CN114557415B

CN114557415B - Oxygen consumption/generation device with water absorption film, oxygen migration device, application of oxygen consumption/generation device and oxygen migration method

Info

Publication number: CN114557415B
Application number: CN202111315038.4A
Authority: CN
Inventors: 孙晓明; 徐岭; 邝允
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2021-11-08
Filing date: 2021-11-08
Publication date: 2024-04-26
Anticipated expiration: 2041-11-08
Also published as: CN114557415A

Abstract

The invention belongs to the field of electrochemistry, and particularly relates to an oxygen consumption/generation device with a water absorption film, an oxygen migration device, application of the oxygen migration device and an oxygen migration method. The oxygen consumption/generation device includes: an oxygen-evolving anode, an oxygen-consuming cathode, a membrane disposed between the oxygen-evolving anode and the oxygen-consuming cathode; the oxygen-evolving anode comprises an anode catalyst, and the oxygen-consuming cathode comprises a cathode catalyst; the membrane is a cation exchange membrane or an anion exchange membrane, two sides of the membrane are respectively contacted with a cathode catalyst and an anode catalyst, and the surface of the anode catalyst is provided with a water absorption membrane; or the membrane is an ion-conducting water-absorbing membrane, and the two sides of the membrane are respectively contacted with a cathode catalyst and an anode catalyst. In the invention, the surface of the anode is covered by the water absorbing film, and the water absorbing film can absorb water vapor in the environment to participate in the reaction so as to separate out oxygen; and the surface of the cathode undergoes an oxygen reduction reaction to consume oxygen. When the ion-conducting type water absorbing film is adopted, the water absorbing film has the functions of conducting ions and absorbing water vapor.

Description

Oxygen consumption/generation device with water absorption film, oxygen migration device, application of oxygen consumption/generation device and oxygen migration method

Technical Field

The invention belongs to the field of electrochemistry, and particularly relates to an oxygen consumption/generation device with a water absorption film, an oxygen migration device, application of the oxygen migration device and an oxygen migration method.

Background

The oxidation reaction can not only cause the degradation of the quality of the grease and the grease-rich food, but also the products of the oxidation reaction can harm the health of human bodies, and the oxidation reaction can also seriously shorten the fresh-keeping time of the food. The existing antioxidant fresh-keeping means have more or less defects which cannot be overcome, and the modified atmosphere fresh-keeping means has good application prospect. The controlled atmosphere storage is to control the temperature of food and change the gas composition in the refrigerating environment, mainly control the concentration of oxygen and carbon dioxide, so as to achieve the purpose of prolonging the storage time. At present, more methods for controlled atmosphere preservation mainly comprise a natural oxygen reduction method, a rapid oxygen reduction method, a mixed oxygen reduction method and the like.

However, the oxygen reduction process is slow, and the oxygen cannot be continuously reduced in real time.

The electrochemical oxygen consumption reaction is used for air-conditioning fresh-keeping, and the method has the advantages of relatively low working voltage (total reaction voltage is not higher than 1.6V), simple reaction, no harm to required reaction materials and solution and the like, and is an ideal mode for reducing the oxygen concentration in gas in air-conditioning fresh-keeping.

The present invention has been made to solve the above problems.

Disclosure of Invention

The first aspect of the present invention provides an oxygen consumption/generation device having a water absorbing film, the oxygen consumption/generation device comprising:

An oxygen-evolving anode, an oxygen-consuming cathode, and a membrane disposed between the oxygen-evolving anode and the oxygen-consuming cathode;

the oxygen-evolving anode comprises an anode catalyst, and the oxygen-consuming cathode comprises a cathode catalyst;

the membrane is a cation exchange membrane or an anion exchange membrane, two sides of the cation exchange membrane or the anion exchange membrane are respectively contacted with a cathode catalyst and an anode catalyst, and the surface of the anode catalyst is provided with a water absorption membrane;

or the membrane is an ion-conducting water-absorbing membrane, and the two sides of the ion-conducting water-absorbing membrane are respectively contacted with a cathode catalyst and an anode catalyst.

Preferably, the anode catalyst comprises: one or more of metal hydroxide, noble metal-supported metal hydroxide, hydroxy metal oxide, noble metal-doped hydroxy metal oxide, metal sulfide, metal nitride and metal phosphide;

and/or derivatised supported complexes of the above compounds;

the cathode catalyst comprises: nitrogen doped carbon, platinum and its alloys, platinum carbon, metal nitrogen carbon compounds, ruthenium and its alloys, metal sulfides, metal phosphides.

Preferably, the metal hydroxide comprises: one or more of nickel-iron hydrotalcite, cobalt-iron hydrotalcite, nickel-iron-vanadium hydrotalcite, cobalt-iron-vanadium hydrotalcite, noble metal loaded cobalt-iron hydrotalcite, noble metal loaded nickel-iron hydrotalcite, iridium hydroxide and ruthenium hydroxide;

the metal oxide comprises: one or more of iridium oxide and ruthenium oxide;

the hydroxy metal oxide comprises: one or more of iridium oxyhydroxide and ruthenium oxyhydroxide.

The preparation method of the metal hydroxide such as cobalt iron hydrotalcite, nickel iron hydrotalcite, cobalt iron vanadium hydrotalcite may use any suitable method commonly used in the art.

Preferably, the iridium hydroxide comprises trivalent iridium. Specifically, trivalent iridium and tetravalent iridium are contained therein.

The preparation method of the iridium hydroxide comprises the following steps: placing iridium trichloride or chloroiridic acid in a reaction vessel, adding deionized water, heating to dissolve completely, adding sodium hydroxide into the reaction vessel, stirring, introducing nitrogen into the reaction vessel for 20-50 minutes, placing the reaction vessel into the reaction vessel, heating the reaction vessel at the constant temperature of 120-180 ℃ for 3-7 hours, cooling the reaction vessel to room temperature, centrifugally washing, and drying the reaction vessel at the temperature of 40-100 ℃ for 8-20 hours to prepare the iridium hydroxide.

Wherein, the mol ratio of iridium trichloride or chloroiridic acid to sodium hydroxide is 13:10-1000, e.g. 13:10, 13:30, 13:50, 13:100, 13:300, 13:500, 13:1000.

Preferably, the iridium hydroxide of the invention has a dispersed cuboid nanoparticle morphology, and the cuboid has a length of 50-300 nm and a width of 50-300 nm. Iridium hydroxide carries water of crystallization.

More preferably, the molar ratio of iridium trichloride or chloroiridic acid to sodium hydroxide is 13:50.

Preferably, the cathode catalyst is an iron-nitrogen co-doped carbon material FeNC-900-Nh which is of a two-dimensional sheet structure, iron is in a monoatomic dispersion state, nitrogen exists in a form comprising pyridine nitrogen and graphite nitrogen, and the BET specific surface area of the iron-nitrogen co-doped carbon material is 750-880 m ²/g.

Preferably, the preparation method of the iron-nitrogen co-doped carbon material FeNC-900-Nh comprises the following steps:

Preparation of step 1, feNC: weighing a certain amount of ferric acetylacetonate, melamine and ZnCl ₂, pouring the ferric acetylacetonate, the melamine and the ZnCl ₂ into a beaker with formamide, carrying out ultrasonic treatment until the ferric acetylacetonate, the ZnCl ₂ and the melamine are dissolved, then adding the mixture into a reaction kettle, heating the mixture at constant temperature for 5-20 h, cooling the reaction kettle to room temperature, carrying out suction filtration, washing, and then freeze-drying the product to obtain FeNC material;

step 2, feNC-900-Nh preparation: pouring the dried product FeNC in the previous step into a porcelain boat, carbonizing in a high-temperature tube furnace in Ar atmosphere, heating to 900 ℃, keeping the temperature for 3-7 hours, cooling to room temperature, and grinding to obtain the iron-nitrogen co-doped carbon material FeNC-900-Nh.

Preferably, the molar ratio of the ferric acetylacetonate, the melamine and the ZnCl ₂ is 1:10-100: 200-1000.

More preferably, the molar ratio of the ferric acetylacetonate, the melamine and the ZnCl ₂ is 1:50:400.

The water absorbing film or the ion-conductive water absorbing film of the present invention may be any suitable water absorbing film or ion-conductive water absorbing film commercially available or self-made.

Preferably, the water absorbing film comprises: one or more of organic film and inorganic film;

Wherein the organic film is selected from one or more of sodium alginate film, polyvinyl alcohol film, sodium polyacrylate film, sodium alginate/polyacrylic acid/polyvinyl alcohol composite aerogel film and nanocellulose-based hydrogel film; the inorganic film is one or more selected from potassium titanate fiber film, sodium titanate fiber film and glass fiber film.

The sodium alginate film, the polyvinyl alcohol film or the sodium polyacrylate film refers to that the main raw materials forming the film are sodium alginate, polyvinyl alcohol or sodium polyacrylate.

The sodium alginate/polyacrylic acid/polyvinyl alcohol composite aerogel film is characterized in that the main raw materials forming the film are sodium alginate, acrylic acid and polyvinyl alcohol.

The preparation methods of the above water absorbing film and the ion-conductive water absorbing film may be any suitable method commonly used in the art.

Preferably, the ion-conducting type water absorbing film is that the water absorbing film contains ion-conducting type substances, and the ion-conducting type substances contain: sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate or potassium bicarbonate.

Preferably, the water absorbing film has a porous structure through which gas can pass. The organic film and the inorganic film mentioned above have a porous structure.

