Catalyst for producing methane by reducing carbon dioxide and air capture carbon dioxide-catalytic conversion device thereof

Abstract

The preparation method comprises the following steps: dispersing zirconium-based metal organic framework powder in a solvent, adding a soluble copper salt and a soluble rare earth metal salt, uniformly dispersing, heating until the solvent is volatilized, calcining in an air atmosphere to obtain a zirconium-based metal organic framework catalyst; the catalyst for producing methane through carbon dioxide reduction is obtained. The rare earth metal atoms introduced by the zirconium-based metal organic framework optimize the charge density of the metal copper atoms and change the valence state of the metal copper atoms, so that the methane selectivity and the continuous electrolysis stability of the catalyst under relatively high current density are remarkably improved compared with those of the previous reported catalyst. Besides, capture of carbon dioxide in the air is achieved through conversion of OH <-> / CO3 < 2->, the prepared catalyst for producing methane through reduction of carbon dioxide serves as a cathode material, and direct conversion from carbon dioxide in the air to methane is achieved through the designed carbon dioxide capture-release-conversion coupled device.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide capture and conversion, and particularly relates to a carbon dioxide reduction to methane catalyst and an air-capturing carbon dioxide-catalytic conversion device. Background Art

[0002] The electrochemical reduction reaction of carbon dioxide is a highly promising technology, which is expected to convert carbon dioxide into fuels and chemical raw materials using renewable energy, thereby reducing the dependence on fossil fuels. Among the many products of carbon dioxide reduction, the deeply reduced product methane has attracted much attention due to its high calorific value, easy storability, and good compatibility with existing natural gas infrastructure. However, the reduction of carbon dioxide to methane involves an 8-electron transfer process, and its sluggish reaction kinetics and high reaction overpotential lead to a slow macroscopic reaction rate. Moreover, the competitive hydrogen evolution reaction and complex multi-electron paths seriously hinder the improvement of methane selectivity, greatly restricting the popularization of related technologies.

[0003] To overcome the above challenges, it is necessary to develop high-activity, selective, and durable electrode catalysts to improve the reaction rate and optimize the reaction selectivity. Current research shows that copper-based catalysts are one of the most effective catalysts for achieving deep carbon dioxide reduction. However, most of the products of copper-based nanomaterials prepared by existing technologies for carbon dioxide reduction are carbon monoxide and ethylene, and they face the competitive hydrogen evolution reaction, with low methane selectivity. On the other hand, the reaction gases used in current related research are mostly high-purity carbon dioxide (>99%). High-purity carbon dioxide usually faces high energy consumption and capital investment during the purification and enrichment processes, thus reducing the economic feasibility of the carbon dioxide electrochemical reduction technology. Using electrochemical technology to achieve the coupling of carbon dioxide capture, release, and conversion in air or flue gas will greatly simplify the related process flow, reduce production costs, and at the same time promote the progress and upgrading of related industrial chains. Summary of the Invention

[0004] The technical problems to be solved by the present invention are the problems of poor selectivity and low current density in the process of carbon dioxide reduction to methane by existing copper-based catalysts, and the direct capture and utilization of carbon dioxide in air / flue gas.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0006] A preparation method of a carbon dioxide reduction to methane catalyst, comprising the following steps:

[0007] Provide zirconium-based metal-organic framework powder, soluble copper salt, soluble rare earth metal salt, and solvent;

[0008] Disperse the zirconium-based metal-organic framework powder in the solvent, add the soluble copper salt and the soluble rare earth metal salt, stir and then heat until the solvent evaporates, and calcine in an air atmosphere to obtain a catalyst for reducing carbon dioxide to methane; wherein, the ratio of the zirconium-based metal-organic framework powder, the soluble copper salt, and the soluble rare earth metal salt is 100 mg: 0.025 - 0.1 mmol: 0.00125 - 0.03 mmol; the calcination temperature is 150 - 250 °C; the pore size of the catalyst is 0.5 - 2 nm; zirconium atoms, copper atoms, and rare earth metal atoms in the catalyst are atomically uniformly dispersed.

[0009] In order to obtain a catalyst with selectivity and high activity for reducing carbon dioxide to methane in the present invention, a catalyst of copper-rare earth metal bimetal supported on a zirconium-based metal framework is prepared. Metal-organic frameworks (MOFs) are a class of novel organic-inorganic hybrid crystalline materials formed by the self-assembly of metal ions and organic ligands through coordination bonds. The zirconium-based metal-organic framework powder in this application is the UiO (University of Oslo) series of zirconium-based metal-organic frameworks. The UiO series of metal-organic frameworks are formed by connecting zirconium ions and terephthalic acid-based organic ligands (i.e., using terephthalic acid and its derivatives as organic ligands) through coordination bonds to form a three-dimensional network structure, which has the following advantages: it has a large surface area and adjustable pore size; its crystal structure is stable and can withstand a high temperature of 500 °C; the framework structure can withstand a certain mechanical pressure; it remains structurally stable in various solutions and has strong acid and alkali resistance. Due to its unique structure and properties, the UiO series of metal-organic frameworks have broad application prospects in the fields of gas adsorption, separation, storage, catalysis, etc. Importantly, when the UiO series of metal-organic frameworks are used as catalyst carriers, their porous structure is conducive to anchoring a large number of active sites and improving the catalytic efficiency. Therefore, in the present invention, UiO powder is used as the carrier of active sites, which is relatively small in size, only about nanoscale, and there are abundant pores. The pore size of the zirconium-based metal-organic framework powder is 0.5 - 2 nm. After loading copper atoms and rare earth metal atoms, the pore size range of the catalyst is still 0.5 - 2 nm at a calcination temperature of 150 - 250 °C. The small pore size and abundant pores expose more edge sites of the zirconium-based metal-organic framework powder. Inevitably, there are zirconium ion vacancies or defects, and these defects can serve as the anchoring sites for copper atoms and rare earth metal atoms. Under the action of stirring, copper ions and rare earth metal ions in the solvent shuttle in the pores or on the surface of the zirconium-based metal-organic framework particles. When they shuttle to the defect sites, they will be captured and coordinated by formate groups, and thus are embedded into the framework of the zirconium-based metal-organic framework powder.

[0010] Methane production by carbon dioxide reduction is an eight-electron transfer process, accompanied by the coupling of eight protons. The reaction process is as follows:

[0011] CO 2 →*COOH→*CO→*CHO→*CHOH→*CH 2 OH→*CH 2 →*CH 3 →CH 4 (Reaction 1).

[0012] Among them, *CO is the key intermediate of the reaction. If the adsorption strength of *CO is weak, it will lead to the premature desorption of CO, causing the reaction to terminate after two electrons are transferred, and the product becomes a two-electron product CO, making it difficult to achieve the deep reduction of CO 2 and reducing the selectivity of methane. Therefore, the reaction process of competing reaction 1 is as follows:

[0013] CO 2 →*COOH→*CO→CO (competing reaction 1).

[0014] In addition, if the distance between two *CO intermediates is relatively close, carbon-carbon coupling may occur to form a *COCO (*CO + *CO) intermediate, and the reaction path changes from a single-carbon product to a multi-carbon product such as ethylene, which will also reduce the selectivity of methane. Therefore, the reaction process of competing reaction 2 is as follows:

[0015] CO 2 →*COOH→*CO→*COCO→ multi-carbon products such as ethylene (competing reaction 2).

[0016] On the other hand, since the electrocatalytic carbon dioxide reduction reaction is usually carried out in an alkaline or neutral electrolyte, protons come from water molecules in the electrolyte. (H 2 O→*OH + *H, reaction 2) During the conversion of a single carbon dioxide molecule into a methane molecule, the coupling of eight protons is accompanied. If the dissociation rate of water molecules is too slow, it will affect the proton coupling process, so it is also not conducive to the formation of methane.

[0017] To address the above challenges, the present invention simultaneously introduces copper atoms and rare earth metal atoms on the UiO support. Among them, copper atoms serve as the active sites for the carbon dioxide reduction reaction, while rare earth metal atoms affect the intrinsic activity of neighboring copper atoms through electronic interactions, etc., in order to achieve high performance in methane production by carbon dioxide reduction. The introduction of rare earth metal atoms plays the following roles:

[0018] (1) In terms of the synthesis of the catalyst, due to the relatively large atomic radius of rare earth metal atoms, which is larger than that of zirconium atoms and copper atoms, after they are embedded in the metal-organic framework, it will cause the distortion of the framework, generating more defect sites, which is beneficial to anchoring copper atoms;

[0019] (2) In terms of electronic structure, the electronegativity of rare earth metal atoms is lower than that of copper atoms, and they can easily act as electron donors. Therefore, adjacent rare earth metal atoms will contribute electrons to the copper sites. When the electron density of copper atoms increases, the number of d-orbital electrons available for bonding increases, and the d-band center rises, which is beneficial to the adsorption and activation of carbon dioxide molecules (CO 2 →*COOH). More importantly, the increase in the number of bonding electrons will strengthen the bonding strength between the metal sites and the key intermediate *CO, enabling it to undergo deep reduction. Therefore, competitive reaction 1 is inhibited, and reaction 1 is promoted, thus facilitating the formation of methane products;

[0020] (3) In addition to electronic structure regulation, rare earth metal atoms can also act as auxiliary sites to assist in the conversion of intermediates at the copper sites. Rare earth metal atoms have an oxygenophilic characteristic and can easily adsorb the oxygen in water molecules, breaking the hydrogen-oxygen bond in water molecules and generating protons, that is, accelerating reaction 2. Eight protons need to be coupled during the process of carbon dioxide reduction to produce methane. The acceleration of proton supply by rare earth metal atoms will lower the energy barrier for methane formation;

[0021] (4) Finally, rare earth metal atoms can also play a role in spatial separation. The radius of rare earth metal atoms is relatively large, which separates adjacent copper sites to a certain extent. Therefore, potential carbon-carbon coupling reactions are blocked, that is, competitive reaction 2 is inhibited, making the reduction products tend to be one-carbon product methane.

