Efficient carbon dioxide electroreduction testing device and method

Abstract

The invention discloses an efficient carbon dioxide electroreduction testing device and method. The invention mainly relates to the technical field of electrochemistry. The device comprises a cathode chamber, an anode chamber, a sealing cover and a working electrode, wherein the cathode chamber is fixed and mounted in the anode chamber through the sealing cover; and the working electrode (testing electrode or self-supporting electrode) is made of a hollow conductive material, is used for conveying carbon dioxide gas and is connected with a wire at the same time. According to the carbon dioxide electroreduction testing device and method, the carbon dioxide electroreduction rate is increased by reducing the ohmic drop of a reaction system; by increasing the contact degree of carbon dioxide gas and the catalyst, the selectivity of carbon dioxide electroreduction products is improved; and the device is simple in structure, easy to operate and very suitable for carbon dioxide electroreduction tests.

Description

Technical Field

[0001] The invention relates to the field of electrochemical technology, in particular to the field of carbon dioxide electroreduction. Background Art

[0002] The rapid development of the global economy in recent years is largely driven by fossil fuels. However, the use of fossil fuels inevitably leads to the emission of carbon dioxide (CO2), which in turn causes a series of environmental problems, such as global warming and rising sea levels. However, efficient CO2 electroreduction technology can accelerate the carbon cycle; it can not only reduce the concentration of CO2 in the environment, but also convert CO2 into high value-added products such as CO, CH4 and C2H4; thus alleviating environmental pollution and energy crisis.

[0003] The current CO2 electroreduction technology is basically implemented in aqueous solution. The principle is: water is oxidized at the anode to release oxygen, CO2 is reduced at the cathode to generate a series of small molecules, and water is also reduced at the cathode to release hydrogen. Therefore, the current CO2 electroreduction technology can easily lead to the occurrence of the side reaction hydrogen evolution reaction, resulting in low selectivity of CO2 electroreduction products; even in laboratory-level H-type electrolytic cells and flow-type electrolytic cells, it is difficult to avoid the occurrence of hydrogen evolution reactions. In addition, the entire reaction system of the H-type electrolytic cell has an excessively high ohmic drop, which makes the CO2 electroreduction rate low; and the flow-type electrolytic cell has a complex structure and cumbersome operation, and there are also limitations when testing self-supporting materials. Therefore, those skilled in the art provide an efficient CO2 electroreduction test device and method to overcome the problems raised in the above-mentioned background technology. Summary of the invention

[0004] In order to overcome the above technical problems, the present invention provides a high-efficiency CO2 electroreduction testing device and method.

[0005] The CO2 electric reduction testing device provided by the present invention comprises: a cathode chamber, an anode chamber, an ion exchange membrane, a working electrode and a sealing cover.

[0006] Furthermore, the cathode chamber can be installed in the anode chamber by fixing the cover; the cover is provided with five holes, which are respectively used to install the working electrode, the reference electrode, the counter electrode, the cathode chamber air duct and the anode chamber air duct.

[0007] Furthermore, the side opening of the cathode chamber is used to fix the ion exchange membrane to separate the cathode chamber and the anode chamber.

[0008] Furthermore, the cathode chamber gas duct is used to guide out the gaseous product of the cathode CO2 electro-reduction reaction.

[0009] Furthermore, the anode chamber gas conduit is used to guide out the gaseous product of the anode oxygen evolution reaction.

[0010] Furthermore, agitators are provided inside the cathode chamber and the anode chamber to improve the mass transfer capacity of the system.

[0011] Through the above technical solution, the cathode chamber is installed in the anode chamber, which shortens the distance between the working electrode and the counter electrode. Compared with the H-type electrolytic cell, the impedance of the electrolyte and the ohmic drop of the entire reaction system are effectively reduced, thereby increasing the rate of CO2 electroreduction.

[0012] The working electrode may be a test electrode, which is a hollow conductive tube wrapped by an insulating tube. The test electrode can be connected to a wire and CO2 gas can be input to achieve CO2 electroreduction.

