A reaction device, system and method for enhancing electrocatalytic CO2 mass transfer process

Abstract

The application discloses a reaction device, system and method for strengthening electrocatalytic CO2 mass transfer process, and is characterized in that: on the basis of the original H-shaped electrolytic cell, an H-shaped electrolytic cell high-pressure reactor is designed, which is suitable for reaction conditions under high pressure, and the problem of low solubility of CO2 in electrolyte is solved by high pressure, and the solubility is improved. The application uses the hydrophobic modification treatment of the electrode surface to construct the three-phase interface of the electrolyte CO2 on the catalyst, reduces the mass transfer resistance of CO2, and further solves the problem of limited mass transfer of CO2 on the electrode surface. The application combines the high pressure with the improvement mode of the electrode hydrophobic treatment, and compared with the prior art, CO2 can be reduced to CO under low potential, wide potential window, high performance and high selectivity, and the best reduction performance of CO2 is obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electric reduction conversion, and particularly relates to a reaction device, system and method for strengthening the mass transfer process of electric catalysis CO2. BACKGROUND

[0002] The electric catalysis CO2 reduction can not only prepare greenhouse gas CO2 into high-value-added chemical products and carbon-hydrogen fuels, etc., reduce the use of traditional fossil energy, but also can utilize the atmospheric CO2 resources.

[0003] At present, the CO2 conversion still faces the bottleneck problems of low conversion rate and poor selectivity, and the main reason is that the mass transfer of the reactant CO2 is limited.

[0004] In order to solve the corresponding mass transfer problem of CO2, scholars have studied the corresponding flow electrolytic cell and the corresponding gas diffusion electrode, so as to improve the mass transfer problem in the process of electric catalysis CO2 reduction. The catalyst is attached to one side of the gas diffusion electrode, which contacts with the electrolyte, and the other side contacts with the reactant gas CO2. The CO2 molecules diffuse to the catalyst layer through the pores of the carbon paper fiber, and the CO2 reduction reaction occurs to generate products. In the flow electrolytic cell, the gas molecules CO2 diffuse from the carbon paper fiber to the catalyst through molecular diffusion, and participate in the reaction, which greatly reduces the thickness and diffusion resistance of the diffusion layer, reduces the transmission distance of CO2, and better improves the mass transfer of the reactant CO2, so that the current density is increased by an order of magnitude. However, due to the structure of the gas diffusion electrode, the stability of the gas diffusion electrode in the alkaline flow electrolytic cell is poor, and water flooding phenomenon is easy to occur, which leads to the intensification of hydrogen evolution reaction (HER) and affects the performance of CO2RR. SUMMARY

[0005] This section aims to summarize some aspects of the embodiments of the application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the application.

[0006] In view of the above and / or problems existing in the prior art, the present application is proposed.

[0007] Therefore, the purpose of the present application is to overcome the deficiencies in the prior art, and to provide a reaction device for strengthening the mass transfer process of electric catalysis CO2.

[0008] To solve the above technical problems, the present application provides the following technical scheme: including,

[0009] The cathode assembly 100 comprises a cathode shell 101, a cathode electrolyte chamber 102 integrally injection molded outside the cathode shell, and a working electrode 103 arranged outside the cathode shell; and

[0010] The anode assembly 200 comprises an anode shell 201 detachably connected with the cathode shell 101, an anode electrolyte chamber M arranged outside the anode shell 201, a counter electrode 202 arranged outside the anode shell 201, and a reference electrode 203; and

[0011] A proton exchange membrane 300 is arranged between the cathode assembly 100 and the anode assembly 200.

[0012] The cathode assembly 100 and the anode assembly 200 face each other.

[0013] As a preferred scheme of the reaction device for strengthening the electrocatalytic CO2 mass transfer process, the working electrode socket 103a is arranged at the top of the cathode electrolyte chamber 102, and the working electrode socket 103a is connected with the working electrode 103.