[0022] Therefore, through the regulation of the electrons of the rare earth metal atoms and the intermediates as described above, the catalyst prepared in the present invention, which is a zirconium-based metal-organic framework loaded with bimetals, achieves excellent activity and selectivity for the reduction of carbon dioxide to methane. It should be noted that when introducing copper atoms and rare earth metal atoms onto the UiO support, a certain mass ratio should be followed, that is, the mass fraction of copper atoms or the ratio of copper atoms / rare earth metal atoms should be appropriate. Copper atoms serve as the active sites for the carbon dioxide reduction reaction. If the content of copper atoms is low, the number of active sites will be insufficient. When the catalytic current density is large, the limited active sites are difficult to bear such a fast reaction rate, resulting in an increase in the side reaction of hydrogen evolution. On the contrary, if the content of copper atoms is high, copper-based nanoclusters or particles with larger sizes will be formed, and the aggregation of active sites shortens the distance between *CO intermediates and strengthens the interaction, causing the reaction to shift towards carbon-carbon coupling, that is, the direction of competing reaction 2. On the other hand, rare earth metal atoms serve as auxiliary sites. When the content of rare earth metal atoms is low, the limited number of rare earth metal atoms cannot effectively regulate the electronic structure of copper atoms. On the contrary, when its content is high, rare earth metal-based nanoclusters or particles with larger sizes will also be formed. Due to the strong adsorption of rare earth metal atoms to water molecules, these nanoclusters or particles will act as the active sites for the hydrogen evolution reaction, exacerbating the occurrence of side reactions. It can be seen that the dosage of copper salt needs to be reasonably controlled. Too little dosage results in a small number of active sites, and too much dosage causes the aggregation of copper sites during the catalysis process. Rare earth metal elements, as auxiliary sites, regulate the electronic structure and geometric distribution of copper atoms, and the dosage should not be too much, otherwise additional hydrogen evolution reaction sites may be introduced. In this application, the ratio of zirconium-based metal-organic framework powder, soluble copper salt, and soluble rare earth metal salt is 100 mg: 0.025 - 0.1 mmol: 0.00125 - 0.03 mmol, and a more appropriate content of copper atoms and rare earth metal atoms can be obtained. Research shows that when the molar ratio of copper atoms to rare earth metal atoms in the feed ratio is 10:1, the performance of reducing carbon dioxide to methane is the best. Research shows that when the ratio of zirconium-based metal-organic framework powder to soluble copper salt is about 100 mg: 0.05 mmol, the performance of reducing carbon dioxide to methane is better.

[0023] The terephthalic acid-based organic ligand contains a benzene ring structure in the plane. After orderly coordinating with zirconium ions to form a framework, the relatively large size of the benzene ring molecule increases the distance between metal nodes, thus forming pores with a width of up to 0.5 - 2 nm. The presence of pores not only increases the specific surface area of the support but also serves as a channel for the diffusion of reactants, intermediates, and ions in the electrolyte. In particular, during the diffusion process of intermediates (such as *CO) in the pores, they may contact new active sites and undergo subsequent adsorption and transformation.

[0024] For comparison, the present invention also prepared zirconium-based metal-organic framework supported single-metal catalysts, including copper supported on zirconium-based metal-organic framework and rare earth metals supported on zirconium-based metal-organic framework. Among them, copper supported on zirconium-based metal-organic framework also showed certain carbon dioxide reduction performance to produce methane, but the overall activity and selectivity were weaker than those of the zirconium-based metal-organic framework supported bimetallic catalysts, indicating that the introduction of rare earth metals had a certain beneficial effect on the performance; while the rare earth metals supported on zirconium-based metal-organic framework showed extremely poor carbon dioxide reduction selectivity, and the reduction products were mainly hydrogen, which indicated that copper atoms were the active sites for carbon dioxide reduction to produce methane, and the introduced rare earth metals mainly played the role of co-catalysts, improving the intrinsic activity of adjacent copper atoms.

[0025] For comparison, the present invention also prepared a copper-based catalyst modified with rare earth metal atoms without a carrier. The catalyst presented a nanosheet morphology and its main component was a copper-rare earth metal alloy. Without the assistance of a carrier, the active sites of this catalyst could not be effectively dispersed, and the residence time of reaction intermediates on the catalyst surface was short, ultimately affecting its ability to catalyze carbon dioxide reduction to produce methane, and the methane selectivity was very poor.

[0026] Preferably, the zirconium-based metal-organic framework powder is obtained by the following steps:

[0027] Dissolve a zirconium salt and an organic ligand in N,N-dimethylformamide, and after ultrasonic dispersion, drop acetic acid to obtain a suspension; wherein, the zirconium salt includes at least one of zirconium nitrate, zirconium chloride, and zirconium sulfate; the organic ligand includes at least one of terephthalic acid, 2-aminoterephthalic acid, 2-bromoterephthalic acid, and sodium 2-sulfoterephthalate monohydrate;

[0028] Place the suspension in a hydrothermal autoclave and keep it at a preset temperature for a preset time;

[0029] Centrifuge and wash the precipitate in the hydrothermal autoclave, dry and grind it evenly to obtain the zirconium-based metal-organic framework powder.

[0030] Specifically, using a zirconium salt and an organic ligand as raw materials, the zirconium salt is a soluble zirconium salt, and the organic ligand is terephthalic acid and its derivatives. There are substituents on the benzene ring in the terephthalic acid derivatives, such as amino, bromo, or sulfonic acid groups, etc. When selecting the ligand, the present invention studied four ligands: terephthalic acid, 2-aminoterephthalic acid, 2-bromoterephthalic acid, and sodium 2-sulfoterephthalate. Among them, the amino group is an electron-donating group, while the bromo group and the sulfonic acid group are electron-withdrawing groups. In the prepared catalyst, the metal atom coordinates with the formyl group on the benzene ring and is anchored. The above three groups are all located at the ortho position of the formyl group. Therefore, the electronic structure of the active metal site can be regulated through long-range electronic interactions. The amino group donates electrons to the metal site, while the bromo group and the sulfonic acid group dilute the electron density of the metal site. Therefore, the presence of the amino group is also beneficial to inhibiting competitive reaction 1 and promoting methane production.

[0031] Preferably, the overall morphology of the zirconium-based metal-organic framework supported bimetallic catalyst is nanoparticles with a size of about 18 - 50 nm and abundant pores. Copper atoms and rare earth metal atoms coordinate with the terephthalic acid-based organic ligand and are dispersed in the metal-organic framework. The functional groups on the terephthalic acid-based organic ligand have electron-donating or electron-withdrawing characteristics and can regulate the electronic structure of copper atoms through long-range electronic interactions. The rare earth metal atoms have a relatively large atomic radius and an oxygenophilic characteristic, and can also affect the affinity adsorption and desorption ability of the adjacent copper sites for carbon dioxide reduction intermediates. The average particle size of the material used for the catalytic reaction should not be too large. The average size of the zirconium-based metal-organic framework supported bimetallic catalyst can ensure sufficient contact between the catalyst and the electrolyte. The abundant pore structure not only increases the contact area between the active site and the electrolyte, but also is beneficial to regulating the local concentration distribution of reactants and products.

[0032] Preferably, the ratios of the zirconium salt, the organic ligand, the N,N-dimethylformamide, and the acetic acid are 0.6 - 1 mmol: 0.6 - 1 mmol: 30 mL: 2 - 4 mL respectively. The raw materials for synthesizing the metal-organic framework should be appropriate. Too little amount results in less synthesized product, and too much amount leads to aggregation of the product, affecting the dispersibility and morphology. The amount of acetic acid added dropwise is 2 - 4 mL. Too little acetic acid will cause the particle size of the synthesized metal-organic framework to be too large, and too much acetic acid will affect the crystallization of the material and reduce its structural stability.

[0033] Preferably, the preset temperature is 110 - 130 °C, and the preset time is 20 - 30 h. A sufficient reaction time enables the full assembly of the metal-organic framework.

[0034] Preferably, the solvent used for centrifugal washing is a mixed solution of methanol and N,N-dimethylformamide to ensure the removal of excess metal ions or organic ligands.

[0035] Preferably, the drying method is freeze-drying, and the drying time is 6 - 10 h. The freeze-drying method can effectively retain the porous structure of the material and reduce the mutual stacking between the material powders.

[0036] Preferably, the solvent includes at least one of deionized water, methanol, and ethanol.

[0037] Preferably, the ratio of the zirconium-based metal-organic framework powder to the solvent is 100 mg: 4 - 8 mL; too much zirconium-based metal-organic framework powder will lead to uneven dispersion, and too little will result in a small amount of synthesized catalyst.

[0038] Preferably, the heating temperature is 60 - 80 °C.

[0039] Preferably, the calcination temperature is 150 - 250 °C, the heating rate of the calcination is 1 - 3 °C / min -1 , and the heat preservation time of the calcination is 1 - 3 h.

[0040] A catalyst for carbon dioxide reduction to produce methane can be obtained by the above preparation method. The overall morphology of the catalyst for carbon dioxide reduction to produce methane is nanoparticles, with a size of about nanoscale and abundant pores. The mass percentage of copper atoms in the catalyst is 1.42 - 5.96 wt%, and the mass percentage of rare earth metal atoms is 0.14 - 3.58 wt%.