A second aspect of the present invention provides an oxygen migration apparatus having a water absorbing film, the oxygen migration apparatus comprising:

a first space and a second space isolated from each other, and an oxygen consuming/generating device disposed between the first space and the second space;

The oxygen consumption/generation device includes: an oxygen-evolving anode, an oxygen-consuming cathode, and a membrane disposed between the oxygen-evolving anode and the oxygen-consuming cathode;

The oxygen-evolving anode comprises an anode catalyst, the oxygen-consuming cathode comprises a cathode catalyst, and the oxygen migration device further comprises a power supply for applying voltages to both ends of the oxygen-consuming cathode and the oxygen-evolving anode;

The membrane is a cation exchange membrane, the surface of the anode catalyst is provided with a water absorption membrane, the cathode catalyst is contacted with the gas containing oxygen in the first space, and the anode catalyst is contacted with water, water vapor or gas with the humidity of 20-100% in the second space;

Or the membrane is an anion exchange membrane, the surface of the anode catalyst is provided with a water absorption membrane, and the cathode catalyst is contacted with oxygen and water, water vapor or gas with the humidity of 20-100% in the first space;

or the membrane is an ion-conducting water-absorbing membrane, two sides of the membrane are respectively contacted with a cathode catalyst and an anode catalyst, the cathode catalyst is contacted with the gas containing oxygen in the first space, and the anode catalyst is contacted with the water, the water vapor or the gas with the humidity of 20% -100% in the second space.

The specific humidity of the gas with the humidity of 20-100% can be 30-100%, 40-100%, 50-100%, 60-100%, 70-100%, 80-100% and 90-100%.

Preferably, the oxygen migration apparatus includes: and a blower device disposed in the first space. The blower is positioned directly opposite the cathode to promote oxygen consuming reactions of oxygen within the environment at the cathode.

Preferably, in the oxygen consumption/oxygen generation device, when the membrane is a cation exchange membrane or an anion exchange membrane, the cathode catalyst and the anode catalyst can be loaded on the ion exchange membrane in a spray hot pressing mode to prepare a membrane electrode; the anode-cathode catalyst can also be loaded on the porous material current collector and then the current collector is clung to the cation exchange membrane or the anion exchange membrane.

Specifically, porous structural materials are used as channels for reaction gases at the cathode, and the gases circularly injected into the environment undergo oxygen consumption reaction.

In addition, the gas in the environment can be circulated and injected in a runner mode to generate oxygen consumption reaction at the cathode.

Preferably, the voltage applied by the oxygen migration device to the two ends of the oxygen consumption cathode and the oxygen evolution anode is 0.3-10V.

In a second aspect, the invention provides an oxygen-deficient fresh-keeping bin or aerator, which comprises the oxygen migration device in the first aspect.

Preferably, the second space communicates with an oxygen collector.

A third aspect of the present invention provides the use of the oxygen transfer device of any one of the first aspects in an environment where oxygen is required to be consumed, the oxygen concentration is reduced or in an environment where oxygen is required to be produced, the oxygen concentration is increased.

More preferably, a water flow pipe is further provided in the first space or the second space.

The principle of the invention is as follows:

When the membrane is a cation exchange membrane, the anode is introduced with circulating water or water vapor to generate oxygen evolution reaction, oxygen and protons are generated, and the protons are transmitted to the cathode through the cation exchange membrane. The cathode is filled with gas in an environment requiring oxygen consumption, and the transported protons and oxygen in the gas undergo oxygen consumption reaction at the cathode to generate water for discharge, so that the design of the oxygen migration device is realized, the oxygen concentration in the first space is reduced, the first space is changed into an oxygen-deficient space, and the second space is changed into an oxygen-enriched space.

OER reaction occurs at the anode, and the reaction formula is:

H₂O→O₂+H⁺。

The cathode undergoes ORR reaction, and the reaction formula is:

O₂+H⁺→H₂O。

When the membrane is an anion exchange membrane, the cathode is filled with circulating water or water vapor and gas in an environment requiring oxygen consumption, wherein oxygen and water undergo an oxygen consumption reaction at the cathode to generate hydroxyl ions, the hydroxyl ions are transmitted to the anode through the anion exchange membrane to undergo an oxygen evolution reaction to generate water and oxygen, the design of an oxygen migration device is realized, the first space is changed into an oxygen-deficient space, and the second space is changed into an oxygen-enriched space.

OER reaction occurs at the anode, and the reaction formula is:

OH^-→O₂+H₂O。

The cathode undergoes ORR reaction, and the reaction formula is:

O₂+H₂O→OH^-。

When the membrane is a conductive ion type water absorption membrane, particularly a conductive ion type water absorption membrane, circulating water or water vapor is introduced into the anode to generate oxygen evolution reaction, oxygen and protons are generated, and the protons are transmitted to the cathode through the water absorption membrane. The cathode is filled with gas in an environment requiring oxygen consumption, and the transported protons and oxygen in the gas undergo oxygen consumption reaction at the cathode to generate water for discharge, so that the design of the oxygen migration device is realized, the oxygen concentration in the first space is reduced, the first space is changed into an oxygen-deficient space, and the second space is changed into an oxygen-enriched space.

Preferably, the ion-conducting water absorbing film is a water absorbing film containing a certain amount of sulfuric acid. The purpose of sulfuric acid is to provide the protons needed to initiate the reaction, to drive the reaction to occur, with a concentration of sulfuric acid of 0-1 mole per liter.

OER reaction occurs at the anode, and the reaction formula is:

H₂O→O₂+H⁺。

The cathode undergoes ORR reaction, and the reaction formula is:

O₂+H⁺→H₂O。

preferably, at least one of the first space and the second space is sealed.

For example, the first space is sealed and the second space is open.

For example, when the second space is open, the anode is exposed to the environment, and water vapor or humid gas in the environment undergoes an oxygen evolution reaction at the anode or an anode oxygen evolution reaction in contact with a water absorbing film of the anode; or when the second space is sealed, introducing water vapor or moist gas or circulating water into the second space to contact the anode, and performing anodic oxygen evolution reaction.

For example, when the first space is open, the cathode is exposed to the environment, oxygen in the environment undergoes an oxygen consuming reaction at the cathode; or when the second space is sealed, oxygen circulated in the first space undergoes an oxygen-consuming reaction at the cathode.

Preferably, the first space is sealed so as to continuously reduce the oxygen content of the first space, changing the first space into an oxygen-depleted space.

Preferably, the second space is sealed so as to continuously increase the oxygen content of the second space, changing the second space into an oxygen-enriched space.

Preferably, the oxygen migration apparatus includes: and the air blowing device is arranged in the first space so as to promote oxygen consumption reaction of oxygen in the first space at the cathode.

The anode catalyst of the invention can be selected from nickel-iron hydrotalcite, noble metal supported nickel-iron hydrotalcite, iridium oxide, ruthenium oxide and composite oxides thereof, derivative supported composites thereof, metal sulfides, metal nitrides, metal phosphides, iridium hydroxide, ruthenium hydroxide and derivative supported composites thereof, noble metal doped oxyhydroxide such as ruthenium, iridium, platinum, rhodium, gold, silver and the like, and derivative supported composites thereof.

The cathode catalyst of the present invention may be selected from the group consisting of nitrogen-doped carbon, platinum carbon, and metal nitrogen carbon compounds.

A fourth aspect of the invention provides the use of an oxygen transfer device according to any one of the first aspects in an environment where oxygen is to be consumed, where the oxygen concentration is to be reduced, or in an environment where oxygen is to be produced, where the oxygen concentration is to be increased.

The environment in which oxygen is consumed and the oxygen concentration is reduced can be: the oxygen migration device is used for deoxidizing and preserving.

The environment in which oxygen generation and oxygen concentration increase are required may be: medical equipment, oxygenators, and the like.

In a fifth aspect the present invention provides an oxygen migration method by placing the oxygen consuming/generating device of the first aspect in an environment in which oxygen is to be consumed such that a first space and a second space in the environment are isolated from each other by means of at least the oxygen consuming/generating device. Isolated means: the air in the first space and the air in the second space are not communicated with each other. The oxygen consuming/generating device may be part of an insulation between the first space and the second space.

The oxygen consumption cathode is contacted with the gas containing oxygen in the first space, and the oxygen-evolving anode is contacted with water, water vapor or gas with the humidity of 10-100% in the second space;

then, the oxygen consuming/generating device is activated to effect migration of oxygen from the first space to the second space.

One innovation point of the invention is that: for the first time, ion-conducting water-absorbing membranes were used instead of ion-exchange membranes. Anode catalyst and cathode catalyst are respectively loaded on two sides of the ion-conductive water-absorbing film, or the catalyst is loaded on a porous current collector and then is attached to the ion-conductive water-absorbing film.

The advantages compared to conventional electrodes or compared to ion exchange membranes are: the ionic water-absorbing film can absorb water vapor in the environment to participate in the reaction, and can also be used for conducting water generated by the cathode to the anode to generate oxygen evolution reaction. And protons generated by the anode oxygen evolution reaction can be supplemented into the ion-conductive water-absorbing film and then transferred to the cathode to generate oxygen consumption reaction, so that the concentration of the protons in the ion-conductive water-absorbing film is kept unchanged, and the stable reaction is kept.

The other innovation point of the invention is that the device can directly circulate and introduce the gas with certain humidity (the air has certain humidity and is not completely dried and has moisture), and the vapor or the moisture in the gas directly generates oxygen evolution reaction with the catalyst at the anode. This changes the knowledge that the previous oxygen evolution reaction can only take liquid water as reactant. The mode can avoid the inconvenience of continuously adding water into the electrolytic tank and the potential safety hazard of water leakage in the electrolytic tank.

For the prior art, the invention has the following beneficial effects:

1. in the oxygen consumption/oxygen generation device or the oxygen migration device, the surface of the cathode or the anode is covered by the water absorption film, and the water absorption film can absorb water vapor in the environment to participate in electrochemical reaction so as to accelerate the electrochemical reaction rate, thereby increasing the oxygen consumption rate. In addition, an ion-conducting water-absorbing membrane may be used as the ion-exchange membrane, and the anode catalyst and the cathode catalyst may be in contact with both surfaces of the membrane. The ion-conductive water-absorbing film has both ion exchange and water vapor absorption functions.

2. When an anion exchange membrane is adopted between the cathode and the anode, the cathode is filled with circulating water and gas in an environment requiring oxygen consumption, wherein oxygen and water undergo an oxygen consumption reaction at the cathode to generate hydroxyl ions, the hydroxyl ions are transmitted to the anode through the anion exchange membrane to undergo an oxygen evolution reaction to generate water and oxygen, the design of an oxygen migration device is realized, the first space is changed into an oxygen-deficient space, and the second space is changed into an oxygen-enriched space. At the same time, the contents of oxygen and water in the first space where the cathode is positioned are reduced, and when the fresh-keeping device is used, the water vapor or the water in the environment is consumed, the humidity of the environment is reduced, and the fresh-keeping effect is enhanced.