[0013] Furthermore, the bottom end of the test electrode is an electrode groove, and an electrode hole is opened on the side for fixing a porous gas diffusion layer coated with a catalyst; the input CO2 gas passes through the porous gas diffusion layer and undergoes an electro-reduction reaction with the catalyst and the electrolyte at the gas-liquid-solid three-phase interface.

[0014] Furthermore, the bottom opening of the test electrode is used to balance the air pressure inside the test electrode.

[0015] The working electrode can also be a self-supporting electrode, which is a hollow porous fiber material with a catalyst grown on it and wrapped in a thermoplastic tube. It can also input CO2 gas while connecting a wire; the input CO2 gas can form a gas-liquid-solid three-phase interface between the catalyst and the electrolyte on the hollow porous fiber material to produce an electric reduction reaction.

[0016] Through the above technical scheme, using the test electrode or the self-supporting electrode as the working electrode, CO2 forms a gas-liquid-solid three-phase interface between the catalyst and the electrolyte. Compared with the H-type electrolytic cell, the contact area between the CO2 gas and the catalyst is increased, and the adsorption of the electrolyte on the catalyst is reduced, thereby improving the selectivity of the CO2 electroreduction product; at the same time, the number of openings in the cover is reduced, reducing the risk of leakage of the CO2 electroreduction gas product.

[0017] The present invention also provides a CO2 electric reduction test method, which is applied to the above-mentioned CO2 electric reduction test device and comprises the following steps:

[0018] In the first step, an electrolyte solution is added to the anode chamber and the cathode chamber; and ions are selectively passed through the ion exchange membrane while preventing the substances in the cathode chamber and the anode chamber from contacting each other.

[0019] In the second step, a test electrode having a porous gas diffusion layer coated with a catalyst fixed in an electrode slot is used as a working electrode; or a self-supporting electrode having a catalyst grown on a hollow porous fiber material is used as a working electrode.

[0020] The third step is to input CO2 gas into the CO2 electro-reduction test device at a constant flow rate from the upper end of the test electrode or the self-supporting electrode.

[0021] The fourth step is to apply voltage to the working electrode and the counter electrode to perform an electrocatalytic reduction test on the CO2 gas.

[0022] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0023] 1. The present invention provides an efficient CO2 electroreduction testing device and method. The cathode chamber is designed inside the anode chamber of the device. Compared with the H-type electrolytic cell, the distance between the working electrode and the counter electrode is shortened, the ohmic drop of the reaction system is effectively reduced, and the rate of CO2 electroreduction is increased.

[0024] 2. The present invention provides an efficient CO2 electro-reduction testing device and method, which uses a test electrode or a self-supporting electrode as a working electrode and eliminates the CO2 gas input pipe. Compared with an H-type electrolytic cell, it not only increases the contact area between CO2 and the catalyst and improves the selectivity of the CO2 electro-reduction product; it also reduces the number of openings in the cover and reduces the risk of leakage of the CO2 electro-reduction gas product.

[0025] 3. The present invention provides an efficient CO2 electroreduction testing device and method, which can not only install a porous gas diffusion layer coated with a catalyst as a working electrode, but also install a hollow porous fiber material with a catalyst grown on it as a working electrode, which makes up for the limitation that a flow-type electrolytic cell is not convenient for testing self-supporting materials.

[0026] 4. The present invention provides a high-efficiency CO2 electroreduction testing device and method, which has many advantages such as simple structure, low cost, and easy installation. Compared with H-type electrolytic cells and flow-type electrolytic cells, it has better universality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and other features and advantages of the present invention will become more apparent by describing in detail embodiments thereof with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic structural diagram of the CO2 electro-reduction testing device provided by the present invention.

[0029] Figure 2 It is a front view of the cathode chamber of the present invention.

[0030] Figure 3 1 is a top view of the closure of the present invention.

[0031] Figure 4 It is a schematic structural diagram of the test electrode of the present invention.

[0032] Figure 5 It is a left side view of the test electrode of the present invention.

[0033] Figure 6 FIG. 4 is a bottom view of a test electrode of the present invention.

[0034] Figure 7 Schematic diagram of the structure of the self-supporting electrode of the present invention.