[0041] An application of the catalyst for carbon dioxide reduction to produce methane as described in any one of the above in carbon dioxide reduction to produce methane. The prepared zirconium-based metal-organic framework supported bimetallic catalyst can be used for the electrocatalytic carbon dioxide reduction reaction to produce methane.

[0042] An air capture carbon dioxide-catalytic conversion device includes: a first housing, a cathode, and an anode; the cathode and the anode are both located in the first housing; the cathode is loaded with the catalyst for carbon dioxide reduction to produce methane as described in any one of the above;

[0043] The cathode divides the first housing into a gas channel and a first electrolyte chamber. The gas channel has a carbon dioxide inlet and a methane outlet, and the first electrolyte chamber is filled with an alkali metal bicarbonate solution;

[0044] The anode is located on the side of the first electrolyte chamber away from the cathode.

[0045] Preferably, the first housing has a first window;

[0046] The anode includes:

[0047] A first bipolar membrane, located at the first window;

[0048] An oxygen evolution material layer, located on the side of the first bipolar membrane facing away from the first electrolyte chamber;

[0049] The air capture carbon dioxide-catalytic conversion device further includes:

[0050] A second housing, the second housing having a second window and a third window, the second window corresponding to the first window;

[0051] A second bipolar membrane, an anion exchange membrane, and an oxygen reduction electrode, arranged in sequence within the second housing;

[0052] Wherein, the oxygen reduction electrode is located at the second window;

[0053] A second electrolyte chamber is formed between the first bipolar membrane and the second bipolar membrane, and the second electrolyte chamber is filled with a strong base solution;

[0054] A third electrolyte chamber is formed between the second bipolar membrane and the anion exchange membrane, and the third electrolyte chamber is filled with an alkali metal bicarbonate solution;

[0055] A fourth electrolyte chamber is formed between the anion exchange membrane and the oxygen reduction electrode, and the fourth electrolyte chamber is filled with an alkali metal bicarbonate solution.

[0056] Preferably, the oxygen evolution material layer is a NiFeO x material layer, and the oxygen reduction electrode is a Pt / C electrode; the second housing is provided with an air inlet, and the air inlet communicates with the fourth electrolyte chamber.

[0057] The beneficial effects of the present invention are as follows:

[0058] (1) The catalyst of bimetal supported on zirconium-based metal-organic framework prepared by the present invention has achieved excellent performance in the electrocatalytic reduction of carbon dioxide to produce methane. The prepared zirconium-based metal-organic framework supported copper rare earth metal catalyst shows high carbon dioxide reduction to methane activity and selectivity in an alkaline medium (1 mol / L KOH), and the methane selectivity exceeds 60% in the current range of 300 - 600 mA cm -2 and can reach up to 73% at most. In addition, the zirconium-based metal-organic framework supported copper rare earth metal catalyst can be continuously electrolyzed for 7 h at a current density of 400 mA cm -2 , during which the methane selectivity exceeds 50%. The methane selectivity and continuous electrolysis stability of the catalyst at a relatively large current density are significantly improved compared with the catalysts reported previously.

[0059] (2) Further, using the prepared zirconium-based metal-organic framework supported copper-rare earth metal catalyst as the electrode material, a device for coupling carbon dioxide capture-release-conversion is designed and assembled, which realizes the capture, release, and conversion of carbon dioxide in the air into methane fuel. During the capture-release process, the collection efficiency of carbon dioxide exceeds 60%, and the purity of the collected carbon dioxide exceeds 99%. After being used as the raw material for the carbon dioxide reduction reaction, a methane mixture with a concentration of 28% is obtained. Using renewable electric energy such as solar power generation, this device can achieve the conversion and utilization of carbon dioxide in the atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is the concentration distribution of CO and CO on the surface of the pore-rich catalyst simulated by the finite element method of the present invention; 2 ;

[0061] Figure 2 is the concentration distribution of CO and CO on the surface of the pore-free catalyst simulated by the finite element method of the present invention; 2 ;

[0062] Figure 3 is the comparison of the CO concentration distributions on the surfaces of the pore-rich catalyst and the pore-free catalyst simulated by the finite element method of the present invention;

[0063] Figure 4 is the comparison of the CO 2 concentration distributions on the surfaces of the pore-rich catalyst and the pore-free catalyst simulated by the finite element method of the present invention;

[0064] Figure 5 is the mechanism of deep reduction of CO on the surfaces of the pore-rich catalyst and the pore-free catalyst of the present invention; 2 ;

[0065] Figure 6 is the XRD pattern of the carriers of UiO-NH 2 -CuLa in Example 1, UiO-NH 2 -Cu in Comparative Example 1, UiO-NH 2 -La in Comparative Example 2, and CuLa and UiO-NH 2 in Comparative Example 3;

[0066] Figure 7 is the TEM image of UiO-NH 2 -CuLa (a) in Example 1, UiO-NH 2 -Cu (b) in Comparative Example 1, UiO-NH 2 -La (c) in Comparative Example 2, and CuLa (d) in Comparative Example 3;

[0067] Figure 8 is UiO-NH in Example 1 of the present invention2 - EDS elemental mapping images of CuLa;

[0068] Figure 9 is UiO-NH in Example 1 of the present invention 2 -CuLa, UiO-NH in Comparative Example 1 2 -Cu, UiO-NH in Comparative Example 2 2 -La and UiO-NH 2 Specific surface area distribution of the support;

[0069] Figure 10 is UiO-NH in Example 1 of the present invention 2 -CuLa, UiO-NH in Comparative Example 1 2 -Cu, UiO-NH in Comparative Example 2 2 -La and UiO-NH 2 Pore size distribution of the support;

[0070] Figure 11 is UiO-NH in Example 1 of the present invention 2 -CuLa, UiO-NH in Comparative Example 1 2 -Cu, UiO-NH in Comparative Example 2 2 -La and XPS survey spectra of CuLa in Comparative Example 3;

[0071] Figure 12 is UiO-NH in Example 1 of the present invention 2 -CuLa, UiO-NH in Comparative Example 1 2 -Cu and Cu 2p XPS results of CuLa in Comparative Example 3;

[0072] Figure 13 is UiO-NH in Example 1 of the present invention 2 -CuLa, UiO-NH in Comparative Example 1 2 -Cu, UiO-NH in Comparative Example 2 2 -La and CuLa in Comparative Example 3 for electrocatalytic CO 2 Reduction linear sweep voltammetry curves;

[0073] Figure 14 is UiO-NH in Example 1 of the present invention 2 -CuLa, UiO-NH in Comparative Example 1 2 -Cu, UiO-NH in Comparative Example 2 2 -La and CuLa in Comparative Example 3 for electrocatalytic CO 2 Reduction methane selectivity;

[0074] Figure 15is UiO-NH in Example 1 of the present invention 2 -CuLa, UiO-NH in Comparative Example 1 2 -Cu, UiO-NH in Comparative Example 2 2 -La and CuLa in Comparative Example 3 for electrocatalytic CO 2 reduction electrochemical impedance spectra;

[0075] Figure 16 are the methane selectivities of the catalysts with different copper-to-lanthanum ratios in Example 1, Examples 4 - 6 of the present invention for electrocatalytic CO 2 reduction;

[0076] Figure 17 is UiO-NH in Example 1 of the present invention 2 -CuLa, UiO-NH in Example 2 2 -CuPr and UiO-NH in Example 3 2 -CuCe for electrocatalytic CO 2 reduction methane selectivity;

[0077] Figure 18 is UiO-NH in Comparative Example 1 of the present invention 2 -Cu, UiO-Cu in Comparative Example 4, UiO-SO 3 -Cu and UiO-Br-Cu in Comparative Example 6 for electrocatalytic CO 2 reduction methane selectivity;

[0078] Figure 19 is UiO-NH in Example 1 of the present invention 2 -CuLa for electrocatalytic CO 2 reduction cell voltage and methane partial current density of a two-electrode electrolyzer;

[0079] Figure 20 is UiO-NH in Example 1 of the present invention 2 -CuLa for electrocatalytic CO 2 reduction electrolytic stability of methane production;

[0080] Figure 21 is the structural schematic diagram of the device for coupling carbon dioxide capture - release - conversion based on UiO-NH 2 -CuLa assembled in Example 1 of the present invention;

[0081] Figure 22 is the principle schematic diagram of the device for coupling carbon dioxide capture - release - conversion based on UiO-NH 2 -CuLa assembled in Example 1 of the present invention;

[0082] Figure 23is the collection rate and collection efficiency of carbon dioxide captured and released by the carbon dioxide capture-release-conversion coupling device assembled based on UiO-NH 2 -CuLa in Example 1 of the present invention;

[0083] Figure 24 is the collection rate and collection efficiency of carbon dioxide captured and released by the carbon dioxide capture-release-conversion coupling device assembled based on UiO-NH 2 -CuLa in Example 1 of the present invention for a long time;

[0084] Figure 25 is the capture rate of carbon dioxide in 4L air and the change in the concentration of carbon dioxide in the air by the carbon dioxide capture-release-conversion coupling device assembled based on UiO-NH 2 -CuLa in Example 1 of the present invention;

[0085] Figure 26 is the products and their concentrations obtained during the electrolysis process of the carbon dioxide capture-release-conversion coupling device assembled based on UiO-NH 2 -CuLa in Example 1 of the present invention;