[0014] As a preferred scheme of the reaction device for strengthening the electrocatalytic CO2 mass transfer process, the counter electrode socket 202a and the reference electrode socket 203a are arranged at the top of the anode electrolyte chamber M, respectively, the counter electrode socket 202a is connected with the counter electrode 202, and the reference electrode socket 203a is connected with the reference electrode 203.

[0015] As a preferred scheme of the reaction device for strengthening the electrocatalytic CO2 mass transfer process, the gas-liquid inlet 101a is arranged on the side of the cathode electrolyte chamber 101, and the gas-liquid inlet 201a and the gas-liquid outlet 201b are arranged on the side of the anode electrolyte chamber, respectively.

[0016] As a preferred scheme of the reaction device for strengthening the electrocatalytic CO2 mass transfer process, the stainless steel plates 401 and 402 are arranged on both sides of the cathode assembly 100 and the anode assembly 200.

[0017] Another object of the present application is to provide a reaction system for strengthening the electrocatalytic CO2 mass transfer process.

[0018] To solve the above technical problems, the present application provides the following technical scheme: comprising a reaction device; and

[0019] The electrochemical workstation 500 is connected with the reaction device through the working electrode 102, the counter electrode 202, and the reference electrode 203, and is used to provide the working voltage required by the reaction device.

[0020] The data recording module 600 comprises a data processor, which is connected to the gas-liquid inlet 101a and the gas-liquid inlet 201a of the reaction device through a pipeline, and a temperature sensor and a pressure sensor are arranged in the pipeline to receive the temperature data and the pressure data of the reaction device.

[0021] The vacuum box 700 is provided with a valve 701 on the communication pipeline of the reaction device to provide the required pressure of the reaction device.

[0022] Another object of the present application is to overcome the deficiencies in the prior art and provide a method for strengthening the electrocatalytic CO2 mass transfer process.

[0023] To solve the above technical problems, the present application provides the following technical scheme: a device and system for strengthening the electrocatalytic CO2 mass transfer process, which further comprises,

[0024] The reaction device is ultrasonically cleaned, and the air tightness of the reaction device is checked and confirmed;

[0025] The pretreated electrolyte is added to the electrolyte chamber through the gas-liquid inlet 101a and the gas-liquid inlet 201a until the volume of the chamber is 2 / 3;

[0026] The vacuum box 700 is evacuated to vacuum, and the valve 701 is opened to discharge the gas in the reaction device;

[0027] High-purity CO2 high-pressure gas is injected into the electrolyte chamber through the gas-liquid inlet 101a and the gas-liquid inlet 201a to increase the pressure in the reaction device, and after standing, a saturated CO2 electrolyte solution is obtained, at this time the pressure in the reaction device is 5-10 atm, and remains relatively stable and does not change;

[0028] The electrochemical workstation 500 is opened, the working voltage is adjusted to -0.5 to -1.3 V, and the reaction electrocatalytic CO2 reduction reaction is carried out;

[0029] After the reaction is completed, the vacuum box 700 is evacuated to vacuum, and the valve 701 is opened to discharge the gas in the reaction device;

[0030] After the gas is discharged, high-purity Ar is injected into the vacuum box 700, the gas product and the electrolyte are extracted, the reaction electrode is removed, and characterization testing is performed.

[0031] As a preferred scheme of the method for strengthening the electrocatalytic CO2 mass transfer process, the working electrode 103 in the reaction device is a modified hydrophobic Ag electrode, which is obtained by compounding a catalyst ink configured from commercial silver powder, anhydrous ethanol and an ionic polymer with a 5% PTFE emulsion, wherein the mass ratio of the catalyst ink to PTFE is 3-10:1.

[0032] As a preferred scheme of the method for strengthening the electrocatalytic CO2 mass transfer process, in the application, the pretreated electrolyte is a 0.1M KHCO3 solution which is treated by exhausting high-purity CO2.

[0033] As a preferred scheme of the method for strengthening the electrocatalytic CO2 mass transfer process, in the application, the method improves the Faraday efficiency by more than 30% compared with the traditional atmospheric hydrophilic electrode electrocatalytic CO2 reduction method.

