channel area is 50mm×50mm. The cathode electrolyte uses a KHCO3 aqueous solution with a concentration of 0.5mol / L, and the anode electrolyte uses deionized water. The cathode electrolyte flow rate is 20mL / min, the carbon dioxide gas flow rate is 200sccm, the anode electrolyte flow rate is 40mL / min, the pressure in the device is controlled to 9bar, a constant current reaction is adopted, and the current density is set to 2kA / m 2 (Total current: 2.9 A). The CO selectivity (Faraday efficiency) at different times during the reaction are shown in Table 2.

[0073] Table 2

[0074] As can be seen from Table 2, in this embodiment, the current density is set to 2kA / m 2 When , CO selectivity can reach more than 75%, and the device voltage is about 3.9V.

[0075] As can be seen from the above examples, the carbon dioxide electroreduction reaction device provided by this application can achieve excellent product selectivity (high Faradaic efficiency for formate and carbon monoxide) and stability while saving space and cost. Due to its simplified structure, it also has greater potential for scale-up and industrial application of the reaction device.

[0076] The above is a preferred embodiment of the present application. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as within the scope of protection of the present application.

[0077] Reference Signs List

[0078] 100 cathode plate

[0079] 110 cathode first feed channel

[0080] 120 cathode second feed channel

[0081] 130 cathode discharge channel

[0082] 140 cathode current collecting joint

[0083] 150 Sealing groove

[0084] 200 cathode electrode

[0085] 210 First Hole

[0086] 220 Second Hole

[0087] 300 cathode flow plate

[0088] 310 District 1

[0089] 311 First Flow Channel

[0090] 312 Second runner

[0091] 313 Third flow channel

[0092] 320 District 2

[0093] 410 ion exchange membrane

[0094] 510 anode electrode

[0095] 600 anode plate

[0096] 610 Anode feed channel

[0097] 620 Anode discharge channel

[0098] 630 Anode plate groove

[0099] 640 anode plate flow channel

[0100] 650 sealing groove

[0101] 700 seal ring

Claims

1. A carbon dioxide electroreduction reaction device with a multiphase flow direct generation function, wherein: Including the order of settings: A cathode plate (100), wherein the cathode plate (100) is provided with a first cathode feed channel (110) and a second cathode feed channel (120), wherein the first cathode feed channel (110) is used for introducing a first cathode material, and the second cathode feed channel (120) is used for introducing a second cathode material; a cathode electrode (200), the cathode electrode (200) being provided with a first hole (210) connected to the cathode first feed channel (110) and a second hole (220) connected to the cathode second feed channel (120); A cathode flow channel plate (300) comprising a first region (310) provided with a non-hollowed groove and a hollowed second region (320), wherein the first region (310) is provided on a side of the cathode flow channel plate (300) close to the cathode electrode (200) in the thickness direction, the first hole (210) and the second hole (220) are both connected to the first region (310), and the first region (310) is connected to the second region (320), so that the cathode first material and the cathode second material can enter the first region (310) through the cathode first feed channel (110) and the cathode second feed channel (120) respectively, intersect and mix in the first region (310), and then enter the second region (320).

2. The carbon dioxide electroreduction reaction device with a multiphase flow direct generation function according to claim 1, characterized in that: The flow channel where the first cathode material and the second cathode material meet is perpendicular to the flow channel where the second cathode material meets.

3. The carbon dioxide electric reduction reaction device with a multiphase flow direct generation function according to claim 2, characterized in that: The first zone (310) includes a first flow channel (311), the first hole (210) and the second hole (220) are respectively connected to the upstream and downstream of the first flow channel (311), and the axial direction of the second hole (220) is perpendicular to the cathode flow channel plate (300).

4. The carbon dioxide electric reduction reaction device with a multiphase flow direct generation function according to claim 3 is characterized in that: The axial direction of the first hole (210) and the axial direction of the second hole (220) are both perpendicular to the cathode flow channel plate (300).

5. The carbon dioxide electric reduction reaction device with a multiphase flow direct generation function according to claim 2, characterized in that: The first area (310) includes a first flow channel (311) and a second flow channel (312) that are perpendicular to each other, the first hole (210) is connected to the first flow channel (311), and the second hole (220) is connected to the second flow channel (312).

6. The carbon dioxide electric reduction reaction device with a multiphase flow direct generation function according to claim 2, characterized in that: The first zone (310) includes a third flow channel (313), and the third flow channel (313) is located downstream of the intersection of the cathode first material and the cathode second material.

7. The carbon dioxide electric reduction reaction device with a multiphase flow direct generation function according to claim 1 is characterized in that: The carbon dioxide electric reduction reaction device further comprises an ion exchange membrane (410), an anode electrode (510), and an anode plate (600) arranged in sequence, wherein the ion exchange membrane (410) is attached to the cathode flow channel plate (300).

8. The carbon dioxide electric reduction reaction device with a multiphase flow direct generation function according to claim 1 is characterized in that: The carbon dioxide electric reduction reaction device further comprises an anode membrane electrode, an anode current collector and an anode plate (600) which are arranged in sequence, and the anode membrane electrode is attached to the cathode flow channel plate (300).

9. The carbon dioxide electric reduction reaction device with a multiphase flow direct generation function according to claim 1, characterized in that: The cathode plate (100) further comprises a cathode discharge channel (130).

10. The carbon dioxide electric reduction reaction device with a multiphase flow direct generation function according to claim 7 or 8, characterized in that: The anode plate (600) has an anode feed channel (610) and an anode discharge channel (620).

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