Catalytic material for flue gas carbon dioxide capture and methanation and preparation method and application thereof

Abstract

The present application relates to the technical field of photocatalytic materials, and discloses flue gas carbon dioxide capture and methanation catalytic material, a preparation method and application thereof.The catalytic material is a Ru atom modified MoS2-COF hierarchical heterojunction composite catalyst, which is composed of a triazine-based covalent organic framework, in-situ grown MoS2 on the surface and in the pores of the triazine-based covalent organic framework, and Ru single atoms dispersed and loaded on the interface of the hierarchical structure formed by the triazine-based covalent organic framework and the MoS2 and the surface of the triazine-based covalent organic framework.The triazine-based covalent organic framework is used as a carrier to in-situ composite MoS2 and Ru single atoms, a heterojunction is constructed, and the integration and synergistic effect of carbon dioxide adsorption and photocatalytic conversion are realized.

Description

Technical Field

[0001] This invention relates to the field of photocatalytic materials technology, and more specifically, to catalytic materials for capturing carbon dioxide from flue gas and methanolization, as well as their preparation methods and applications. Background Technology

[0002] In the process of global industrial modernization, the environmental problems caused by fossil fuel shortages and greenhouse gas emissions are becoming increasingly severe, making the resource utilization of carbon dioxide a key pathway. Traditional carbon dioxide capture technologies require a large amount of energy for adsorbent regeneration and air transport, and the captured CO2 still faces challenges in transportation, compression, and long-term storage, resulting in overall energy efficiency and economic viability that need improvement. Meanwhile, photocatalytic reduction of carbon dioxide to methanol technology, which can directly utilize solar energy to convert greenhouse gases into high-value-added fuels, possesses both carbon reduction and energy recovery value, making it a research hotspot.

[0003] However, most existing catalytic systems rely on high concentrations or pure CO2 as feedstock. Pre-purifying and concentrating CO2, which has extremely low concentrations in the atmosphere, to the concentration required for the reaction is itself a high-energy-consuming process (requiring approximately 440-600 kJ / mol CO2), severely reducing the environmental benefits of the conversion process.

[0004] In addition, traditional photocatalytic materials such as metal oxides, metal compounds, and nitrides / oxygen compounds have disadvantages mainly concentrated in three core bottlenecks: light utilization efficiency, charge separation capability, and catalytic selectivity. The root cause lies in their intrinsic electronic structure, physicochemical stability, and surface characteristics, making it difficult to simultaneously achieve efficiency, selectivity, and stability. In contrast, the design concept of novel materials such as COFs aims to fundamentally solve these problems. However, pure COF materials also have inherent problems. Generally speaking, COF materials have weak conductivity, and electron-hole pairs generated by light easily recombine rapidly, failing to effectively participate in subsequent reactions. Furthermore, while the high specific surface area of ​​COF channels is beneficial for CO2 adsorption, methanol requires a complex six-electron reduction process, demanding extremely high precision in the design of catalytic sites and electron transfer efficiency. This results in loose interfacial bonding and low charge transport efficiency, presenting certain drawbacks.

[0005] Therefore, there is an urgent need for a photocatalytic material that integrates carbon dioxide capture, light absorption, charge transport, and catalytic conversion units through chemical bonds. Summary of the Invention

[0006] In view of this, the present invention provides a catalytic material for capturing carbon dioxide and methanolizing flue gas, a preparation method and application. The catalytic material uses a triazine-based covalent organic framework as a carrier to in-situ composite molybdenum disulfide and ruthenium single atoms to construct a heterojunction, thereby realizing the integrated synergistic effect of carbon dioxide adsorption and photocatalytic conversion in flue gas.

[0007] The technical solution of this invention is as follows:

[0008] In a first aspect, the present invention provides a catalytic material for capturing carbon dioxide and methanolizing flue gas. The catalytic material is composed of a triazine covalent organic framework, molybdenum disulfide grown in situ on the surface and pores of the triazine covalent organic framework, and ruthenium single atoms dispersed and loaded on the hierarchical structure interface formed by the triazine covalent organic framework and the molybdenum disulfide and on the surface of the triazine covalent organic framework.

[0009] The triazine covalent organic framework is prepared by a solvothermal method via Schiff base condensation reaction of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer and 1,2-acenaphthoquinone.

[0010] The molybdenum disulfide and ruthenium single atoms are in situ composited on the surface and within the pores of the triazine-based covalent organic framework via a one-step hydrothermal method to form a heterojunction.

[0011] Further, the preparation method of the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer includes the following steps:

[0012] 4-Aminobenzonitrile was placed in an ice-water bath, and trifluoromethanesulfonic acid was added dropwise. The internal temperature was controlled to be no higher than 5°C. After reacting for 0.5-1.5 h, the mixture was stirred at room temperature for 20-25 h under a nitrogen atmosphere. The mixture was then quenched in ice water, and the pH was neutralized to neutral with 2M sodium hydroxide solution. After filtration, washing, and vacuum drying at 50-60°C for 10-15 h, the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer was obtained.

