CN110724966B - Directional gas transport electrode, preparation method and application thereof, and electrolytic cell comprising directional gas transport electrode - Google Patents

Directional gas transport electrode, preparation method and application thereof, and electrolytic cell comprising directional gas transport electrode Download PDF

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CN110724966B
CN110724966B CN201911011135.7A CN201911011135A CN110724966B CN 110724966 B CN110724966 B CN 110724966B CN 201911011135 A CN201911011135 A CN 201911011135A CN 110724966 B CN110724966 B CN 110724966B
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electrode
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gas transport
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layer
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CN110724966A (en
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罗亮
盛思雨
孙晓明
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Beijing University of Chemical Technology
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C26/00—Coating not provided for in groups C23C2/00 - C23C24/00
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
    • C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
    • C25B11/031—Porous electrodes
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
    • C25B11/081—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the element being a noble metal
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis

Abstract

The invention discloses a directional gas transport electrode for directional gas transmission, which comprises a conductive substrate, and a hydrophilic layer and a catalyst layer which are loaded on two sides of the conductive substrate, wherein the bubble contact angle of the catalyst layer is 90-110 degrees, and the conductive substrate is provided with a through hole with the equivalent diameter of 30-80 microns. The invention also discloses a preparation method and application of the electrode. The invention also discloses an electrolytic cell comprising the same. The electrode of the invention can produce the unexpected effect of directional guidance on bubbles generated by electrolysis. And air bubbles pass through the through-channels of the conductive substrate from the gas-permeable surface of the electrode and migrate to the gas-permeable surface. The electrode of the invention has two beneficial effects: (1) the adhesion of bubbles generated by electrolysis on the electrode catalyst layer is avoided, so that the working efficiency of the electrode is improved; (2) prevent the random diffusion of bubbles in the electrolyte and directionally collect the gas.

Description

Directional gas transport electrode, preparation method and application thereof, and electrolytic cell comprising directional gas transport electrode
Technical Field
The invention belongs to the field of electrode preparation, and particularly relates to a directional gas transport electrode, a preparation method and application thereof, and an electrolytic cell comprising the directional gas transport electrode.
Background
Many electrochemical reactions involve the precipitation of gas, and if bubbles generated in the reaction process are not easy to desorb from the surface of an electrode, the bubbles can be gathered on the surface of the electrode to form a gas film to cover reaction sites, so that the working efficiency of the electrode is influenced. At present, the wettability treatment of the electrode is mainly used for reducing the adhesion force of the electrode to bubbles generated, and the treatment method comprises the steps of constructing an array structure on the surface of the electrode, modifying a low-surface-energy substance on the surface of the electrode and the like. The methods are complex in treatment process, bubbles still grow on the surface of the electrode to a certain size and then escape, and the desorption process of the bubbles can damage the structure of the catalyst and finally affect the activity of the electrode. And under the condition of zero (micro) gravity, the generated bubbles can be adhered to the surface of the electrode, and the electrolytic reaction can be influenced.
The present invention has been made to solve the above problems.
Disclosure of Invention
The invention provides a directional gas transport electrode, which consists of a conductive substrate, and a gas-philic layer and a catalyst layer which are loaded on two sides of the conductive substrate, wherein the bubble contact angle of the catalyst layer is 90-110 degrees, and the conductive substrate is provided with a through hole with the equivalent diameter of 30-80 microns.
Preferably, the conductive substrate is a stainless steel mesh, and the equivalent diameter of the mesh is 30-80 microns; or the conductive substrate is a porous conductive material, and the pore diameter of the porous conductive material is 30-80 microns.
Preferably, the catalyst layer is a platinum carbon layer or an iridium carbon layer.
Preferably, the gas-philic layer is a polytetrafluoroethylene layer.
Preferably, the polytetrafluoroethylene distribution density in the directional gas transport electrode has a gradient in a direction perpendicular to the plane of the porous electrode.
The directional gas transport electrode is perpendicular to the plane direction of the porous electrode, the gas affinity performance is gradually improved from the gas-permeable layer to the gas affinity layer, and the directional gas transport electrode has traction force on gas in the direction from the gas-permeable layer to the gas affinity layer.
The reason is that the hydrophilic treatment method is to spray polytetrafluoroethylene solution on one surface of the conductive substrate, and the conductive substrate has a certain thickness, so that more polytetrafluoroethylene solution is loaded on the inner side of the conductive substrate close to the spraying source, and the polytetrafluoroethylene solution is loaded on the inner side of the pore channel due to infiltration outward along the pore channel direction, so that the hydrophilic performance is gradually improved from the gas-permeable layer to the hydrophilic layer.
