Zinc hollow fiber electrode, preparation method and application thereof

Abstract

The invention provides a zinc hollow fiber electrode, a preparation method and application thereof, the preparation method comprises the following steps: S1, at room temperature, ball-milling a zinc source, an organic solvent and a binder in proportion to obtain a uniform slurry liquid, and degassing the slurry liquid; s2, extruding the degassed slurry through core liquid and a spinning head to form initial fibers, and performing phase inversion on the initial fibers to obtain a hollow fiber soft body; s3, washing and shaping the hollow fiber soft body to obtain a hollow fiber blank; s4, placing the hollow fiber blank in an oxidizing gas atmosphere to be roasted and oxidized to obtain an oxide precursor; and S5, performing in-situ electrochemical reduction to obtain the zinc hollow fiber electrode. The preparation method is simple and low in cost, and the obtained oxide precursor is subjected to in-situ electrochemical reduction to obtain the zinc hollow fiber electrode; when being applied to CO2 electrocatalytic reduction, the composite material has good electrocatalytic activity, good CO and synthesis gas selectivity, high current density and high stability.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical reduction conversion of carbon dioxide, and in particular relates to a zinc hollow fiber electrode, a preparation method and application thereof. Background Art

[0002] As the global industrialization process continues to accelerate, excessive emissions of carbon dioxide (CO2) have caused a serious greenhouse effect, posing a huge threat to the ecological environment and human health. Therefore, how to efficiently utilize and convert CO2 has become one of the hot areas of current scientific research. The electrocatalytic reduction of CO2 to prepare high-value-added chemicals can not only convert renewable electricity into chemical energy that is easy to store and transport, but also has significant environmental and energy benefits, showing broad application prospects.

[0003] In electrocatalytic CO2 reduction technology, the performance of electrode materials plays a vital role. As a cost-effective alternative to precious metal silver catalysts, zinc (Zn) has attracted much attention and become more attractive due to its higher abundance on Earth, the adjustability of its structural morphology, and its selectivity for CO in electrocatalytic CO2. However, there are still some urgent problems to be solved in zinc-based materials. Its limited CO production capacity limits its potential for large-scale industrial applications. Therefore, the selectivity, catalytic activity and state stability of zinc-based catalysts still need to be further improved. At present, gas diffusion electrode is one of the commonly used electrode types. However, it has many limitations, such as the need to use a large amount of binder during the preparation process, which not only increases the preparation cost of the electrode, but also leads to poor catalyst stability, which seriously affects its potential in large-scale applications and limits the further development of electrocatalytic CO2 reduction technology.

[0004] In contrast, hollow fiber electrodes have unique advantages due to their unique porous structure, large specific surface area and good mass transfer performance. The development of innovative electrodes such as hollow fiber permeable electrodes (HPE) has brought new breakthroughs in electrocatalytic CO2 reduction technology. This electrode can significantly enhance the mass transfer and reaction kinetics of electrochemical reactions at the gas-liquid-solid three-phase interface, effectively overcoming the problem of slow supply of gas reactants on traditional electrodes. The unique hollow fiber structure helps gas reactants (such as CO2) to pass through the porous wall, ensuring its unlimited supply and direct contact with the active sites on the catalyst surface and the electrolyte, thereby greatly improving the overall efficiency of the reaction and providing strong support for achieving efficient CO2 conversion.

[0005] However, despite the many advantages of hollow fiber electrodes, the preparation of zinc hollow fiber electrodes cannot be prepared by thermal reduction methods in a hydrogen atmosphere or wet chemical reduction methods such as sodium borohydride, because metal zinc is more active and its metal activity order is before hydrogen. There is no mature and efficient method to prepare zinc hollow fiber electrodes in the prior art. In particular, there are still many challenges in ensuring electrode stability and catalytic performance, which to a certain extent restricts the wide application of zinc hollow fiber electrodes in the field of electrocatalytic CO2 reduction. Therefore, it is necessary to provide an improved technical solution for the above-mentioned shortcomings of the prior art. Summary of the invention

[0006] In view of the shortcomings of the prior art mentioned above, the object of the present invention is to provide a zinc hollow fiber electrode, a preparation method and its application, so as to solve the problem that zinc hollow fiber electrodes cannot be prepared efficiently in the prior art, and the problem that the stability and catalytic performance of zinc hollow fiber electrodes in electrocatalytic CO2 reduction are insufficient.

[0007] To achieve the above object and other related objects, the present invention provides a method for preparing a zinc hollow fiber electrode, the preparation method comprising the following steps:

[0008] S1. At room temperature, the zinc source, the organic solvent and the binder are ball-milled in a certain proportion to be uniformly mixed to obtain a uniform slurry, and then the slurry is placed in a vacuum drying oven for degassing;

[0009] S2, the degassed slurry is extruded through the core liquid and the spinning head at a certain flow rate to form initial fibers, and the initial fibers are then passed through an air bath and then enter the coagulation liquid to undergo phase transformation to obtain a hollow fiber soft body;

[0010] S3, after the hollow fiber soft body is washed and shaped, a hollow fiber embryo is obtained;

[0011] S4, placing the hollow fiber embryo in an oxidizing gas atmosphere, heating it to a certain temperature at a certain heating rate for calcination and oxidation, to obtain an oxide precursor;

[0012] S5. In-situ electrochemical reduction of the oxide precursor to obtain a zinc hollow fiber electrode.

[0013] Preferably, in step S1, the zinc source includes one or a combination of zinc powder and zinc oxide powder, the organic solvent includes one or a combination of N-methyl-2-pyrrolidone and N,N-dimethylformamide, and the binder includes one or a combination of polyethyleneimine and polyethersulfone.