[0013] Furthermore, the molar ratio of the 4-aminobenzonitrile to the trifluoromethanesulfonic acid is (2-3):(8-9).

[0014] Furthermore, the preparation method of the triazine-based covalent organic framework includes the following steps:

[0015] The 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer and 1,2-acenaphthoquinone were dissolved in a mixture of dioxane, acetonitrile, and glacial acetic acid, and ultrasonically dispersed for 10-15 min. The mixture was subjected to a cycle of freezing, vacuuming, and thawing for degassing, which was repeated at least 3 times. The mixture was then sealed under nitrogen protection and solvothermal reacted at 100-150 °C for 70-75 h. After washing, Soxhlet extraction, and vacuum drying at 100-150 °C for 10-15 h, the triazine-based covalent organic framework was obtained.

[0016] Further, the molar ratio of the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer to the 1,2-acenaphthoquinone is 1:(1-2); the molar ratio of the dioxane, the acetonitrile and the glacial acetic acid is (4-6):(4-6):1.

[0017] Secondly, based on the same inventive concept, the present invention provides a method for preparing the flue gas carbon dioxide capture and methanolization catalyst material as described in any of the first aspects, comprising the following steps:

[0018] S1. Dissolve ammonium molybdate tetrahydrate and thiourea in deionized water and stir at room temperature for 20-40 min to obtain a homogeneous precursor solution;

[0019] S2. Add ruthenium trichloride hydrate and triazine covalent organic framework powder to the homogeneous solution of the precursor, and stir at room temperature for 5-8 hours to obtain a mixture;

[0020] S3. The mixture is transferred to a high-pressure reactor with a polytetrafluoroethylene liner and sealed at 200-240°C for 15-20 hours to obtain a black precipitate;

[0021] S4. The black precipitate is separated by centrifugation or filtration, washed at least 3 times with deionized water and anhydrous ethanol alternately, dried at 50-80℃ for 5-7 hours, and ground to obtain MoS2-Ru-COF black solid powder, which is the catalyst material.

[0022] Furthermore, the mass ratio of the ammonium molybdate tetrahydrate to the thiourea is 1:(2-4).

[0023] Furthermore, the amount of ruthenium trichloride hydrate added is 20wt%-40wt% of the total solid mass; the amount of triazine covalent organic framework powder added is 10wt%-50wt% of the total solid mass.

[0024] Thirdly, based on the same inventive concept, this invention provides the application of the flue gas carbon dioxide capture and methanolization catalytic material described in the first aspect or the flue gas carbon dioxide capture and methanolization catalytic material prepared by the preparation method described in the second aspect in the integrated flue gas carbon dioxide capture and conversion to methanol.

[0025] Furthermore, the selectivity of the photocatalytic reduction of carbon dioxide to methanol by the catalytic material is ≤82%, and the cumulative methanol yield within 2 hours is ≤715 μmol / g.

[0026] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0027] 1. The catalytic material of the present invention exhibits excellent performance in the direct production of methanol from carbon dioxide by photocatalytic reduction and in activity tests. Without the addition of sacrificial agents, the cumulative methanol (CH3OH) can reach 715 μmol / g after two hours, with a selectivity of 82%. The content of by-products formaldehyde (HCHO) and carbon monoxide is low, demonstrating excellent selectivity.

[0028] 2. The catalytic material of this invention maintains high activity and selectivity even after more than five cycles, indicating that it possesses excellent structural stability and recyclability. Directly converting greenhouse gas CO2 into high-value-added chemical fuels achieves the dual goals of "carbon-negative" and "value-added" production. Its environmental benefits and potential product value can offset part of the material's research and development and manufacturing costs.

[0029] 3. The catalytic material of the present invention can directly produce methanol under mild conditions (room temperature and pressure). This material integrates adsorption, light capture and catalysis, which simplifies the design of the reaction system, reduces the complexity of system operation and maintenance, and has a simple and efficient process with low energy consumption and low cost. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 The UV-Vis absorption spectra of the products of the embodiments and comparative examples of this invention are shown below.

[0032] Figure 2 These are the steady-state fluorescence spectra of the products from the embodiments and comparative examples of the present invention;

[0033] Figure 3 The accompanying drawings are for embodiments and comparative examples of carbon dioxide adsorption and desorption in this invention;

[0034] Figure 4 This is a graph showing the production of methanol, the main catalytic product of the embodiments and comparative examples of the present invention, over time.

[0035] Figure 5 The catalytic product yields of the embodiments and comparative examples of this invention are shown below. Figure 1 ;

[0036] Figure 6 The catalytic product yields of the embodiments and comparative examples of this invention are shown below. Figure 2 ;

[0037] Figure 7This is a distribution diagram of the catalytic products in the embodiments and comparative examples of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0040] To address the problems existing in the prior art, according to one aspect of the present disclosure, a flue gas carbon dioxide capture and methanolization catalyst is provided, which is composed of a triazine covalent organic framework, molybdenum disulfide grown in situ on the surface and pores of the triazine covalent organic framework, a hierarchical structure interface dispersed and loaded on the triazine covalent organic framework and molybdenum disulfide, and ruthenium single atoms on the surface of the triazine covalent organic framework.