[0035] Figure 8 It is a schematic diagram of the assembly of the self-supporting electrode of the present invention.

[0036] Description of reference numerals:

[0037] 1. Anode chamber air duct; 2. Sealing ring; 3. Sealing cover; 3-1. Anode outlet hole; 3-2. Anode hole; 3-3. Cathode hole; 3-4. Reference electrode hole; 3-5. Cathode outlet hole; 4. Counter electrode; 5. Anode chamber agitator; 6. Anode chamber; 7. Cathode chamber; 7-1. Cathode chamber side hole; 7-2. Sealing gasket; 7-3. Ion exchange membrane; 7-4. Cathode chamber side cover; 8. Cathode chamber agitator; 9. Reference electrode; 1 0. Working electrode; 10-1. Hollow conductive tube; 10-2. Insulating tube; 10-3. Electrode slot; 10-4. Electrode hole; 10-5. Balance hole; 10-6. Current collector; 10-7. Electrode gasket; 10-8. Electrode cover; 10-9. Bolt; 10-10. Thermoplastic tube; 10-11. Hollow porous fiber material; 10-12. Electrode wire; 11. Cathode chamber air duct; 12. Rubber ring; 13. Hose. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0040] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0041] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0042] In addition, the terms "installed", "set", "provided with", "connected", "connected", "sleeved", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the accompanying drawings and specific implementations.

[0044] like Figure 1As shown, a schematic diagram of the structure of the CO2 electroreduction test device of the present invention is given, which consists of an anode chamber air duct 1, a cover 3, a counter electrode 4, an anode chamber 6, a cathode chamber 7, a reference electrode 9, a working electrode 10, a cathode chamber air duct 11 and a hose 13. The cathode chamber 7 shown is installed in the anode chamber 6 through the cover 3. Compared with the H-type electrolytic cell, the distance between the anode chamber 6 and the cathode chamber 7 is shortened, thereby shortening the distance between the working electrode 10 and the counter electrode 4, effectively reducing the impedance of the electrolyte and the ohmic drop of the entire reaction system, and improving the rate of CO2 electroreduction. At the same time, an anode chamber agitator 5 and a cathode chamber agitator 8 are provided in the anode chamber 6 and the cathode chamber 7, which can improve the mass transfer capacity of the test system and accelerate the release rate of bubbles, which further optimizes the rate of CO2 electroreduction.

[0045] like Figure 2 As shown, a front view of the cathode chamber in the present invention is given, and a hole is opened on the side of the cathode chamber 7 as the cathode chamber side hole 7-1, which is used to fix the ion exchange membrane 7-3. Sealing gaskets 7-2 are arranged on both sides of the ion exchange membrane 7-3, and then the ion exchange membrane 7-3 is fixed to the cathode chamber side hole 7-1 with the cathode chamber side cover 7-4. The ion exchange membrane 7-3 fixed at the cathode chamber side hole 7-1 can separate the cathode chamber 7 and the anode chamber 6, and allow the ions in the electrolyte to pass selectively. This can not only separate the electrolyte of the cathode chamber 7 and the anode chamber 6, but also avoid the mixing of the products of the cathode and the anode.

[0046] like Figure 3 As shown, a top view of the cover of the present invention is given. Five holes are opened on the cover 3, which are the anode outlet hole 3-1, the anode hole 3-2, the cathode hole 3-3, the reference electrode hole 3-4 and the cathode outlet hole 3-5. These five holes are used to install the anode chamber air duct 1, the counter electrode 4, the working electrode 10, the reference electrode 9 and the cathode chamber air duct 11, respectively, and sealing rings 2 are provided at the connection between them and the cover to ensure the sealing of the device. The anode hole 3-2 and the cathode hole 3-3 are opened opposite to each other just above the cathode chamber side hole 7-1, so that the installed counter electrode 4 and the working electrode 10 can be as close as possible to reduce the solution impedance between the counter electrode 4 and the working electrode 10.