3. The oxygen consumption/generation device or the oxygen transfer device can be used in the environment needing to consume oxygen and reduce the oxygen concentration, and can also be used in the environment needing to generate oxygen and improve the oxygen concentration.

4. The water required by the anode reaction of the invention can be gas which is humidified in an environment requiring oxygen consumption and is circularly introduced, the humidity of the ambient gas is 20-100%, and the moisture contained in the gas is enough to promote the occurrence of OER. The mode can avoid the inconvenience of continuously adding water into the electrolytic tank and the potential safety hazard of water leakage in the electrolytic tank.

5. The gas required for the cathode reaction of the invention is from the gas which needs to contain a certain concentration (about 21%) of oxygen in the oxygen consumption environment, and three contact modes of the gas and the cathode exist. The first is that the cathode is directly opened in an environment requiring oxygen consumption, and a blower device is arranged near the cathode to accelerate the contact between the gas in the environment and the cathode, so that the reaction efficiency of ORR is increased. The second is to use porous material as the channel of the reaction gas, the gas can be fully contacted with the catalyst, the effective area is large, and the oxygen consumption reaction efficiency is higher. And thirdly, the cathode is airtight, gas flows directionally through a flow channel on the cathode plate, and the gas can fully contact with the catalyst due to the flow mode of the gas at the cathode being limited by the flow channel, so that oxygen consumption reaction is more fully generated.

6. On one hand, the cathode and anode catalyst can be loaded on the ion exchange membrane in a spray hot-pressing mode, and the membrane electrode prepared in the mode can enable the catalyst to be in full contact with the membrane, so that the internal resistance of an electrolytic cell is reduced, and the energy consumption of the whole device is reduced.

On the other hand, the cathode and anode catalysts of the invention can also be directly loaded on a current collector, and finally are respectively clung to two sides of an ion exchange membrane, and the electrolytic tank in the mode can realize the array of the cathode and anode catalysts. In contrast, for the cathode catalyst, a hydrophobic and aerophilic structure can be constructed on the porous material of the current collector, so that on one hand, oxygen in the gas in the environment can better contact with the cathode catalyst, and on the other hand, water generated by the cathode can be easily separated from the surface of the catalyst, and the coverage of the generated water on the surface of the catalyst is reduced.

In yet another aspect, the cathode and anode catalysts of the present invention may be directly supported on a water absorbing membrane of a conductive type. The ionic water-absorbing film can absorb water vapor in the environment to participate in the reaction, and can also be used for conducting water generated by the cathode to the anode to generate oxygen evolution reaction. And protons generated by the anode oxygen evolution reaction can be supplemented into the ion-conductive water-absorbing film and then transferred to the cathode to generate oxygen consumption reaction, so that the concentration of the protons in the ion-conductive water-absorbing film is kept unchanged, and the stable reaction is kept.

7. The invention also uses metal hydroxide as an anode oxygen evolution reaction catalyst for the first time, and is used for OER reaction of gaseous water. The metal hydroxide contains abundant hydroxyl groups, and terminal hydrogen atoms of the metal hydroxide are very easy to form hydrogen bonds with oxygen in water molecules in the air, so that the effect of capturing the water molecules in the water vapor is achieved. Therefore, as long as proper bias voltage is applied to enable water molecules to generate OER reaction on the catalyst, the effect of reaction with water vapor in air is achieved, and the purpose that the device can work under the condition of introducing water vapor is achieved.

The metal oxide can not react with water vapor in the air in the anode oxygen evolution reaction catalyst, because the oxygen in the metal oxide is relatively stable, only a small amount of hydroxyl can be adsorbed, so that water molecules in the air are not easy to bond with the metal oxide catalyst, and therefore, the water vapor in the air is difficult to capture by the metal oxide.

8. In addition, the invention prepares the iridium hydroxide catalyst for the anodic oxygen evolution reaction for the first time. The innovation point is that iridium oxide is directly used as an oxygen evolution reaction catalyst in the past, and iridium hydroxide is never used. Because: the conventional iridium hydroxide is mostly considered to be obtained by adding a base to a hot iridium solution and then annealing the solution at a high temperature, and cannot exist stably in the form of IrO ₂.2H₂ O. The commercial IrO ₂ has larger particle size in the range of 200 nanometers to 1 micrometer, and iridium exists in a tetravalent form, so that the catalyst has relatively high stability but low electrocatalytic activity, and is not beneficial to commercial use.

According to the invention, iridium trichloride or iridium chloride is used as a raw material for the first time, so that iridium hydroxide is prepared, and particularly, nitrogen is introduced in the reaction process to ensure that iridium in the catalyst exists in a trivalent form, so that the catalyst has good electrocatalytic activity and stability. And the iridium hydroxide synthesized by hydrothermal synthesis has a small particle size of 2-50nm, more active sites are exposed, and the electrocatalytic activity of the catalyst is improved.

The technical effects are as follows: the iridium hydroxide provided by the invention shows the optimal OER activity as an anode catalyst, the initial potential is 1.4V, the potential is 1.43V under the current density of 10 milliamperes per square centimeter, and the iridium hydroxide is obviously superior to the commercial IrO2 catalyst (1.5V), so that the iridium hydroxide has the good OER catalytic activity. The current density of the catalyst increases by 20mV after 200 hours in a constant current stability test of 10 milliamperes per square centimeter, which proves that the catalyst has good stability and can be put into use and production in devices.

9. The prior iron-nitrogen-carbon doped materials are in an amorphous state. The invention prepares the two-dimensional porous iron-nitrogen co-doped carbon material for the first time, and is used for cathode oxygen consumption reaction. The preparation of the non-noble metal catalyst is realized by introducing melamine with a planar structure and iron on the basis of analyzing a formamide polymerization structure. The two-dimensional porous material with high specific surface area can be obtained after high-temperature roasting by utilizing the polymerization of three amino groups in melamine and carbonyl groups in formamide, and the structure can provide channels which are beneficial to oxygen transmission and a large number of catalytic active sites, so that the electrochemical reaction kinetics is enhanced by improving the mass transmission rate, and the high performance in the electrochemical reaction process is realized.

The technical effects are as follows: the BET specific surface area of the iron-nitrogen co-doped carbon material catalyst is 810.3196m ²/g, shows a type II isotherm, has a medium pore and large pore structure, has larger specific surface area and pore size distribution, and can provide a better transmission channel for oxygen in the oxygen reduction process. And the potential E at 10mAcm ^-2(E₁₀) of the material is smaller, 0.70V, and also smaller than E of most of the electrocatalysts of this type reported in the literature, possibly as advanced bifunctional electrocatalysts for rechargeable ZAB.

Drawings

FIG. 1 is a graph of characterization (SEM) of the morphology of several iridium hydroxide compounds obtained in example 1. (a) SEM image of iridium hydroxide after 120 ℃ hydrothermal treatment; (b) SEM image of iridium hydroxide after 150 ℃ hydrothermal treatment, (c) SEM image of iridium hydroxide after 180 ℃ hydrothermal treatment.

FIG. 2 is a graph of several iridium hydroxide-related morphologies (TEMs) obtained in example 1. (a) a TEM image of iridium hydroxide after 120 ℃ hydrothermal treatment; (b) TEM image of iridium hydroxide after 150℃hydrothermal treatment.

Fig. 3 is an XRD characterization of iridium hydroxide corresponding to fig. 1b of example 1 and iridium hydroxide prepared in example 2.

FIG. 4 is a FT-IR characterization of iridium hydroxide corresponding to FIG. 1b in example 1 and iridium hydroxide prepared in example 2.

FIG. 5 is a thermogravimetric analysis of iridium hydroxide corresponding to FIG. 1b in example 1 and iridium hydroxide prepared in example 2.

FIG. 6 is a linear Cyclic Voltammetry (CV) curve of the iridium hydroxide catalyst prepared in example 3 under acidic conditions. FIGS. 6a-g are Cyclic Voltammograms (CV) of iridium hydride catalysts prepared in example 3 at 120 degrees Celsius with different sodium hydroxide additions (samples 1-7) in 0.5 moles per liter of sulfuric acid, FIGS. 6h-i (sample 3.4.8.9.10.11) are Linear Sweep Voltammograms (LSV) of iridium hydroxide prepared in example 1 at different hydrothermal temperatures in 0.5 moles per liter of sulfuric acid, and FIG. 6j is a constant current polarization curve of iridium hydroxide prepared in example 3 at a current density of 10 milliamps per square centimeter.

FIG. 7 is a graph of Ir 4f orbital xps of the iridium hydroxide catalyst prepared in example 2.

FIG. 8 is a characterization (SEM) of the FeNC and FeNC-900-Nh related features prepared in example 4. (a) SEM images of uncarbonized FeNC; (b) Is an SEM image of FeNC for 3 hours (FeNC-900-3 hours) at 900 ℃, an SEM image of FeNC for 5 hours (FeNC-900-5 hours) at 900 ℃, and an SEM image of FeNC for 7 hours (FeNC-900-7 hours) at 900 ℃.

FIG. 9 is a diagram of FeNC-900-Nh correlation morphology characterization (TEM) prepared in example 4. (a) a TEM image of FeNC h (FeNC-900-5 h) calcined at 900 ℃ for 3h (FeNC-900-3 h), (b) a TEM image of FeNC calcined at 900 ℃ for 5h (FeNC-900-7 h), and (c) a TEM image of FeNC calcined at 900 ℃ for 7 h.

FIG. 10 is a diagram of the FeNC-900-Nh Raman characterization prepared in example 4. (a) XRD characterization patterns (b) FeNC-900-3h, feNC-900-5h and FeNC-900-7h, and Raman characterization patterns of FeNC-900-5h and FeNC-900-7h of FeNC-900-3 h.

FIG. 11 is a FeNC-900-3h spectrum prepared in example 4. (a) an XPS survey of FeNC-900-3 h; (b) a N1S spectrum of FeNC-900-3 h; (c) a Fe 2p spectrum of FeNC-900-3 h.

