Preparation method and application of binary metal hollow fiber electrode

Abstract

The application discloses a preparation method and application of a binary metal hollow fiber electrode, and comprises the following steps: mixing metal powder A, metal powder B and N-methyl pyrrolidone, adding polyetherimide in batches, stirring overnight, degassing in a vacuum oven to obtain slurry; pushing the slurry and core liquid to a spinning nozzle by using a syringe pump, and phase change conversion occurs in a coagulation liquid to obtain soft hollow fiber; soaking the soft hollow fiber in deionized water, and performing shaping and drying to obtain a hollow fiber green body; sequentially placing the hollow fiber green body into three kinds of gas atmosphere for calcination to obtain binary metal hollow fiber; and performing electrochemical treatment on the surface of the binary metal hollow fiber to reconstruct the surface, so that the binary metal hollow fiber electrode is prepared. The binary metal hollow fiber electrode is prepared through dry-wet spinning for the first time, and the post-treatment mode of heat treatment enables the electrode to have high mechanical strength and stability.

Description

Technical Field

[0001] This invention belongs to the field of electrode preparation technology, specifically relating to a method for preparing a binary metal hollow fiber electrode and its application. Background Technology

[0002] Currently, gas diffusion electrodes are widely used in electrocatalytic reactions. However, the use of a large amount of binder in gas diffusion electrodes leads to poor catalyst stability. Therefore, hollow fibers have become a research hotspot.

[0003] However, most hollow fibers are single-component hollow fibers, and the selectivity of the product is limited. Therefore, multi-component hollow fibers can only be prepared by electrochemical means, which has poor stability and is prone to the shedding of added components during the reaction process.

[0004] Therefore, there is an urgent need in this field for a binary metal hollow fiber electrode and its preparation method. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

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

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a binary metal hollow fiber electrode.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a binary metal hollow fiber electrode, comprising,

[0009] Metal powder A, metal powder B and N-methylpyrrolidone were mixed, and polyetherimide was added in batches. The mixture was stirred overnight and then degassed in a vacuum oven to obtain a slurry.

[0010] The slurry and core liquid are pushed into the spinning nozzle by an injection pump and enter the coagulation liquid to undergo phase change transformation, thus obtaining soft hollow fibers.

[0011] The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber preform;

[0012] Hollow fiber preforms were sequentially placed into three different gas atmospheres for calcination to obtain binary metal hollow fibers.

[0013] The surface of the binary metal hollow fiber is reconstructed by electrochemical treatment to obtain the binary metal hollow fiber electrode.

[0014] Metal powder A includes copper powder and CuO powder, and metal powder B includes Bi2O3 powder and Co3O4 powder.

[0015] As a preferred embodiment of the preparation method of the present invention, wherein: based on the mass of the slurry, the metal powder A is 20-25 parts by weight, the metal powder B is 10-15 parts by weight, the N-methylpyrrolidone is 40-48 parts by weight, and the polyetherimide is 8-12 parts by weight.

[0016] As a preferred embodiment of the preparation method described in this invention, the polyetherimide is added in batches, wherein the polyetherimide is added in three equal parts by mass.

[0017] In a preferred embodiment of the preparation method described in this invention, the slurry and core liquid are pushed to the spinning nozzle by an injection pump, wherein the slurry flow rate is 1 ml / min and the core liquid flow rate is 1 ml / min.

[0018] The spinning head size is Φ1.5*0.7mm.

[0019] As a preferred embodiment of the preparation method described in this invention, the hollow fiber preform is sequentially placed into three gas atmospheres for calcination, wherein the first atmosphere is argon, the calcination temperature is 700℃, the heating rate is 5℃ / min, the gas flow rate is 100ml / min, and the heating time is 2h.

[0020] The second atmosphere is air, the calcination temperature is 600℃, the heating rate is 5℃ / min, the gas flow rate is 100ml / min, and the heating time is 4h.

[0021] The third atmosphere is a 5% argon-hydrogen mixed atmosphere, with a calcination temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 3h.