[0034] The application has the following beneficial effects:

[0035] (1) The application improves the design of the H-type electrolytic cell high-pressure reactor based on the original H-type electrolytic cell, which is suitable for reaction conditions under high pressure. The problem of low solubility of CO2 in the electrolyte is solved by high pressure, and the solubility is improved.

[0036] (2) The application uses hydrophobic modification treatment of the electrode surface to construct a three-phase interface of electrolyte-CO2 on the catalyst, which reduces the mass transfer resistance of CO2, and further solves the problem of limited mass transfer of CO2 on the electrode surface.

[0037] (3) The application combines high pressure with the improvement of electrode hydrophobic treatment, which further improves the catalytic performance of CO2 and solves the performance problem. Compared with the prior art, the application proposes a method for strengthening the electrocatalytic CO2 reduction reaction of the mass transfer process, which can make the hydrophobic Ag electrode under high pressure reduce CO2 to CO at low potential, wide potential window, high performance and high selectivity, and obtain the best reduction performance of CO2. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor. Among them:

[0039] Figure 1 The reaction device diagram for strengthening the electrocatalytic CO2 mass transfer process of the application.

[0040] Figure 2 The side view of the anode shell in the reaction device for strengthening the electrocatalytic CO2 mass transfer process of the application.

[0041] Figure 3 The reaction system diagram for strengthening the electrocatalytic CO2 mass transfer process of the application.

[0042] Figure 4The graph shows the performance characteristics of the modified hydrophobic Ag electrode prepared in Example 3 of this invention.

[0043] Figure 5 The image shows the performance curve of electrocatalytic CO2 reduction under the scheme of Example 4 of this invention.

[0044] Figure 6 The figure shows the performance curve of electrocatalytic CO2 reduction under the scheme of Comparative Example 1 of this invention.

[0045] Figure 7 The figure shows the performance curve of electrocatalytic CO2 reduction under the scheme of Comparative Example 2 of this invention.

[0046] Figure 8 The image shows the performance curve of electrocatalytic CO2 reduction under the scheme of Comparative Example 3 of this invention. Detailed Implementation

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0048] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0049] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0050] Example 1

[0051] like Figures 1-2 As shown, this is the first embodiment of the present invention. This embodiment provides a reaction device for enhancing the electrocatalytic CO2 mass transfer process, specifically including a cathode assembly, a cathode assembly 100, including a cathode housing 101, a cathode electrolyte chamber 102 integrally injection-molded outside the cathode housing, and a working electrode 103 disposed outside the cathode housing; and,

[0052] The anode assembly 200 includes an anode housing 201 detachably connected to the cathode housing 101, an anode electrolyte chamber M disposed outside the anode housing 201, a counter electrode 202 disposed outside the anode housing 201, and a reference electrode 203; and,

[0053] A proton exchange membrane 300 separates the cathode assembly 100 and the anode assembly 200;

[0054] The cathode assembly 100 and the anode assembly 200 face each other, and are provided with a stainless steel plate (401) and a stainless steel plate (402) on both sides.

[0055] Specifically, the stainless steel plates 401 and 402 serve to fix and clamp the device body to prevent gas in the reaction device from escaping under high pressure; the main body of the reaction device is supported by an acrylic plate, which has good chemical stability and mechanical properties and can maintain normal and stable operation of the internal system;

[0056] The top of the cathode electrolyte chamber 101 is provided with a working electrode socket 103a, and the working electrode socket 103a is connected with the working electrode 103; the top of the anode electrolyte chamber is respectively provided with a counter electrode socket 201a and a reference electrode socket 202a, the counter electrode socket 201a is connected with the counter electrode 201, and the reference electrode socket 202a is connected with the reference electrode 202

[0057] Further, the cathode electrolyte chamber and the anode electrolyte chamber are both provided with a gas passage, which transmits gas and electrolyte into the chambers through the gas-liquid inlets 100a and 200a after ensuring the airtightness of the reaction device.