FIG. 12 is a FeNC-900-5h spectrum prepared in example 4. (a) an XPS survey of FeNC-900-5 h; (b) a N1S spectrum of FeNC-900-5 h; (c) a Fe 2p spectrum of FeNC-900-5 h.

FIG. 13 is a FeNC-900-7h spectrum prepared in example 4. (a) an XPS survey of FeNC-900-7 h; (b) N1S spectrum of FeNC-900-7 h.

FIG. 14 is a map of the distribution characterization of FeNC-900-5h elements. (a) FeNC-900-5h element distribution image, showing a uniform distribution of C, N, fe, (b) FeNC-900-5h HR-TEM, (c) FeNC-900-5h HAADF-STEM.

FIG. 15 is a N ₂ adsorption/desorption curve (pore size in inset) for FeNC-900-5 h.

FIG. 16 is a chart of ORR performance tests for FeNC-900-Nh in example 5. (a) FeNC-900-3h, feNC-900-5h, feNC-900-7h and Pt/C cyclic voltammograms (50 mV/s ^-1); (b) Linear scan curves for FeNC-900-3h, fenC-900-5h, fenC-900-7h and Pt/C (5 mV/s ^-1, 1600 rpm) (C) FeNC-900-5h OER linear scan curves

FIG. 17 is a graph of OER performance test at FeNC-900-Nh of example 5. (a) FeNC-900-3h, feNC-900-5h, feNC-900-7h and Pt/C cyclic voltammograms (50 mV/s ^-1); (b) Linear scan curves (5 mV/s ^-1, 1600 rpm) for FeNC-900-3h, feNC-900-5h, feNC-900-7h, and Pt/C; testing under saturated oxygen atmosphere.

FIG. 18 is a schematic view of an oxygen consuming/generating device of application example 1.

FIG. 19 is a graph showing the concentration time of oxygen in application example 1.

Fig. 20 is a current-voltage curve of application example 1.

FIG. 21 is a schematic view of an oxygen consuming/generating device of application example 2.

FIG. 22 is a graph showing the concentration time of oxygen in application example 2.

Fig. 23 is a current-voltage curve of application example 2.

FIG. 24 is a schematic view of an oxygen consuming/generating device of application example 3.

FIG. 25 is a graph showing the concentration time of oxygen in application example 3.

Fig. 26 is a current-voltage curve of application example 3.

FIG. 27 is a schematic view of an oxygen consuming/generating device of application example 4.

FIG. 28 is a graph showing the concentration time of oxygen in application example 4.

Fig. 29 is a current-voltage curve of application example 4.

FIG. 30 is a schematic view of an oxygen consuming/generating device of application example 5.

FIG. 31 is a graph showing the concentration time of oxygen in application example 5.

Fig. 32 is a current-voltage curve of application example 5.

FIG. 33 is a graph of the concentration time of oxygen in comparative example 1.

Fig. 34 is a current-voltage curve of comparative example 1.

FIG. 35 is a schematic view of an oxygen consuming/generating device of application example 6.

FIG. 36 is a schematic view of another oxygen consuming/generating device of application example 6.

Reference numerals:

1A, an anion membrane electrode, 1B, a cation membrane electrode, 2, a current collector, 3, a hollow gasket, 4A, a cathode plate, 4B, an anode plate, 5A, a cathode cover plate, 5B, an anode cover plate, 6 and carbon paper.

Detailed Description

The present invention will be described in further detail with reference to examples.

It will be appreciated by those skilled in the art that the following examples are illustrative of the present invention and should not be construed as limiting the scope of the invention. The specific techniques or conditions are not identified in the examples and are performed according to techniques or conditions described in the literature in this field or according to the product specifications. The materials or equipment used are conventional products available from commercial sources, not identified to the manufacturer.

Example 1

A preparation method of iridium hydroxide:

20mg of iridium trichloride is taken in a reaction bottle, 5ml of deionized water is added into the reaction bottle, and the reaction bottle is placed in a 40 ℃ ultrasonic cleaner for half an hour to be completely dissolved. 10mg of sodium hydroxide was added thereto and stirred for 48 hours. Introducing nitrogen gas into the reaction kettle for 30 minutes, respectively heating the reaction kettle at the constant temperature of 120 ℃ and 150 ℃ and 180 ℃ for 4 hours to carry out hydrothermal reaction, cooling the reaction kettle to room temperature, centrifuging the reaction kettle for 20 minutes at the speed of 12000rpm with ethanol and water, decanting the supernatant, repeatedly centrifuging for 6 times, and drying the reaction kettle at 70 ℃ for 12 hours to prepare three iridium hydroxide samples.

The iridium hydroxide of this example 1 can be used for the anode catalyst of the oxygen transfer oxygen consuming/generating apparatus of the present invention.

The morphology of the three iridium hydroxide samples is characterized, and the results are as follows:

FIG. 1 is a graph of morphology characterization (SEM) associated with three iridium hydroxide samples. (a) SEM image of iridium hydroxide after 120 ℃ hydrothermal treatment; (b) SEM image of iridium hydroxide after 150 ℃ hydrothermal treatment, (c) SEM image of iridium hydroxide after 180 ℃ hydrothermal treatment.

As can be seen in fig. 1a, iridium hydroxide is a round nanoparticle aggregate, and the boundaries between particles are not clear, and the particles are not dispersed. As can be seen in FIG. 1b, iridium hydroxide exhibits a dispersed, rectangular nanoparticle morphology, the length of the cuboid being 50-300 nm and the width being 50-300 nm. As can be seen in fig. 1c, the iridium hydroxide is in the micrometer range, being entirely one monolithic piece with undulations.

Fig. 2 is a graph of morphology characterization (TEM) associated with three iridium hydroxide samples. (a) a TEM image of iridium hydroxide after 120 ℃ hydrothermal treatment; (b) TEM image of iridium hydroxide after 150℃hydrothermal treatment.

Example 2

Iridium hydroxide was prepared using the procedure of example 1, with the only differences: the iridium precursor is replaced by iridium trichloride with chloroiridic acid. The hydrothermal reaction temperature was 150 ℃.

Fig. 3 is an XRD pattern of iridium hydroxide corresponding to fig. 1b in example 1 and iridium hydroxide prepared in example 2. Namely, the XRD characterization diagram of the iridium hydroxide prepared by taking iridium trichloride and chloroiridic acid as iridium sources under the condition of hydrothermal reaction at 150 ℃ for 4 hours.

As can be seen from fig. 3, when the iridium precursor is iridium trichloride or chloroiridate, the iridium hydroxide was prepared using this synthesis method, and both samples had two broad characteristic peaks around only 34 ° and 58 °, indicating that a low crystallinity catalyst was formed, and no characteristic peaks related to metallic iridium or iridium oxide or other derived metal oxides were observed, demonstrating successful preparation of low crystallinity iridium hydroxide compound samples.

The FT-IR spectrum of iridium hydroxide is shown in FIG. 4. Its infrared spectral characteristics in the range 2600-4000cm ^-1 can be attributed to the hydroxyl groups in the crystal water and the hydroxyl groups in the iridium hydroxide sample. From the infrared spectrum, two peaks were seen, a distinct peak at two positions, 3545cm ^-1 and 3150cm ^-1. Peaks around 3150 correspond to stretching vibrations of hydrogen bonding hydroxyl groups, which are caused by adsorbed water molecules in the sample. The peak shifts to lower wavenumbers compared to the free hydroxyl group (3600 cm ^-1) because of the hydrogen bonding between the water molecules and the hydroxyl groups. The peak at 3545cm ^-1 corresponds to the stretching vibration of the free hydroxyl group, indicating that the sample contains non-hydrogen bonded hydroxyl groups, corresponding to the hydroxyl groups in iridium hydroxide. The FT-IR spectrum was consistent with the previous characterization, again demonstrating that the final product synthesized after hydrothermal reaction was iridium hydroxide.

The test conditions were elevated from 40 degrees celsius to 1000 degrees celsius at an elevated rate of 5 degrees celsius per minute under air conditions. The thermogravimetric analysis spectrogram characteristics of the catalyst at the temperature of between 40 and 1000 ℃ can be attributed to the mass loss of adsorbed water in a sample, the mass loss of crystal water, the mass loss of hydroxyl groups in hydroxide converted into oxide and the mass loss caused by collapse of a catalyst structure at an ultrahigh temperature. From the simultaneous thermograms, it can be seen that distinct peaks appear at both 155 degrees celsius and 180 degrees celsius in the range of 40-200 degrees celsius. The significant quality drop at 155 degrees celsius corresponds to a loss of crystal water, which proves that the catalyst contains crystal water. The mass loss of converting hydroxide into oxide corresponds to 180 ℃, which proves that the sample contains a large amount of hydroxyl groups. The thermogravimetric analysis is consistent with the previous characterization results, and again demonstrates that the final product synthesized after hydrothermal reaction is iridium hydroxide with water of crystallization.

FIG. 7 is an Ir 4f orbital XPS spectrum of the iridium hydroxide catalyst prepared in example 2.

The XPS spectrum of iridium hydroxide shown in FIG. 7 clearly shows the presence of trivalent iridium. Observations of the asymmetry and width of the 4f peak of Ir in iridium hydroxide indicate the possible presence of trivalent and tetravalent iridium species. Thus, after decomposing the original convolved peak of iridium hydroxide into different peaks (different icons), the binding energy of the Ir 4f peak was recorded as 61.9eV (ir4+4f7/2) and 63.1eV (ir3+4f7/2) with the charge correction effect. The presence of trivalent iridium in the catalyst suggests that iridium hydroxide has good catalyst activity, which is consistent with the activity of trivalent iridium reported previously being superior to tetravalent iridium.

Example 3

Iridium hydroxide was prepared using the method of example 1. The differences are only: the hydrothermal reaction temperature was varied and the concentrations of IrCl ₃ and NaOH in the hydrothermal reaction solution were controlled, and the reaction conditions were as shown in the following table. The volume of the solution was 5ml and the hydrothermal reaction time was 4 hours, giving iridium hydroxide catalyst samples No. 1 to 11.