[0041] The triazine covalent organic framework was prepared by a solvothermal method via Schiff base condensation reaction of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer and 1,2-acenaphthoquinone.

[0042] Molybdenum disulfide and ruthenium single atoms are in situ composited on the surface and within the pores of a triazine-based covalent organic framework via a one-step hydrothermal method to form a heterojunction.

[0043] It is worth noting that photocatalytic carbon dioxide reduction technology is an artificial process that simulates photosynthesis in nature. It aims to utilize sunlight, a clean energy source, to convert the greenhouse gas carbon dioxide into valuable fuels or chemicals. Its core objective is to transform the "carbon burden" that causes climate problems into renewable "carbon resources," thereby simultaneously addressing the energy crisis and environmental challenges.

[0044] The key to this technology lies in a special material—a photocatalytic material. When sunlight shines on the surface of the photocatalytic material, it excites and generates high-energy electrons and positively charged holes. These photogenerated charges migrate to the surface of the photocatalytic material and process adsorbed carbon dioxide and water molecules. The stable carbon-oxygen double bonds in the carbon dioxide molecules are broken and rearranged, while the water molecules provide the necessary hydrogen atoms and electrons. Through a series of complex electron transfer and proton coupling reactions, different products such as carbon monoxide, methane, methanol, or formic acid may eventually be generated. The ideal driving force for the entire process is simply sunlight, directly utilizing solar energy to convert low-energy-density waste carbon dioxide into a high-energy-density storage carrier, with oxygen as a byproduct. Therefore, it is considered a highly promising green chemistry solution.

[0045] In this invention, covalent organic frameworks (COFs) are a novel type of porous crystalline material formed by precisely and periodically connecting organic structural units in two-dimensional or three-dimensional space through strong covalent bonds. Their structure is composed of lightweight elements, exhibiting low density, high specific surface area, well-ordered nanopores, and excellent chemical and thermal stability. Their topological structures are classified into two-dimensional and three-dimensional types. Their extended π-conjugated framework acts like a molecular highway, efficiently capturing visible light and promoting the rapid separation and migration of photogenerated electrons and holes, which is the physical basis for achieving efficient photocatalysis. Simultaneously, their precisely tunable nanopores can not only adsorb and enrich low concentrations of carbon dioxide gas but also pre-activate carbon dioxide molecules by introducing functional groups into the pore walls.

[0046] Furthermore, in this invention, ruthenium (Ru) single-atom modification serves as a highly selective CO2 reduction active center. In photocatalytic carbon dioxide reduction experiments, due to the high C=O bond dissociation energy of the CO2 molecule (750 kJ mol), -1 Ru, with its weak affinity for electrons, presents a significant challenge in adsorbing and activating CO2. However, the unique d-electron orbital structure and unsaturated coordination environment of a single Ru atom enable it to effectively interact with the oxygen or carbon atoms in the CO2 molecule. Through an electron "anti-donation" mechanism, it weakens the C=O bond, significantly lowering the activation energy barrier and making the originally inert CO2 molecule more readily reactant. Furthermore, using single-atom Ru ensures that every Ru atom is exposed on the surface and participates in catalysis, theoretically achieving 100% atom utilization. This maximizes the number of active sites with minimal use of precious metals, enabling high-efficiency catalytic conversion of carbon dioxide at a lower cost.

[0047] Furthermore, in this invention, molybdenum disulfide (MoS2) serves as a multifunctional cocatalyst and charge bridge. As a two-dimensional semiconductor material, MoS2's two-dimensional layered structure exhibits high carrier mobility. It can act as an "electronic bridge" between COF and Ru sites, rapidly extracting photogenerated electrons from the COF and directionally transporting them to the Ru active centers, greatly accelerating charge separation and transport processes and inhibiting recombination. Moreover, as a typical transition metal sulfide, MoS2 possesses inherent sulfur resistance properties, protecting Ru sites from the influence of trace sulfur oxides in flue gas.

[0048] Based on the above material properties, it should be noted that the present invention integrates carbon dioxide adsorption and direct conversion and utilization in a synergistic manner. The COF material itself has a high specific surface area and ordered pores, which can directly physically adsorb carbon dioxide. At the same time, its nitrogen-rich environment can chemically adsorb CO2, increasing the local CO2 concentration. This can be further applied to photocatalytic conversion. When applied to flue gas environments where the carbon dioxide concentration is relatively low, the carbon dioxide can be directly converted into methanol by utilizing the effective adsorption properties of COF.