[0086] Figure 27 is the first structural schematic diagram of the carbon dioxide conversion device assembled based on UiO-NH 2 -CuLa in Example 1 of the present invention;

[0087] Figure 28 is the second structural schematic diagram of the carbon dioxide conversion device assembled based on UiO-NH 2 -CuLa in Example 1 of the present invention;

[0088] Figure 29 is the first photo of the carbon dioxide capture-release-conversion coupling device assembled based on UiO-NH 2 -CuLa in Example 1 of the present invention;

[0089] Figure 30 is the second photo of the carbon dioxide capture-release-conversion coupling device assembled based on UiO-NH 2 -CuLa in Example 1 of the present invention. Detailed implementation manners

[0090] In the prior art, an N-heterocyclic carbene-linked copper single-atom site electrocatalyst embedded in a metal-organic framework has been reported. The N-heterocyclic carbene anchors copper atoms through metal-carbon bonds as the active center, optimizing the adsorption of the CHO* intermediate. Experimental tests show that this catalyst achieves a high selectivity for carbon dioxide reduction to methane, with a methane selectivity higher than 70% in a wide potential range. However, the N-heterocyclic carbene-linked copper single-atom site is extremely unstable. After electrolysis for 6 minutes at a current density of about 400 mA cm -2 the methane selectivity drops to 40%, thus greatly limiting the practicality and feasibility of industrial methane production. Moreover, this study used high-purity carbon dioxide gas as the reaction gas and did not study the application of the catalyst in the conversion of carbon dioxide captured from the air (MOF encapsulating N-heterocyclic carbene-ligated copper single-atom site catalyst towards efficient methane electrosynthesis. Angew. Chem. Int. Ed. 2022, 61, e202114450).

[0091] The patent document with the publication number CN 117599848A discloses a highly stable MOF-based non-noble metal single-atom catalyst, its preparation method and application. The catalyst consists of a zirconium-based MOF support and a non-noble metal. The prepared zirconium-based MOF support introduces non-noble metal sites through impregnation, including Cu, Ni, Mn, and Zn, which are dispersed in the zirconium-oxygen cluster nodes of the zirconium-based MOF support in the form of single atoms. This MOF-based non-noble metal single-atom catalyst has the advantages of mild reaction conditions, high activity, and high selectivity for oxygenates in the application of methane catalytic conversion. However, this study only investigated several transition metal single atoms and did not involve rare earth metal atoms, and the application field could not be extended to the field of electrocatalytic carbon dioxide reduction.

[0092] More importantly, the above work, or rather the existing work so far, basically only introduced a single active metal site on the metal-organic framework support, failing to exert and clarify the synergistic effect between the dual metal sites. Moreover, most of the work only stays at the catalyst level and fails to combine the preparation of the catalyst with the design of the device, although this is an important basis for the practical application of electrode materials. In particular, for the deep reduction of electrocatalytic carbon dioxide, there is still a large research space to achieve the direct conversion and utilization of carbon dioxide in air / flue gas while maintaining the high activity and high selectivity of the catalyst.

[0093] The present invention will be further described below in conjunction with the embodiments and the drawings.

[0094] The raw materials or chemical reagents used in the embodiments of the present invention are all obtained through conventional commercial channels unless otherwise specified.

[0095] Example 1: The catalyst for carbon dioxide reduction to methane is specifically a copper-lanthanum catalyst supported on amino-modified zirconium-based metal-organic framework (denoted as UiO-NH 2 -CuLa). The appearance and morphology of UiO-NH 2 -CuLa are nanoparticles with a minimum size of about 20 nm and abundant pores. The mass fractions of copper atoms and lanthanum atoms are 2.95 wt% and 0.61 wt%, respectively.

[0096] Preparation method of Example 1: (1) Dissolve 0.8 mmol of zirconium nitrate and 0.8 mmol of 2-aminoterephthalic acid in 30 mL of N,N-dimethylformamide, add 3 mL of acetic acid after ultrasonic dispersion to obtain a suspension, and then place the suspension in a hydrothermal autoclave, heat it to 120 °C and keep it warm for 24 h. The obtained precipitate is washed 3 times with methanol and N,N-dimethylformamide (volume ratio 1:4) and then dried in vacuum, and the product is ground evenly to obtain amino-modified zirconium-based metal-organic framework powder (denoted as UiO-NH 2 ). (2) Weigh 100 mg of UiO-NH 2 , disperse it in 6 mL of ethanol, and after ultrasonic dispersion, add 0.05 mmol of copper nitrate and 0.005 mmol of lanthanum nitrate in sequence. Stir at 80 °C until completely dry and the ethanol volatilizes, grind evenly, and then heat it to 200 °C at a rate of 2 °C / min -1 in an air atmosphere and keep it warm for 2 h to obtain a copper-lanthanum catalyst supported on amino-modified zirconium-based metal-organic framework (i.e., UiO-NH 2 -CuLa).

[0097] In the present invention, the influence of the geometric characteristics of the carrier on the local concentration distribution of reactants (CO 2 molecules) or intermediate products (CO molecules) is studied by finite element simulation. Two models are constructed, namely a solid catalyst particle and a catalyst particle with pores inside. During the reaction process, only the part in contact with the electrolyte can undergo carbon dioxide reduction, and the inside of the catalyst cannot participate in the catalytic reaction. As Figure 1 shown in Figure a, CO intermediate products (CO 2 →CO) are generated on both the outer surface and the inner surface of the pore-rich catalyst particle. The CO generated on the outer surface diffuses into the electrolyte after desorption, while the CO generated on the inner surface accumulates in the pores due to the confinement effect of the pores. Its long diffusion path not only leads to an increase in the local CO concentration but also increases the contact opportunity between CO and the active sites in the pores, which is beneficial to further reduction to methane (CO→CH 4 ). As Figure 2As shown in Figure a, for the poreless catalyst particles, only the outer surface can generate the CO intermediate product (CO 2 →CO). The generated CO diffuses into the electrolyte after desorption, so the local CO concentration is low. Figure 3 By comparing the change trend of CO concentration with the distance from the electrode surface, it can be found that the CO concentration in the pores of the pore-rich catalyst is significantly higher than that on the surface of the poreless catalyst. Therefore, it has a significant advantage for the deep reduction of carbon dioxide. In addition to the concentration of the intermediate product CO, Figure 1 Figure b of Figure 2 Figure b of Figure 4 also compares the carbon dioxide reactant concentrations on the surfaces of the pore-rich catalyst and the poreless catalyst. Similarly, the pore-rich catalyst particles also have a confinement effect on carbon dioxide molecules, which is beneficial to increasing the reactant concentration near the active sites and has a promoting effect on increasing the catalytic current density. Figure 5 Summarizes the effects of the pore-rich catalyst and the poreless catalyst on the deep reduction of carbon dioxide, that is, the catalyst pores increase the diffusion path of the key CO intermediate at the catalyst particles and extend its residence time. Therefore, the probability of the intermediate being adsorbed and transformed on the active sites is increased, and finally the methane selectivity is improved. It should be noted that a carrier pore diameter of 1 - 5 nm is more favorable for the deep reduction of carbon dioxide to produce methane. Larger pore diameters are difficult to extend the residence time of *CO intermediates on the electrode surface, while finer pore diameters, although having a confinement effect on the reaction intermediates, also affect the diffusion of reactant molecules to the surface of the active sites, resulting in insufficient carbon dioxide supply.

[0098] As Figure 6 shown, in the XRD pattern of UiO-NH 2 -CuLa in Example 1 of the present invention, there are only two peaks corresponding to the UiO-NH 2 carrier, and no obvious peaks of metallic copper, metallic lanthanum and their compounds are detected, indicating that copper atoms and lanthanum atoms are dispersed in the UiO-NH 2 framework, and their introduction reduces the crystallinity of the carrier. As Figure 7 shown in Figure a, UiO-NH 2 -CuLa in Example 1 of the present invention presents a nanometer particle morphology, with small size, as low as 20 nm. As Figure 8 shown, in UiO-NH 2 -CuLa in Example 1 of the present invention, zirconium atoms, copper atoms and lanthanum atoms are evenly dispersed, and the proportion of lanthanum atoms is very small, probably existing in the form of single atoms. As Figure 9 shown, the specific surface area of UiO-NH 2 -CuLa in Example 1 of the present invention is about 440 cm 3 g -1 , compared with UiO-NH2 The carrier is reduced due to the local structural collapse caused by the introduction of copper atoms and lanthanum atoms. Figure 10 As shown, in Example 1 of the present invention, UiO-NH 2 -CuLa has abundant pores, and the pore size distribution is mainly between 0.7nm and 1-2nm. 2 The reduction in the pore volume of the support is due to the local structural collapse caused by the introduction of copper and lanthanum atoms. Figure 11 As shown, in Example 1 of the present invention, UiO-NH 2 -CuLa's XPS spectrum clearly detected carbon, oxygen, nitrogen, zirconium, and copper elements, proving the presence of amino and copper atoms. The lanthanum element has a small proportion and its peak shape is not obvious. Figure 12 As shown, in Example 1 of the present invention, UiO-NH 2 In the Cu 2p spectrum of -CuLa, copper atoms exist in two valence states, +1 and +2, which excludes the existence of copper metal alone, and copper with a valence of +1 is dominant.