[0022] As a preferred embodiment of the preparation method described in this invention, the step of reconstructing the surface of the binary metal hollow fiber by electrochemical treatment includes,

[0023] First, a three-electrode electrochemical oxidation system was performed, with Hg / HgO as the reference electrode, a graphite electrode as the counter electrode, and hollow fiber as the working electrode. The electrolyte was 3M KOH, and the current density was 25 mA / cm². -2 Time: 10 minutes;

[0024] Then, a three-electrode electrochemical reduction was performed, with Ag / AgCl as the reference electrode, a platinum sheet electrode as the counter electrode, and a hollow fiber electrode as the working electrode. The electrolyte was 0.5M KHCO3, the potential was -0.7V vs. Ag / AgCl, and the reduction time was 30min.

[0025] Another objective of this invention is to overcome the shortcomings of the prior art and provide a binary metal hollow fiber electrode prepared by a method for preparing a binary metal hollow fiber electrode.

[0026] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of a binary metal hollow fiber electrode in the electrocatalysis of carbon dioxide.

[0027] Beneficial effects of this invention:

[0028] This invention provides a method for preparing a binary metal hollow fiber electrode. For the first time, a binary metal hollow fiber electrode is prepared by dry-wet spinning. The post-treatment method of heat treatment enables the electrode to have high stability. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0030] Figure 1 This is a scanning electron microscope image of the binary bimetallic hollow fiber electrode prepared in Example 1 of the present invention.

[0031] Figure 2 This is a scanning electron microscope image of the binary bimetallic hollow fiber electrode prepared in Example 2 of the present invention.

[0032] Figure 3 This is a scanning electron microscope image of the binary bimetallic hollow fiber electrode prepared in Comparative Example 1 of the present invention.

[0033] Figure 4 This is a scanning electron microscope image of the binary bimetallic hollow fiber electrode prepared in Comparative Example 2 of the present invention.

[0034] Figure 5 This is a scanning electron microscope image of the binary bimetallic hollow fiber electrode prepared in Comparative Example 3 of the present invention.

[0035] Figure 6 This is a scanning electron microscope image of the binary bimetallic hollow fiber electrode prepared in Comparative Example 4 of the present invention.

[0036] Figure 7This is the linear scanning voltammetry obtained in Comparative Example 5 of the present invention.

[0037] Figure 8 This is a scanning electron microscope image of the binary bimetallic hollow fiber electrode prepared in Comparative Example 6 of the present invention. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] 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.

[0041] In this invention, NMP was purchased from Aladdin anhydrous grade; PEI was purchased from SABIC PEI 1000 series; other raw materials were all commercially available products.

[0042] Example 1

[0043] (1) Copper powder with a particle size of 100nm, Bi2O3 powder with a particle size of 100nm and NMP are ultrasonically mixed for 2h. PEI is added in three portions at 10min intervals. The mixture is stirred at 60℃ overnight to obtain a slurry. Then, it is degassed in a vacuum oven for 2h to remove the bubbles generated during the stirring process.

[0044] Based on the quality of the slurry, the amount of copper powder used is 36 parts by weight, the amount of Bi2O3 powder used is 4 parts by weight, the amount of NMP used is 48 parts by weight, and the amount of PEI used is 12 parts by weight.

[0045] (2) The slurry and core liquid (deionized water) are pushed to the spinning nozzle by an injection pump at a certain flow rate and then enter the coagulation liquid to undergo phase change transformation to obtain soft hollow fiber;

[0046] The slurry flow rate is 1 ml / min, and the core liquid deionized water flow rate is 1 ml / min.

[0047] The spinning head size is Φ1.5*0.7mm;

[0048] The distance between the spinning head and the coagulation solution is 1.5 cm; the coagulation solution is deionized water.

[0049] (3) The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber embryo;

[0050] The soaking time is 24 hours to fully remove NMP from the soft hollow fibers;

[0051] The shape is achieved by straightening in the air and drying in a 60℃ oven for 24 hours.