[0047] The working electrode 10 may be a test electrode ( Figure 4 , Figure 5 and Figure 6 The structural schematic diagram, left view and bottom view of the test electrode of the present invention are respectively given) or the self-supporting electrode ( Figure 7 and Figure 8The structural schematic diagram and assembly schematic diagram of the self-supporting electrode of the present invention are respectively given). It should be noted that both the test electrode and the self-supporting electrode can be connected to the hose 13 and the external wire at the same time to realize the input of CO2 gas and the external electrochemical workstation; and the connection between the hose 13 and the test electrode or the self-supporting electrode is installed with a rubber ring 12 to ensure the sealing of the connection. The working electrode 10 is designed in this way, which can save the installation of the CO2 gas input pipe, that is, the number of openings of the cover 3 is reduced, and the risk of gas leakage of the device is reduced. More importantly, CO2 gas can form a gas-liquid-solid three-phase interface between the catalyst and the electrolyte. Compared with the H-type electrolytic cell, the contact area between CO2 gas and the catalyst is increased, and the adsorption of the electrolyte on the catalyst is reduced, which effectively inhibits the hydrogen evolution side reaction, thereby improving the selectivity of the CO2 electroreduction product.

[0048] like Figure 4 , 5 The working electrode 10 shown in Figure 6 can be a test electrode. The test electrode includes a hollow conductive tube 10-1, an insulating tube 10-2, an electrode slot 10-3, a current collector 10-6, an electrode gasket 10-7, an electrode cover 10-8 and a bolt 10-9. A hole is opened on the side of the electrode slot 10-3 as an electrode hole 10-4, and a porous gas diffusion layer coated with a catalyst can be fixed to the electrode hole 10-4. In addition, the current collector 10-6 is fixed to the back of the porous gas diffusion layer to receive current and transmit current to the hollow conductive tube 10-1, and the surface of the hollow conductive tube 10-1 is wrapped with an insulating tube 10-2 to prevent leakage.

[0049] The hollow conductive tube 10-1, the insulating tube 10-2 and the current collector 10-6 are all fixed on the upper side of the electrode slot 10-3. After the porous gas diffusion layer is fixed in the electrode hole 10-4, the electrode gasket 10-7 and the electrode cover 10-8 are gradually installed and fixed with bolts 10-9. In addition, a balance hole 10-5 is provided at the bottom of the electrode slot 10-3 to balance the internal gas pressure of the test electrode.

[0050] like Figure 7 and 8 The working electrode 10 shown can be a self-supporting electrode. The self-supporting electrode includes a thermoplastic tube 10-10, a hollow porous fiber material 10-11 and an electrode wire 10-12. The hollow porous fiber material 10-11 is a hollow porous fiber material on which a catalyst is grown. In order to prevent gas leakage and leakage, the thermoplastic tube 10-10 is wrapped on the surface of the hollow porous fiber material 10-11, but a part of the upper and lower ends are exposed, the lower end is used for CO2 electric reduction test, and the upper end is used to connect the electrode wire 10-12 and the hose 13.

[0051] The working principle of the CO2 electroreduction test device provided by the present invention is as follows:

[0052] For the test electrode, CO2 gas is input from the hose 13 and enters the test electrode through the hollow conductive tube 10-1. Then, the CO2 gas passes through the porous gas diffusion layer and forms a gas-liquid-solid three-phase interface with the catalyst and the electrolyte. When a voltage is applied from the outside, the CO2 gas undergoes an electro-reduction reaction at the gas-liquid-solid three-phase interface. Subsequently, the gaseous product of the CO2 electro-reduction is output through the cathode chamber gas conduit 11, while the liquid product remains in the electrolyte of the cathode chamber 7.

[0053] For the self-supporting electrode, CO2 gas is also introduced into the hollow porous fiber material 10-11 through the hose 13, and then the CO2 gas forms a gas-liquid-solid three-phase interface with the electrolyte at the lower end of the hollow porous fiber material 10-11. When voltage is applied from the outside, the CO2 gas undergoes an electro-reduction reaction at the gas-liquid-solid three-phase interface. Finally, the gaseous product of CO2 electro-reduction is output through the cathode chamber gas guide pipe 11, while the liquid product remains in the electrolyte of the cathode chamber 7.