[0058] Example 2

[0059] Reference Figure 3 For the second embodiment of the present application, the present embodiment provides a method for strengthening the electrocatalytic CO2 mass transfer process according to a reaction system for strengthening the electrocatalytic CO2 mass transfer process, specifically:

[0060] S1: ultrasonic cleaning of each component of the reaction device to remove possible impurities, assembly of the reactor and checking of the airtightness of the device;

[0061] Specifically, high-purity CO2 gas is introduced into the device, which aims to remove the remaining gas (such as N2, O2, etc.) dissolved in the electrolyte, so as to avoid the generation of other side reactions during the reaction;

[0062] The working electrode 103, the reference electrode 203 and the counter electrode 202 of the device are respectively connected with the electrochemical workstation 500, the data receiving module 600 is connected with the gas-liquid inlets 101a and 201a of the device through pipes, temperature sensors and pressure sensors are arranged in the pipes, the vacuum box 700 is connected with the gas-liquid outlet 201b of the device through pipes, and a valve 701 is arranged on the pipes.

[0063] S2: adding electrolyte into the reaction device through the gas passage;

[0064] Specifically, first, the electrolyte is pretreated, high-purity CO2 gas is introduced into the electrolyte solution, and the remaining gas (such as N2, O2, etc.) dissolved in the electrolyte is discharged to avoid the generation of remaining side reactions during the reaction.

[0065] Further, after the electrolyte is discharged, the electrolyte is injected into the cathode and anode electrolyte chambers of the reaction device through the needle cylinder.

[0066] S3: providing high pressure conditions in the process of strengthening the electrocatalytic CO2 mass transfer;

[0067] Specifically, the vacuum box 700 is pumped to vacuum, the valve 701 connected to the device is opened, and the remaining gas in the reaction device is pumped out through the gas-liquid outlet 200b by utilizing the pressure difference between the inside and outside. Then, high-purity CO2 high-pressure gas is injected into the reaction device to increase the pressure of the reaction device and maintain it for a period of time to obtain a saturated CO2 electrolyte solution. At this time, the pressure in the reaction device remains stable and does not change.

[0068] S4: connecting the power supply and performing electrocatalytic CO2 reduction;

[0069] Specifically, the electrochemical workstation 500 is connected, and the power supply is turned on to perform electrocatalytic CO2 reduction.

[0070] Further, after the reaction is completed, the vacuum box 700 is pumped to a vacuum state, the valve is opened, and the products in the reaction device are discharged into the vacuum box by utilizing the pressure difference.

[0071] Further, after the exhaust is completed, an appropriate amount of high-purity Ar is injected into the vacuum box and part of the gas product is pumped out for analysis by gas chromatography. The electrolyte after the reaction is pumped out and the electrode after the reaction is removed and washed with deionized water for characterization test.

[0072] Example 3

[0073] Reference Figure 4 For the third embodiment of the present application, a preparation method of a modified hydrophobic Ag electrode is provided, specifically:

[0074] The carbon paper is cut into a rectangular size of 3 cm x 1 cm for standby;

[0075] The commercial silver powder, anhydrous ethanol, and Nafion (ionic polymer) are prepared into a catalyst ink in a ratio of 30 mg, 4 ml, and 30 μl. A mass fraction of 5% PTFE emulsion is added to the catalyst ink, and the catalyst: PTFE is added in a ratio of 5:1. The catalyst ink is placed in an ultrasonic for 30 min to make the catalyst uniformly dispersed. After taking out, the laser lamp's Tyndall effect is used to confirm whether the dispersion is uniform. After uniform dispersion, it is standby.

[0076] The catalyst ink is sprayed on the prepared carbon paper using a spraying method, and after the catalyst is fully dried, the mass before and after loading the catalyst on the carbon paper is repeatedly measured to control the catalyst loading amount to be 1 mg / cm 2 ;

[0077] After spraying is completed, the prepared electrode is placed in a muffle furnace, which is heated from room temperature to 330 DEG C within 30 min, and the temperature is maintained for 1 h, and finally the electrode is naturally cooled from 330 DEG C to room temperature, and the working electrode is prepared by using an insulating tape, and thus the modified hydrophobic electrode prepared in the embodiment is obtained.