[0099] In order to further evaluate the UiO-NH 2 -CuLa gain effect, taking the electrocatalytic carbon dioxide reduction reaction as the target scenario, the performance test was carried out at different current densities in the flow cell configuration, and the electrolyte was 1 mol L -1 The products were collected and tested by gas chromatography and nuclear magnetic resonance spectroscopy, and the catalytic selectivity of different products was calculated. Figure 13 As shown, in Example 1 of the present invention, UiO-NH 2 The current density of -CuLa increases rapidly with the increase of applied voltage, and the current density is close to -400mAcm at -2.0V. -2 , which is higher than other comparative samples. By comparing the linear scanning voltammetry curves under carbon dioxide and argon atmospheres, it can be found that the starting potential of the curve under carbon dioxide atmosphere is much lower than that under argon atmosphere, and the current density is significantly increased, indicating that the UiO-NH 2 -CuLa has the ability to catalyze the conversion of carbon dioxide. Figure 14 As shown, in Example 1 of the present invention, UiO-NH 2 -CuLa exhibits excellent selectivity for CO2 reduction to produce methane, with a range of 300-600 mA cm -2 The methane selectivity is over 60% at 400 mA cm -2 The maximum value can reach 73%, which is significantly better than other comparative samples. In addition, UiO-NH 2 The methane selectivity of the carrier is close to 0, indicating that the introduced copper atoms or lanthanum atoms are the main active sites for catalytic carbon dioxide conversion.Figure 15 As shown, in Example 1 of the present invention, UiO-NH 2 -CuLa exhibits the smallest interfacial charge transfer resistance, indicating that the energy barrier for its catalytic reduction of carbon dioxide is lower than that of other comparative sample. As Figure 19 shown, in Example 1 of the present invention, UiO-NH 2 -CuLa assembled electrolytic cell has a cell voltage of 4.42 V at a current density of 600 mA cm -2 . At 600 mA cm -2 , the partial current density of methane reaches 384 mA cm -2 . As Figure 20 shown, in Example 1 of the present invention, UiO-NH 2 -CuLa can continuously electrolyze for 7 h at a current density of 400 mA cm -2 , and during this period, the methane selectivity exceeds 50%.

[0100] In order to further evaluate the gain effect brought by UiO-NH 2 -CuLa in Example 1 of the present invention, using UiO-NH 2 -CuLa as one of the electrode materials, a device for coupling carbon dioxide capture-release-conversion is designed and assembled.

[0101] As Figure 27 shown, an air capture carbon dioxide-catalytic conversion device includes: a first housing 1, a cathode 2, and an anode 3; the cathode 2 and the anode 3 are both located inside the first housing 1; the cathode 2 is loaded with a carbon dioxide reduction to methane catalyst; the cathode 2 divides the first housing 1 into a gas channel and a first electrolyte chamber 41, the gas channel has a carbon dioxide inlet and a methane outlet, and an alkali metal bicarbonate solution is loaded in the first electrolyte chamber 41; the anode 3 is located on the side of the first electrolyte chamber 41 away from the cathode 2.

[0102] Specifically, a receiving cavity is formed inside the first housing 1. The two openings of the receiving cavity are respectively a carbon dioxide inlet and a methane outlet. The cathode 2 divides the receiving cavity of the first housing 1 into a gas channel and a first electrolyte chamber 41. Carbon dioxide enters the gas channel from the carbon dioxide inlet, contacts the carbon dioxide reduction to methane catalyst loaded on the cathode 2, and is reduced to methane, and then is discharged from the methane outlet. The cathode 2 includes: a current collector, a waterproof and breathable membrane, and a carbon dioxide reduction to methane catalyst arranged in sequence. The current collector faces the gas channel, and the catalyst faces the first electrolyte chamber 41. The current collector can be made of nickel foam. Both carbon dioxide and gas products (including methane) can pass through the current collector and the waterproof and breathable membrane, and the alkali metal bicarbonate solution in the first electrolyte chamber 41 cannot pass through the waterproof and breathable membrane. The gas channel can adopt a serpentine channel to increase the contact area, and the gas flows from the carbon dioxide inlet to the methane outlet. The anode 3 is specifically an oxygen evolution anode, which is used to evolve oxygen and release electrons. As Figure 28 shown, a first bipolar membrane 32 can also be added. The cathode 2 and the first bipolar membrane 32 divide the receiving cavity of the first housing 1 into a gas channel, a first electrolyte chamber 41, and a second electrolyte chamber 42. The first electrolyte chamber 41 is filled with an alkali metal bicarbonate solution, and the second electrolyte chamber 42 is filled with a strong alkali solution. The oxygen evolution material layer 31 of the anode 3 is located in the second electrolyte chamber 42, and the strong alkali solution is beneficial to improving the oxygen evolution activity of the anode 3. By applying a voltage to the cathode 2 and the anode 3 for an electrocatalytic reaction, CO 2 is reduced to CH 4 .

[0103] As Figure 21 , Figure 22 , Figure 29 and Figure 30 shown, a carbon dioxide capture-release structure can also be added on the basis of the first housing 1. The carbon dioxide capture-release structure can be assembled with the first housing 1 and share the same anode 3. The carbon dioxide capture-release structure is used to capture carbon dioxide in the air, improve the purity of carbon dioxide, and release it to the carbon dioxide inlet to be reduced to methane. The first housing 1 has a first window; the anode 3 includes: a first bipolar membrane 32 and an oxygen evolution material layer 31. The first bipolar membrane 32 is located at the first window; the oxygen evolution material layer 31 is located on the side of the first bipolar membrane 32 away from the first electrolyte chamber 41.

[0104] Specifically, a first window is formed on the first housing 1, and the anode 3 is arranged at the position of the first window, then the same anode 3 can be shared. The first bipolar membrane 32 seals the first window, and the oxygen evolution material layer 31 is located on the side of the first bipolar membrane 32 away from the first electrolyte chamber 41.

[0105] The air capture carbon dioxide-catalytic conversion device further includes: a second housing 5, a second bipolar membrane 6, an anion exchange membrane 7, and an oxygen reduction electrode 8. The second housing 5 has a second window and a third window, and the second window corresponds to the first window; the second bipolar membrane 6, the anion exchange membrane 7, and the oxygen reduction electrode 8 are sequentially arranged in the second housing 5; the oxygen reduction electrode 8 is located at the second window; a second electrolyte chamber 42 is formed between the first bipolar membrane 32 and the second bipolar membrane 6, and the second electrolyte chamber 42 is filled with a strong base solution; a third electrolyte chamber 43 is formed between the second bipolar membrane 6 and the anion exchange membrane 7, and the third electrolyte chamber 43 is filled with an alkali metal bicarbonate solution; a fourth electrolyte chamber 44 is formed between the anion exchange membrane 7 and the oxygen reduction electrode 8, and the fourth electrolyte chamber 44 is filled with an alkali metal bicarbonate solution.

[0106] Specifically, a second electrolyte chamber 42 is formed between the first bipolar membrane 32 and the second bipolar membrane 6. The oxygen evolution material layer 31 can be located in the second electrolyte chamber 42. The first bipolar membrane 32 releases OH - into the first electrolyte chamber and releases H + into the second electrolyte chamber 42; the second bipolar membrane 6 releases OH - into the second electrolyte chamber 42 and releases H + into the third electrolyte chamber 43. The strong base solution can be KOH or NaOH, etc. A third electrolyte chamber 43 is formed between the second bipolar membrane 6 and the anion exchange membrane 7, and the third electrolyte chamber 43 is filled with an alkali metal bicarbonate solution. The alkali metal bicarbonate solution can be KHCO 3 , etc. A fourth electrolyte chamber 44 is formed between the anion exchange membrane 7 and the oxygen reduction electrode 8, and the fourth electrolyte chamber 44 is filled with an alkali metal bicarbonate solution. The alkali metal bicarbonate solution can be KHCO 3 , etc.

[0107] Such as Figure 21 and Figure 22 shown, during the process of carbon dioxide capture, the oxygen reduction electrode and the anode form a circuit. The oxygen evolution material layer of the anode oxidizes OH - to form O 2 and releases electrons. The oxygen evolution material layer is a NiFeO x material layer, and can also be RuO 2 supported on a titanium mesh, IrO 2 supported on a titanium mesh, etc. O 2 and CO 2 in the air can both pass through the oxygen reduction electrode and enter the fourth electrolyte chamber. The oxygen reduction electrode obtains electrons and reduces O 2 in the air to OH - , OH- React with CO 2 to form HCO 3 - . The oxygen reduction electrode is a Pt / C electrode. In addition, the second housing may be provided with an air inlet, and the air inlet communicates with the fourth electrolyte chamber. Injecting additional air into the fourth electrolyte chamber from the air inlet, and there is CO in the additionally injected air 2 , and the OH formed by the oxygen reduction electrode - reacts with CO 2 to form HCO 3 - . The HCO in the fourth electrolyte chamber 3 - passes through the anion exchange membrane, reaches the third electrolyte chamber, and reacts with the H + released by the second bipolar membrane to generate CO 2 , thereby obtaining relatively pure CO 2 . As Figure 21 shown, the air capture carbon dioxide-catalytic conversion device further includes: a collector 9 for collecting the CO generated in the third electrolyte chamber 43 2 , and releasing carbon dioxide to the carbon dioxide inlet. For example, after the collector 9 collects a certain amount of CO 2 , it can release CO to the carbon dioxide inlet 2 . The methane outlet communicates with the collector 9, and the unreacted CO 2 returns to the collector 9 and is further released. During the release and reduction of carbon dioxide, the oxygen evolution material layer oxidizes OH - to form O 2 , and releases electrons. The catalyst for carbon dioxide reduction to methane on the cathode obtains electrons and reduces CO 2 to methane.