[0014] Preferably, in the slurry of step S1, by mass percentage, the mass percentage of the zinc source is 40wt% to 70wt%, the mass percentage of the organic solvent is 20wt% to 50wt%, and the mass percentage of the binder is 5wt% to 15wt%.

[0015] Preferably, the particle size of the zinc source particles in step S1 is 50 nm to 10 μm.

[0016] Preferably, the shape of the zinc source particles in step S1 is one or more of spherical, flake, granular, and irregular.

[0017] Preferably, the ball milling time in step S1 is 12 h to 48 h.

[0018] Preferably, the degassing time in step S1 is 4 h to 24 h.

[0019] Preferably, in step S2, the slurry is extruded through a spinning head at a flow rate of 5 to 25 mL / min.

[0020] Preferably, the size of the spinning head in step S2 is one or a combination of Φ1.0×0.3mm, Φ1.5×0.3mm, Φ1.5×0.5mm, Φ2.0×1.0mm.

[0021] Preferably, the flow rate of the core liquid in step S2 is 5 to 25 mL / min.

[0022] Preferably, in step S2, the air distance between the spinning head and the surface of the coagulation liquid is 0.1 to 3 cm.

[0023] Preferably, the oxidizing gas in step S4 is air or oxygen.

[0024] Preferably, the flow rate of the oxidizing gas in step S4 is 50-400 mL / min.

[0025] Preferably, the heating rate in step S4 is 0.5-8°C / min.

[0026] Preferably, the temperature of the calcination oxidation in step S4 is 500-1200°C.

[0027] Preferably, the calcination and oxidation time in step S4 is 1 to 8 hours.

[0028] Preferably, the in-situ electrochemical reduction in step S5 specifically comprises the following steps: first subjecting the oxide precursor to cathode constant potential reduction in an electrolyte, and then subjecting it to constant current reduction.

[0029] Preferably, the in-situ electrochemical reduction in step S5 needs to be performed under a gas atmosphere, and the gas atmosphere includes one or a combination of carbon dioxide, nitrogen, and argon.

[0030] Preferably, the electrolyte in step S5 is one or a combination of K2CO3, KHCO3, K2SO4, KOH, KCl, Na2CO3, NaHCO3, Na2SO4, NaOH, and NaCl.

[0031] Preferably, the concentration of the electrolyte in step S5 is 0.1-3M.

[0032] Preferably, the potential range of the constant potential reduction in step S5 is -1.2 to -10 V vs. Ag / AgCl electrode, the time of the constant potential reduction is 5 min to 60 min; the current density of the constant current reduction is -0.1 to -1.0 A / cm 2 The constant current reduction time is 5 min to 60 min.

[0033] The present invention also provides a zinc hollow fiber electrode prepared by the above-mentioned method for preparing a zinc hollow fiber electrode, wherein the zinc hollow fiber electrode is a porous hollow fiber tubular structure, including an inner tube surface and an outer tube surface; the tube wall thickness of the zinc hollow fiber electrode is 0.1 mm to 1 mm, and the average pore size of the inner tube surface and the outer tube surface is 0.5 μm to 10 μm.

[0034] The present invention also provides an application of a zinc hollow fiber electrode, which is used for electrocatalytic conversion of CO2 to prepare CO and synthesis gas, and specifically comprises the following steps: CO2 is introduced into the zinc hollow fiber electrode, the zinc hollow fiber electrode is placed in an electrolyte, a constant potential or a constant current is applied to electrochemically reduce CO2, and CO2 is electrocatalytically converted into CO and synthesis gas with an adjustable ratio of CO and H2.

[0035] Preferably, the electrolyte comprises a cathode liquid and an anode liquid, the cathode liquid is one or a combination of K2CO3, KHCO3, K2SO4, KCl, Na2CO3, NaHCO3, Na2SO4, and NaCl, and the anode liquid is one or a combination of K2CO3, KHCO3, K2SO4, KOH, Na2CO3, NaHCO3, Na2SO4, and NaOH.

[0036] Preferably, the concentrations of the cathode liquid and the anode liquid are both 0.1-5M.

[0037] Preferably, the potential range applied during the electrochemical reduction of CO2 is -0.5 to -10 V vs. RHE.

[0038] Preferably, the current density applied during the electrochemical reduction of CO2 is in the range of -0.01 to -5 A / cm 2 .

[0039] As described above, the zinc hollow fiber electrode, preparation method and application of the present invention have the following beneficial effects:

[0040] The preparation method of the present invention is simple and low in cost. A simple phase conversion method can be used to efficiently prepare a hollow fiber embryo. After calcination in an oxidizing atmosphere, an oxide precursor is obtained. The oxide precursor is further subjected to in-situ electrochemical reduction to obtain a zinc hollow fiber electrode. The zinc hollow fiber electrode prepared by the present invention is applied to CO2 electrocatalytic reduction, and can be particularly applied to the reaction of CO2 electrocatalytic conversion to generate CO and synthesis gas. The Faraday current efficiency of CO at normal temperature and pressure can be as high as 93.8%, and the ratio of CO and H2 in the generated synthesis gas can be adjusted. The zinc hollow fiber electrode has good electrocatalytic activity, good CO and synthesis gas selectivity, high current density and high stability, and has extremely high application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Shown is a SEM image of the cross section of the oxide precursor obtained in Example 2 of the present invention.

[0042] Figure 2 Shown is a SEM image of the cross section of the zinc hollow fiber electrode obtained in Example 2 of the present invention. DETAILED DESCRIPTION

[0043] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0044] Before further describing the specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the examples of the present invention are intended to describe specific embodiments, rather than to limit the scope of protection of the present invention. The test methods in the following examples without specifying specific conditions are generally carried out under conventional conditions or under conditions recommended by the manufacturers.