[0078] Figure 3 For the related characterization of the Ag electrode prepared in the embodiment, the catalyst Ag dendrite surface morphology and structure on the surface of the hydrophobic electrode are characterized and observed by using a scanning electron microscope (SEM), and it can be seen that the catalyst Ag nanoparticles are uniformly attached to the carbon fibers of the substrate; since the hydrophobic Ag electrode is modified by using the FAS hydrothermal method for hydrophobic modification, the FAS contains F elements, so the corresponding distribution of F elements can be detected on the surface of the hydrophobic electrode, which proves the success of the hydrophobic modification, and the hydrophobic structure is successfully constructed on the surface of the Ag electrode.

[0079] And the X-ray photoelectron spectroscopy characterization can know that two other characteristic peaks of 531.48 eV and 533.35 eV corresponding to Ag-O-Si bond and Si-O-Si bond are found in the O 1s spectrum of the hydrophobic Ag electrode, which is because the hydrophobic modification is performed by using trimethoxy (1H, 1H, 2H, 2H-heptadecafluorodecyl) silane (FAS), which contains Si elements, and after hydrolysis and dehydration condensation, the Ag-O-Si bond and the Si-O-Si bond are formed, which can also indicate the success of the hydrophobicity.

[0080] Embodiment 4

[0081] Reference Figure 5 For the fourth embodiment of the application, referring to the methods of embodiments 2-3, the embodiment provides an actual application of a method for strengthening the electrocatalytic CO2 mass transfer process, specifically:

[0082] S1: ultrasonic cleaning of each component of the reaction device to remove possible impurities, assembling the reactor and checking the gas tightness of the device;

[0083] Specifically, high-purity CO2 gas is introduced into the device, and the gas flow is controlled to be 20 ml / min, and the process is continued for 30 min;

[0084] Further, the reaction device uses the modified hydrophobic Ag electrode prepared in embodiment 3 as the working electrode, IrO2 as the counter electrode, Ag / AgCl as the reference electrode, and Nation 117 proton exchange membrane as the proton exchange membrane.

[0085] S2: adding electrolyte into the reaction device through the gas channel;

[0086] First, the electrolyte is pretreated. Specifically, the electrolyte is 0.1M KHCO3, and high-purity CO2 gas is introduced into the electrolyte solution at a flow rate of 20ml / min for 30min. The purpose is to remove the remaining gas (such as N2, O2, etc.) dissolved in the electrolyte, so as to avoid the generation of other side reactions during the reaction.

[0087] Further, after the electrolyte is removed, the needle cylinder is used to inject 2 / 3 of the volume of KHCO3 electrolyte into the anode and cathode electrolyte chambers of the reaction device.

[0088] S3: providing high-pressure conditions in the process of strengthening electrocatalytic CO2 mass transfer;

[0089] Specifically, the vacuum box 700 is evacuated to vacuum, the valve 701 connected to the device is opened, and the remaining gas in the reaction device is removed by utilizing the pressure difference between the inside and outside. Then, high-purity CO2 high-pressure gas is injected into the reaction device, and the pressure in the reactor is increased to 8.5atm. After standing for 1.5h, a saturated CO2 electrolyte solution is obtained. At this time, the pressure in the reaction device decreases to 5atm and remains stable without further change.

[0090] S4: connecting the power supply and performing electrocatalytic CO2 reduction;

[0091] Specifically, the electrochemical workstation 500 is connected, the power supply is turned on, and the working voltage is set to -0.5~-1.3. Then, electrocatalytic CO2 reduction is performed.

[0092] Further, after the reaction is completed, the vacuum box 700 is evacuated to vacuum, the valve is opened, and the products in the reaction device are discharged into the vacuum box by utilizing the pressure difference. The exhaust time is maintained for 20min.

[0093] Further, after the exhaust is completed, a proper amount of high-purity Ar is injected into the vacuum box, and part of the gas product is extracted and analyzed by gas chromatography. The electrolyte after the reaction is extracted, and the electrode after the reaction is removed and washed with deionized water for standard testing.

[0094] The electrocatalytic CO2 reduction performance curve of the embodiment is shown in Figure 4 .