[0049] Secondly, the photocatalytic material of this invention possesses a highly efficient catalytic conversion pathway. By combining the narrow-bandgap semiconductor MoS2 with a Ru-rich COF material, a heterojunction is constructed, achieving more efficient visible light absorption (extending to the near-infrared region) and separation of photogenerated carriers. The built-in electric field formed at the heterojunction interface accelerates the separation of electron-hole pairs, prolongs carrier lifetime, and provides more photogenerated electrons for CO2 reduction. Simultaneously, the proton conduction channels on the material surface (hydrogen bond network in COF) facilitate proton transport, promote a multi-electron reduction pathway, and are beneficial for the direct conversion of carbon dioxide to methanol.

[0050] It should be noted that the synergy among the three is not a simple contact, but rather a unified whole formed through strong chemical coupling. Through the coordination locking effect between Ru and COF, the Ru center is coordinated and anchored by heteroatoms such as nitrogen (N) or phosphorus (P) on the COF framework. This chemical bond (Ru-N bond) not only prevents the aggregation of Ru nanoclusters, but more importantly, it changes the electron cloud distribution of COF, enabling its excited electrons to be instantly captured to Ru sites. The edge active sites of MoS2 are also responsible for water oxidation, generating a continuous stream of active protons. These protons migrate rapidly through the interlayer channels of MoS2, thereby quickly combining with photoelectrons from COF.

[0051] It should also be noted that the composite material has stable complementary support. The porous framework of COF provides a growth template for the layered structure of MoS2, which restricts the stacking of its layers and exposes more edge active sites. In turn, the introduction of MoS2 enhances the resistance of the organic COF framework to photocorrosion, while Ru atoms are firmly bound in the "chemical pocket" formed by the two. This dual effect of spatial confinement and chemical bonding ensures that the active sites are not lost or deactivated during long-term reaction cycles.

[0052] Furthermore, this invention achieves zero-carbon footprint energy input through solar energy drive. Photocatalysis directly converts abundant and inexhaustible solar energy into chemical energy to drive the chemical reaction, providing heat through solar energy. This eliminates the need for intermediate conversion steps involving "light energy, electrical energy, and chemical energy," resulting in less energy loss and a simpler system. It also differs from the conventional high-temperature, high-pressure application system for producing methanol via carbon dioxide hydrogenation.

[0053] Therefore, based on the above effects, in the CO2 conversion scenario, the catalyst of this invention can be made into various forms such as thin film and particles, and can be adapted to the integrated "photovoltaic and photocatalytic" device for on-site CO2 capture and conversion of industrial exhaust gas and building exhaust gas. The generated methanol can be directly used as fuel or chemical raw material, achieving the dual goals of "carbon emission reduction and resource recovery".

[0054] In some examples, the preparation method of the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer includes the following steps:

[0055] 4-Aminobenzonitrile was placed in an ice-water bath, and trifluoromethanesulfonic acid was added dropwise. The internal temperature was controlled to be no higher than 5°C. After reacting for 0.5-1.5 h, the mixture was stirred at room temperature for 20-25 h under a nitrogen atmosphere. The mixture was then quenched in ice water, and the pH was neutralized to neutral with 2M sodium hydroxide solution. After filtration, washing, and vacuum drying at 50-60°C for 10-15 h, 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer was obtained.

[0056] In some examples, the molar ratio of 4-aminobenzonitrile to trifluoromethanesulfonic acid is (2-3):(8-9).

[0057] In some examples, the preparation method of the triazine-based covalent organic framework includes the following steps:

[0058] The monomers 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and 1,2-acenaphthoquinone were dissolved in a mixture of dioxane, acetonitrile and glacial acetic acid, and ultrasonically dispersed for 10-15 min. The mixture was subjected to a cycle of freezing, vacuuming and thawing for degassing, which was repeated at least 3 times. The mixture was then sealed under nitrogen protection and solvothermal reaction at 100-150 °C for 70-75 h. After washing, Soxhlet extraction and vacuum drying at 100-150 °C for 10-15 h, the triazine covalent organic framework was obtained.

[0059] In some examples, the molar ratio of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer to 1,2-acenaphthoquinone is 1:(1-2); the molar ratio of dioxane, acetonitrile and glacial acetic acid is (4-6):(4-6):1.

[0060] According to another aspect of the embodiments of this application, a method for preparing a flue gas carbon dioxide capture and methanolization catalyst is also provided, comprising the following steps:

[0061] S1. Dissolve ammonium molybdate tetrahydrate and thiourea in deionized water and stir at room temperature for 20-40 min to obtain a homogeneous precursor solution;

[0062] S2. Add ruthenium trichloride hydrate and triazine covalent organic framework powder to the homogeneous solution of the precursor, and stir at room temperature for 5-8 hours to obtain a mixture;

[0063] S3. Transfer the mixture to a high-pressure reactor with a polytetrafluoroethylene liner, and seal it at 200-240℃ for 15-20 hours to obtain a black precipitate;

[0064] S4. Separate the black precipitate by centrifugation or vacuum filtration, wash it with deionized water and anhydrous ethanol alternately at least 3 times, dry it at 50-80℃ for 5-7 hours, and grind it to obtain MoS2-Ru-COF black solid powder, which is the catalyst material.