[0045] When the embodiments give numerical ranges, it should be understood that, unless otherwise specified in the present invention, both endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those generally understood by those skilled in the art. In addition to the specific methods, equipment, and materials used in the embodiments, according to the grasp of the prior art by those skilled in the art and the record of the present invention, any methods, equipment, and materials of the prior art similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to realize the present invention.

[0046] The present invention provides a method for preparing a zinc hollow fiber electrode, the preparation method comprising the following steps:

[0047] S1. At room temperature, the zinc source, the organic solvent and the binder are ball-milled in a certain proportion to be uniformly mixed to obtain a uniform slurry, and then the slurry is placed in a vacuum drying oven for degassing;

[0048] S2, the degassed slurry is extruded through the core liquid and the spinning head at a certain flow rate to form initial fibers, and the initial fibers are then passed through an air bath and then enter the coagulation liquid to undergo phase transformation to obtain a hollow fiber soft body;

[0049] S3, after the hollow fiber soft body is washed and shaped, a hollow fiber embryo is obtained;

[0050] S4, placing the hollow fiber embryo in an oxidizing gas atmosphere, heating it to a certain temperature at a certain heating rate for calcination and oxidation, to obtain an oxide precursor;

[0051] S5. In-situ electrochemical reduction of the oxide precursor to obtain a zinc hollow fiber electrode.

[0052] First, step S1 is performed to ball-mill the zinc source, the organic solvent and the binder in a certain proportion at room temperature to uniformly mix them to obtain a uniform slurry, and then the slurry is placed in a vacuum drying oven for degassing.

[0053] As an example, in step S1, the zinc source includes one or a combination of zinc powder and zinc oxide powder, the organic solvent includes one or a combination of N-methyl-2-pyrrolidone and N,N-dimethylformamide, and the binder includes one or a combination of polyethyleneimine and polyethersulfone.

[0054] As an example, in the slurry of step S1, by mass percentage, the mass percentage of the zinc source is 40wt% to 70wt%, the mass percentage of the organic solvent is 20wt% to 50wt%, and the mass percentage of the binder is 5wt% to 15wt%.

[0055] Specifically, in terms of mass percentage, the mass percentage of the zinc source is 40wt% to 70wt%, such as 40wt%, 50wt%, 60wt%, 70wt% and the like; the mass percentage of the organic solvent is 20wt% to 50wt%, such as 20wt%, 30wt%, 40wt%, 50wt% and the like; the mass percentage of the binder is 5wt% to 15wt%, such as 5wt%, 8wt%, 10wt%, 12wt%, 15wt% and the like.

[0056] As an example, the particle size of the zinc source particles in step S1 is 50 nm to 10 μm.

[0057] Specifically, the particle size of the zinc source particles may be within any range of 50 nm, 100 nm, 500 nm, 1 μm, 5 μm, 10 μm, etc.

[0058] As an example, the shape of the zinc source particles in step S1 is one or more of spherical, flake, granular, and irregular shapes.

[0059] Preferably, the zinc source is spherical zinc powder with a particle size of 50 nm to 10 μm.

[0060] As an example, the ball milling time in step S1 is 12 to 48 hours.

[0061] Specifically, the ball milling time may include values ​​within any range such as 12 h, 24 h, 36 h, 48 h, etc. Preferably, the ball milling time is 18 to 24 h, such as 18 h, 19 h, 20 h, 21 h, 22 h, 23 h, 24 h, etc.

[0062] As an example, the degassing time in step S1 is 4 to 24 hours.

[0063] Specifically, the degassing time may include values ​​within any range such as 4h, 8h, 12h, 16h, 20h, 24h, etc.; preferably, the degassing time is 10 to 15h, such as 10h, 11h, 12h, 13h, 14h, 15h, etc.

[0064] Then, step S2 is performed, the degassed slurry liquid is extruded through the core liquid and the spinning head at a certain flow rate to form initial fibers, and the initial fibers are then passed through an air bath and then enter the coagulation liquid to undergo phase transformation to obtain a hollow fiber soft body.

[0065] As an example, in step S2, the slurry is extruded through the spinning head at a flow rate of 5 to 25 mL / min.

[0066] Specifically, the flow rate of the slurry liquid passing through the spinning head may include values ​​within any range such as 5 mL / min, 10 mL / min, 15 mL / min, 20 mL / min, 25 mL / min, etc.

[0067] As an example, the size of the spinning head in step S2 is one or a combination of Φ1.0×0.3 mm, Φ1.5×0.3 mm, Φ1.5×0.5 mm, and Φ2.0×1.0 mm.

[0068] As an example, the flow rate of the core liquid in step S2 is 5 to 25 mL / min.

[0069] Specifically, the flow rate of the core liquid may include values ​​within any range such as 5 mL / min, 10 mL / min, 15 mL / min, 20 mL / min, 25 mL / min, etc.

[0070] As an example, in step S2, the air distance between the spinning head and the surface of the coagulation liquid is 0.1 to 3 cm.

[0071] Specifically, the air distance between the spinning head and the liquid surface of the coagulating liquid may include values ​​within any range such as 0.1 cm, 0.5 cm, 1 cm, 2 cm, 3 cm, etc.; preferably, the air distance between the spinning head and the liquid surface of the coagulating liquid is 1 cm.

[0072] Then, step S3 is performed, and the hollow fiber soft body is washed and shaped to obtain a hollow fiber embryo.