[0052] (4) The hollow fiber preform is placed in three gas atmospheres in sequence, and post-processed with corresponding calcination temperature, heating rate, heating time and gas flow rate to obtain a binary copper-bismuth bimetallic hollow fiber electrode.

[0053] The first calcination was carried out in an argon atmosphere at a temperature of 700℃, with a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 2h.

[0054] Second air atmosphere, calcination temperature 600℃, heating rate 5℃ / min, gas flow rate 100ml / min, heating time 4h;

[0055] The third calcination was performed in a 5% hydrogen-argon mixture (H2:Ar = 5:95, V / V) atmosphere at a temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 100 ml / min, and a heating time of 3 h, reducing oxidized copper powder and Bi2O3 powder to metallic copper and bismuth. See the electron microscope image of the resulting electrode. Figure 1 .

[0056] (5) The surface of the binary metal hollow fiber electrode is reconstructed by electrochemical means.

[0057] First, a three-electrode electrochemical oxidation system is performed, with Hg / HgO as the reference electrode, a graphite electrode as the counter electrode, and a hollow fiber electrode as the working electrode. The electrolyte is 3M KOH, and the current density is 25 mA / cm². -2 Time: 10 minutes;

[0058] Then, a three-electrode electrochemical reduction was performed, with Ag / AgCl as the reference electrode, a platinum sheet electrode as the counter electrode, and a hollow fiber electrode as the working electrode. The electrolyte was 0.5M KHCO3, the potential was -0.7V vs. Ag / AgCl, and the reduction time was 30min.

[0059] (6) The binary bimetallic hollow fiber prepared by the above method was encapsulated inside a 3mm copper tube with epoxy resin and conductive silver paste, and the ends were sealed to obtain the working electrode. The catholyte was a mixture of 3.5M KCl and 0.5M KHCO3, the anolyte was 3M KOH, and the counter electrode was 1cm.2 The reaction was carried out in a self-made electrolytic cell using a platinum sheet and an Ag / AgCl reference electrode.

[0060] The electrochemical reduction of CO2 specifically includes the following steps: CO2 is introduced into the surface-reconstructed hollow fiber, the surface-reconstructed hollow fiber is placed in a catholyte, and a constant potential or constant current is applied to electrochemically reduce CO2, converting CO2 into formic acid. Geometric area S = πDL = 3.14159 × 415 × 0.0001 × 1.2 = 0.156 cm² 2 .

[0061] At a potential of -1.9V, the current density is 3A cm⁻¹. -2 Formic acid has a Faraday efficiency of 90%.

[0062] Example 2

[0063] (1) CuO powder with a particle size of 100nm, Co3O4 powder with a particle size of 100nm and NMP are ultrasonically mixed for 2h. PEI is added in three portions at 10min intervals. The mixture is stirred at 60℃ overnight to obtain a slurry. Then, it is degassed in a vacuum oven for 2h to remove the bubbles generated during the stirring process.

[0064] Based on the quality of the slurry, the amount of CuO powder used is 25 parts by weight, the amount of Co3O4 powder used is 15 parts by weight, the amount of NMP used is 48 parts by weight, and the amount of PEI used is 12 parts by weight.

[0065] (2) The slurry and core liquid are pushed to the spinning nozzle by an injection pump at a certain flow rate, and then enter the coagulation liquid to undergo phase change transformation to obtain soft hollow fiber.

[0066] The slurry flow rate is 1 ml / min, and the core liquid flow rate is 1 ml / min.

[0067] The spinning head size is Φ1.5*0.7mm;

[0068] The distance between the spinning head and the coagulation solution is 1.5 cm; the coagulation solution is deionized water.

[0069] (3) The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber embryo;

[0070] The soaking time is 24 hours to fully remove NMP from the soft hollow fibers;

[0071] The shape is achieved by straightening in the air and drying in a 60℃ oven for 24 hours.

[0072] (4) The hollow fiber preform is placed in three gas atmospheres in sequence, and post-processed with corresponding calcination temperature, heating rate, heating time and gas flow rate to obtain a binary copper-cobalt bimetallic hollow fiber electrode.