Then, samples 1 to 11 of iridium hydroxide catalyst were subjected to electrochemical test in a three-electrode system, a platinum electrode was selected as a counter electrode, a saturated calomel electrode was used as a reference electrode, and a working electrode was prepared by drying an ink drop of iridium hydroxide catalyst on 1 x 1cm ² carbon paper, and was subjected to test in 0.5 mol/liter sulfuric acid.

TABLE 1 reaction conditions

From FIGS. 6a-g, it can be seen that the starting potentials of the No. 1-7 catalysts were 1.451V, 1.442V, 1.431V, 1.439V, 1.442V, 1.446V, 1.451V, and the starting potentials of the No. 1-7 catalysts were 1.456V, 1.452V, 1.438V, 1.461V, 1.475V, 1.552V, and 1.532V, respectively, at current densities of 10 milliamperes per square centimeter, and that the iridium hydroxide prepared at the added sodium hydroxide levels of 10mg (sample 3) and 20mg (sample 4) was relatively good, and significantly superior to the commercial iridium oxide catalyst starting potentials of 1.5V.

Further adjusting the temperature of iridium hydroxide for hydrothermal synthesis, it can be seen from fig. 6h-j that the prepared catalyst No. 9 has the best catalytic activity when the hydrothermal temperature is 150 ℃, the initial potential is 1.40V, which is improved by 100mV compared with the commercial iridium oxide catalyst, and that the catalyst No. 9 has good stability under the current density of 10mA per square centimeter as shown in fig. 6j, and the 160h stability test only increases the potential by 10mV, which is obviously superior to the commercially available RuO2 catalyst.

Example 4

The iron-nitrogen co-doped carbon material of this example 4 can be used for the cathode catalyst of the oxygen transfer oxygen consuming/generating device of the present invention.

The preparation method of the iron-nitrogen co-doped carbon material comprises the following steps:

Preparation of step 1, feNC: 0.01056g of iron acetylacetonate, 0.18918g of melamine and 1.632g of ZnCl ₂ are weighed together into a beaker with formamide and sonicated until dissolved, giving a homogeneous clear and transparent solution. Adding the mixture into a 50ml reaction kettle, heating the mixture at a constant temperature for 12 hours, cooling the reaction kettle to room temperature, performing suction filtration, washing a black insoluble sample with deionized water for 3 times, and then placing the product in a freeze dryer for 24 hours to obtain FeNC materials.

Step 2, feNC-900-Nh preparation: and pouring the dried product FeNC in the previous step into a porcelain boat, carbonizing in a high-temperature tube furnace in Ar atmosphere, heating to 900 ℃ at a certain heating speed of 5 ℃/min, respectively keeping the temperature for 3 hours, 5 hours or 7 hours, cooling to room temperature, and grinding the materials into powder by using a mortar to obtain three iron-nitrogen co-doped carbon materials FeNC-900-3 hours, feNC-900-5 hours and FeNC-900-7 hours respectively.

The following are physical characterizations of the above materials:

(1) SEM characterization and analysis

It can be seen from fig. 8a-8c that FeNC obtained in step 1 is a two-dimensional sheet-like structure prior to carbonization. Then, a scanning electron microscope test is also carried out on samples FeNC-900-Nh of the carbonized material, and the carbonized material FeNC-900-Nh still maintains the morphology before carbonization, which indicates that the catalytic material has a certain stability at high temperature. From SEM images, the two-dimensional structure has a larger specific surface area than the one-dimensional structure, with more metal atoms anchored, resulting in more active site conditions.

(2) TEM characterization and analysis

For a clearer understanding of the two-dimensional structure, the prepared sample was again subjected to TEM, the structure being shown in fig. 9a-9 c. It can be seen that FeNC-900-Nh are spatially interconnected lamellar structures, the shade of color on the electron microscope being due to the lamellar structures being superimposed. In addition, feNC-900-3h, fenC-900-5h, and FenC-900-7h after calcination exhibited a pore-like structure due to the disappearance of unstable nitrogen at high temperatures. This channel structure can provide a better transport path for oxygen. And no particles exist on the surface before and after calcination, which indicates the monodispersed state of the metal in the material.

(3) XRD and Raman characterization

FIG. 10 (a) is an XRD characterization of FeNC-900-3h, feNC-900-5h, and FeNC-900-7 h. As can be seen from fig. 10, the three showed two broad peaks at about 26 ° and 44 °, which correspond to the (002) and (100) crystal planes of the graphitic carbon, respectively, whereby it was seen that the high temperature calcination caused a portion of the carbon in FeNC-900-Nh to take on the graphitized form, and no diffraction peak associated with iron was observed, indicating that Fe in the three samples was in an atomic dispersed state. Comparing the XRD patterns of the three samples, it can be seen that the position of the peak at (002) shows a slight positive shift trend with increasing calcination time, and the peak area gradually increases, and the peak area of the (100) crystal face increases and then decreases. These all demonstrate that FeNC-900-5h possess a structure that is more conducive to electron transport for oxygen reduction reactions.

As can be seen from FIG. 10 (b), the D peaks for FeNC-900-3h, fenC-900-5h and FeNC-900-7h appear at 1322cm ^-1、1341cm^-1 and 1351cm ^-1, respectively, and the G peaks are located at 1581cm ^-1、1600cm^-1 and 1600cm ^-1, respectively. Typically, the I _D/I_G intensity ratio represents the defect level, and the larger the value, the more defects the material will have. As a result of calculation, feNC-900-3h had an I _D/I_G of 2.35, feNC-900-5h had an I _D/I_G of 3.18, and FeNC-900-7h had an I _D/I_G of 2.31. It is shown that the graphitization degree of the material is firstly increased and decreased with the increase of the calcination time, and the D peak and the G peak both show weak right shift trend. This trend may have an impact on the electrocatalytic properties of the material.

(4) XPS characterization

The chemical properties of FeNC-900-Nh were each characterized by XPS.

FIG. 11 (a) shows XPS survey spectra at FeNC-900-3 h.

The Fe 2p, O1 s, N1 s and C1s peaks are given in sequence from left to right, indicating the presence of Fe, O, N and C. The oxygen reduction performance of the nitrogen-doped carbon material is generally indistinguishable from that of the nitrogen-doped carbon material, and the higher the nitrogen content is, the better the oxygen reduction performance is; the existence of pyridine nitrogen and graphite nitrogen is catalytically active to oxygen reduction reaction, while the existence of other two nitrogen forms does not have the effect, the existence of pyridyl-N is beneficial to enhancing ORR initial potential, and graphite N is positioned at the edge of defective carbon and provides electrons for p conjugated system, which is beneficial to the electrocatalytic effect of oxygen. In addition, the doping of Fe element can also improve the oxygen reduction performance of the catalyst, so the improvement of Fe content is also beneficial to the oxygen reduction reaction.

FIG. 11 (b) is a FeNC-900-3h high resolution N1s spectrum deconvoluted to 398.5 and 400.3eV, corresponding to pyridine-N and graphite-N, respectively. The presence of these nitrogens is very beneficial for reversible ORR and OER.

FIG. 11c is a FeNC-900-3h XPS Fe 2p spectrum. Fig. 11c shows that no zero-valent metal is present in the material, again illustrating the monoatomic state of the metal in the material.

Successful doping of Fe in FeNC-900-5h can be seen. The Fe signal of FeNC-900-7h is blurred to almost no, due to its low concentration, which may be due to the too long calcination time.

The XPS test results for samples FeNC-900-5h and FeNC-900-7h after calcination at 900℃for 5h and 7h, respectively, are shown in FIGS. 12 and 13.

FIGS. 12 (b) and 13 (b) are fitted curves after peak splitting for high resolution N1s of FeNC-900-5h FeNC-900-7h, respectively, and it is seen that nitrogen in FeNC-900-5h and FeNC-900-7h exists mainly as pyridine nitrogen (398.5 eV) and graphite nitrogen (400.3 eV).

Table 2 FeNC-900-3/5/7h table of the percentage of iron and nitrogen of different forms

Table 2 summarizes the nitrogen content and Fe content of the different species in the three FeNC-900-3/5/7h samples. The three samples all contained pyridine nitrogen and graphite nitrogen only, and the comparison shows that FeNC-900-5h has the most nitrogen content and the most Fe content, and the data suggest that FeNC-900-5h may have better ORR performance.

(5) Related element distribution characterization (mapping)/high resolution

In this embodiment, feNC-900-5h are selected as the element distribution, high resolution and spherical aberration characterization, as shown in fig. 14 (a).

Elemental analysis confirmed the presence of C, N and Fe elements and the uniform distribution of Fe and N. To further determine the presence of Fe, HR-TEM characterization was performed. The absence of metal particles can be seen from fig. 14 (b). By using HAADF-STEM technology to identify FeNC-900-5h atomic structure, as shown in FIG. 14 (c), single bright spots can be clearly identified in the nitrogen-doped carbon matrix, which is caused by the isolation of Fe atoms. The above results again illustrate the monodisperse state of the metal.

(6) Nitrogen adsorption and desorption curve and pore diameter distribution curve

FIG. 15 shows N ₂ adsorption/desorption isotherms (pore size in inset) for FeNC-900-5 h. BET specific surface area is 810.3196m ²/g, shows type II isotherms, has a medium pore (20-50) and large pore (50-1000 nm) structure, has larger specific surface area and pore size distribution, and has a specific pore size distribution range of 10-100nm. Thus, better transport channels for oxygen can be provided during the oxygen reduction process.

Example 5

The electrochemical performance test of the material prepared in example 4 is as follows:

(1) ORR and OER Performance test

As shown in FIG. 16, preliminary experiments were performed on the catalytic activity of FeNC-900 catalysts prepared at the same pyrolysis temperature and different pyrolysis times.

The results show that FeNC-900-5h showed the best ORR activity and had the best half-wave potential (E _1/2). The CV curves of the catalysts showed clear cathodic peaks, confirming their ORR catalytic ability.