[0065] In some examples, the mass ratio of ammonium molybdate tetrahydrate to thiourea is 1:(2-4).

[0066] In some examples, the amount of ruthenium trichloride hydrate added was 20wt%-40wt% of the total solids mass; the amount of triazine covalent organic framework powder added was 10wt%-50wt% of the total solids mass.

[0067] According to another aspect of the embodiments of this application, the application of the flue gas carbon dioxide capture and methanolization catalyst material as described in any of the first aspects or the flue gas carbon dioxide capture and methanolization catalyst material prepared by the preparation method described in any of the second aspects in the integrated flue gas carbon dioxide capture and conversion to methanol is also provided.

[0068] In some examples, the selectivity of the catalytic material for photocatalytic reduction of carbon dioxide to methanol reached 82%, and the cumulative methanol yield reached 715 μmol / g within 2 hours.

[0069] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then common international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0070] Example 1

[0071] Please refer to Figure 1 This embodiment 1 provides a flue gas carbon dioxide capture and methanolization catalytic material and its preparation method. The preparation method includes the following steps:

[0072] Synthesis of S1,2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer (TAPT):

[0073] S1.1. Reaction System Setup and Low-Temperature Reaction: First, accurately weigh 1.544 g (equivalent to 13.076 mmol) of 4-aminobenzonitrile solid and place it in a dry, appropriately sized round-bottom flask. Place the flask in an ice-water bath to ensure the reactant temperature is stably maintained at 0°C. While continuously stirring, use a constant-pressure dropping funnel or syringe pump to very slowly add 4.0 mL (approximately 44.4 mmol, excess) of trifluoromethanesulfonic acid to the flask. This step is a strongly exothermic process, and the dropping rate must be strictly controlled to ensure that the internal temperature of the reaction mixture does not exceed 5°C to prevent side reactions or reactant decomposition caused by local overheating. After the addition is complete, maintain the ice bath conditions and continue to vigorously stir the reaction mixture at 0°C for 1 hour to ensure the reaction proceeds completely.

[0074] S1.2. Room temperature extension reaction and atmosphere control: Subsequently, remove the ice bath and connect the reaction system to the nitrogen protection line. By continuously introducing inert nitrogen gas to purge the air in the bottle, an oxygen-free environment is created to prevent product oxidation. Under the nitrogen atmosphere, allow the reaction mixture to naturally heat up to room temperature (usually around 25°C) and continue stirring for 24 hours. During this period, the color of the reaction solution will usually gradually darken.

[0075] S1.3. Reaction quenching and product precipitation: After the reaction is completed, the reaction mixture is slowly poured into a beaker containing 20 ml of crushed ice and deionized water under stirring to quench and dilute the reaction.

[0076] S1.4. Neutralization and pH control: Subsequently, under ice bath cooling and stirring, the acidic mixture was neutralized with a 2M sodium hydroxide aqueous solution. The pH was monitored using precision pH test paper or a pH meter. The alkali solution was added dropwise until the aqueous phase of the mixture reached neutrality (pH≈7.0). Care was taken to avoid excessive alkali solution to prevent potential products from undergoing structural changes under strong alkaline conditions. During the neutralization process, the target product TAPT will precipitate out of the solution in large quantities in solid form, forming a yellow suspension.

[0077] S1.5. Product Separation and Purification: Vacuum filtration is performed using a Buchner funnel or a sintered glass funnel to collect the yellow crude product solid. To thoroughly remove adsorbed sodium salts, residual acids and alkalis, and other water-soluble impurities, the filter cake needs to be washed thoroughly multiple times (5 times or more) with a large amount (20-30 ml each time) of deionized water until the washing solution is neutral and no chloride ions are detected by silver nitrate solution. The washed solid is then spread evenly on a watch glass and transferred to a vacuum drying oven at 60°C for 12 hours to obtain high-purity TAPT yellow crystals or powder, which can be used for the next reaction.

[0078] S2. Synthesis of triazine-based covalent organic framework materials (Tr-COF):

[0079] S2.1. Monomer weighing and solvent mixing: Accurately weigh 0.1 mmol of TAPT monomer and 0.15 mmol of 1,2-acenaphthoquinone and place them in a 10 mL Pyrex pressure-resistant glass tube (equipped with a polytetrafluoroethylene sealing stopper) that has been baked and dried. Then, using a precision pipette, add 0.5 mL of dioxane, 0.5 mL of acetonitrile and 0.1 mL of glacial acetic acid in sequence to form a mixed solvent system. Dioxane and acetonitrile are used as the main reaction solvents, while glacial acetic acid is used as a catalyst to promote the Schiff base condensation (iminolation) reaction.

