阅读说明：本技术 一种用于二氧化碳电解的电解池结构 (Electrolytic cell structure for carbon dioxide electrolysis ) 是由 谢佳芳 赵全保 郑煜铭 俞汉青 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种用于二氧化碳电解的电解池结构,包括中空筒状多孔催化阴极,保水层,分离膜和柱状多孔阳极,上述中空筒状多孔催化阴极上开设有纵向孔道和横向孔道,所述柱状多孔阳极位于所述中空筒状多孔催化阴极的中空结构内设置,所述分离膜分布于所述中空筒状多孔催化阴极和所述柱状多孔阳极之间,所述保水层则设置于所述中空筒状多孔催化阴极和所述分离膜之间。本发明电解池结构简单,二氧化碳的供给速度高、量大,成本可控,电解性能的稳定性好,操作简便。(The invention discloses an electrolytic cell structure for carbon dioxide electrolysis, which comprises a hollow cylindrical porous catalytic cathode, a water retention layer, a separation membrane and a cylindrical porous anode, wherein the hollow cylindrical porous catalytic cathode is provided with longitudinal pore channels and transverse pore channels, the cylindrical porous anode is positioned in the hollow structure of the hollow cylindrical porous catalytic cathode, the separation membrane is distributed between the hollow cylindrical porous catalytic cathode and the cylindrical porous anode, and the water retention layer is arranged between the hollow cylindrical porous catalytic cathode and the separation membrane. The electrolytic cell has the advantages of simple structure, high carbon dioxide supply speed, large amount, controllable cost, good stability of electrolytic performance and simple and convenient operation.)

1. The utility model provides an electrolytic cell structure for carbon dioxide electrolysis, a serial communication port, including the porous catalytic cathode of cavity tube-shape, water retaining layer, separating membrane and the porous anode of column, longitudinal duct and horizontal duct have been seted up on the porous catalytic cathode of above-mentioned cavity tube-shape, the porous anode of column, separating membrane and water retaining layer all are located set up in the hollow structure of the porous catalytic cathode of cavity tube-shape, the separating membrane distribute in the porous catalytic cathode of cavity tube-shape with between the porous anode of column, water retaining layer then set up in the porous catalytic cathode of cavity tube-shape with between the separating membrane.

2. The electrolytic cell structure for carbon dioxide electrolysis according to claim 1, wherein said hollow cylindrical porous catalytic cathode or said cylindrical porous anode is a metal or an electrically conductive non-metal.

3. An electrolytic cell structure for carbon dioxide electrolysis according to claim 1, wherein said cylindrical porous anode is a cylindrical porous anode.

4. The electrolytic cell structure for carbon dioxide electrolysis according to claim 1, wherein the water retaining layer is made of acid and alkali resistant inorganic or organic materials such as non-woven fabric, glass fiber paper, polyacrylonitrile, etc.

5. The electrolytic cell structure for carbon dioxide electrolysis according to claim 1, wherein the outer surface of the side of the hollow cylindrical porous catalytic cathode has a hydrophobic layer.

6. The electrolytic cell structure for carbon dioxide electrolysis according to claim 1, further comprising a gas-liquid separator in communication with said hollow cylindrical porous catalytic cathode.

7. An electrolytic cell structure for carbon dioxide electrolysis according to claim 1, wherein anolyte is disposed between said cylindrical porous anode and said separation membrane, and catholyte is disposed between said hollow cylindrical porous catalytic cathode and said separation membrane.

8. An electrolytic cell structure for carbon dioxide electrolysis according to claim 7 wherein the water retention layer is capable of holding catholyte above room temperature.

Technical Field

The invention belongs to the technical field of carbon dioxide electrochemistry, and particularly relates to an electrolytic cell structure for carbon dioxide electrolysis.

Background

The method for producing carbon-based chemicals and fuels by driving electrochemical carbon dioxide reduction by using the valley electricity or the waste electricity can improve the energy utilization efficiency, reduce the carbon dioxide, replace the traditional petrochemical production, decouple the economic development from the fossil resources and realize a feasible strategy of sustainable human development.

The conventional electrochemical carbon dioxide reduction reaction takes place on the surface of the cathode in an H-type electrolytic cell, the cathode reacting with carbon dioxide molecules dissolved in water. The reaction current is therefore limited by the solubility of carbon dioxide gas in water. At present, the improvement of the H-type electrolytic cell is mainly a plate-type fluid electrolytic cell. There is a document (Science 2018,360,783) that uses a plate-type fluid electrolytic cell to adapt a gas diffusion layer-based cathode to separate a carbon dioxide gas flow layer and a catholyte flow layer in a cathode chamber, thereby realizing direct supply of a large amount of carbon dioxide gas to a catalyst instead of transferring to the catalyst surface by catholyte dissolution, thereby realizing high-concentration carbon dioxide supply and rapid mass transfer, and thus realizing large-current carbon dioxide electrolysis. Plate fluid electrolyzers, although capable of high current carbon dioxide electrolysis, rely heavily on gas diffusion layers. However, the existing commercial gas diffusion layer is expensive, and the hydrophobicity of the existing commercial gas diffusion layer is difficult to maintain under the condition of large-current electrolysis, so that the plane where the catalyst is located is completely submerged by the catholyte, the carbon dioxide electrolysis performance is reduced, the hydrogen evolution competition is enhanced, and the actual application requirements cannot be met.