[0073] The first argon atmosphere calcination was carried out at a temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 200ml / min, and a heating time of 2h. The purpose was to sinter the green body first to maintain its high mechanical strength.

[0074] The second calcination was carried out in a pure oxygen atmosphere at a temperature of 600℃, a heating rate of 5℃ / min, a gas flow rate of 20ml / min, and a heating time of 4h. The purpose was to remove the polymer PEI from the green body.

[0075] The third calcination was carried out in a 5% argon-hydrogen mixed gas atmosphere (H2:Ar = 5:95, V / V), at a calcination temperature of 600℃, a heating rate of 5℃ / min, a gas flow rate of 5ml / min, and a heating time of 2h. The purpose was to pre-reduce CuO powder and Co3O4 powder into metallic copper and cobalt.

[0076] The fourth calcination was performed in a 5% argon-hydrogen mixture atmosphere (H2:Ar = 5:95, V / V), at a temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 20ml / min, and a heating time of 3h. The purpose was to completely reduce CuO powder and Co3O4 powder to metallic copper and cobalt. The resulting electrode is shown in [reference needed]. Figure 2 .

[0077] (5) The surface of the binary metal hollow fiber electrode is reconstructed by electrochemical means.

[0078] First, a three-electrode electrochemical oxidation system is performed, with Hg / HgO as the reference electrode, a graphite electrode as the counter electrode, and a hollow fiber electrode as the working electrode. The electrolyte is 3M KOH, and the current density is 25 mA / cm². -2 Time: 10 minutes;

[0079] Then, a three-electrode electrochemical reduction was performed, with Ag / AgCl as the reference electrode, a platinum sheet electrode as the counter electrode, and a hollow fiber electrode as the working electrode. The electrolyte was 0.5M KHCO3, the potential was -0.7V vs. Ag / AgCl, and the reduction time was 30min.

[0080] The binary copper-cobalt bimetallic hollow fiber electrode prepared by the above method was encapsulated inside a 3mm copper tube with epoxy resin and conductive silver paste, and then end-sealed to obtain the working electrode. The catholyte was a mixture of 1M KOH and 0.1M KNO3, the anolyte was 1M KOH, and the counter electrode was 1cm. 2 The reaction was carried out in a self-made electrolytic cell using a platinum sheet and an Ag / AgCl reference electrode.

[0081] The electrochemical nitrate reduction specifically includes the following steps: H2 is introduced into the surface-reconstructed hollow fiber; the surface-reconstructed hollow fiber is placed in a catholy solution; a constant potential is applied to perform electrochemical nitrate reduction, reducing NO3... - It is converted to NH3. The geometric area S = πDL = 3.14159 × 415 × 0.0001 × 1.2 = 0.156 cm² 2 .

[0082] At a potential of -0.3V, the current density is 0.8A cm⁻², and the Faraday efficiency of NH₃ is 95%.

[0083] Comparative Example 1

[0084] (1) Copper powder with a particle size of 100nm, Bi2O3 powder with a particle size of 100nm and NMP are ultrasonically mixed for 2h. PEI is added in three portions at 10min intervals. The mixture is stirred at 60℃ overnight to obtain a slurry. Then, it is degassed in a vacuum oven for 2h to remove the bubbles generated during the stirring process.

[0085] Based on the quality of the slurry, the amount of copper powder used is 36 parts by weight, the amount of Bi2O3 powder used is 4 parts by weight, the amount of NMP used is 48 parts by weight, and the amount of PEI used is 12 parts by weight.

[0086] (2) The slurry and core liquid are pushed to the spinning nozzle by an injection pump at a certain flow rate, and then enter the coagulation liquid to undergo phase change transformation to obtain soft hollow fiber.

[0087] The slurry flow rate is 1 ml / min, and the core liquid flow rate is 1 ml / min.

[0088] The spinning head size is Φ1.5*0.7mm;

[0089] The distance between the spinning head and the coagulation solution is 1.5 cm; the coagulation solution is deionized water.