[0080] S2.2. Mixing and Degassing: Place the glass tube in an ultrasonic cleaner and sonicate for 15 minutes to ensure that the solid monomers are completely dissolved or uniformly dispersed to form a homogeneous solution. Then, perform a cycle of freezing, vacuuming, and thawing to degas the reaction solution, repeating this process three times. Specifically, immerse the glass tube in liquid nitrogen or an acetone-dry ice bath to completely freeze the solution. Then connect it to a high vacuum line and evacuate the system until the pressure is below 0.1 Torr. Finally, close the vacuum valve and allow the solution to thaw slowly at room temperature. This step aims to completely remove oxygen dissolved in the solvent, prevent oxidation side reactions, and avoid excessive pressure inside the tube due to solvent vaporization during heating.

[0081] S2.3. Sealing and thermal reaction: After degassing, under the protection of nitrogen flow, use an oxygen-natural gas or hydrogen-oxygen torch to quickly seal the glass tube opening. Place the sealed glass tube in a forced-air drying oven or muffle furnace preheated to 120°C and react at a constant temperature for 72 hours. During this period, the amino group of TAPT condenses with the carbonyl group of 1,2-acenaphthoquinone, forming a highly ordered two-dimensional layered framework and crystallizing through dynamic covalent chemistry.

[0082] S2.4. Product collection and washing: After the reaction is completed, the product is allowed to cool naturally to room temperature. The glass tube is carefully broken and the contents are transferred to a sintered glass funnel. The dark red precipitate is collected by vacuum filtration. The filter cake is first washed three times with acetone to remove high-boiling solvents and some oligomers. Then it is washed three times with tetrahydrofuran to further remove organic impurities.

[0083] S2.5. Soxhlet extraction and purification: In order to deeply remove unreacted monomers or small molecule byproducts encapsulated in the COF channels, the above crude product is placed in a Soxhlet extractor and extracted continuously by reflux for at least 24 hours in an oil bath with N,N-dimethylformamide as solvent until the reflux liquid becomes colorless.

[0084] S2.6. Drying and storage: The purified framework material was transferred to a petri dish and dried overnight in a vacuum drying oven at 120°C to completely remove solvent molecules from the pores, finally obtaining a dark red, fluffy Tr-COF powder. According to the weighing calculation, the separation yield of this method can reach 88%. The product should be stored in a desiccator for later use.

[0085] Synthesis of S3.MoS2-Ru-COF nanocomposites:

[0086] S3.1. Preparation of precursor solution: Accurately weigh 0.309 g of ammonium molybdate tetrahydrate and 0.63 g of thiourea, dissolve them together in 60 mL of deionized water, place the solution on a magnetic stirrer and stir vigorously at room temperature for 30 minutes until a clear and transparent homogeneous solution is obtained.

[0087] S3.2. Addition of support and metal source: Add 40 mg of precisely weighed ruthenium trichloride hydrate and 60 mg of Tr-COF powder to the above solution, and continue stirring at room temperature for 6 hours to ensure Ru 3+ Ions are fully adsorbed on the surface and pores of negatively charged or nitrogen-rich Tr-COF support through electrostatic and coordination interactions, while the components are highly dispersed.

[0088] S3.3. Hydrothermal Reaction: Transfer the thoroughly mixed suspension to a 100 mL PTFE-lined stainless steel high-pressure reactor, ensuring a filling density of 70%–80%. After sealing the reactor, place it in a preheated oven and react at 220°C for 18 hours. During this process, thiourea decomposes and releases S... 2- , with MoO4 2- The reaction produces MoS2, while Ru... 3+ It was partially reduced and assembled with Tr-COF and MoS2 into a composite material;

[0089] S3.4. Post-processing: After the reaction is completed, the reaction vessel is allowed to cool naturally to room temperature before the product is collected. The black precipitate is separated by centrifugation or filtration and washed three times each with deionized water and anhydrous ethanol to remove ionic impurities and residual organic matter. Finally, the washed sample is placed in a 60°C forced-air drying oven and dried for 6 hours. After grinding, the final MoS2-Ru-COF black solid powder is obtained, which is the catalyst material.

[0090] Example 2

[0091] Example 2 provides a catalytic material and preparation method for capturing carbon dioxide and methanolizing flue gas, which is basically the same as Example 1, except that the amount of ruthenium trichloride hydrate added in step S3.2 is 80 mg.

[0092] Example 3

[0093] Example 3 provides a catalytic material and preparation method for capturing carbon dioxide and methanolizing flue gas, which is basically the same as Example 1, except that the amount of ruthenium trichloride hydrate added in step S3.2 is 120 mg.

[0094] Example 4

[0095] Example 4 provides a catalytic material and preparation method for capturing carbon dioxide and methanol from flue gas. It is basically the same as Example 1, except that the amount of Tr-COF added in step S3.2 is 16 mg (accounting for about 10 wt% of the total theoretical solid mass).

[0096] Example 5

[0097] Example 5 provides a catalytic material and preparation method for capturing carbon dioxide and methanol from flue gas. It is basically the same as Example 1, except that the amount of Tr-COF added in step S3.2 is 140 mg (accounting for about 50 wt% of the total theoretical solid mass).