[0054] The CO2 electro-reduction testing device provided by the present invention can also be used for electro-catalytic testing of gases such as CO, H2, CH4 and C2H4.

[0055] The present invention also provides a CO2 electric reduction test method, which is applied to the above-mentioned CO2 electric reduction test device and comprises the following steps:

[0056] In the first step, the electrolyte solution is added to the anode chamber and the cathode chamber; at the same time, the ion exchange membrane prevents the substances in the cathode chamber and the anode chamber from contacting each other and selectively allows ions to pass through.

[0057] In the second step, a test electrode having a porous gas diffusion layer coated with a catalyst fixed in an electrode slot is used as a working electrode; or a self-supporting electrode having a catalyst grown on a hollow porous fiber material is used as a working electrode.

[0058] The third step is to input CO2 gas into the CO2 electro-reduction test device at a constant flow rate from the upper end of the test electrode or the self-supporting electrode.

[0059] The fourth step is to apply voltage to the working electrode and the counter electrode to perform an electrocatalytic reduction test on the CO2 gas.

[0060] Through the above description of the device and method of the present invention, it can be known that whether it is a porous gas diffusion layer coated with a catalyst or a hollow porous fiber material with a catalyst grown, it can be tested with this device. In addition, compared with the H-type electrolytic cell, the device reduces the distance between the cathode and the anode, reduces the solution impedance, and reduces the ohmic drop of the system; and reduces the number of openings in the cover, reducing the risk of gas leakage in the system; more importantly, it increases the contact area between the gas and the catalyst, and improves the efficiency of CO2 electroreduction. Compared with the flow-type electrolytic cell, the device can not only realize the test of self-supporting electrodes, but also make the test operation simpler. Therefore, the high-efficiency CO2 electroreduction test device and method provided by the present invention not only improves the rate and efficiency of CO2 electroreduction; but also has better universality than the H-type electrolytic cell and the flow-type electrolytic cell.

[0061] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-efficiency carbon dioxide electroreduction test device, comprising an anode chamber air duct (1), a cover (3), a counter electrode (4), an anode chamber (6), a cathode chamber (7), a reference electrode (9), a working electrode (10), a cathode chamber air duct (11) and a hose (13), wherein the cathode chamber (7) can be fixedly mounted on the anode chamber (6) through the cover (3).

2. The carbon dioxide electric reduction test device according to claim 1, characterized in that The cathode chamber (7) has a side opening for fixing an ion exchange membrane (7-3) to separate the anode chamber (6) and the cathode chamber (7).

3. The carbon dioxide electric reduction test device according to claim 1, characterized in that The sealing cover (3) has five holes for installing the anode chamber air guide tube (1), the counter electrode (4), the reference electrode (9), the working electrode (10) and the cathode chamber air guide tube (11).

4. The carbon dioxide electric reduction test device according to claim 1, characterized in that The working electrode (10) can be a test electrode or a self-supporting electrode.

5. The carbon dioxide electric reduction test device according to claim 4, characterized in that The test electrode is a hollow conductive tube (10-1) wrapped by an insulating tube (10-2), which can be connected to a wire and a hose (13) to input CO2 gas to achieve CO2 electroreduction.

6. The carbon dioxide electric reduction test device according to claim 5, characterized in that The bottom of the test electrode is provided with an electrode groove (10-3), and the side thereof is provided with an electrode hole (10-4) for fixing a porous gas diffusion layer coated with a catalyst.

7. The carbon dioxide electric reduction test device according to claim 6, characterized in that The bottom of the electrode slot (10-3) of the test electrode is provided with a balance hole (10-5) for balancing the air pressure inside the test electrode.

8. The carbon dioxide electric reduction test device according to claim 4, characterized in that The self-supporting electrode is a hollow porous fiber material (10-11) on which a catalyst is grown and wrapped by a thermoplastic tube (10-10). It can be connected to a wire and can also input CO2 gas.

9. The carbon dioxide electric reduction test device according to claim 8, characterized in that The hollow porous fiber material (10-11) exposes a part of the upper and lower ends, the lower end is used for CO2 electroreduction testing, and the upper end is used to connect the electrode wire (10-12) and the hose (13).

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