Therefore, there is a need to develop new electrolytic cell structures that improve carbon dioxide mass transfer rates and electrolysis current.

Disclosure of Invention

In order to solve the above technical problems, an object of the present invention is to provide an electrolytic cell structure for carbon dioxide electrolysis.

The invention is realized by the following technical scheme: the utility model provides an electrolytic cell structure for carbon dioxide electrolysis, includes the porous catalytic cathode of cavity tube-shape, protects the water layer, and separating membrane and the porous anode of column have seted up longitudinal duct and transverse duct on the porous catalytic cathode of above-mentioned cavity tube-shape, the porous anode of column, separating membrane and water layer all are located set up in the hollow structure of the porous catalytic cathode of cavity tube-shape, the separating membrane distribute in the porous catalytic cathode of cavity tube-shape with between the porous anode of column, water layer then set up in the porous catalytic cathode of cavity tube-shape with between the separating membrane.

Preferably, the hollow cylindrical porous catalytic cathode or the cylindrical porous anode is a metal or a conductive nonmetal.

Preferably, the cylindrical porous anode is a cylindrical porous anode.

Preferably, the water retention layer is made of acid and alkali resistant inorganic or organic materials such as non-woven fabrics, glass fiber paper, polyacrylonitrile and the like.

Preferably, the outer surface of the side surface of the hollow cylindrical porous catalytic cathode is provided with a hydrophobic layer.

Preferably, the device further comprises a gas-liquid separator, and the gas-liquid separator is communicated with the hollow cylindrical porous catalytic cathode.

Preferably, anolyte is placed between the cylindrical porous anode and the separation membrane, and catholyte is placed between the hollow cylindrical porous catalytic cathode and the separation membrane.

Preferably, the water retaining layer can contain catholyte which is higher than room temperature.

Compared with the existing carbon dioxide electrolytic cell structure, the electrolytic cell structure has the following beneficial effects:

firstly, the electrolytic cell has simple structure, high carbon dioxide supply speed and large amount, and particularly compared with the traditional H-shaped electrolytic cell, the electrolytic cell can directly supply gaseous carbon dioxide to a plurality of pore passages of catalytic sites, and the mass transfer speed is far higher than the diffusion speed in a liquid phase, so that the electrolytic current of the carbon dioxide can be improved; compared with a plate type electrolytic cell in which a catalyst is coated on a gas diffusion layer to form a thin layer, the invention constructs the three-dimensional hollow cylindrical porous catalytic cathode, and the catalyst is not only distributed on an interface contacted with catholyte, so that the carbon dioxide electrolysis current can be improved based on richer catalytic sites.

Secondly, the electrolytic cell has good stability of electrolytic performance, and particularly compared with a plate type electrolytic cell, the invention constructs a three-dimensional hollow cylindrical porous catalytic cathode, performs carbon dioxide reaction in a plurality of channels based on catalytic sites distributed on a three-dimensional metal or conductive non-metal framework, performs gas-liquid separation based on a hydrophobic layer on the outer surface, and adjusts the vapor pressure of a cathode liquid layer by combining a water retention layer, thereby improving the stability of the electrolytic performance of the carbon dioxide.

Thirdly, the electrolytic cell of the present invention has controllable cost and simple operation, does not need to use expensive commercial gas diffusion layers, and the used carbon dioxide gas can be recycled, which can control the performance of carbon dioxide electrolysis through simple pressure and temperature regulation.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a front view of the construction of an electrolytic cell for carbon dioxide electrolysis of the present invention.

Fig. 2 is a top view of the structure of the electrolytic cell for carbon dioxide electrolysis of the present invention.