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 4 is that step S1 is adjusted to use a hydrophilic electrode as the working electrode for the electrocatalytic CO2 reduction reaction, and step S3 is adjusted to control the device pressure after the electrolyte solution is saturated to 1 atm. The electrocatalytic CO2 reduction reaction is carried out under this pressure, and the results are as follows: Figure 6 As shown.

[0097] Comparative Example 2

[0098] The difference between this comparative example and Comparative Example 1 is that step S3 is adjusted to control the device pressure after the electrolyte solution is saturated to 1 atm. The result is as follows: Figure 7 As shown.

[0099] Comparative Example 3

[0100] The difference between this comparative example and Example 4 is that step S1 was adjusted, and a hydrophilic electrode was used as the working electrode to perform the electrocatalytic CO2 reduction reaction. The results are as follows: Figure 8 As shown.

[0101] from Figures 5-7 It can be seen that by combining high pressure and hydrophobicity, the Faraday efficiency of CO at each potential is increased by about 30% compared with atmospheric pressure or hydrophobicity alone. This shows that the method has higher performance, higher current density and higher product selectivity than the traditional electrocatalytic CO2 reduction method.

[0102] This is because the hydrophobic modification of the electrode creates a three-phase interface, improving the diffusion and mass transfer process on the electrode surface. The increased pressure also increases the solubility of CO2 in the electrolyte, thereby increasing the *CO2 coverage of the reactant and consequently the *CO2δ- coverage of the intermediate. This, in turn, enhances the CO2 reduction reaction rate. Furthermore, while high pressure increases *CO2 coverage, it also decreases *H2O coverage, thus inhibiting the HER (heritage-response reaction). Therefore, the CO2 reduction efficiency under high pressure is higher than that under normal pressure in terms of reaction rate, product selectivity, and catalytic performance.

[0103] Example 5

[0104] This embodiment is used to investigate the effect of different pressures on the enhanced electrocatalytic CO2 mass transfer process under hydrophobic electrode conditions. Specifically, the difference from Example 4 is that step S3 is adjusted to control the device pressure after electrolyte solution saturation to be 1, 3, 5, 7, and 9 atm, respectively. The rest of the process is the same as in Example 4. The CO Faraday efficiency at each pressure when the working potential is 1.1V is recorded, and the results are shown in Table 1.

[0105] Table 1. CO Faraday efficiency at different pressures

[0106] Pressure / atm Faradaic efficiency / % 1 62.7 3 85.4 5 94.5 7 96.2 9 97.3

[0107] Example 6

[0108] This example is used to explore the effect of different pressures on the process of strengthening electrocatalytic CO2 mass transfer under the condition of hydrophilic electrode. Specifically, unlike Example 4, step S1 is adjusted to use a hydrophilic electrode as the working electrode for electrocatalytic CO2 reduction reaction, step S3 is adjusted to control the gas pressure of the electrolyte solution after saturation at 1, 3, 5, 7, and 9 atm, respectively, and the rest of the process is the same as Example 4. The CO faradaic efficiency under each pressure at a working potential of 1.1 V is recorded, and the results are shown in Table 2.

[0109] Table 2 CO faradaic efficiency under different pressures

[0110] Pressure / atm Faradaic efficiency / % 1 62.7 3 80.3 5 90.1 7 94.5 9 97.2

[0111] As can be seen from Table 1 and Table 2, with the increase of pressure, whether using a hydrophilic electrode or a hydrophobic electrode, the faradaic efficiency of CO shows a continuous upward trend. Under normal pressure, the use of a hydrophilic electrode and a hydrophobic electrode has no significant effect on the faradaic efficiency of CO, but when the pressure is increased, the faradaic efficiency of CO under each pressure using a hydrophobic electrode is better than that using a hydrophilic electrode. This shows that by combining electrode modification and high pressure conditions, the mass transfer process of CO2 reduction catalytic reaction can be effectively strengthened, and the combined treatment greatly improves the strengthening efficiency.