[0108] As Figure 22 shown, as the electrolysis current density increases, the rate of carbon dioxide collection gradually increases, and the collection efficiency basically exceeds 60%. At 150 mA cm -2 , 1.5 mL of carbon dioxide can be collected per minute, and the collection efficiency reaches 72%. As Figure 23 shown, the air capture carbon dioxide-catalytic conversion device can achieve continuous carbon dioxide capture and release. At 200 mA cm -2 , continuous electrolysis has been carried out for more than 56 h, during which the collection efficiency exceeds 50%, and the purity of the collected carbon dioxide exceeds 99%, which can be directly used as a raw material for the carbon dioxide reduction reaction. As Figure 24 shown, using 4 L of air as the raw material for the oxygen reduction reaction on the oxygen reduction electrode, at 200 mA cm -2After electrolysis for 6 h, the carbon dioxide concentration in the air decreased from nearly 1000 ppm to about 400 ppm, and the carbon dioxide capture rate reached 60%. As Figure 25 shown, using the carbon dioxide captured and collected from the air as raw material, after electrolysis for 7.5 h, the concentrations of fuel gases such as methane, carbon monoxide, and hydrogen in the gas collection bag reached 28%, 5%, and 13% respectively (as Figure 26 shown), indicating that the air-captured carbon dioxide-catalytic conversion device achieved the conversion of carbon dioxide in the air to methane fuel.

[0109] Example 2: The catalyst for carbon dioxide reduction to produce methane is specifically a copper-praseodymium catalyst supported on amino-modified zirconium-based metal-organic framework (denoted as UiO-NH 2 -CuPr). The appearance and morphology of UiO-NH 2 -CuPr are all nanoparticles, with the smallest size of about 20 nm and abundant pores. The mass fraction of copper atoms is 2.94 wt%, and the mass fraction of praseodymium atoms is 0.63 wt%.

[0110] Preparation method of Example 2: Different from the preparation method of Example 1, lanthanum nitrate was replaced with an equimolar amount of praseodymium nitrate to obtain a copper-praseodymium catalyst supported on amino-modified zirconium-based metal-organic framework (UiO-NH 2 -CuPr).

[0111] Example 3: The catalyst for carbon dioxide reduction to produce methane is specifically a copper-cerium catalyst supported on amino-modified zirconium-based metal-organic framework (denoted as UiO-NH 2 -CuCe). The appearance and morphology of UiO-NH 2 -CuCe are all nanoparticles, with the smallest size of about 20 nm and abundant pores. The mass fraction of copper atoms is 2.96 wt%, and the mass fraction of cerium atoms is 0.61 wt%.

[0112] Preparation method of Example 3: Different from the preparation method of Example 1, lanthanum nitrate was replaced with an equimolar amount of cerium nitrate to obtain a copper-cerium catalyst supported on amino-modified zirconium-based metal-organic framework (UiO-NH 2 -CuCe).

[0113] As Figure 17 shown, UiO-NH 2 -CuPr in Example 2 of the present invention and UiO-NH 2 -CuCe in Example 3 of the present invention showed high selectivity for carbon dioxide reduction to produce methane. Among them, UiO-NH 2 -CuPr in Example 2 of the present invention at 300 mA cm -2The methane selectivity reached 48% at a current density of, and in Example 3 of the present invention, UiO-NH 2 -CuCe had a methane selectivity of 55% at a current density of 300 mA cm -2 .

[0114] Example 4: The catalyst for carbon dioxide reduction to methane was specifically a copper-lanthanum catalyst supported on an amino-modified zirconium-based metal-organic framework (denoted as UiO-NH 2 -Cu 10 La 0.5 ). The appearance and morphology of UiO-NH 2 -Cu 10 La 0.5 were all nanoparticles with a minimum size of about 20 nm and abundant pores. The mass fraction of copper atoms was 2.92 wt%, and the mass fraction of lanthanum atoms was 0.29 wt%.

[0115] Preparation method of Example 4: Different from the preparation method of Example 1, 0.005 mmol of lanthanum nitrate was replaced with 0.0025 mmol of lanthanum nitrate to obtain a copper-lanthanum catalyst supported on an amino-modified zirconium-based metal-organic framework (UiO-NH 2 -Cu 10 La 0.5 ).

[0116] Example 5: The catalyst for carbon dioxide reduction to methane was specifically a copper-lanthanum catalyst supported on an amino-modified zirconium-based metal-organic framework (denoted as UiO-NH 2 -Cu 10 La 2 ). The appearance and morphology of UiO-NH 2 -Cu 10 La 2 were all nanoparticles with a minimum size of about 20 nm and abundant pores. The mass fraction of copper atoms was 2.98 wt%, and the mass fraction of lanthanum atoms was 1.23 wt%.

[0117] Preparation method of Example 5: Different from the preparation method of Example 1, 0.005 mmol of lanthanum nitrate was replaced with 0.01 mmol of lanthanum nitrate to obtain a copper-lanthanum catalyst supported on an amino-modified zirconium-based metal-organic framework (UiO-NH 2 -Cu 10 La 2 ).

[0118] Example 6: The catalyst for carbon dioxide reduction to methane was specifically a copper-lanthanum catalyst supported on an amino-modified zirconium-based metal-organic framework (denoted as UiO-NH 2 -Cu 10 La 3)。UiO-NH 2 -Cu 10 La 3 The external morphologies of all are nanoparticles, with the smallest size being about 20 nm and there being abundant pores. The mass fractions of copper atoms are 3.01 wt%, and the mass fraction of lanthanum atoms is 1.86 wt%.

[0119] Preparation method of Example 6: Different from the preparation method of Example 1, 0.005 mmol of lanthanum nitrate was replaced with 0.015 mmol of lanthanum nitrate to obtain a copper-lanthanum catalyst supported on amino-modified zirconium-based metal-organic framework (UiO-NH 2 -Cu 10 La 3 ).

[0120] Specifically, as Figure 16 shown, after changing the ratio of Cu and La, it was found that in the current range of 300 - 400 mA cm -2 , the copper-lanthanum ratio corresponding to UiO-NH 2 -CuLa in Example 1 of the present invention (the molar ratio of copper and lanthanum is 10:1) is the optimal ratio, and its selectivity for methane production is the highest. The selectivities for methane production in Example 5 and Example 6 are also relatively high, and the selectivity for methane production in Example 4 is slightly lower.

[0121] Example 7: The catalyst for carbon dioxide reduction to methane is specifically a copper-lanthanum catalyst supported on unmodified zirconium-based metal-organic framework (denoted as UiO-Cu 5 La 0.25 ). The external morphology of UiO-Cu 5 La 0.25 is nanoparticles, with the smallest size being about 20 nm and there being abundant pores. The mass fractions of copper atoms and lanthanum atoms are 1.42 wt% and 0.14 wt% respectively.

[0122] Preparation method of Example 7: (1) Dissolve 0.6 mmol of zirconium nitrate and 0.6 mmol of terephthalic acid in 30 mL of N,N-dimethylformamide, ultrasonically disperse evenly, add 2 mL of acetic acid to obtain a suspension, then place the suspension in a hydrothermal autoclave, heat up to 110 °C and keep warm for 20 h. The obtained precipitate was washed 3 times with methanol and N,N-dimethylformamide (volume ratio 1:4) and then dried in vacuum, and the product was ground evenly to obtain unmodified zirconium-based metal-organic framework powder (denoted as UiO). (2) Weigh 100 mg of UiO and disperse it in 4 mL of ethanol, ultrasonically disperse evenly, and then successively add 0.025 mmol of copper nitrate and 0.00125 mmol of lanthanum nitrate. Stir at 60 °C until completely dry and the ethanol volatilizes, grind evenly, and then in an air atmosphere at 1 °C min -1Heat it up to 150 °C at a rate of and keep it warm for 1 h to obtain a copper-lanthanum catalyst supported on an unmodified zirconium-based metal-organic framework (i.e., UiO-Cu 5 La 0.25 ).

[0123] Example 8: The catalyst for carbon dioxide reduction to methane is specifically a copper-lanthanum catalyst supported on a sulfonic acid group-modified zirconium-based metal-organic framework (denoted as UiO-SO 3 -Cu 20 La 6 ). The appearance and morphology of UiO-SO 3 -Cu 20 La 6 are nanoparticles with a minimum size of about 20 nm and abundant pores. The mass fractions of copper atoms and lanthanum atoms are 5.96 wt% and 3.58 wt% respectively.

[0124] Preparation method of Example 8: (1) Dissolve 0.6 mmol of zirconium nitrate and 1 mmol of 2-sulfonic acid terephthalic acid in 30 mL of N,N-dimethylformamide, add 4 mL of acetic acid after ultrasonic dispersion to obtain a suspension, and then place the suspension in a hydrothermal kettle, heat it up to 130 °C and keep it warm for 30 h. The obtained precipitate is washed 3 times with methanol and N,N-dimethylformamide (volume ratio 1:4) and then dried in vacuum, and the product is ground evenly to obtain a sulfonic acid group-modified zirconium-based metal-organic framework powder (denoted as UiO-SO 3 ). (2) Weigh 100 mg of UiO-SO 3 , disperse it in 4 mL of ethanol, after ultrasonic dispersion, add 0.1 mmol of copper nitrate and 0.03 mmol of lanthanum nitrate in sequence. Stir at 80 °C until completely dry and the ethanol volatilizes, grind evenly and then heat it up to 250 °C at a rate of 1 °C min -1 in an air atmosphere and keep it warm for 1 h to obtain a copper-lanthanum catalyst supported on a sulfonic acid group-modified zirconium-based metal-organic framework (i.e., UiO-SO 3 -Cu 20 La 6 ).