FIG. 3 is a flow chart of a preparation method of the cathode of the bamboo-wood based gas diffusion catalytic electrode.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

Referring to the accompanying drawings 1 and 2 in the specification, an electrolytic cell structure for carbon dioxide electrolysis comprises an electrolytic cell for carbon dioxide electrolysis, and comprises a hollow cylindrical porous catalytic cathode 1, a water retention layer 2, a separation membrane 3 and a cylindrical porous anode 4, wherein a large number of longitudinal channels and transverse channels are arranged in the hollow cylindrical porous catalytic cathode 1, metal catalytic sites are loaded in the channels, the outer surface of the side surface of the porous catalytic cathode is hydrophobic, and the hollow cylindrical porous catalytic cathode 1 is made of metal or conductive nonmetal; preferably, the columnar porous anode 4 is a cylindrical porous anode. The columnar porous anode 4 is positioned in the hollow structure of the hollow cylindrical porous catalytic cathode 1, catalytic sites are uniformly distributed on the inner surface and the outer surface of the columnar porous anode 4, so that the reaction active area is increased, and the columnar porous anode 4 is made of metal or conductive nonmetal; the separation membrane 3 is distributed between the hollow cylindrical porous catalytic cathode 1 and the cylindrical porous anode 4, wherein anolyte is placed between the cylindrical porous anode 4 and the separation membrane 3, catholyte is placed between the hollow cylindrical porous catalytic cathode 1 and the separation membrane, and anolyte enters the electrolytic cell from the inner bottom of the ring, fully infiltrates the anode and leaves the electrolytic cell from the inner top of the ring; keep water layer 2 then sets up between cavity tube-shape porous catalysis negative pole 1 and separating membrane 3, contain the catholyte in this water layer 2 of keeping, and then through the horizontal pore of negative pole to the porous catalysis negative pole 1 transmission gaseous state hydrone of cavity tube-shape, of course, this water layer 2 of keeping also can hold the catholyte that is higher than the room temperature, and then supply with the volume of gaseous state water through the regulation and control negative pole of regulation and control temperature developments, above-mentioned controllable temperature's catholyte gets into the electrolytic bath from the bottom, leave the electrolytic bath from the top, and through the horizontal pore of negative pole to negative pole transmission gaseous state hydrone, wherein, the material of this water layer of keeping is non-woven fabrics, glass fiber paper, inorganic or organic material of acid and alkali resistance such as polyacrylonitrile.

Furthermore, the electrolytic cell also comprises a gas-liquid separator, and the gas-liquid separator can be used at minus 10 to 30 ℃, so that the liquid in the outlet gas from the cathode can be rapidly cooled and separated. When the electrolytic cell is used for carbon dioxide electrolysis, gaseous carbon dioxide enters from the bottom of the hollow cylindrical porous catalytic cathode 1, reacts through the longitudinal pore channels and the transverse pore channels, is mixed with product gas, leaves from the top of the hollow cylindrical porous catalytic cathode 1, can be collected and detected by specific gas components after passing through the gas-liquid separator, and can also return to the cathode for secondary reaction, and liquid products drop to the bottom of the catalytic cathode and leave the cathode for collection and detection. Wherein the gaseous carbon dioxide can be pure and dry carbon dioxide, pure and wet carbon dioxide, dry carbon dioxide containing inert gas components or wet carbon dioxide containing inert gas components, which can achieve the purpose of carbon dioxide electrolysis of the invention. The electrolytic cell of the present invention is suitable for carbon dioxide electrolysis in both gas and liquid phases, and can be used either at atmospheric or elevated pressure or at ambient or below 105 ℃.

The invention provides an electrolytic cell for carbon dioxide electrolysis, which is low in cost and improves the electrolysis performance, in the electrolytic cell, a gas diffusion component is a three-dimensional ring porous column shape and has rich longitudinal pore channels, the outer wall of the ring is provided with a hydrophobic layer, catalytic sites are distributed in a porous structure in the ring body, and carbon dioxide enters the gas diffusion component from the longitudinal pore channels and reacts at the catalytic sites, so that the mass supply of the carbon dioxide is ensured, and the carbon dioxide is stably separated from catholyte.

The electrolytic cell structure can be prepared by using a metal material for the cathode and the anode, and can also be prepared by using a conductive non-metal material, for example, the hollow cylindrical porous catalytic cathode 1 is made of a conductive non-metal material, and the hollow cylindrical porous catalytic cathode 1 can obtain good electrical property by using a bamboo-based gas diffusion catalytic electrode. Referring to the attached figure 3, the preparation method of the bamboo-wood-based gas diffusion catalytic electrode comprises the following steps:

the method comprises the following steps: dissolving metal salt in water, fully immersing the bamboo and wood materials, taking out, and heating at low temperature to remove water to obtain a bamboo and wood precursor; preferably, the metal solution residue on the outer surface of the bamboo material after the bamboo material is taken out of the metal salt solution and then is removed after impregnation, so that the metal loading capacity on the outer surface of the bamboo material can be prevented from being too high. In the catalytic electrode, the thickness of the bamboo and wood raw material is 1-4 cm, and when the thickness is too low, the reaction area is small, so that the increase of electrolytic current is not facilitated; when the thickness is too high, the transverse mass transfer speed limits the reaction speed of the outer area; in addition, the bamboo and wood raw materials can be transversely cut to form a hollow annular columnar structure, and can also be continuously vertically cut to form a thick sheet structure, and the structure can be used as the bamboo and wood material.