[0090] (3) The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber embryo;

[0091] The soaking time is 24 hours to fully remove NMP from the soft hollow fibers;

[0092] The shape is achieved by straightening in the air and drying in a 60℃ oven for 24 hours.

[0093] (4) The hollow fiber preform is placed in three gas atmospheres in sequence, and post-processed with corresponding calcination temperature, heating rate, heating time and gas flow rate to obtain a binary copper-bismuth bimetallic hollow fiber electrode.

[0094] The first calcination was carried out in an argon atmosphere at a temperature of 500℃, a heating rate of 10℃ / min, a gas flow rate of 100ml / min, and a heating time of 2h.

[0095] The second calcination was carried out in an air atmosphere at a temperature of 800℃, a heating rate of 10℃ / min, a gas flow rate of 100ml / min, and a heating time of 4h.

[0096] The third calcination was carried out in a 5% argon-hydrogen mixed gas atmosphere (H2:Ar = 5:95, V / V), at a calcination temperature of 500℃, a heating rate of 10℃ / min, a gas flow rate of 100ml / min, and a heating time of 2h.

[0097] See electron microscope image of the fabricated electrode. Figure 3 It can be seen that the prepared binary copper-bismuth bimetallic hollow fiber electrode is incomplete, with some components falling off, and has poor stability.

[0098] Comparative Example 2

[0099] (1) Copper powder with a particle size of 100nm, Bi2O3 powder with a particle size of 100nm and NMP are ultrasonically mixed for 2h. PEI is added in three portions at 10min intervals. The mixture is stirred at 60℃ overnight to obtain a slurry. Then, it is degassed in a vacuum oven for 2h to remove the bubbles generated during the stirring process.

[0100] Based on the quality of the slurry, the amount of copper powder used is 36 parts by weight, the amount of Bi2O3 powder used is 4 parts by weight, the amount of NMP used is 48 parts by weight, and the amount of PEI used is 12 parts by weight.

[0101] (2) The slurry and core liquid are pushed to the spinning nozzle by an injection pump at a certain flow rate, and then enter the coagulation liquid to undergo phase change transformation to obtain soft hollow fiber.

[0102] The slurry flow rate is 1 ml / min, and the core liquid flow rate is 1 ml / min.

[0103] The spinning head size is Φ1.5*0.7mm;

[0104] The distance between the spinning head and the coagulation solution is 1.5 cm; the coagulation solution is deionized water.

[0105] (3) The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber embryo;

[0106] The soaking time is 24 hours to fully remove NMP from the soft hollow fibers;

[0107] The shape is achieved by straightening in the air and drying in a 60℃ oven for 24 hours.

[0108] (4) The hollow fiber preform is placed in three gas atmospheres in sequence, and post-processed with corresponding calcination temperature, heating rate, heating time and gas flow rate to obtain a binary copper-bismuth bimetallic hollow fiber electrode.

[0109] The first calcination was carried out in an argon atmosphere at a temperature of 1000℃, with a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 2h.

[0110] Second air atmosphere, calcination temperature 800℃, heating rate 5℃ / min, gas flow rate 100ml / min, heating time 4h;

[0111] The third calcination was carried out in a 5% argon-hydrogen mixture (H2:Ar = 5:95, V / V) atmosphere at a calcination temperature of 1000℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 2h.

[0112] See electron microscope image of the fabricated electrode. Figure 4 It can be seen that the prepared binary copper-bismuth bimetallic hollow fiber electrode is incomplete, with some components falling off, and has poor stability.

[0113] Comparative Example 3

[0114] (1) Copper powder with a particle size of 100nm, Bi2O3 powder with a particle size of 100nm and NMP are ultrasonically mixed for 2h. PEI is added in three portions at 10min intervals. The mixture is stirred at 60℃ overnight to obtain a slurry. Then, it is degassed in a vacuum oven for 2h to remove the bubbles generated during the stirring process.

[0115] Based on the quality of the slurry, the amount of copper powder used is 36 parts by weight, the amount of Bi2O3 powder used is 4 parts by weight, the amount of NMP used is 48 parts by weight, and the amount of PEI used is 12 parts by weight.