[0073] Specifically, the organic solvent in the hollow fiber soft body is removed by washing with a large amount of tap water, and the shaping is specifically performed by straightening and fixing the hollow fiber soft body, and then drying it naturally in the air.

[0074] Then, step S4 is performed to place the hollow fiber embryo in an oxidizing gas atmosphere, heat it to a certain temperature at a certain heating rate, and perform calcination and oxidation to obtain an oxide precursor.

[0075] As an example, the oxidizing gas in step S4 is air or oxygen.

[0076] As an example, the flow rate of the oxidizing gas in step S4 is 50-400 mL / min.

[0077] Specifically, the flow rate of the oxidizing gas may include a value within any range of 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, 300 mL / min, 400 mL / min, etc.; preferably, the flow rate of the oxidizing gas is 100-200 mL / min, such as 100 mL / min, 120 mL / min, 140 mL / min, 160 mL / min, 180 mL / min, 200 mL / min, etc.

[0078] As an example, the heating rate in step S4 is 0.5-8° C. / min.

[0079] Specifically, the heating rate may include values ​​within any range such as 0.5°C / min, 1°C / min, 2°C / min, 4°C / min, 6°C / min, 8°C / min, etc.

[0080] As an example, the temperature of the calcination oxidation in step S4 is 500-1200°C.

[0081] Specifically, the temperature of calcination and oxidation may include any value within the range of 500°C, 800°C, 1000°C, 1200°C, etc.; preferably, the temperature of calcination and oxidation is 500-800°C, such as 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, etc.

[0082] As an example, the calcination and oxidation time in step S4 is 1 to 8 hours.

[0083] Specifically, the calcination and oxidation time may include values ​​within any range of 1h, 2h, 4h, 6h, 8h, etc.; preferably, the calcination and oxidation time is 2 to 6h, such as 2h, 3h, 4h, 5h, 6h, etc.

[0084] Finally, step S5 is performed to perform in-situ electrochemical reduction of the oxide precursor to obtain a zinc hollow fiber electrode.

[0085] As an example, the in-situ electrochemical reduction in step S5 specifically includes the following steps: firstly subjecting the oxide precursor to cathode constant potential reduction in an electrolyte, and then subjecting it to constant current reduction.

[0086] Specifically, the oxide precursor is first subjected to cathode constant potential reduction in an electrolyte to slowly reduce its surface oxide species to metal and improve its electronic conductivity; then constant current reduction is performed to quickly reduce the bulk oxide species to metal, and finally the zinc hollow fiber electrode is obtained.

[0087] As an example, the in-situ electrochemical reduction in step S5 needs to be performed under a gas atmosphere, and the gas atmosphere includes one or a combination of carbon dioxide, nitrogen, and argon.

[0088] Specifically, during the in-situ electrochemical reduction reaction, the gas can be directly introduced into the oxide precursor of the tubular structure, or the gas can be directly introduced into the electrolyte, and the flow rate of the gas atmosphere is 1 to 100 mL / min, such as 1 mL / min, 5 mL / min, 10 mL / min, 20 mL / min, 50 mL / min, 100 mL / min, etc.; preferably, the flow rate of the gas atmosphere is 5 to 50 mL / min, such as 5 mL / min, 10 mL / min, 20 mL / min, 50 mL / min, etc.

[0089] As an example, the electrolyte in step S5 is one or a combination of K2CO3, KHCO3, K2SO4, KOH, KCl, Na2CO3, NaHCO3, Na2SO4, NaOH, and NaCl.

[0090] As an example, the concentration of the electrolyte in step S5 is 0.1-3M.

[0091] Specifically, the concentration of the electrolyte may include values ​​within any range such as 0.1M, 0.5M, 1M, 2M, 3M, etc.; preferably, the electrolyte is 3.0M KHCO3.

[0092] As an example, the potential range of the constant potential reduction in step S5 is -1.2 to -10 V vs. Ag / AgCl electrode, the time of the constant potential reduction is 5 to 60 min; the current density of the constant current reduction is -0.1 to -1.0 A / cm 2 The constant current reduction time is 5 to 60 minutes.

[0093] Specifically, the potential range of constant potential reduction may include values ​​within any range such as -1.2V vs.Ag / AgCl electrode, -1.4V vs.Ag / AgCl electrode, -2.0V vs.Ag / AgCl electrode, -4.0V vs.Ag / AgCl electrode, -6.0V vs.Ag / AgCl electrode, -8.0Vvs.Ag / AgCl electrode, -10.0V vs.Ag / AgCl electrode, and the time of constant potential reduction may include values ​​within any range such as 5min, 10min, 20min, 40min, 60min, etc.

[0094] The current density of the constant current reduction may include -0.1A / cm 2 、-0.2A / cm 2 、-0.4A / cm 2 、-0.6A / cm2 、-1.0A / cm 2 The constant current reduction time may include any value within a range of 5 min, 10 min, 20 min, 40 min, 60 min, etc.

[0095] Preferably, the potential of the constant potential reduction is -1.8V vs. Ag / AgCl electrode, the time of the constant potential reduction is 10min; the current density of the constant current reduction is -0.2A / cm 2 The constant current reduction time is 10 min.

[0096] The present invention also provides a zinc hollow fiber electrode prepared by the above-mentioned method for preparing a zinc hollow fiber electrode, wherein the zinc hollow fiber electrode is a porous hollow fiber tubular structure, including an inner tube surface and an outer tube surface; the tube wall thickness of the zinc hollow fiber electrode is 0.1 mm to 1 mm, and the average pore size of the inner tube surface and the outer tube surface is 0.5 μm to 10 μm.

[0097] Specifically, the wall thickness of the zinc hollow fiber electrode may include any value in the range of 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, etc. The average pore size of the inner and outer surfaces of the tube may include any value in the range of 0.5 μm, 0.6 μm, 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, 10 μm, etc.