In a second aspect, the present invention provides a method for preparing the directional gas transport electrode of the first aspect, comprising the steps of:
A. selecting a conductive material with a through-hole with an equivalent diameter of 30-80 microns as a conductive substrate;
B. carrying out gas-loving treatment on one surface of the conductive substrate, so that the surface of the conductive substrate is loaded with an upper gas-loving layer; then the
C. And coating the catalyst slurry on the other surface of the conductive substrate to enable the contact angle of bubbles to be 90-110 degrees, and drying to obtain the directional gas transport electrode.
Preferably, the hydrophilic treatment method in the step B is to spray a polytetrafluoroethylene solution on one surface of the conductive substrate, and then to dry, bake and cool the conductive substrate;
the catalyst slurry of the step C comprises a catalyst, a perfluorosulfonic acid polymer solution and alcohols.
Preferably, the concentration of the polytetrafluoroethylene solution is 1-30 wt%.
Preferably, the spraying operation is repeated three times.
A third aspect of the invention provides an electrolytic cell having a working electrode which is a directional gas transport electrode as claimed in claim 1.
Wherein the electrolytic cell can be used under microgravity or zero gravity conditions.
In a fourth aspect the invention provides the use of a directional gas transport electrode according to the first aspect of the invention for the electrolysis of water in space to produce oxygen and for directional gas transport.
Preferably, the catalyst layer of the said directional gas transport electrode used at the anode of the electrolyser in the electrolysis of water is an iridium carbon layer.
Preferably, the catalyst layer of the said directional gas transport electrode used by the cathode of the electrolyser in the electrolysis of water is a platinum carbon layer.
A fifth aspect of the invention provides the use of a directional gas transport electrode according to the first aspect of the invention for directional gas transport in a gas consuming reaction.
Preferably, when the directional gas transport electrode is applied to the field of oxygen reduction, the directional gas transport electrode can float on the electrolyte to carry out oxygen consumption reaction, wherein the gas-loving layer faces to the air, and the gas-dispersing layer faces to the electrolyte. At the moment, the directional gas transport electrode can grab oxygen in the air to participate in reaction as a reactant, and oxygen does not need to be exposed into the system.
The wettability refers to the hydrophilicity and hydrophobicity or the hydrophilicity and hydrophobicity and the air permeability of the electrode material, and the better the wettability, the better the hydrophilicity and the air permeability, and the worse the hydrophobicity and the air permeability; and vice versa.
The invention has the following beneficial effects:
1. the invention discovers for the first time that in the field of asymmetric wettability electrodes, when the contact angle of bubbles of a catalyst layer on the gas-permeable side of the asymmetric wettability electrode is 90-110 degrees and a conductive substrate is provided with a through channel with the equivalent diameter of 30-80 microns, the asymmetric wettability electrode can generate an unexpected effect of directional guidance on bubbles generated by electrolysis, namely, the asymmetric wettability electrode becomes a directional gas transport electrode. And the bubbles pass through the through-channels of the conductive substrate from the gas-phobic surface of the directional gas transport electrode and migrate to the gas-philic surface. The electrode of the invention has two beneficial effects: (1) the adhesion of bubbles generated by electrolysis on the electrode catalyst layer is avoided, so that the working efficiency of the electrode is improved; (2) prevent the random diffusion of bubbles in the electrolyte and directionally collect the gas.
2. The invention discovers for the first time that iridium carbon and platinum carbon are used as catalysts in the electrode, can control the bubble contact angle of the catalyst layer on the gas-repellent side to be 90-110 degrees, can be just applied to the electrolytic oxygen evolution or hydrogen evolution reaction, can ensure the efficient electrolysis efficiency and guide bubbles directionally, and has wide application prospect.
3. The invention solves the problem that the bubble behavior in the electrolysis gas-evolution reaction can not be controlled, can directionally guide and collect gas in specific environments such as microgravity conditions and space, can be used for supplying oxygen to space personnel in an electrolysis water reactor, and is a simpler and more economic scheme for supplying oxygen to the space.
4. The electrode of the invention can also be applied to gas consumption reaction, and the directional gas conveying electrode can float on electrolyte to carry out oxygen consumption reaction. At the moment, the directional gas transport electrode can grab oxygen in the air as a reactant to participate in reaction, oxygen does not need to be exposed into the system, and the application range is wide.