[0116] (2) The slurry and core liquid are pushed to the spinning nozzle by an injection pump at a certain flow rate, and then enter the coagulation liquid to undergo phase change transformation to obtain soft hollow fiber.

[0117] The slurry flow rate is 1 ml / min, and the core liquid flow rate is 1 ml / min.

[0118] The spinning head size is Φ1.5*0.7mm;

[0119] The distance between the spinning head and the coagulation solution is 1.5 cm; the coagulation solution is deionized water.

[0120] (3) The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber embryo;

[0121] The soaking time is 24 hours to fully remove NMP from the soft hollow fibers;

[0122] The shape is achieved by straightening in the air and drying in a 60℃ oven for 24 hours.

[0123] (4) The hollow fiber preform is placed in three gas atmospheres in sequence, and post-processed with corresponding calcination temperature, heating rate, heating time and gas flow rate to obtain a binary copper-bismuth bimetallic hollow fiber electrode.

[0124] The first calcination was performed under an argon atmosphere at a temperature of 800℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 2 hours.

[0125] Second calcination in air atmosphere, calcination temperature 800℃, heating rate 5℃ / min, gas flow rate 100ml / min, heating time 4h.

[0126] The third calcination was carried out in a 5% argon-hydrogen mixture (H2:Ar = 5:95, V / V) atmosphere at a calcination temperature of 800℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 3h.

[0127] See electron microscope image of the fabricated electrode. Figure 5 It can be seen that the prepared binary copper-bismuth bimetallic hollow fiber electrode is incomplete, with some components falling off, and has poor stability.

[0128] Comparative Example 4

[0129] (1) Copper powder with a particle size of 100nm, Bi2O3 powder with a particle size of 100nm and NMP are ultrasonically mixed for 2h. PEI is added in three portions at 10min intervals. The mixture is stirred at 60℃ overnight to obtain a slurry. Then, it is degassed in a vacuum oven for 2h to remove the bubbles generated during the stirring process.

[0130] Based on the quality of the slurry, the amount of copper powder used is 36 parts by weight, the amount of Bi2O3 powder used is 4 parts by weight, the amount of NMP used is 48 parts by weight, and the amount of PEI used is 12 parts by weight.

[0131] (2) The slurry and core liquid are pushed to the spinning nozzle by an injection pump at a certain flow rate, and then enter the coagulation liquid to undergo phase change transformation to obtain soft hollow fiber.

[0132] The slurry flow rate is 1 ml / min, and the core liquid flow rate is 1 ml / min.

[0133] The spinning head size is Φ1.5*0.7mm;

[0134] The distance between the spinning head and the coagulation solution is 1.5 cm; the coagulation solution is deionized water.

[0135] (3) The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber embryo;

[0136] The soaking time is 24 hours to fully remove NMP from the soft hollow fibers;

[0137] The shape is achieved by straightening in the air and drying in a 60℃ oven for 24 hours.

[0138] (4) The hollow fiber preform is placed in three gas atmospheres in sequence, and post-processed with corresponding calcination temperature, heating rate, heating time and gas flow rate to obtain a binary copper-bismuth bimetallic hollow fiber electrode.

[0139] The first calcination was performed under an argon atmosphere at a temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 2 hours.

[0140] Second calcination in air atmosphere, calcination temperature 800℃, heating rate 5℃ / min, gas flow rate 100ml / min, heating time 4h.

[0141] The third calcination was carried out in a 5% argon-hydrogen mixture (H2:Ar = 5:95, V / V) atmosphere at a calcination temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 3h.

[0142] See electron microscope image of the fabricated electrode. Figure 6 It can be seen that the prepared binary copper-bismuth bimetallic hollow fiber electrode is incomplete and has poor stability.

[0143] Comparative Example 5

[0144] Preparation method of Cu hollow fiber:

[0145] Copper powder with a particle size of 100nm and NMP were ultrasonically mixed for 2 hours. PEI was added in three portions at 10-minute intervals. The mixture was stirred overnight at 60°C to obtain a slurry. The slurry was then degassed in a vacuum oven for 2 hours to remove air bubbles generated during the stirring process.