[0125] Example 9: The catalyst for carbon dioxide reduction to methane is specifically a copper-lanthanum catalyst supported on a bromine group-modified zirconium-based metal-organic framework (denoted as UiO-Br-Cu 10 La 1 ). The appearance and morphology of UiO-Br-Cu 10 La 1 are nanoparticles with a minimum size of about 20 nm and abundant pores. The mass fractions of copper atoms and lanthanum atoms are 2.94 wt% and 0.59 wt% respectively.

[0126] Preparation method of Example 9: (1) Dissolve 1 mmol of zirconium nitrate and 0.6 mmol of 2-bromoterephthalic acid in 30 mL of N,N-dimethylformamide. After ultrasonic dispersion, add 3 mL of acetic acid to obtain a suspension. Then place the suspension in a hydrothermal autoclave, heat it to 120 °C and keep it warm for 25 h. The obtained precipitate is washed 3 times with methanol and N,N-dimethylformamide (volume ratio 1:4) and then dried in vacuum. The product is ground evenly to obtain bromine-modified zirconium-based metal-organic framework powder (denoted as UiO-Br). (2) Weigh 100 mg of UiO-Br and disperse it in 3 mL of ethanol. After ultrasonic dispersion, add 0.05 mmol of copper nitrate and 0.005 mmol of lanthanum nitrate in sequence. Stir at 80 °C until completely dry and the ethanol evaporates. After grinding evenly, heat it to 200 °C at a rate of 2 °C min -1 and keep it warm for 1 h to obtain a copper-lanthanum catalyst supported on bromine-modified zirconium-based metal-organic framework (i.e., UiO-Br-Cu 10 La 1 ).

[0127] Comparative Example 1: Copper catalyst supported on amino-modified zirconium-based metal-organic framework (denoted as UiO-NH 2 -Cu). The copper catalyst supported on amino-modified zirconium-based metal-organic framework (UiO-NH 2 -Cu) is Comparative Example 1. Its appearance and morphology are nanoparticles with a size of about 20 nm and abundant pores. The mass fraction of copper atoms is 3.00 wt%.

[0128] Preparation method of Comparative Example 1: (1) Dissolve 0.8 mmol of zirconium nitrate and 0.8 mmol of 2-aminoterephthalic acid in 30 mL of N,N-dimethylformamide. After ultrasonic dispersion, add 3 mL of acetic acid to obtain a suspension. Then place the suspension in a hydrothermal autoclave, heat it to 120 °C and keep it warm for 24 h. The obtained precipitate is washed 3 times with methanol and N,N-dimethylformamide (volume ratio 1:4) and then dried in vacuum. The product is ground evenly to obtain amino-modified zirconium-based metal-organic framework powder (denoted as UiO-NH 2 ). (2) Weigh 100 mg of UiO-NH 2 and disperse it in 6 mL of ethanol. After ultrasonic dispersion, add 0.05 mmol of copper nitrate. Stir at 80 °C until completely dry and the ethanol evaporates. After grinding evenly, heat it to 200 °C at a rate of 2 °C min -1 and keep it warm for 2 h to obtain a copper catalyst supported on amino-modified zirconium-based metal-organic framework (UiO-NH 2 -Cu).

[0129] As Figure 6 shown, in Comparative Example 1 of the present invention, UiO-NH 2-Cu has only UiO-NH 2 The two peaks corresponding to the carrier did not detect obvious peaks of metallic copper and its compounds, indicating that copper atoms are dispersed in the UiO-NH 2 Their introduction into the framework reduces the crystallinity of the carrier. Figure 7 As shown in Figure b, UiO-NH 2 -Cu presents the morphology of nanoparticles with a small size as low as 20nm. Figure 9 As shown, in Comparative Example 1 of the present invention, UiO-NH 2 -The specific surface area of ​​Cu is about 510cm 3 g -1 , compared with UiO-NH 2 The carrier is reduced due to the local structural collapse caused by the introduction of copper atoms. Figure 10 As shown, in Comparative Example 1 of the present invention, UiO-NH 2 -Cu has abundant pores, and the pore size distribution is mainly between 0.7nm and 1-2nm. 2 The reduction in the pore volume of the support is due to the local structural collapse caused by the introduction of copper atoms. Figure 11 As shown, in Comparative Example 1 of the present invention, UiO-NH 2 -Cu XPS spectrum clearly detected carbon, oxygen, nitrogen, zirconium, and copper elements, proving the existence of amino groups and copper atoms. Figure 12 As shown, in Comparative Example 1 of the present invention, UiO-NH 2 In the Cu 2p spectrum of UiO-NH-Cu, copper atoms exist in two valence states of +1 and +2, excluding the existence of copper metal alone. The proportion of +2 valence copper is significantly higher than that of UiO-NH-Cu in Example 1 of the present invention. 2 -CuLa, indicating that the copper atom has a higher valence state and a lower local electron density. Figure 13 As shown, in Comparative Example 1 of the present invention, UiO-NH 2 The current density of UiO-NH 2 -CuLa. Figure 14 As shown, in Comparative Example 1 of the present invention, UiO-NH 2 -Cu at 400mA cm -2 The methane selectivity is 64%, which is lower than that of UiO-NH 2 -CuLa, and decreases rapidly as the current density continues to increase. Figure 15 As shown, in Comparative Example 1 of the present invention, UiO-NH 2 -Cu has a higher interfacial charge transfer resistance than UiO-NH 2-CuLa, i.e., has a higher energy barrier for catalyzing carbon dioxide reduction.

[0130] Comparative Example 2: Lanthanum catalyst supported on amino-modified zirconium-based metal-organic framework (denoted as UiO-NH 2 -La). The lanthanum catalyst supported on amino-modified zirconium-based metal-organic framework (UiO-NH 2 -La) of Comparative Example 2 has a nanometer particle appearance morphology, with a size of about 20 nm and abundant pores. The mass fraction of lanthanum atoms is 5.01 wt%.

[0131] Preparation method of Comparative Example 2: (1) Dissolve 0.8 mmol of zirconium nitrate and 0.8 mmol of 2-aminoterephthalic acid in 30 mL of N,N-dimethylformamide, ultrasonically disperse evenly, add 3 mL of acetic acid, and then place it in a hydrothermal autoclave, heat to 120 °C and keep warm for 24 h. The obtained precipitate is washed 3 times with methanol / N,N-dimethylformamide (volume ratio 1:4) and then vacuum dried, and the product is ground evenly to obtain amino-modified zirconium-based metal-organic framework (UiO-NH 2 ). (2) Weigh 100 mg of UiO-NH 2 , disperse it in 6 mL of ethanol, ultrasonically disperse evenly, and add 0.05 mmol of lanthanum nitrate. The obtained suspension is stirred at 80 °C until completely dry, ground evenly, and then heated to 200 °C at a rate of 2 °C min -1 in an air atmosphere and keep warm for 2 h to obtain a lanthanum catalyst supported on amino-modified zirconium-based metal-organic framework (UiO-NH 2 -La).

[0132] As Figure 6 shown, in the XRD pattern of UiO-NH 2 -La in Comparative Example 2 of the present invention, there are only two peaks corresponding to the UiO-NH 2 support, and no obvious peaks of metallic lanthanum and its compounds are detected, indicating that lanthanum atoms are dispersed in the UiO-NH 2 framework, and their introduction reduces the crystallinity of the support. As shown in Figure c of Figure 7 , UiO-NH 2 -La in Comparative Example 2 of the present invention presents a nanometer particle morphology, with a small size, as low as 20 nm. As Figure 9 shown, the specific surface area of UiO-NH 2 -La in Comparative Example 2 of the present invention is about 440 cm 3 g -1 , which is lower than that of the UiO-NH 2 support, due to the local structure collapse caused by the introduction of lanthanum atoms. As Figure 10 shown, UiO-NH 2-La has abundant pores, and the pore size distribution is mainly between 0.7 nm and 1 - 2 nm. Compared with the carrier pore volume of UiO-NH 2 it decreases, which is due to the local structural collapse caused by the introduction of lanthanum atoms. As Figure 11 shown, in Comparative Example 2 of the present invention, obvious carbon, oxygen, nitrogen, zirconium, and lanthanum elements were detected in the XPS full spectrum of UiO-NH 2 -La, which proves the existence of amino groups and lanthanum atoms. As Figure 13 shown, in Comparative Example 2 of the present invention, the current density of UiO-NH 2 -La increases with the increase of the applied voltage, but the current density is only about -320 mA cm -2 at -2.0 V, which is significantly lower than that of UiO-NH 2 -CuLa in Example 1 of the present invention. As Figure 14 shown, in Comparative Example 2 of the present invention, the methane selectivity of UiO-NH 2 -La does not exceed 1% at each current density, and almost no methane is generated, indicating that lanthanum atoms are not the active sites for catalyzing carbon dioxide reduction. As Figure 15 shown, in Comparative Example 2 of the present invention, the interfacial charge transfer resistance of UiO-NH 2 -La is the highest, that is, the energy barrier for catalyzing carbon dioxide reduction is high.

[0133] Comparative Example 3: CuLa alloy catalyst (denoted as CuLa). The CuLa alloy catalyst (CuLa) in Comparative Example 3 has a nanosheet appearance morphology with uneven size distribution, and there are abundant defects and pores on the nanosheets.

[0134] Preparation method of Comparative Example 3: Dissolve 1.0 mmol of copper nitrate and 0.1 mmol of lanthanum nitrate in 30 mL of ethylene glycol, add 0.5 mL of n-butylamine after ultrasonic dispersion, then place it in a hydrothermal kettle, heat it to 180 °C and keep it warm for 10 h. The obtained precipitate is washed 3 times with ethanol and then dried in vacuum, ground evenly, and heated to 200 °C at a rate of 2 °C min -1 in an air atmosphere and kept warm for 2 h to obtain the CuLa alloy catalyst (CuLa).