As shown in FIG. 16 (a), LSV curves under alkaline conditions are given for FeNC-900-3h, feNC-900-5h, feNC-900-7h and Pt/C. It can be seen that between 0.8 and 1.0V, the current density rises rapidly with the negative sweep of the potential, and the catalyst is electrochemically controlled at this stage; after the potential continues to scan, a plateau appears at which the catalyst is diffusion controlled. FeNC-900-5h electrodes showed excellent ORR activity with an initial potential (Eonset) of 1.06V, higher than FeNC-900-3h (1.03V), feNC-900-7h (1.00V) and commercial Pt/C (1.05V). Further comparing its half-wave potential (E _1/2), it was found that FeNC-900-5h (E _1/2 =0.900V) was significantly higher than FeNC-900-3h (E _1/2＝0.890V)、FeNC-900-7h(E_1/2 =0.820V) and Pt/C (E _1/2 =0.860V), where the half-wave potential of FeNC-900-5h was 40mV higher than commercial Pt/C.

Similarly, FIG. 16 (b) is CV curves under alkaline conditions for FeNC-900-3h, feNC-900-5h, feNC-900-7h and Pt/C. As can be seen from FIG. 16 (b), the oxygen reduction peaks for FeNC-900-5h were significantly shifted forward over FeNC-900-3h and FeNC-900-7h, and the ORR peak and CV ring area values were maximized for FeNC-900-5 h. This also indicates that FeNC-900-5h has higher oxygen reduction catalytic activity and larger accessible surface area.

OER activity was also analyzed to determine if FeNC-900-5h could act as a dual-function electrocatalyst. 10mAcm ^-2(E₁₀) is a critical parameter, as shown in FIG. 16 (c), E ₁₀ for FeNC-900-5h is 1.60V, E=E ₁₀(OER)-E_1/2 (ORR). In general, the smaller E, the better the bifunctional catalyst activity that can be achieved. The E of FeNC-900-5h is smaller and is 0.70V, and the E of FeNC-900-5h is smaller than the E of most of the electrocatalysts reported in the literature, so that one of the high-grade bifunctional electrocatalysts which can be used for charging ZAB is further proved to be prepared by the invention.

In addition, FIGS. 17 (a) and (b) show CV curves and linear scan curves of FeNC-900-3h, feNC-900-5h, feNC-900-7h, and Pt/C, respectively, under acidic conditions.

As can be seen from the CV curve of FIG. 17 (a), feNC-900-3h, fenC-900-5h and FeNC-900-7h and Pt/C all exhibited distinct oxygen reduction peaks. FIG. 17 (b) shows LSV curves, and it can be seen that the half-wave potentials (E _1/2) for FeNC-900-3h, fenC-900-5h and FeNC-900-7h and Pt/C were 0.73V, 0.76V, 0.57 and 0.85V, respectively, and FeNC-900-5h had the best catalytic activity under these conditions.

Example 6

Preparation of a water absorbing film:

1 st: preparation of SA/PAA/PVA composite aerogel film

In order to improve the breaking strength and breaking elongation of Sodium Alginate (SA) fiber, acrylic Acid (AA) is taken as a chemical crosslinking component, SA is taken as an ionic crosslinking component, polyvinyl alcohol (PVA) is taken as a microcrystalline crosslinking component, a freeze thawing cycle method is adopted to prepare sodium alginate/polyacrylic acid/polyvinyl alcohol (SA/PAA/PVA) composite fiber containing PVA microcrystalline crosslinking points and a sodium alginate/polyacrylic acid (SA/PAA) double-network structure; the addition of PAA and PVA improves the crystallinity of the composite fiber; the surface morphology of the composite fiber tends to be smooth and regular, and the fiber section is more compact. And freeze-drying for 60 hours to prepare the SA/PAA/PVA xerogel. The detailed operation steps are as follows:

The first step: low temperature dissolution for preparing SA/urea solution

100G of mixed solution of NaOH/urea/H ₂ O (mass ratio 7:12:81) is prepared, the pH value of the solution is regulated to 10-10.5 by AA, SA is added, and 1000r/min is stirred for 10H at-12 ℃ to obtain SA/urea solution. Continuously adopting a freezing-thawing method to dissolve SA, sampling, thawing and vacuum defoaming each time of freezing cycle to obtain SA liquid; the remaining solution was again frozen in a refrigerator and recycled 4 times to give a clear SA/urea solution. Adjusting the pH value of the SA/urea solution to 6-6.5 by AA, and storing at 4 ℃ for standby.

And a second step of: preparation of SA/PAA/PVA composite aerogel

10G of PVA powder was added to 90g of deionized water, dissolved at 90℃to obtain a PVA solution having a mass fraction of 10%, and then 30g of the PVA solution was added to 100g of the above SA/urea solution to obtain a SA/PAA/PVA mixed solution. Stirring at 1000r/min for 2h, pouring the mixed solution into a mould, freezing and forming at-25deg.C, and lyophilizing in a lyophilizing machine (-78deg.C, <1 Pa) for 60h to obtain SA/PAA/PVA composite aerogel film with thickness of about 5mm. Shearing to obtain SA/PAA/PVA composite aerogel film with proper size for standby.

2 Nd: preparation of sodium alginate film

The method comprises the following specific steps:

The first step: low temperature dissolution for preparing SA/urea solution

And a second step of: preparation of sodium alginate aerogel

Stirring the SA/urea solution at 1000r/min for 2h, pouring the mixed solution into a mold, freezing and forming at-25 ℃, and freeze-drying in a freeze dryer (at (-78 ℃ and less than 1 Pa) for 60h to obtain the sodium alginate aerogel film with the thickness of about 5mm. Shearing to obtain sodium alginate gel film with proper size for use.

3 Rd: preparation of polyvinyl alcohol film

The method comprises the following specific steps:

the first step: low temperature dissolving process of preparing PVA/urea solution

100G of mixed solution of NaOH/urea/H ₂ O (mass ratio of 7:12:81) is prepared, the pH value of the solution is regulated to 10-10.5 by AA, SA is added, and 1000r/min is stirred for 10H at-12 ℃ to obtain the polyvinyl alcohol/urea solution. Dissolving SA by a freezing-thawing method, sampling and thawing vacuum defoaming each time in a freezing cycle to obtain polyvinyl alcohol liquid; the remaining solution was again frozen in a refrigerator and recycled 4 times to give a clear polyvinyl alcohol/urea solution. Adjusting the pH value of the SA/urea solution to 6-6.5 by AA, and storing at 4 ℃ for standby.

And a second step of: preparation of polyvinyl alcohol aerogel

Stirring the polyvinyl alcohol/urea solution for 2 hours at 1000r/min, pouring the mixed solution into a mould, freezing and forming at-25 ℃, and then putting into a freeze dryer (-78 ℃ and less than 1 Pa) for freeze drying for 60 hours to obtain the polyvinyl alcohol aerogel film with the thickness of about 5mm. Shearing to obtain a polyvinyl alcohol gel film with proper size for standby.

4 Th: preparation of inorganic Potassium titanate films

The method comprises the following specific steps:

10-15g of TiO2 powder with an average diameter of 4nm prepared using the reported method are dispersed in 400mL of 4-10mol/LKOH aqueous solution. The resulting suspension was stirred for 20 minutes, then transferred to a teflon-lined stainless steel autoclave, sealed and maintained at 160-180 ℃ for 48 hours. The resulting white precipitate was filtered, washed with deionized water, and finally placed in a specific mold and dried in vacuum at 60 ℃ for 3 hours.

In 5 th: preparing an ion-conducting type water absorbing film:

The first step: low temperature dissolution for preparing SA/urea solution

And a second step of: preparation of conductive ion type SA/PAA/PVA composite aerogel

10G of PVA powder was added to 90g of deionized water, dissolved at 90℃to obtain a PVA solution having a mass fraction of 10%, and then 30g of the PVA solution was added to 100g of the above SA/urea solution to obtain a SA/PAA/PVA mixed solution. Stirring at 1000r/min for 2h, pouring the mixed solution into a mould, freezing and forming at-25 ℃, then putting into a freeze dryer (-78 ℃, < 1 Pa) and freeze-drying for 60h to obtain an SA/PAA/PVA composite aerogel film, adding 10ml of 0.5mol/L dilute sulfuric acid into the SA/PAA/PVA composite aerogel film to soak for 24h, carrying out vacuum drying, carrying out hot pressing at 50 ℃ under 3Mpa pressure for 20 min to obtain an ion-conducting water absorption film with the thickness of about 5mm, and shearing to obtain a proper size for standby.

Example 7

Synthesis of anode catalyst material:

The preparation method of the hydroxide such as ferrocobalt hydrotalcite, ferronickel hydrotalcite, ferrocobalt vanadium hydrotalcite may use any suitable method commonly used in the art, and the present example merely provides the following as an example.

Synthesizing a NiFe LDHs nano-sheet array: ni (NO ₃)₂·6H₂O(0.75mmol)、Fe(NO₃)₃·9H₂ O (0.25 mmol) and CO (NH ₂)₂ (5 mmol)) were dissolved in 36mL distilled water and stirred to form a clear solution, then the above solution was transferred to a 40mL polytetrafluoroethylene-lined stainless steel autoclave, sealed and held at 120℃for 12h, then naturally cooled to room temperature ethanol and water at 5000rpm for 10 minutes, the supernatant was decanted, centrifuged repeatedly 3 times, and dried at 80℃for 6 hours to obtain nickel iron hydrotalcite as anode catalyst for use.

And (3) synthesizing NIFEV LDHS nanometer sheet arrays: Ni(NO₃)₂·6H₂O(2.4mmol)、Fe(NO₃)₃·9H₂O(0.4mmol)、VCl₃(0.4mmol) and CO (NH ₂)₂ (5 mmol)) were dissolved in 35mL of distilled water and stirred to form a clear solution, then the above solution was transferred to a 40mL stainless steel autoclave lined with polytetrafluoroethylene, sealed and maintained at 120℃for 12 hours, then naturally cooled to room temperature, ethanol and water were centrifuged at 5000rpm for 10 minutes, the supernatant was decanted, centrifuged repeatedly 3 times, and dried at 80℃for 6 hours to obtain nickel iron vanadium hydrotalcite as an anode catalyst for use.