[0146] Based on the quality of the slurry, the amount of copper powder used is 40 parts by weight, the amount of NMP used is 48 parts by weight, and the amount of PEI used is 12 parts by weight.

[0147] (2) The slurry and core liquid are pushed to the spinning nozzle by an injection pump at a certain flow rate, and then enter the coagulation liquid to undergo phase change transformation to obtain soft hollow fiber.

[0148] The slurry flow rate is 1 ml / min, and the core liquid flow rate is 1 ml / min.

[0149] The spinning head size is Φ1.5*0.7mm;

[0150] The distance between the spinning head and the coagulation solution is 1.5 cm; the coagulation solution is deionized water.

[0151] (3) The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber embryo;

[0152] The soaking time is 24 hours to fully remove NMP from the soft hollow fibers;

[0153] The shape is achieved by straightening in the air and drying in a 60℃ oven for 24 hours.

[0154] (4) The hollow fiber preform is placed in three gas atmospheres in sequence, and post-processed with corresponding calcination temperature, heating rate, heating time and gas flow rate to obtain copper metal hollow fiber electrode.

[0155] The first calcination was carried out in an argon atmosphere at a temperature of 600℃, with a heating rate of 5℃ / min, a gas flow rate of 50ml / min, and a heating time of 3h.

[0156] Second air atmosphere, calcination temperature 600℃, heating rate 5℃ / min, gas flow rate 100ml / min, heating time 4h;

[0157] The third calcination was carried out in a 5% argon-hydrogen mixture (H2:Ar = 5:95, V / V) atmosphere at a calcination temperature of 600℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 2h.

[0158] Figure 7 In an electrolytic cell under argon gas conditions, Cu hollow fiber and CuBi bimetallic hollow fiber were used as working electrodes, platinum sheet as counter electrode, and Ag / AgCl as reference electrode. The catholyte was a mixture of 3.5M KCl and 0.5M KHCO3, and the anolyte was 3M KOH. LSV tests were performed. The test results show that the activity of the single-metal hollow fiber is much lower than that of the bimetallic hollow fiber.

[0159] Comparative Example 6

[0160] (1) CuO powder with a particle size of 100nm, Co3O4 powder with a particle size of 100nm and NMP are ultrasonically mixed for 2h. PEI is added in three portions at 10min intervals. The mixture is stirred at 60℃ overnight to obtain a slurry. Then, it is degassed in a vacuum oven for 2h to remove the bubbles generated during the stirring process.

[0161] Based on the quality of the slurry, the amount of CuO powder used is 25 parts by weight, the amount of Co3O4 powder used is 15 parts by weight, the amount of NMP used is 48 parts by weight, and the amount of PEI used is 12 parts by weight.

[0162] (2) The slurry and core liquid are pushed to the spinning nozzle by an injection pump at a certain flow rate, and then enter the coagulation liquid to undergo phase change transformation to obtain soft hollow fiber.

[0163] The slurry flow rate is 1 ml / min, and the core liquid flow rate is 1 ml / min.

[0164] The spinning head size is Φ1.5*0.7mm;

[0165] The distance between the spinning head and the coagulation solution is 1.5 cm; the coagulation solution is deionized water.

[0166] (3) The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber embryo;

[0167] The soaking time is 24 hours to fully remove NMP from the soft hollow fibers;

[0168] The shape is achieved by straightening in the air and drying in a 60℃ oven for 24 hours.

[0169] (4) The hollow fiber preform is placed in three gas atmospheres in sequence, and post-processed with corresponding calcination temperature, heating rate, heating time and gas flow rate to obtain a binary copper-cobalt bimetallic hollow fiber electrode.

[0170] The first argon atmosphere calcination was carried out at a temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 200ml / min, and a heating time of 2h. The purpose was to sinter the green body first to maintain its high mechanical strength.