[0098] Comparative Example 1

[0099] Comparative Example 1 provides a catalytic material for capturing carbon dioxide and methanolizing flue gas and its preparation method, which is basically the same as Example 1, except that Tr-COF was not added and 80 mg of ruthenium trichloride hydrate was used for synthesis to verify the composite state of MoS2 and Ru without a support.

[0100] Comparative Example 2

[0101] Comparative Example 2 provides a flue gas carbon dioxide capture and methanolization catalyst and its preparation method, which is basically the same as Example 1, except that MoS2 is not added and a one-step impregnation method is used for synthesis. 50 mg of Tr-COF is dispersed in 50 mL of deionized water, 60 mg of ruthenium trichloride hydrate is added, and the mixture is stirred at room temperature for 12 h, then filtered, washed and dried to verify the loading of Ru on the pure COF support.

[0102] Comparative Example 3

[0103] Comparative Example 3 provides a mixed catalytic material and its preparation method. 140 mg of MoS2-Ru obtained from Comparative Example 1 and 60 mg of Tr-COF powder were added together to deionized water and magnetically stirred at room temperature for 6 hours to make them evenly mixed. Then, after filtration, washing and drying, a physically mixed sample was obtained to verify the performance difference between in-situ composite and physical mixing.

[0104] Comparative Example 4

[0105] Comparative Example 4 provides a mixed catalytic material and its preparation method. 60 mg of ruthenium trichloride hydrate is dispersed in 10 mL of anhydrous ethanol, and 20 mg of polyethyleneimine (a commercial carbon dioxide capture agent) is added to the dispersion to verify the capture performance of the loaded commercial capture agent.

[0106] It should be noted that the preparation method of molybdenum disulfide (MoS2) used in the above embodiments and comparative examples is as follows:

[0107] First, 3 mmol of ammonium molybdate tetrahydrate ((NH4)6Mo7O) 24Dissolve 4H₂O (>99.99%) and 90 mmol of thiourea (CH₄N₂S,>99.0%) in 105 mL of ethylene glycol (C₂H₆O₂,>99%). Place the beaker on a magnetic stirrer with a stir bar and stir vigorously at 600–800 rpm for 30–60 minutes until a homogeneous, transparent, pale yellow solution is formed. Seal the resulting mixture in a 200 mL stainless steel autoclave with a PTFE liner. Heat the autoclave to 180 °C at a rate of 2–5 °C / min, avoiding drastic temperature changes, and maintain the temperature at 180 °C for 24 hours. After the reaction is complete, open the autoclave. After the reaction, the suspension was transferred to a centrifuge tube and centrifuged at 8000–10000 rpm for 5–10 minutes. The supernatant was discarded, and a black precipitate was obtained. The precipitate was washed in the following order: Deionized water washing: Add 40 mL of deionized water, sonicate for 5 minutes, centrifuge, repeat 3–4 times until the supernatant is close to neutral (pH≈7). Anhydrous ethanol washing: Add 40 mL of anhydrous ethanol, sonicate and centrifuge, repeat 2–3 times to remove organic residues. After processing, the sample was placed in a vacuum drying oven and dried at 60 °C for 12 hours. The dried sample was ground into a fine powder to obtain molybdenum disulfide, which was stored in a desiccator for later use.

[0108] The products of Examples 1-2 and Comparative Examples 1-2 were subjected to UV-Vis (ultraviolet-visible) absorption spectroscopy tests, and the results are as follows: Figure 1 As shown in the figure, the pure Ru-MoS2 in Comparative Example 1 exhibits the strongest absorption capacity and maintains extremely high absorption in the entire visible light region (400-700nm). This is due to the excellent light-harvesting ability of molybdenum disulfide. The absorption value of the pure Ru-COF material is the weakest. The absorption values ​​of the composite materials in Example 1 and Example 2 are between the two, indicating that the two are successfully composited in situ. The absorption of Example 1 is slightly higher than that of Example 2, indicating that its implementation scheme is more effective in improving the light absorption efficiency of the material.

[0109] Please refer to Figure 2 , Figure 2 The figures show the steady-state fluorescence spectra of Examples 1-2 and Comparative Examples 1-2. As can be seen from the figures, the luminescence of the simple Ru-MoS2 multilayer structure in Comparative Example 1 is relatively low. The fluorescence of the composite materials in Examples 1 and 2 is significantly stronger than that of the two single materials. This is because the enhanced fluorescence after the two materials are combined comes from the unique heterojunction structure of the composite material.

[0110] To better understand the present invention, carbon dioxide adsorption performance tests were conducted on the embodiments and comparative examples. The test steps are as follows:

[0111] (1) Material pretreatment: All catalyst samples to be tested were placed in a vacuum oven at 60°C and dried for at least 12 hours to remove adsorbed moisture and gas;

[0112] (2) Weigh 30 mg of sample and place it in a sample tube. Connect the adsorption-desorption instrument and heat the sample to 200 °C in an inert gas (Ar) atmosphere. Keep it for 1 hour to completely remove water molecules, carbon dioxide and other impurities remaining on the surface and inside the sample. Then cool it to the adsorption temperature.