The adding mass ratio of the metal salt to the bamboo material is 1: 1000-1: 10, and the time for soaking the bamboo material in the metal salt solution is 10 min-12 h; by simultaneously controlling the addition amount and the dipping time of the metal salt, the depth and the quantity of the metal salt adsorbed on the inner surface of the bamboo and wood biomass pore canal can be more accurately regulated and controlled. The metal substances in the metal salt are selected from gold, palladium, platinum, copper, zinc, tin, selenium, iron, nickel and cobalt, the salt substances in the metal salt are selected from one of nitrate, chloride and acid salt, and the salt has good water solubility and low cost.

And taking out the bamboo after impregnation, placing the bamboo between 353K and 423K, and heating at low temperature to obtain a bamboo precursor material, wherein the aim of low-temperature heating is mainly to remove redundant water so that the subsequent bamboo material is uniformly heated. When the reaction temperature is too low, too much water remains in the bamboo and wood material cells, and the subsequent material synthesis steps are influenced; when the reaction temperature is too high, the bamboo and wood materials begin to be carbonized, which is not beneficial to controlling the metal loading position.

Step two: and (3) heating the bamboo wood precursor prepared in the step one in an ammonia atmosphere to react to obtain the bamboo wood matrix biomass material.

The heating reaction conditions are as follows: heating to 523-673K at the speed of 2-10K/min, reacting at constant temperature for 10-12 min, continuing heating to 873-1373K, keeping the temperature for 10-2 min, and cooling to room temperature. If the heating speed is too low, the reaction time and energy consumption can be increased, if the heating speed is too high, the pore structure in the bamboo precursor material can be seriously damaged, and meanwhile, if the temperature is directly raised to the required temperature at one time, the metal size is not uniform, so that the catalytic activity and selectivity of the final material are influenced, and the adjustment and control of the heating reaction condition are very necessary.

Preferably, the temperature is reduced to 573K at the speed of 2-10K/min, then the catalyst electrode is naturally cooled to room temperature, and the pore channel structure of the catalyst electrode obtained under the condition is more complete.

Step three: and (4) performing hydrophobic treatment on the bamboo-wood-based biomass material prepared in the step two to obtain the bamboo-wood-based gas diffusion catalytic electrode. The hydrophobization treatment can be performed by vapor deposition or a brush coating method, in addition to immersion in a solution.

Preferably, the hydrophobicizing material is selected from polytetrafluoroethylene, expanded polytetrafluoroethylene, polyvinylidene fluoride, fluorinated polyethylene, polystyrene, ethylene-tetrafluoroethylene copolymer, meltable polytetrafluoroethylene, perfluorodecyltrichlorosilane.

The bamboo-wood-based gas diffusion catalytic electrode comprises bamboo-wood-based biomass, a metal or nonmetal catalytic active component and a hydrophobic component, wherein a plurality of mass transfer channels are arranged in the bamboo-wood-based biomass, the loading capacity of the metal is 0.1% -5%, the size of the metal is 0.1-100 nm, and when the loading capacity of the metal is too low, the upper limit of current is insufficient; when the metal loading is too high, competitive hydrogen evolution occurs primarily.

The preparation method of the bamboo-wood-based gas diffusion catalytic electrode provided in the application example is simple, can be carried out under normal pressure, has rich raw material sources, is easy for large-scale preparation, has wide application prospect, and is beneficial to solving the problems of economic development and living environment faced at present. In addition, the bamboo-wood-based gas diffusion catalytic electrode can supply gaseous CO by utilizing the pore structure in the bamboo wood and using the pore structure as a gas diffusion layer for the electrochemical reduction reaction of carbon dioxide₂And enriching reaction intermediate products, thereby realizing large-current carbon dioxide electrolysis. The bamboo-wood-based gas diffusion catalytic electrode provided in the application example is prepared by taking bamboo-wood biomass as a main material body, performing surface functionalization treatment on the bamboo-wood biomass to make the bamboo-wood biomass hydrophobic, and catalyzing electricity through gas diffusionIn the electrocatalytic carbon dioxide reduction reaction, the porous channel structure of bamboo can be utilized to perform sufficient mass transfer of carbon dioxide gas, so that the limitations of low solubility and slow mass transfer of carbon dioxide in water are broken, and the reaction intermediate product can be enriched based on a limited pore channel, wherein in the application of the electrocatalytic bamboo-wood-based gas diffusion catalytic electrode, the reaction can be performed in a water phase or a gas phase containing water vapor, and the electrolytic current of carbon dioxide can reach 50-500 mA/cm²。

While the foregoing description shows and describes the preferred embodiments of the present invention, it is to be understood that the invention is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as described herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.