[0112] Example 7

[0113] This example is used to explore the effect of different hydrophobic modification conditions on the process of strengthening electrocatalytic CO2 mass transfer under normal pressure (1 atm). Specifically, unlike Example 4, the modified hydrophobic electrode in step S3 is adjusted, and the specific electrode preparation method refers to the preparation method of Example 3. The ratio of catalyst: PTFE is adjusted to 10:1, 5:1, and 3:1 to obtain working electrodes under different hydrophobic modification conditions. Electro-catalysis is carried out according to the method of Example 4, and the CO faradaic efficiency under each pressure at a working potential of 1.1 V is recorded. The results are shown in Table 3.

[0114] Table 3 Faradaic efficiency of different hydrophobic modification treatments under normal pressure

[0115] Catalyst: PTFE Faradaic efficiency / % 3：1 58.7 5：1 62.7 10：1 55.1

[0116] Example 8

[0117] This embodiment is used to explore the effect of different hydrophobic modification conditions on the enhancement of electrocatalytic CO2 mass transfer process under high pressure (5 atm). The difference from embodiment 4 is that the modified hydrophobic electrode in step S3 is adjusted. The electrode preparation method is referred to the preparation method of embodiment 3. The catalyst: PTFE ratio is adjusted to 10:1, 5:1 and 3:1. The working electrode under different hydrophobic modification conditions is obtained. The electrocatalysis is carried out according to the method of embodiment 4. The CO faraday efficiency under each pressure when the working potential is 1.1 V is recorded. The results are shown in Table 4.

[0118] Table 4 Faraday efficiency under different hydrophobic modification treatment under high pressure

[0119] Catalyst: PTFE Faradaic efficiency / % 3：1 90.2 5：1 95.4 10：1 88.9

[0120] As can be seen from Table 3 and Table 4, when the pressure is 1 atm and the working potential is-1.1 V vs. RHE, the CO faraday efficiency changes with the change of the ratio of catalyst to PTFE. As can be seen from the table, when the ratio of PTFE is low, the efficiency is low because the hydrophobicity is not enough, but when the ratio of PTFE is too high, the active sites of the catalyst on the electrode surface will be affected, thereby affecting the specific reaction efficiency, therefore, the ratio of catalyst to PTFE is selected as 5:1.

[0121] When the pressure is 5 atm, the faraday efficiency changes with the change of the hydrophobic modification condition, and under each modification condition, the faraday efficiency under the pressure of 5 atm is increased by more than 30% compared with that under the pressure of 1 atm. At the same time, it is not that the stronger the hydrophobicity is, the better the mass transfer effect is. By adjusting the hydrophobicity and high pressure condition, the best catalytic efficiency can be obtained at the lowest cost.

[0122] In summary, on the basis of the original H-type electrolytic cell, the H-type electrolytic cell high-pressure reactor is designed and improved, which is suitable for reaction conditions under high pressure. The problem of low solubility of CO2 in electrolyte is solved by high pressure, and the solubility is improved.

[0123] The electrode surface is treated by hydrophobic modification, a three-phase interface of electrolyte-CO2 on the catalyst is constructed, the mass transfer resistance of CO2 is reduced, and the problem of limited mass transfer of CO2 on the electrode surface is further solved.

[0124] The application combines high pressure and improved electrode hydrophobic treatment, thereby further improving the catalytic performance of CO2, solving the performance problem, and compared with the prior art, the method for electrocatalytic CO2 reduction reaction of strong mass transfer process can make the hydrophobic Ag electrode under high pressure reduce CO2 into CO at low potential, wide potential window, high performance and high selectivity, and the best reduction performance of CO2 is obtained.