5. The preparation method of the directional gas transport electrode is simple, and the electrode can be obtained by respectively carrying out gas-dispersing and gas-dispersing treatment on two surfaces of the same conductive substrate to obtain a gas-dispersing layer and a gas-dispersing layer, wherein the gas-dispersing layer is a catalyst layer and has the dual effects of gas-dispersing and catalysis.
6. The directional gas transport electrode of the present invention has a wettability gradient perpendicular to the plane of the porous electrode. The directional gas transport electrode is perpendicular to the plane direction of the porous electrode, the gas affinity performance is gradually improved from the gas-permeable layer to the gas affinity layer, and the directional gas transport electrode has traction force on gas in the direction from the gas-permeable layer to the gas affinity layer. When used in an electrolytic gassing reaction, the effect of the directionally guided gas bubbles of the electrode of the present invention is further enhanced.
Drawings
FIG. 1 is a scanning electron micrograph of a directional gas transport electrode prepared in example 1.
FIG. 2 shows the bubble contact angles on both sides of the directional gas transport electrode prepared in example 1.
Fig. 3 shows the bubble behavior of the electrode surface recorded by the camera of example 2.
FIG. 4 is a graph of recorded current versus time for the electrochemical workstation of example 2.
FIG. 5 shows three cases of the electrolytic reaction in which the electrodes are completely immersed in the electrolyte, recorded by the camera of example 3.
FIG. 6 is a graph comparing the performance of the directional gas transport electrode of example 4 when fixed at the gas-liquid interface and immersed in an electrolyte.
FIG. 7 is a scanning electron microscope representation of four different catalytic layers of the directional gas transport electrode and a comparison of bubble guiding effects. (a: platinum carbon b: platinum particles c: platinum nanospheres d: platinum nanoflowers)
FIG. 8 is a graph showing the bubble contact angles measured for the catalyst faces of four directional gas transport electrodes in comparative example 4.
FIG. 9 is a graph comparing the performance of the directional gas transport electrode of example 5 when fixed at the gas-liquid interface and immersed in an electrolyte.
FIG. 10 shows three cases of the electrolytic reaction in which the electrodes are completely immersed in the electrolyte, recorded by the camera of example 5.
FIG. 11 is a scanning electron micrograph, i.e., a schematic view of the wettability gradient, of the mesh side of the stainless steel mesh of the directional gas transport electrode prepared in example 1.
Detailed Description
The present invention will be further described with reference to the following embodiments.
Example 1
(1) A stainless steel net with the aperture of 37 microns is selected as a substrate of the electrode, and the stainless steel net is cut into the size of 1cm multiplied by 3 cm. And (4) carrying out ultrasonic cleaning on the stainless steel mesh by hydrochloric acid in sequence to remove impurities on the surface, and drying at 60 ℃ for later use.
(2) Uniformly spraying a polytetrafluoroethylene solution with the mass concentration of 20% by using a high-pressure spray gun on one surface of the net material obtained in the step (1), drying at 120 ℃, repeatedly operating for 3 times, finally placing in a tubular furnace, burning for half an hour at 350 ℃ in an air atmosphere, and cooling to load an upper hydrophilic layer on the surface of the stainless steel net;
(3) preparing catalyst slurry from 2mg of platinum-carbon catalyst, 10 microliters of Nafion solution (perfluorosulfonic acid polymer solution) and 1 milliliter of ethanol, uniformly dispersing by using ultrasound, uniformly coating the catalyst slurry on the other surface of the electrode obtained in the step (2), and drying by using an infrared lamp, wherein a catalyst layer is loaded on the other surface of the stainless steel mesh, and the surface is a gas-permeable surface and is used as a catalytic reaction active surface for electrode reaction, so that the whole directional gas transport electrode is obtained.
Characterization of the prepared electrodes:
FIG. 1 is a scanning electron micrograph of a directional gas transport electrode prepared in example 1, showing that the conductive substrate is a uniform mesh structure, and elemental analysis shows that platinum particles and polytetrafluoroethylene are uniformly supported on both surfaces of the electrode.
FIG. 2 is a graph of the contact angle of the gas bubbles on both sides of the oriented gas transport electrode prepared in example 1, showing that the difference in wettability between the two sides of the electrode is significant, with the contact angle of the gas bubbles on the gas-philic side A being about 52.4 degrees and the contact angle of the gas bubbles on the gas-phobic side B being about 104.2 degrees.