[0135] As Figure 6 shown, in the XRD pattern of CuLa in Comparative Example 3 of the present invention, the peaks corresponding to metallic copper (PDF#85 - 1326) appear, indicating that the main crystal phase of the catalyst is metallic copper, and lanthanum atoms are doped in the lattice of metallic copper. As Figure 7 shown in the d figure, CuLa in Comparative Example 3 of the present invention presents a nanosheet morphology with uneven nanosheet size distribution and abundant defects and pores. As Figure 11 shown, obvious copper and lanthanum elements were detected in the XPS full spectrum of CuLa in Comparative Example 3 of the present invention.Figure 13 As shown, in Comparative Example 3 of the present invention, the current density of CuLa increases with the increase of the applied voltage, but the current density is slightly lower than that of UiO-NH in Example 1 of the present invention 2 -CuLa. As Figure 14 shown, the methane selectivity of CuLa in Comparative Example 3 of the present invention does not exceed 15% at each current density, and the highest is only 14% (600 mA cm -2 ), indicating that zirconium-based metal-organic frameworks have an important influence on the dispersion of active sites and the enrichment of reactants / intermediate products, and determine the selectivity of the final methane product. As Figure 15 shown, the interfacial charge transfer resistance of UiO-NH in Comparative Example 2 of the present invention 2 -La is higher than that of UiO-NH in Example 1 of the present invention 2 -CuLa, that is, the energy barrier for catalyzing carbon dioxide reduction is high.

[0136] Comparative Example 4: Copper catalyst supported on unmodified zirconium-based metal-organic framework (denoted as UiO-Cu). The copper catalyst supported on unmodified zirconium-based metal-organic framework (UiO-Cu) in Comparative Example 4 has a nanometer particle appearance morphology, with a size of about 20 nm and abundant pores. The mass fraction of copper atoms is 2.95 wt%.

[0137] Preparation method of Comparative Example 4: Different from the preparation method of Comparative Example 1, 2-aminoterephthalic acid was replaced with an equimolar amount of terephthalic acid to obtain a copper catalyst supported on unmodified zirconium-based metal-organic framework (UiO-Cu).

[0138] Comparative Example 5: Copper catalyst supported on sulfonic acid group-modified zirconium-based metal-organic framework (denoted as UiO-SO 3 -Cu). The copper catalyst supported on sulfonic acid group-modified zirconium-based metal-organic framework (UiO-SO 3 -Cu) in Comparative Example 5 has a nanometer particle appearance morphology, with a size of about 20 nm and abundant pores. The mass fraction of copper atoms is 2.98 wt%.

[0139] Preparation method of Comparative Example 5: Different from the preparation method of Comparative Example 1, 2-aminoterephthalic acid was replaced with an equimolar amount of 2-sulfoterephthalic acid to obtain a copper catalyst supported on sulfonic acid group-modified zirconium-based metal-organic framework (UiO-SO 3 -Cu).

[0140] Comparative Example 6: Copper catalyst supported on bromine-modified zirconium-based metal-organic framework (denoted as UiO-Br-Cu). The copper catalyst supported on bromine-modified zirconium-based metal-organic framework (UiO-Br-Cu) in Comparative Example 6 has a nanometer particle appearance morphology, with a size of about 20 nm and abundant pores. The mass fraction of copper atoms is 2.92 wt%.

[0141] Preparation method of Comparative Example 6: Different from the preparation method of Comparative Example 1, 2-aminoterephthalic acid was replaced with an equimolar amount of 2-bromoterephthalic acid to obtain a copper catalyst supported on bromine-modified zirconium-based metal-organic framework (UiO-Br-Cu).

[0142] As Figure 18 shown, compared with Comparative Examples 4 to 6 of the present invention, the copper catalyst supported on amino-modified zirconium-based metal-organic framework (UiO-NH 2 -Cu) in Comparative Example 1 exhibits higher selectivity for carbon dioxide reduction to methane, indicating that the electron-donating amino group is more conducive to the reduction of carbon dioxide to methane than other electron-withdrawing groups.

Claims

1. A method for preparing a carbon dioxide reduction methanogenesis catalyst, characterized in that: The following steps are involved: Provide zirconium-based metal organic framework powder, soluble copper salt, soluble rare earth metal salt and solvent; The zirconium-based metal organic framework powder is dispersed in the solvent, and the soluble copper salt and the soluble rare earth metal salt are added, stirred and heated until the solvent is volatilized, and calcined in an air atmosphere to obtain a catalyst for carbon dioxide reduction to methane; wherein the ratio of the zirconium-based metal organic framework powder, the soluble copper salt and the soluble rare earth metal salt is 100 mg: 0.025-0.1 mmol: 0.00125-0.03 mmol; the rare earth metal in the soluble rare earth metal salt includes: at least one of lanthanum, cerium and praseodymium; the calcination temperature is 150-250° C.; the pore size of the catalyst is 0.5-2 nm; the zirconium atoms, copper atoms and rare earth metal atoms in the catalyst are uniformly dispersed at the atomic level.

2. The method for preparing a carbon dioxide reduction methanogenesis catalyst according to claim 1, characterized in that: The zirconium-based metal organic framework powder is obtained by the following steps: Dissolving a zirconium salt and an organic ligand in N,N-dimethylformamide, uniformly dispersing by ultrasonication, and then dropping acetic acid to obtain a suspension; wherein the zirconium salt comprises at least one of zirconium nitrate, zirconium chloride, and zirconium sulfate; and the organic ligand comprises at least one of terephthalic acid, 2-aminoterephthalic acid, 2-bromoterephthalic acid, and 2-sulfonato terephthalic acid monosodium; The suspension is placed in a hydrothermal kettle and kept at a preset temperature for a preset time; The precipitate in the hydrothermal reactor is centrifuged, washed, dried and ground evenly to obtain a zirconium-based metal organic framework powder.

3. The method for preparing a catalyst for methanogenesis by carbon dioxide reduction according to claim 2, characterized in that: The ratio of the zirconium salt, the organic ligand, the N,N-dimethylformamide and the acetic acid is 0.6-1 mmol: 0.6-1 mmol: 30 mL: 2-4 mL; The preset temperature is 110-130° C., and the preset time is 20-30 hours. The centrifugal washing adopts a mixed solution of methanol and N,N-dimethylformamide. The drying method is freeze drying, and the drying time is 6-10 hours.

4. The method for preparing a catalyst for methanogenesis by carbon dioxide reduction according to any one of claims 1 to 3, characterized in that: The ratio of the zirconium-based metal organic framework powder to the solvent is 100 mg: 4-8 mL; the heating rate of the calcination is 1-3 ° C min -1 The calcination holding time is 1 to 3 hours.

5. The method for preparing a catalyst for methanogenesis by carbon dioxide reduction according to any one of claims 1 to 3, characterized in that: The solvent includes: at least one of deionized water, methanol and ethanol; the heating temperature is 60-80°C.

6. A carbon dioxide reduction methanogenesis catalyst, characterized in that: The catalyst is prepared by the method for preparing a carbon dioxide reduction methanogenesis catalyst as claimed in any one of claims 1 to 5.

7. The carbon dioxide reduction methanogenesis catalyst according to claim 6, characterized in that: The mass percentage of copper atoms in the catalyst is 1.42-5.96 wt %, and the mass percentage of rare earth metal atoms is 0.14-3.58 wt %.

8. A carbon dioxide reduction methanogenesis catalyst as claimed in any one of claims 6 to 7, used for electrocatalytic carbon dioxide reduction methanogenesis.

9. An air capture carbon dioxide-catalytic conversion device, comprising: A first shell, a cathode and an anode; the cathode and the anode are both located in the first shell; characterized in that the cathode is loaded with the carbon dioxide reduction methanogenesis catalyst according to any one of claims 6 to 7; The cathode divides the first shell into a gas channel and a first electrolyte chamber, the gas channel has a carbon dioxide inlet and a methane outlet, and the first electrolyte chamber is loaded with an alkali metal bicarbonate solution; The anode is located at a side of the first electrolyte chamber away from the cathode.

10. The air capture carbon dioxide-catalytic converter according to claim 9, characterized in that: The first housing has a first window; The anode comprises: a first bipolar membrane, located at the first window; an oxygen evolution material layer, located on a side of the first bipolar membrane away from the first electrolyte chamber; The air capture carbon dioxide-catalytic converter also includes: a second shell, the second shell having a second window and a third window, the second window corresponding to the first window; The second bipolar membrane, the anion exchange membrane and the oxygen reduction electrode are sequentially arranged in the second shell; Wherein, the oxygen reduction electrode is located at the second window; A second electrolyte chamber is formed between the first bipolar membrane and the second bipolar membrane, and the second electrolyte chamber is loaded with a strong alkaline solution; A third electrolyte chamber is formed between the second bipolar membrane and the anion exchange membrane, and the third electrolyte chamber is loaded with an alkali metal bicarbonate solution; A fourth electrolyte chamber is formed between the anion exchange membrane and the oxygen reduction electrode, and the fourth electrolyte chamber is loaded with an alkali metal bicarbonate solution; Wherein, the oxygen evolution material layer is NiFeO x Material layer, the oxygen reduction electrode is a Pt / C electrode; The second shell is provided with an air inlet, and the air inlet is communicated with the fourth electrolyte chamber.

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