[0098] The present invention also provides an application of a zinc hollow fiber electrode, which is applied to the electrocatalytic conversion of CO2, specifically comprising the following steps: passing CO2 into the zinc hollow fiber electrode, placing the zinc hollow fiber electrode in an electrolyte, applying a constant potential or a constant current to electrochemically reduce CO2, and electrocatalytically converting CO2 into CO and a synthesis gas with an adjustable ratio of CO and H2.

[0099] Specifically, the bottom end of the zinc hollow fiber electrode is closed, CO2 is introduced from the top, CO2 is dispersed from the porous wall of the zinc hollow fiber electrode, the raw gas CO2 contacts the electrolyte, the gas-liquid-solid three-phase reaction interface is enhanced, and the mass transfer process between the reactants and products is strengthened. The total flow rate of the introduced CO2 is 1 to 100 mL / min, and the temperature of the CO2 electrocatalytic conversion is 10 to 60°C.

[0100] As an example, the electrolyte includes a cathode liquid and an anode liquid, the cathode liquid is one or a combination of K2CO3, KHCO3, K2SO4, KCl, Na2CO3, NaHCO3, Na2SO4, and NaCl, and the anode liquid includes one or a combination of K2CO3, KHCO3, K2SO4, KOH, Na2CO3, NaHCO3, Na2SO4, and NaOH.

[0101] As an example, the concentrations of the cathode liquid and the anode liquid are both 0.1 to 5M.

[0102] Specifically, the concentrations of the cathode liquid and the anode liquid may include values ​​within any range such as 0.1M, 0.5M, 1M, 2M, 3M, 4M, 5M, etc.; preferably, the cathode liquid is 3.0M KCl and the anode liquid is 3.0M KOH.

[0103] As an example, the potential range applied during electrochemical reduction of CO2 is -0.5 to -10 V vs. RHE.

[0104] Specifically, the potential applied during the electrochemical reduction of CO2 may include any range of values ​​such as -0.5V vs.RHE, -1.0V vs.RHE, -2.0V vs.RHE, -5.0V vs.RHE, -8.0V vs.RHE, -10.0V vs.RHE, etc.; preferably, the applied potential is -0.8 to -1.4V vs.RHE, such as -0.8V vs.RHE, -0.9V vs.RHE, -1.0V vs.RHE, -1.2Vvs.RHE, -1.4V vs.RHE, etc.

[0105] As an example, the current density applied during electrochemical reduction of CO2 ranges from -0.1 to -5 A / cm 2 .

[0106] Specifically, the current density applied during electrochemical reduction of CO2 may include -0.1A / cm 2 、-1A / cm 2 、-2A / cm 2 、-3A / cm 2 、-4A / cm 2 、-5A / cm 2 Preferably, the applied current density is -0.05 to -1.2 A / cm 2 , for example -0.05A / cm 2 、-0.2A / cm 2 、-0.4A / cm 2 、-0.8A / cm 2 、-1.2A / cm 2 wait.

[0107] In order to better understand the zinc hollow fiber electrode, preparation method and application thereof in the present invention, the zinc hollow fiber electrode, preparation method and application thereof in the present invention are described below with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0108] Example 1

[0109] This embodiment provides a method for preparing a zinc hollow fiber electrode, and the preparation method comprises the following steps:

[0110] S1. At room temperature, spherical zinc powder with a particle size of 1 μm, N-methyl-2-pyrrolidone and polyethyleneimine were mixed in a ratio of 50 wt%, 40 wt% and 10 wt% respectively, and ball-milled at a speed of 300 r / min for 24 h to obtain a uniform slurry, and then the slurry was placed in a vacuum drying oven for degassing for 5 h;

[0111] S2, the degassed slurry is extruded through the core liquid and the spinning head of Φ1.5×0.3mm at a flow rate of 5mL / min to form initial fibers, and the initial fibers are then passed through an air bath and then enter the coagulation liquid to undergo phase transformation to obtain a hollow fiber soft body; wherein the core liquid is ultrapure water, the flow rate of the core liquid is 5mL / min, the coagulation liquid is tap water, and the air distance between the spinning head and the surface of the coagulation liquid is 1cm;

[0112] S3, washing the hollow fiber soft body with a large amount of tap water to remove the organic solvent, and shaping it to obtain a hollow fiber embryo;

[0113] S4, placing the hollow fiber embryo in an air atmosphere with a flow rate of 100 mL / min, heating to 600° C. at a heating rate of 5° C. / min for calcination and oxidation for 2 h, so as to remove the polyethyleneimine in the hollow fiber embryo and cause sintering and oxidation of the zinc particles to obtain an oxide precursor;

[0114] S5. A carbon dioxide atmosphere was introduced into the electrolyte at a flow rate of 100 mL / min. The oxide precursor was electrochemically reduced in a 3 M KHCO3 electrolyte. The reduction was first carried out at a constant potential of -1.8 V vs. Ag / AgCl for 10 min, and then at -0.2 A / cm 2 The zinc hollow fiber electrode was obtained by constant current reduction for 10 min.

[0115] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0116] Example 2

[0117] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Embodiment 1 is that the electrolyte in step S5 is a 3M KCl electrolyte, and the other steps and methods are the same as those in Embodiment 1, which will not be repeated here.

[0118] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment.

[0119] See also Figure 1 This is a SEM image of the oxide precursor obtained in this example. The left image is the outer surface magnified 10,000 times, and the right image is the cross section magnified 200 times. It can be seen from the image that the surface of the oxide precursor is nano-peaks with uniform wall thickness.