Example 2
The electrode prepared in example 1 was applied to an electrolytic reaction as a working electrode, and the electrode was fixed to a gas-liquid interface, with the gas-permeable layer facing downward and being in direct contact with an electrolyte, and the gas-permeable layer facing upward and being in contact with air. A carbon rod is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, a constant potential hydrogen evolution reaction of-0.3 v is carried out in a system taking 0.5mol/L sulfuric acid as electrolyte, an electrochemical workstation records the change of current along with time, as shown in figure 4, and a camera records the bubble behavior on the surface of the electrode, as shown in figure 3.
From fig. 4, it can be seen that a stable current exists in the electrolysis process, and the electrode is shown in the dotted line frame of fig. 3, and no bubble is adhered to the surface of the electrode, which indicates that the electrode achieves the effect of high-efficiency electrolysis without adhering bubbles to the surface of the electrode.
Example 3
The electrode in the present invention was immersed horizontally or vertically in the electrolyte to perform a reaction under the same conditions as in example 2, and the behavior of bubbles on the electrode surface at this time was recorded by a camera. Fig. 5 shows three cases of the camera recording that the electrode is completely immersed in the electrolyte for electrolytic reaction, the electrode is placed in the order of a hydrophilic surface a facing downwards, a hydrophilic surface B facing upwards, and a hydrophilic surface C facing right, and the arrow in the figure is the bubble transmission direction.
The results show that: no matter how the electrode is placed, the gas is migrated from the gas-phobic surface to the gas-philic surface and is separated out, and the catalytic active area is not influenced, which shows that the electrode realizes the effect of directionally guiding the bubble transmission.
In particular, the embodiment shown in fig. 5A and 5C, in which the bubble migration process is resistant to the buoyancy of the bubbles when the electrode is immersed in the electrolyte vertically with the gas-attracting surface facing downward, demonstrates that the electrode of the present invention can directionally guide the transport of bubbles under microgravity or weight loss conditions, leading the bubbles from the gas-repelling surface to the gas-attracting surface of the electrode.
Example 4
Under the same conditions as other experiments of example 2, the electrodes of the present invention were horizontally fixed at the gas-liquid interface or horizontally completely immersed in the electrolyte, respectively, to perform an electrolytic reaction, the electrochemical workstation recorded the change in current with time, and then the electrode performances when the electrodes were fixed at the gas-liquid interface and immersed in the electrolyte were compared with those of fig. 6. FIG. 6 shows: when the electrode is placed on the electrolyte, the current is large, and when the electrode is immersed in the electrolyte, the current is small, so that compared with the electrode in the former working state, the performance of the electrode in the former working state is improved by about 5 times.
Comparative example 4
According to the method of the embodiment 1, a stainless steel mesh with a pore size of 74 micrometers is selected as a substrate of the electrode, and a platinum carbon catalyst, platinum particles, platinum nanospheres and platinum nanoflowers are respectively selected to prepare four different directional gas transport electrodes.
The experiment described in example 2 was carried out using these four directional gas transport electrodes as working electrodes in the electrolysis reaction instead of the electrode prepared in example 1, and the behavior of bubbles on the electrode surface at this time was recorded by a camera.
FIG. 7 is a scanning electron microscope representation of four different catalytic layers of the directional gas transport electrode and a comparison of bubble guiding effects. (a: platinum carbon b: platinum particles c: platinum nanospheres d: platinum nanoflowers)
FIG. 7 shows that: the directional gas transport electrode with platinum-carbon catalytic layer has the capability of directionally guiding the bubble transmission, and no bubble adheres to the surface of the electrode. The directional gas transport electrode using platinum particles, platinum nanospheres and platinum nanoflowers as a catalytic layer has no capability of directionally guiding bubble transmission, and bubbles are adhered to the surface of the electrode.
FIG. 8 is a graph showing the measured bubble contact angles of the catalyst faces of the four directional gas transport electrodes. The catalyst surface is respectively A, platinum carbon, B, platinum particles, C, platinum nanospheres and D platinum nanoflowers.
Fig. 8 demonstrates that only electrodes with a catalyst layer having a bubble contact angle of 90-110 degrees have the ability to directionally guide the transport of bubbles. The electrode with the catalyst layer being more gas-repellent, such as platinum particles, platinum nanospheres and platinum nanoflowers, have no ability to directionally guide the bubble transmission when being used as the catalyst layer. Therefore, the selection of the bubble contact angle of the catalyst layer of the electrode of the present invention has an unexpected technical effect.