[0125] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A method of intensifying an electrocatalytic CO2 mass transfer process, characterized by: The method for the enhanced electrocatalytic CO2 mass transfer process is, The cathode assembly (100) comprises a cathode shell (101), a catholyte chamber (102) integrally injection molded outside the cathode shell (101), and a working electrode (103) arranged outside the cathode shell (101); and The anode assembly (200) comprises an anode shell (201) detachably connected with the cathode shell (101), an anolyte chamber (M) arranged outside the anode shell (201), and a counter electrode (202) and a reference electrode (203) arranged outside the anode shell (201); and A proton exchange membrane (300) separates the cathode assembly (100) and the anode assembly (200). The cathode assembly (100) and the anode assembly (200) face each other. The system for the enhanced electrocatalytic CO2 mass transfer process comprises, An electrochemical workstation (500) is connected with the reaction device through the working electrode (103), the counter electrode (202), and the reference electrode (203) to provide the working voltage required by the reaction device. A data recording module (600) comprises a data processor, and the gas-liquid inlet (101a) and the gas-liquid inlet (201a) of the reaction device are connected through a pipeline, and a temperature sensor and a pressure sensor are arranged inside the pipeline to receive the temperature data and the pressure data of the reaction device. A vacuum box (700) is provided with a valve (701) on the communication pipeline of the reaction device to provide the pressure required by the reaction device. The method for the enhanced electrocatalytic CO2 mass transfer process is, The reaction device is ultrasonically cleaned, and the air tightness of the reaction device is checked and confirmed; The pretreated electrolyte is added to the electrolyte chamber through the gas-liquid inlet (101a) and the gas-liquid inlet (201a) to 2 / 3 of the volume of the chamber; The vacuum box (700) is evacuated to vacuum, and the valve (701) is opened to discharge the gas in the reaction device; High-purity CO2 high-pressure gas is injected into the electrolyte chamber through the gas-liquid inlet (101a) and the gas-liquid inlet (201a) to increase the pressure in the reaction device, and after standing, a saturated CO2 electrolyte solution is obtained. At this time, the pressure in the reaction device is 5-10 atm, and it remains relatively stable and does not change. The electrochemical workstation (500) is opened, the working voltage is adjusted to -0.5 to -1.3 V, and the reaction electrocatalytic CO2 reduction reaction is carried out. After the reaction is completed, the vacuum box (700) is evacuated to vacuum, and the valve (701) is opened to discharge the gas in the reaction device. After the gas is discharged, high-purity Ar is injected into the vacuum box (700), the gas product and the electrolyte are extracted, the reaction electrode is removed, and characterization testing is performed. The working electrode (103) in the reaction device is a modified hydrophobic Ag electrode, which is obtained by compounding a catalyst ink configured from commercial silver powder, anhydrous ethanol, and an ionic polymer with 5% PTFE emulsion, wherein the mass ratio of the catalyst ink to PTFE is 5:

1.

2. The method of intensifying the electrocatalytic CO2 mass transfer process of claim 1, wherein: The top of the cathode electrolyte chamber (102) is provided with a working electrode socket (103a), and the working electrode socket (103a) is connected with a working electrode (103).

3. The method of intensifying the electrocatalytic CO2 mass transfer process of claim 1, wherein: The top of the anode electrolyte chamber (M) is respectively provided with a counter electrode socket (202a) and a reference electrode socket (203a), the counter electrode socket (202a) is connected with a counter electrode (202), and the reference electrode socket (203a) is connected with a reference electrode (203).

4. The method of intensifying the electrocatalytic CO2 mass transfer process of claim 1 or 2, characterized by: The side of the cathode electrolyte chamber (102) is provided with a gas-liquid inlet (101a), and the side of the anode electrolyte chamber is respectively provided with a gas-liquid inlet (201a) and a gas-liquid outlet (201b).

5. The method of intensifying the electrocatalytic CO2 mass transfer process as claimed in claim 1 or 3, wherein: The cathode assembly (100) and the anode assembly (200) are respectively provided with a stainless steel plate (401) and a stainless steel plate (402) on both sides.

6. The method of intensifying the electrocatalytic CO2 mass transfer process of claim 1, wherein: The pretreated electrolyte is a 0.1M KHCO3 solution which is treated by passing high-purity CO2.

7. The method of intensifying the electrocatalytic CO2 mass transfer process of claim 1, wherein: Compared with the traditional atmospheric hydrophilic electrode electrocatalytic CO2 reduction method, the method can improve the Faraday efficiency by more than 30%.

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