[0120] See also Figure 2 This is an SEM image of the cross section of the zinc hollow fiber electrode prepared in this embodiment. The left image is magnified 10,000 times, and the right image is magnified 200 times. It can be seen from the image that the cross section of the zinc hollow fiber electrode formed after the oxide is converted into metallic zinc is roughened and the tube wall thickness is reduced.

[0121] Example 3

[0122] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Example 1 is that the electrolyte in step S5 is a 3M NaCl electrolyte, and the other steps and methods are the same as those in Example 1, which will not be repeated here.

[0123] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment.

[0124] Example 4

[0125] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Example 1 is that the electrolyte in step S5 is a 0.5M KHCO3 electrolyte, and the other steps and methods are the same as those in Example 1, which will not be repeated here.

[0126] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0127] Example 5

[0128] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in embodiment 1 is that in step S5, the electrode is first subjected to constant potential reduction at a potential of -1.2 V vs. Ag / AgCl for 10 min, and then subjected to constant potential reduction at -0.2 A / cm 2 The other steps and methods are the same as those in Example 1 and will not be described in detail here.

[0129] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0130] Example 6

[0131] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in embodiment 1 is that in step S5, the electrode is first subjected to constant potential reduction at a potential of -3 V vs. Ag / AgCl for 10 min, and then subjected to constant potential reduction at -0.2 A / cm 2 The other steps and methods are the same as those in Example 1 and will not be described in detail here.

[0132] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0133] Example 7

[0134] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in embodiment 1 is that in step S5, the electrode is first subjected to constant potential reduction at a potential of -1.8 V vs. Ag / AgCl for 30 min, and then subjected to constant potential reduction at -0.2 A / cm 2 The other steps and methods are the same as those in Example 1 and will not be described in detail here.

[0135] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0136] Example 8

[0137] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in embodiment 1 is that in step S5, the electrode is first subjected to constant potential reduction at a potential of -1.8 V vs. Ag / AgCl for 10 min, and then subjected to constant potential reduction at -0.1 A / cm 2 The other steps and methods are the same as those in Example 1 and will not be described in detail here.

[0138] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0139] Example 9

[0140] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in embodiment 1 is that in step S5, the electrode is first subjected to constant potential reduction at a potential of -1.8 V vs. Ag / AgCl for 10 min, and then subjected to constant potential reduction at -0.5 A / cm 2 The other steps and methods are the same as those in Example 1 and will not be described in detail here.

[0141] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0142] Example 10

[0143] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in embodiment 1 is that in step S5, the electrode is first subjected to constant potential reduction at a potential of -1.8 V vs. Ag / AgCl for 10 min, and then subjected to constant potential reduction at -0.2 A / cm 2 The constant current reduction was carried out for 30 min. The other steps and methods were the same as those in Example 1 and will not be described again.

[0144] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0145] Embodiment 11

[0146] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Embodiment 1 is that the gas atmosphere in step S5 is nitrogen, and the other steps and methods are the same as those in Embodiment 1, which will not be repeated here.

[0147] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0148] Example 12

[0149] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Embodiment 1 is that the gas atmosphere in step S5 is argon gas, and the other steps and methods are the same as those in Embodiment 1, which will not be described again.

[0150] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0151] Embodiment 13

[0152] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Example 1 is that in step S1, spherical zinc powder, N-methyl-2-pyrrolidone and polyethyleneimine are mixed in a ratio of 50wt%, 45wt% and 5wt%, respectively, and the other steps and methods are the same as those in Example 1 and will not be repeated here.

[0153] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0154] Embodiment 14

[0155] The present embodiment provides a method for preparing a zinc hollow fiber electrode, and the difference between the preparation method and that in Example 1 is that in step S1, spherical zinc powder, N-methyl-2-pyrrolidone and polyethyleneimine are mixed in proportions of 50wt%, 35wt% and 15wt%, respectively, and the other steps and methods are the same as those in Example 1 and will not be repeated here.

[0156] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0157] Embodiment 15

[0158] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Example 1 is that in step S1, spherical zinc powder, N-methyl-2-pyrrolidone and polyethyleneimine are mixed in a ratio of 65wt%, 20wt% and 15wt%, respectively, and the other steps and methods are the same as those in Example 1 and will not be repeated here.

[0159] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0160] Example 16

[0161] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Example 1 is that in step S1, spherical zinc powder, N-methyl-2-pyrrolidone and polyethyleneimine are mixed in a ratio of 70wt%, 20wt% and 10wt%, respectively, and the other steps and methods are the same as those in Example 1 and will not be repeated here.

[0162] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0163] Embodiment 17

[0164] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Example 1 is that spherical zinc oxide powder with a particle size of 1 μm is used in step S1, and the hollow fiber embryo in S4 is calcined and oxidized at 1200° C. for 2 h. The other steps and methods are the same as those in Example 1 and will not be repeated here.

[0165] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0166] Embodiment 18

[0167] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Example 1 is that the organic solvent used in step S1 is N,N-dimethylformamide, and the other steps and methods are the same as those in Example 1, which will not be repeated here.

[0168] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0169] Embodiment 19

[0170] This embodiment provides a method for preparing a zinc hollow fiber electrode. The difference between the preparation method and that in Embodiment 1 is that the binder used in step S1 is polyethersulfone, and the other steps and methods are the same as those in Embodiment 1, which will not be repeated here.

[0171] This embodiment also provides a zinc hollow fiber electrode, which is prepared by the preparation method of the zinc hollow fiber electrode in this embodiment, and the zinc hollow fiber electrode is a porous hollow fiber tubular structure.