Example 5
According to the method of example 1, a platinum carbon catalyst is replaced with an iridium carbon catalyst to prepare a directional gas transport electrode, the directional gas transport electrode is used as a working electrode for an electrolytic oxygen evolution reaction, the electrode is fixed at a gas-liquid interface, a gas-permeable layer faces downwards to be in direct contact with an electrolyte, and a gas-permeable layer faces upwards to be in contact with air. A carbon rod is used as a counter electrode, a saturated calomel electrode is used as a reference electrode, a 0.5v constant potential hydrogen evolution reaction is carried out in a system taking 0.1mol/L potassium hydroxide as electrolyte, an electrochemical workstation records the change of current along with time, and the bubble behavior on the surface of the electrode is observed. The electrodes of the invention are respectively horizontally fixed at the gas-liquid interface or horizontally and completely immersed in the electrolyte to carry out the electrolytic reaction, the electrochemical workstation records the relation of the current changing along with the time, and then the electrode performances when the electrodes are fixed at the gas-liquid interface and immersed in the electrolyte are compared with the figure 9. Compared with the former working state, the performance of the former working state is obviously improved. In this example, a stable current was present during electrolysis but no bubbles adhered to the electrode surface.
As shown in fig. 10, the electrode placement method is as follows: A. the electrode is fixed at a gas-liquid interface, the gas-permeable layer faces downwards to be directly contacted with the electrolyte, and the gas-permeable layer faces upwards to be contacted with air; immersing the electrode B in the electrolyte with the hydrophilic surface facing downwards; C. the electrode is immersed in the electrolyte, and the hydrophilic surface faces upwards; D. the electrode is immersed in the electrolyte, and the gas-loving surface faces the right; the arrows in the figure indicate the transport direction of the bubbles.
FIG. 10A shows that when the electrode is fixed at the gas-liquid interface, the effect of high-efficiency electrolysis without adhesion of bubbles to the electrode surface is achieved. Fig. 10B-D show that, with the electrode immersed in the electrolyte, the electrode migrates from the gas-phobic surface to the gas-philic surface, and precipitates, regardless of the placement of the electrode. Thus, the iridium carbon catalyst performs similarly to a directional gas transport electrode prepared with a platinum carbon catalyst.
Example 6
FIG. 11 is a scanning electron microscope photograph of the mesh side of the stainless steel mesh of the directional gas transport electrode prepared in example 1, and elemental analysis shows that the density distribution of polytetrafluoroethylene has a gradient in the thickness direction of the electrode, with the density increasing from the gas-phobic layer to the gas-philic layer. It is shown that the directional gas transport electrode prepared in example 1 has a wettability gradient perpendicular to the plane of the porous electrode. The electrode has gradually improved hydrophilic performance from the gas-phobic layer to the gas-philic layer in the direction vertical to the plane of the porous electrode,
the above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (6)

1. A directional gas transport electrode is characterized in that the electrode comprises a conductive substrate, and a hydrophilic layer and a catalyst layer which are loaded on two sides of the conductive substrate, wherein the bubble contact angle of the catalyst layer is 90-110 degrees, and the conductive substrate is provided with a through hole with the equivalent diameter of 30-80 microns;
the gas-philic layer is a polytetrafluoroethylene layer, and the distribution density of the polytetrafluoroethylene in the directional gas transport electrode has gradient in the direction vertical to the plane of the porous electrode.
2. A directional gas transport electrode according to claim 1, wherein the electrically conductive substrate is a stainless steel mesh and the mesh equivalent diameter is 30-80 microns.
3. A directional gas transport electrode according to claim 1, wherein the catalyst layer is a platinum carbon layer or an iridium carbon layer.
4. A method of preparing a directional gas transport electrode according to claim 1, comprising the steps of:
A. selecting a conductive material with a through-hole with an equivalent diameter of 30-80 microns as a conductive substrate;
B. carrying out gas-loving treatment on one surface of the conductive substrate, so that the surface of the conductive substrate is loaded with an upper gas-loving layer; then, the user can use the device to perform the operation,
C. coating the catalyst slurry on the other surface of the conductive substrate to enable the contact angle of bubbles to be 90-110 degrees, and drying to obtain the directional gas transport electrode;
b, spraying a polytetrafluoroethylene solution on one surface of the conductive substrate, drying, roasting and cooling;
the catalyst slurry of the step C comprises a catalyst, a perfluorosulfonic acid polymer solution and alcohols.
5. An electrolytic cell characterized in that the working electrode of the electrolytic cell is the directional gas transport electrode of claim 1.
6. Use of a directional gas transport electrode as defined in claim 1 for electrolysis of water in space to produce oxygen and for directional gas transport.
CN201911011135.7A 2019-10-23 2019-10-23 Directional gas transport electrode, preparation method and application thereof, and electrolytic cell comprising directional gas transport electrode Active CN110724966B (en)

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