[0171] The second calcination was carried out in a pure oxygen atmosphere at a temperature of 600℃, a heating rate of 5℃ / min, a gas flow rate of 20ml / min, and a heating time of 4h. The purpose was to remove the polymer PEI from the green body.

[0172] The third calcination was carried out in a 5% argon-hydrogen mixed gas atmosphere (H2:Ar = 5:95, V / V), at a calcination temperature of 600℃, a heating rate of 5℃ / min, a gas flow rate of 5ml / min, and a heating time of 2h. The purpose was to pre-reduce CuO powder and Co3O4 powder into metallic copper and cobalt.

[0173] See electron microscope image of the prepared electrode. Figure 8 It can be seen that excessively high or low calcination temperatures may lead to the destruction of fiber structure and sintering of metal particles, thereby reducing the catalytic activity and stability of the fiber.

[0174] Therefore, the calcination temperature needs to be precisely controlled during the preparation process to ensure the integrity of the fiber structure and catalytic performance.

[0175] In summary, this invention proposes for the first time a method for preparing binary metal hollow fiber electrodes. Compared with the preparation of single-metal hollow fibers, the preparation of multi-component hollow fibers is more difficult because the interaction forces between the multi-component metals during sintering may lead to the aggregation and sintering of metal particles, affecting the structure and performance of the fiber. This method cannot be derived from the preparation process of single-metal hollow fibers. Furthermore, current binary metal hollow fiber electrodes mostly employ chemical deposition methods, which are completely different from the technical direction of this invention. This invention is the first to propose a method for preparing binary metal hollow fiber electrodes, and it is original.

[0176] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for preparing a binary metal hollow fiber electrode, characterized in that: include, Metal powder A, metal powder B, and N-methylpyrrolidone are mixed, and polyetherimide is added in batches. The mixture is stirred overnight and degassed in a vacuum oven to obtain a slurry. Based on the mass of the slurry, the metal powder A is 20-25 parts by weight, the metal powder B is 10-15 parts by weight, the N-methylpyrrolidone is 40-48 parts by weight, and the polyetherimide is 8-12 parts by weight. The polyetherimide is added in three equal parts by weight. The slurry and core liquid are pushed into the spinning nozzle by an injection pump and enter the coagulation liquid to undergo phase change transformation, thus obtaining soft hollow fibers. The soft hollow fiber is soaked in deionized water, shaped and dried to obtain hollow fiber preform; Hollow fiber preforms were sequentially calcined in three different gas atmospheres to obtain binary metal hollow fibers. The first atmosphere was argon, with a calcination temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 2 hours. The second atmosphere was air, with a calcination temperature of 600℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 4 hours. The third atmosphere was a 5% argon-hydrogen mixture, with a calcination temperature of 700℃, a heating rate of 5℃ / min, a gas flow rate of 100ml / min, and a heating time of 3 hours. The binary metal hollow fiber electrode is prepared by reconstructing its surface through electrochemical treatment. The reconstructing process includes: first, performing electrochemical oxidation using a three-electrode system, with Hg / HgO as the reference electrode, a graphite electrode as the counter electrode, and the hollow fiber as the working electrode; the electrolyte being 3M KOH; and the current density being 25 mA / cm². -2 Time: 10 minutes; Then, a three-electrode electrochemical reduction was performed, with Ag / AgCl as the reference electrode, a platinum sheet electrode as the counter electrode, and a hollow fiber electrode as the working electrode. The electrolyte was 0.5M KHCO3, the potential was -0.7V vs. Ag / AgCl, and the reduction time was 30min. Metal powder A includes copper powder and CuO powder, and metal powder B includes Bi2O3 powder and Co3O4 powder.

2. The preparation method according to claim 1, characterized in that: The slurry and core liquid are pushed to the spinning nozzle by an injection pump, wherein the slurry flow rate is 1 ml / min and the core liquid flow rate is 1 ml / min; The spinning head size is Φ1.5*0.7mm.

3. The binary metal hollow fiber electrode prepared by the preparation method according to claim 1 or 2.

4. The application of the binary metal hollow fiber electrode according to claim 3 in the electrocatalysis of carbon dioxide.

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