[0172] Application Example 1

[0173] The zinc hollow fiber electrodes prepared in Examples 1 to 19 were applied to CO2 electrocatalytic conversion, and CO2 was reduced by a constant potential method, comprising the following steps: CO2 was introduced into the zinc hollow fiber electrode, the zinc hollow fiber electrode was placed in an electrolyte, the anolyte was 3.0M KCl, the anolyte was 3.0M KOH, a voltage of -1.25V vs. RHE was applied to electrocatalyze CO2 for 1 hour, CO and H2 products were obtained, and finally the total current density, the Faraday current efficiency of CO and the volume ratio of CO to H2 in the synthesis gas were obtained (see Table 1).

[0174] Table 1. Results of the zinc hollow fiber electrodes prepared in Examples 1 to 19 in the application of CO2 electrocatalytic conversion

[0175]

[0176]

[0177] Application Example 2

[0178] The zinc hollow fiber electrode prepared in Example 1 was applied to the electrocatalytic conversion of CO2, and the constant current method was used to reduce CO2, including the following steps: CO2 was introduced into the zinc hollow fiber electrode, and the zinc hollow fiber electrode was placed in an electrolyte, the anolyte was 0.5M KCl, the anolyte was 3.0M KOH, and the applied current density was -1.0A / cm 2 Electrochemical reduction was carried out for 1 h to obtain CO and H2 products at a potential of -1.52 V vs. RHE. The Faraday current efficiency of CO was 82.2%, and the CO:H2 ratio in the synthesis gas was 4.5:1.

[0179] Application Example 3

[0180] The zinc hollow fiber electrode prepared in Example 1 was applied to the electrocatalytic conversion of CO2, and the CO2 was reduced by constant potential method. The difference between the steps in Example 1 was that the voltage was -1.34V vs. RHE for electrochemical reduction for 1h to obtain CO and H2 products, and the total current density was finally -0.6A / cm 2 , the Faraday current efficiency of CO is 92.5%, and the CO:H2 ratio in the synthesis gas is 12.33:1.

[0181] Application Example 4

[0182] The zinc hollow fiber electrode prepared in Example 1 was applied to the electrocatalytic conversion of CO2, and the CO2 was reduced by constant potential method. The difference between the steps in Example 1 was that the voltage was -1.43V vs. RHE for electrochemical reduction for 1h to obtain CO and H2 products, and the total current density was finally -0.8A / cm 2, the Faraday current efficiency of CO is 87.5%, and the CO:H2 ratio in the synthesis gas is 7:1.

[0183] Application Example 5

[0184] The zinc hollow fiber electrode prepared in Example 1 was applied to the electrocatalytic conversion of CO2, and the constant potential method was used to reduce CO2. The steps were the same as those in Example 1 except that the anolyte was 0.5M KHCO3, the anolyte was 0.5M KHCO3, the applied voltage was -0.96V vs. RHE, and the electrochemical reduction was performed for 1h to obtain CO and H2 products, and the total current density was finally obtained to be -0.2A / cm 2 , the Faraday current efficiency of CO is 93.3%, and the CO:H2 ratio in the synthesis gas is 13.92:1.

[0185] Application Example 6

[0186] The zinc hollow fiber electrode prepared in Example 1 was applied to the electrocatalytic conversion of CO2, and the constant current method was used to reduce CO2. The steps were the same as those in Example 2 except that the anolyte was 0.5M KHCO3, the anolyte was 0.5M KHCO3, and the applied current density was -0.4A / cm 2 Electrochemical reduction was carried out for 1 h to obtain CO and H2 products at a potential of -1.13 V vs. RHE. The Faraday current efficiency of CO was 89.8%, and the CO:H2 ratio in the synthesis gas was 8.8:1.

[0187] Application Example 7

[0188] The zinc hollow fiber electrode prepared in Example 1 was applied to the electrocatalytic conversion of CO2, and the constant potential method was used to reduce CO2. The steps were the same as those in Example 2 except that the anolyte was 0.5M KHCO3, the anolyte was 0.5M KHCO3, the applied voltage was -1.28V vs. RHE, and the electrochemical reduction was performed for 1h to obtain CO and H2 products, and the total current density was finally obtained to be -0.6A / cm 2 , the Faraday current efficiency of CO is 86.7%, and the CO:H2 ratio in the synthesis gas is 8.8:1.

[0189] Application Example 8

[0190] The zinc hollow fiber electrode prepared in Example 1 was applied to the electrocatalytic conversion of CO2, and the constant potential method was used to reduce CO2. The steps were the same as those in Example 2 except that the anolyte was 0.5M KHCO3, the anolyte was 0.5M KHCO3, the applied voltage was -1.44V vs. RHE, and the electrochemical reduction was performed for 1h to obtain CO and H2 products, and the total current density was finally obtained to be -0.8A / cm 2, the Faraday current efficiency of CO is 81.7%, and the CO:H2 ratio in the synthesis gas is 4.46:1.