Synthesis of CoFe LDHs nanosheet arrays: co (NO ₃)₂·6H2O(0.75mmol)、Fe(NO₃)₃·9H₂ O (0.25 mmol) and CO (NH ₂)₂ (5 mmol)) were dissolved in 36mL distilled water and stirred to form a clear solution, then the above solution was transferred to a 40mL polytetrafluoroethylene-lined stainless steel autoclave, sealed and held at 120℃for 12h, then naturally cooled to room temperature ethanol and water at 5000rpm for 10 minutes, the supernatant was decanted, centrifuged repeatedly 3 times and dried at 80℃for 6 hours to give cobalt iron hydrotalcite as anode catalyst for use.

In addition, using the above method, the ratio of trivalent metal and divalent metal ions was controlled to 3:1, other metal ions such as NiCo, mgAl, niMn, znAl and ternary doped hydrotalcite thereof can be doped.

Application example 1

The application example 1 provides an oxygen-deficient fresh-keeping bin comprising a cation exchange membrane oxygen migration device, wherein the cavity of the oxygen-deficient fresh-keeping bin is used for placing articles to be kept fresh.

In the example, the catalyst used for the cathode is FeNC-900-5h prepared in example 4, the anode catalyst is No. 9 iridium hydroxide prepared in example 3, and the cathode catalyst and the anode catalyst are respectively sprayed on two sides of the cation exchange membrane and then subjected to hot pressing step to finally form the cation membrane electrode 1B.

A schematic of the oxygen consumption/generation device is shown in fig. 18.

The oxygen-consuming cathode comprises: a hollow gasket 3 (made of plastic and provided with a porous current collector 2), a cathode plate 4A (used for connecting with a power supply) and a cathode cover plate 5A are sequentially arranged from the center of the oxygen consumption/oxygen generation device to the outside of one side and fixed by screws. The cathode cover plate 5A is provided with a cathode fluid inlet and a cathode fluid outlet to allow gas or water to flow into or out of the oxygen consuming/generating device so that the gas or water reaches the cathode catalyst surface on the cation membrane electrode 1B for reaction.

The oxygen evolution anode comprises: a hollow gasket 3 (in which the porous current collector 2 is accommodated), an anode plate 4B (for connection with a power supply), and a hollow anode cover plate 5B, which are sequentially disposed from the center of the oxygen consumption/generation device to the outside of the other side and are fixed by screws. The hollow anode cover plate 5B allows gas or water to pass into the oxygen consuming/generating device and reach the anode catalyst surface on the cation membrane electrode 1B for reaction.

The SA/PAA/PVA composite aerogel film prepared in example 6 is attached to one side of the porous current collector 2 on the oxygen evolution anode, which is provided with the cationic membrane electrode 1B. A cation membrane electrode 1B is arranged between the oxygen consumption cathode and the oxygen evolution anode.

Specific mounting means for the oxygen consuming/generating device one skilled in the art may depend on the specific construction and shape of the oxygen-depleted fresh food compartment.

The working mode is as follows:

And (3) starting a power supply of the oxygen migration device, applying a voltage of 1.5V to the device, and generating OER reaction of water vapor in the second space at the oxygen consumption anode to generate protons and oxygen. The oxygen is discharged, and the generated protons pass through the cation exchange membrane to the oxygen-consuming cathode. Oxygen in the first space fresh-keeping bin gas reacts with protons transported by the anode in an oxygen consumption reaction. Namely, the anode of the device generates oxygen evolution reaction and the cathode generates oxygen consumption reaction. The consumption volume of the device is 30L, the concentration time curve of oxygen in the sealed oxygen-deficient fresh-keeping bin is shown in the accompanying drawing 19, the current-voltage curve is shown in the accompanying drawing 20, the current density of the oxygen-consuming/oxygen-generating device can reach 30mA cm ^-2,12.56cm², the effective working area oxygen consumption rate can reach 27.51cm ³/h, the oxygen consumption efficiency can almost reach 82%, and the oxygen generation rate of the anode per square centimeter is 2.19cm ³/h.

Application example 2

The anode of the oxygen consumption/oxygen generation device in application example 2 adopts a mode of circulating water vapor, and the cathode structure is similar to that of application example 1.

A schematic of the oxygen consumption/generation device is shown in figure 21. Unlike application example 1, the device has a certain serpentine flow path in the cavity of the cathode, specifically, the cathode plate 4A is carved with the serpentine flow path. The gas that the cathode participates in the reaction can flow at the cathode through the flow channel. The cathode catalyst is FeNC-900-5h prepared in example 4, the anode catalyst is 9 # iridium hydroxide prepared in example 3, and the cathode catalyst and the anode catalyst are respectively sprayed on two sides of the ion-conducting water absorbing film prepared in example 6 to finally form a film electrode.

After the device is assembled, a voltage of 1.5V is applied to the device, the anode of the device generates oxygen evolution reaction, and the cathode generates oxygen consumption reaction. The consumption volume of the device is 30L, the concentration time curve of oxygen in the sealed box is shown in figure 22, the current-voltage curve is shown in figure 23, the current density of the oxygen consumption/generation device can reach 110mA cm ^-2,9cm², the effective working area oxygen consumption rate can reach 86.7cm ³/h, the oxygen consumption efficiency can almost reach 85%, and the oxygen generation rate of the anode per square centimeter is 9.6cm ³/h.

Application example 3

The anode of the oxygen consumption/oxygen generation device in the application example 3 adopts a mode of circulating water vapor, and the cathode structure is similar to that in the application example 2. A schematic of the oxygen consumption/generation device is shown in fig. 24. Unlike application example 2, the device has a certain serpentine flow channel in the cavities of the cathode and the anode, and the water vapor participating in the reaction of the anode can flow in the anode through the flow channel. The cathode catalyst is FeNC-900-5h prepared in example 4, the anode catalyst is ferronickel hydrotalcite prepared in example 7, the cathode catalyst and the anode catalyst are respectively sprayed on two sides of an anion exchange membrane and then subjected to a hot pressing step to finally form an anion membrane electrode 1A, an inorganic potassium titanate membrane prepared in example 6 is attached to an oxygen evolution anode, and specifically, the inorganic potassium titanate membrane is attached to the outer surface of the anion membrane electrode 1A.

After the device is assembled, a voltage of 1.5V is applied to the device, the anode of the device generates oxygen evolution reaction, and the cathode generates oxygen consumption reaction. The consumption volume of the device is 30L, the concentration time curve of oxygen in the sealed box is shown in the accompanying figure 25, the current-voltage curve is shown in the accompanying figure 26, the current density of the oxygen consumption/generation device can reach 40mA cm ^-2, the effective working area oxygen consumption rate of the cathode 9cm ² can reach 31.3cm ³/h, the oxygen consumption efficiency can reach 88%, and the oxygen generation rate of the anode per square centimeter is 3.2cm ³/h.

Application example 4

The anode of the oxygen consumption/oxygen generation device in the application example is connected with moist steam in a circulating environment, the current collector uses hydrophobic carbon paper 6, the permeability of gas is increased, and the rapid removal of generated water is facilitated. The cavity of the cathode is provided with a certain snake-shaped flow passage. The cathode catalyst is FeNC-900-5h prepared in example 4, the anode catalyst is cobalt-iron hydrotalcite prepared in example 7, the anode catalyst and the cathode catalyst are respectively sprayed on two sides of an anion exchange membrane, and then the anion membrane electrode 1A is finally formed through a hot pressing step. And assembling the cathode and anode and the cathode treated current collector into a device. A schematic of the oxygen consumption/generation device is shown in fig. 27. The polyvinyl alcohol film prepared in example 6 was attached to the anode plate 4B, and specifically, the polyvinyl alcohol film prepared in example 6 was attached to and fixed between the anion membrane electrode 1A and the anode plate 4B, which is not shown in fig. 27.

After the device is assembled, a voltage of 1.5V is applied to the device, the anode of the device generates oxygen evolution reaction, and the cathode generates oxygen consumption reaction. The consumption volume of the device is shown in fig. 28 for the concentration time curve of oxygen in a 30L sealed box, and in fig. 29 for the current-voltage curve. FIG. 28 shows that the effective working area oxygen consumption rate of 9cm ² can reach 92.8cm ³/h, the oxygen consumption efficiency can reach almost 89.2%, and the oxygen generation rate of the anode per square centimeter is 10.1m ³/h. Fig. 29 shows that at a given voltage of 1.5V, the current density of the device can reach 152mA cm ^-2. The water-absorbing aerogel is placed on the cathode for treatment, so that water vapor and moisture in the environment are absorbed, the water vapor and oxygen in the gas in the environment are better contacted with the cathode catalyst, the ORR reaction efficiency is improved, and the hydrophobic carbon paper 6 is placed on the anode, so that water generated by the OER reaction is easy to separate from the surface of the catalyst. The coverage of the generated water on the surface of the catalyst is reduced, the active site of the anode catalyst is effectively increased, the reaction efficiency of the cathode ORR is increased, the overall current density of the device is improved, and the oxygen consumption rate of the oxygen consumption/oxygen generation device is improved.

Application example 5

An oxygen-deficient fresh-keeping bin comprising a cation exchange membrane oxygen migration device, wherein an oxygen consumption/generation component with a water absorption membrane is arranged on the inner wall of the fresh-keeping bin of the refrigerator.

The cavity of the oxygen-deficient fresh-keeping bin is used for placing objects to be kept fresh.

The oxygen consuming/generating component comprises: the SA/PAA/PVA composite aerogel film prepared in the embodiment 6 is specifically attached to the outer surface of the cation exchange membrane.

In this embodiment, the catalyst used for the cathode is platinum carbon, the catalyst used for the anode is oxidation, and the anode and cathode catalysts are respectively sprayed on two sides of the cation exchange membrane and then subjected to a hot pressing step, so as to finally form the cation membrane electrode 1B.

A schematic of the oxygen consumption/generation device is shown in fig. 30.