[0191] In summary, the preparation method of the present invention is simple and low-cost. A simple phase conversion method can be used to efficiently prepare a hollow fiber embryo. After calcination in an oxidizing atmosphere, an oxide precursor is obtained. The oxide precursor is further electrochemically reduced in situ to obtain a zinc hollow fiber electrode. The zinc hollow fiber electrode prepared by the present invention is used in the electrocatalytic reduction of CO2, and can be particularly used in the reaction of electrocatalytic conversion of CO2 to generate CO and synthesis gas. The Faraday current efficiency of CO at room temperature and pressure can be as high as 93.8%, and the ratio of CO and H2 in the generated synthesis gas is adjustable. The zinc hollow fiber electrode has good electrocatalytic activity, good CO and synthesis gas selectivity, high current density and high stability, and has extremely high application prospects. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0192] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing a zinc hollow fiber electrode, characterized in that: The preparation method comprises the following steps: S1. At room temperature, the zinc source, the organic solvent and the binder are ball-milled in a certain proportion to be uniformly mixed to obtain a uniform slurry, and then the slurry is placed in a vacuum drying oven for degassing; S2, the degassed slurry is extruded through the core liquid and the spinning head at a certain flow rate to form initial fibers, and the initial fibers are then passed through an air bath and then enter the coagulation liquid to undergo phase transformation to obtain a hollow fiber soft body; S3, after the hollow fiber soft body is washed and shaped, a hollow fiber embryo is obtained; S4, placing the hollow fiber embryo in an oxidizing gas atmosphere, heating it to a certain temperature at a certain heating rate for calcination and oxidation, to obtain an oxide precursor; S5. In-situ electrochemical reduction of the oxide precursor to obtain a zinc hollow fiber electrode.

2. The method for preparing a zinc hollow fiber electrode according to claim 1, characterized in that: Step S1 includes one or a combination of the following conditions: The zinc source includes one or a combination of zinc powder and zinc oxide powder, the organic solvent includes one or a combination of N-methyl-2-pyrrolidone and N,N-dimethylformamide, and the binder includes one or a combination of polyethyleneimine and polyethersulfone; In the slurry, the mass percentage of the zinc source is 40wt% to 70wt%, the mass percentage of the organic solvent is 20wt% to 50wt%, and the mass percentage of the binder is 5wt% to 15wt%; The particle size of the zinc source particles is 50nm to 10μm; The shape of the zinc source particles is one or more of spherical, flake, granular, and irregular shapes; The ball milling time is 12h to 48h; The degassing time is 4h to 24h.

3. The method for preparing a zinc hollow fiber electrode according to claim 1, characterized in that: Step S2 includes any one or a combination of the following conditions: The slurry is extruded through a spinning head at a flow rate of 5 to 25 mL / min; The size of the spinning head is one or a combination of Φ1.0×0.3mm, Φ1.5×0.3mm, Φ1.5×0.5mm, Φ2.0×1.0mm; The flow rate of the core liquid is 5 to 25 mL / min; The air distance between the spinning head and the surface of the coagulation liquid is 0.1 to 3 cm.

4. The method for preparing a zinc hollow fiber electrode according to claim 1, characterized in that: Step S4 includes any one or a combination of the following conditions: The oxidizing gas is air or oxygen; The flow rate of the oxidizing gas is 50-400 mL / min; The heating rate is 0.5-8°C / min; The temperature of the calcination oxidation is 500-1200°C; The calcination and oxidation time is 1 to 8 hours.

5. The method for preparing a zinc hollow fiber electrode according to claim 1, characterized in that: The in-situ electrochemical reduction in step S5 specifically includes the following steps: firstly subjecting the oxide precursor to cathode constant potential reduction in an electrolyte, and then subjecting it to constant current reduction.

6. The method for preparing the zinc hollow fiber electrode according to claim 5, characterized in that: The in-situ electrochemical reduction in step S5 needs to be performed in a gas atmosphere, and the gas atmosphere includes one or a combination of carbon dioxide, nitrogen, and argon.

7. The method for preparing a zinc hollow fiber electrode according to claim 5, characterized in that: The in-situ electrochemical reduction in step S5 includes any one or a combination of the following conditions: The electrolyte is one or a combination of K2CO3, KHCO3, K2SO4, KOH, KCl, Na2CO3, NaHCO3, Na2SO4, NaOH, and NaCl; The concentration of the electrolyte is 0.1 to 3 M; The potential range of the constant potential reduction is -1.2 to -10 V vs. Ag / AgCl electrode, the time of the constant potential reduction is 5 min to 60 min; the current density of the constant current reduction is -0.1 to -1.0 A / cm 2 The constant current reduction time is 5 to 60 minutes.

8. A zinc hollow fiber electrode prepared by the method for preparing a zinc hollow fiber electrode according to any one of claims 1 to 7, characterized in that: The zinc hollow fiber electrode is a porous hollow fiber tubular structure, including an inner tube surface and an outer tube surface; the tube wall thickness of the zinc hollow fiber electrode is 0.1mm-1mm, and the average pore size of the inner tube surface and the outer tube surface is 0.5μm-10μm.

9. An application of the zinc hollow fiber electrode as claimed in claim 8, characterized in that: The zinc hollow fiber electrode is used for the electrocatalytic conversion of CO2 to prepare CO and synthesis gas, which specifically includes the following steps: CO2 is introduced into the zinc hollow fiber electrode, the zinc hollow fiber electrode is placed in an electrolyte, a constant potential or a constant current is applied to electrochemically reduce CO2, and CO2 is electrocatalytically converted into CO and synthesis gas with an adjustable ratio of CO and H2.

10. The use of the zinc hollow fiber electrode according to claim 9, characterized in that: Includes one or a combination of the following conditions: The electrolyte includes a cathode liquid and an anode liquid, the cathode liquid includes one or a combination of K2CO3, KHCO3, K2SO4, KCl, Na2CO3, NaHCO3, Na2SO4, and NaCl, and the anode liquid includes one or a combination of K2CO3, KHCO3, K2SO4, KOH, Na2CO3, NaHCO3, Na2SO4, and NaOH; The concentrations of the cathode liquid and the anode liquid are both 0.1 to 5 M; The potential range applied during the electrochemical reduction of CO2 is -0.5 to -10 V vs. RHE; The current density applied during the electrochemical reduction of CO2 is in the range of -0.01 to -5 A / cm 2 .

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