The oxygen-consuming cathode comprises: a hollow washer 3 (made of plastic and containing a porous cathode current collector 2), a porous cathode plate 4A (for connection with a power supply), and a cathode cover plate 5A are sequentially arranged from the center of the oxygen consumption/oxygen generation device to the outside of one side and fixed by screws. The cathode cover plate 5A is hollow in the middle, and the cathode is directly exposed to the gas environment to allow gas or water to flow into or out of the oxygen consuming/generating device so that the gas or water reaches the cathode catalyst surface on the cation membrane electrode 1B to react.

The oxygen evolution anode comprises: the hollow gasket 3 (in which a water absorbing film, namely SA/PAA/PVA composite aerogel film is arranged), the porous anode plate 4B (used for connecting with a power supply) and the hollow anode cover plate 5B are arranged in sequence from the center of the oxygen consumption/oxygen generation device to the outside of the other side through screws. The hollow anode cover plate 5B allows gas or water to be introduced into the oxygen consuming/generating device, adsorbed by the water absorbing film and reaching the anode catalyst surface on the cation membrane electrode 1B for reaction.

A cation membrane electrode 1B is arranged between the oxygen consumption cathode and the oxygen evolution anode.

The oxygen consumption/oxygen generation device adopts a mode that the anode is introduced with circulated gas with certain humidity (80% humidity). After the device is assembled, a voltage of 1.5V is applied to the device, the anode of the device generates oxygen evolution reaction, and the cathode generates oxygen consumption reaction. The consumption volume of the device is 30L, the concentration time curve of oxygen in the sealed box is shown in fig. 31, and the current-voltage curve is shown in fig. 32.

FIG. 31 shows that the volume concentration of oxygen in the seal box was reduced from 21% to about 15% after 1900 minutes of operation of the device at a given voltage of 1.5V. FIG. 32 shows that the current density of the oxygen consuming/generating device can reach 75mA cm ^-2 given a voltage of 1.5V.

The water absorption film is added to the anode, so that the effect of absorbing water vapor in air can be effectively achieved, even if gas with certain humidity in the environment is utilized, OER and ORR can be promoted to occur, water leakage and inconvenience in use caused by adding circulating water can be reduced, and the anode is filled with the gas with certain humidity, so that oxygen generated by the anode is easier to discharge, the anode catalyst is not easy to cover, active sites of the anode catalyst are increased, and the overall current density of the device under the voltage of 1.5V is obviously improved.

Comparative example 1

The water-absorbing film in application example 5 was removed, and the other conditions were unchanged, and an experiment was performed. After the device is assembled, a voltage of 1.5V is applied to the device, the anode of the device generates oxygen evolution reaction, and the cathode generates oxygen consumption reaction. The consumption volume of the device is 30L, the concentration time curve of oxygen in the sealed box is shown in fig. 33, and the current-voltage curve is shown in fig. 34.

FIG. 33 shows that at a given voltage of 1.5V, the volume concentration of oxygen in the sealed box is reduced from 21% to about 15% after 2050 minutes of operation of the device. As can be seen from fig. 34, at a given voltage of 1.5V, the current density of the device can reach 65mA cm ^-2, indicating that the anode of the device can achieve a certain oxygen consumption effect even without using a water absorbing film, but the device performance is reduced compared to application example 5, because the anode lacks the water absorbing film to effectively capture the moisture, resulting in coverage of the active site affecting the device performance.

Application example 6

This application example 6 provides an oxygen-deficient fresh-keeping storehouse of oxygen migration apparatus that contains water absorption film, install the oxygen migration apparatus that has water absorption film on the inner wall of fresh-keeping storehouse of refrigerator.

The oxygen migration apparatus includes: the ionic water absorbing film has oxygen consuming cathode catalyst and oxygen evolving anode catalyst supported separately on two sides to form oxygen consuming cathode and oxygen evolving anode.

A schematic of the oxygen consumption/generation device is shown in fig. 35.

The oxygen-consuming cathode comprises: a hollow washer 3 and a porous cathode plate 4A are arranged from the center of the oxygen consumption/oxygen generation device to the outside of one side in sequence. The oxygen evolution anode comprises: a hollow gasket 3 (in which an ion-conducting water-absorbing film is arranged) and a porous anode plate 4B are arranged in sequence from the center of the oxygen consumption/oxygen generation device to the outside of the other side. The porous cathode plate 4A and the porous anode plate 4B allow gas or water to pass through so as to be adsorbed by the water absorbing film and reach the anode catalyst and the cathode catalyst surface to react.

This example is merely illustrative: for example, the fresh-keeping bin is arranged into a double-layer structure and comprises an inner wall and an outer wall, and a cavity is formed between the inner wall and the outer wall. The oxygen migration device is arranged on the notch of the inner wall, the oxygen migration device is basically parallel to the plane where the side wall of the inner layer of the fresh-keeping bin is positioned, one side of the oxygen consumption cathode faces the cavity of the oxygen-deficient fresh-keeping bin, and one side of the oxygen separation anode faces the space between the inner wall and the outer wall to form a cavity. At this time, the cavity inside the oxygen-deficient fresh-keeping bin is used as the first space. And a second space is formed between the outer wall of the oxygen-deficient fresh-keeping bin and the oxygen-evolving anode. The oxygen consuming/generating component and its outer first and second spaces, the power source, form the oxygen transfer device in this embodiment. The first space and the second space are isolated from each other.

Fig. 36 is a schematic view showing another structure of the oxygen consuming/generating device of the present application example. The anode catalyst and the cathode catalyst are respectively loaded on the porous current collector 2 and then are pressed onto the ion-conducting water absorption film from two sides to form an oxygen consumption cathode and an oxygen evolution anode.

Claims

1. An oxygen consumption/generation device having a water absorbing film, the oxygen consumption/generation device comprising:

the anode catalyst comprises one or more of nickel-iron hydrotalcite, cobalt-iron hydrotalcite, iridium hydroxide and iridium oxide;

The cathode catalyst comprises one or more of nitrogen-doped carbon and platinum carbon, wherein the nitrogen-doped carbon is an iron-nitrogen co-doped carbon material FeNC-900-Nh which is of a two-dimensional lamellar structure, iron is in a single-atom dispersion state, nitrogen exists in a form comprising pyridine nitrogen and graphite nitrogen, and the BET specific surface area of the iron-nitrogen co-doped carbon material is 750-880 m ²/g;

The membrane is a cation exchange membrane or an anion exchange membrane, two sides of the cation exchange membrane or the anion exchange membrane are respectively contacted with a cathode catalyst and an anode catalyst, and the surface of the anode catalyst is provided with a water absorption membrane; the water absorbing film comprises: one or more of organic film and inorganic film; wherein the organic film is selected from one or more of sodium alginate film, polyvinyl alcohol film, sodium polyacrylate film, sodium alginate/polyacrylic acid/polyvinyl alcohol composite aerogel film or nano cellulose-based hydrogel film; the inorganic film is one or more selected from potassium titanate fiber film, sodium titanate fiber film and glass fiber film;

Or the membrane is an ion-conducting water absorbing membrane, the ion-conducting water absorbing membrane is a water absorbing membrane containing ion-conducting substances, and the ion-conducting substances comprise: sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate or potassium bicarbonate, and the cathode catalyst and the anode catalyst are respectively contacted with two sides of the ion-conductive water absorbing film.

2. The oxygen consumption/generation device according to claim 1, wherein the iridium hydroxide comprises trivalent iridium.

3. An oxygen migration apparatus having a water absorbing film, characterized in that the oxygen migration apparatus comprises:

A first space and a second space isolated from each other, and the oxygen consuming/generating device of claim 1 disposed between the first space and the second space;

the oxygen migration device also comprises a power supply for applying voltages to the two ends of the oxygen consumption cathode and the oxygen evolution anode, and the voltage applied to the two ends of the oxygen consumption cathode and the oxygen evolution anode by the oxygen migration device is 0.3-10V;

4. An oxygen migration apparatus according to claim 3, wherein at least one of the first space and the second space is sealed.

5. The oxygen transfer device according to claim 3, wherein when the membrane is a cation exchange membrane or an anion exchange membrane, in the oxygen consumption/generation device, the cathode catalyst is supported on the cation exchange membrane or the anion exchange membrane in a spray hot pressing manner to form a membrane electrode; or the cathode and anode catalysts are loaded on the porous material current collector, and then the current collector is clung to the cation exchange membrane or the anion exchange membrane.

6. An oxygen-deficient fresh-keeping bin or aerator, which comprises the oxygen consumption/generation device according to claim 1 or the oxygen migration device according to claim 3.

7. Use of an oxygen consumption/generation device according to claim 1, wherein the oxygen consumption/generation device is used in an environment where oxygen consumption, oxygen concentration reduction, or in an environment where oxygen production, oxygen concentration increase is required.

8. Use of an oxygen transfer device according to claim 3, in an environment where oxygen is to be consumed, where the oxygen concentration is to be reduced, or in an environment where oxygen is to be produced, where the oxygen concentration is to be increased.

9. An oxygen migration method, characterized in that an oxygen consumption cathode of the oxygen consumption/generation device according to claim 1 is placed in an environment where the concentration of oxygen needs to be reduced, an oxygen-evolving anode is communicated with the outside, so that a first space and a second space in the environment are isolated from each other at least by means of the oxygen consumption/generation device, the oxygen consumption cathode is contacted with a gas containing oxygen in the first space, and the oxygen-evolving anode is contacted with water, steam or a gas with the humidity of 20% -100% in the second space;

then, the oxygen consumption/generating device is started to work, namely, the migration of oxygen from the first space to the second space is realized, so that the oxygen concentration in the first space is reduced.

10. An oxygen migration method, characterized in that an oxygen-evolving anode of the oxygen-consuming/generating device according to claim 1 is placed in an environment where an oxygen concentration needs to be increased, and an oxygen-consuming cathode is communicated with the outside, so that a first space and a second space in the environment are isolated from each other at least by means of the oxygen-consuming/generating device, the oxygen-consuming cathode is in contact with a gas containing oxygen in the first space, and the oxygen-evolving anode is in contact with water, water vapor or a gas with a humidity of 20% -100% in the second space;

Then, the oxygen consuming/generating device is activated to effect migration of oxygen from the first space to the second space such that the oxygen concentration in the second space is increased.