[0113] (3) Room temperature adsorption: Carbon dioxide in 20% helium was slowly blown in at a fixed flow rate of 30 mL / min for 30 minutes until adsorption saturation was achieved;

[0114] (4) Programmed temperature desorption: The temperature is increased to 170°C at a rate of 10°C / minute, and the composition of the outflowing gas is continuously recorded by a thermal conductivity detector to determine the strength of carbon dioxide adsorption.

[0115] Please refer to Figure 3 , Figure 3 This is a schematic diagram illustrating the relative strength of carbon dioxide adsorption between Example 1 and Comparative Examples 1, 2, and 4, used to verify the catalyst's ability to capture carbon dioxide. Figure 3 It can be seen that the commercial adsorbent in Comparative Example 4 exhibits the strongest carbon dioxide adsorption capacity, while the Ru-MoS2 material alone has extremely weak adsorption capacity for carbon dioxide. However, thanks to its excellent pore volume, Ru-COF alone exhibits excellent carbon dioxide adsorption capacity. After the two are combined to form Example 1, its carbon dioxide adsorption capacity is slightly reduced, but it still exhibits excellent adsorption capacity. Simultaneously, it can directly photocatalytically convert carbon dioxide.

[0116] To better understand the present invention, the photocatalytic carbon dioxide reduction performance of the embodiments and comparative examples was tested. The test steps are as follows:

[0117] S1. Preparations before testing:

[0118] S1.1. Catalyst pretreatment:

[0119] S1.1.1. Drying: Place all catalyst samples to be tested in a vacuum oven at 60°C and dry for at least 12 hours to remove adsorbed moisture and gas;

[0120] S1.1.2. Weighing: Accurately weigh 10.0 mg of catalyst on a precision analytical balance and set aside for use. Prepare at least 3 parallel samples for each sample to improve data reliability.

[0121] S1.2. Reaction system setup and leak detection:

[0122] S1.2.1. Reactor: A closed photocatalytic reaction cell (volume 250 mL) with a quartz window at the top (to ensure the transmission of ultraviolet-visible light) and multiple sampling / injection valves is used.

[0123] S1.2.2. System Connection: Connect the reaction cell to the vacuum system, high-purity gas cylinder (CO2 source, Ar) and online / offline gas chromatography system through high-airtight stainless steel pipeline;

[0124] S1.2.3. Leak detection: Close all valves, evacuate the system to a vacuum, close the vacuum pump valve, and monitor whether the system pressure rises significantly within 30 minutes to ensure that the entire system is absolutely airtight and has no leaks.

[0125] S1.3. Preparation of reagents and gases:

[0126] S1.3.1. Reaction medium: Prepare ultrapure water (resistivity 18.2 MΩ·cm).

[0127] S1.3.2. High-purity gas: Prepare argon gas with a purity ≥ 99.99% for system purging and impurity removal;

[0128] S2. Photocatalytic reaction steps:

[0129] S2.1. Catalyst dispersion and reaction solution preparation: Transfer 10.0 mg of the weighed catalyst to a clean and dry reaction tank; add 50 mL of ultrapure water to make the catalyst concentration 0.2 g / L; then seal the reaction tank and connect it to the system through a pipeline.

[0130] S2.2. System impurity removal and adsorption-desorption equilibrium:

[0131] S2.2.1. Vacuuming and Argon Purging Cycle: Open the valve connecting the reaction tank to the vacuum system, evacuate the reaction tank for 5 minutes, then close the vacuum valve and introduce high-purity argon gas to a pressure slightly higher than atmospheric pressure. Repeat this cycle at least 3 times to thoroughly remove impurity gases from the reaction liquid and catalyst surface.

[0132] S2.2.2. Stirring and dispersing: After the last purging of argon gas to atmospheric pressure, turn on the magnetic stirrer in the reaction tank and stir evenly for 30 minutes in the dark. This step is intended to make the catalyst evenly dispersed in the solution.

[0133] S2.3. CO2 saturation and reaction initiation:

[0134] S2.3.1. Replace with flue gas (the CO2 content in the flue gas is usually around 20%) atmosphere: Under continuous stirring, connect the reaction tank to the vacuum system, slowly evacuate for 5 minutes (be careful to avoid the liquid boiling violently), then close the vacuum valve, and introduce the prepared flue gas into the reaction tank until the pressure is slightly higher than 1 standard atmosphere. Repeat this "evacuation-induction" process 3 times to ensure that the gas environment in the reaction tank is flue gas;

[0135] S2.3.2.CO2 dissolution equilibrium: Under flue gas atmosphere, continue stirring in the dark for 30 minutes to saturate the gas in the solution;

[0136] S2.3.3. Background sample collection: After equilibration, immediately use an airtight syringe to extract 0.5 mL of gas from the headspace of the reaction cell and inject it into the gas chromatograph to analyze the background concentration of substances such as CO2, CO, and CH3OH. Record the data at the zero time point and mark it as the blank group.

[0137] S2.3.4. Turn on the illumination: Turn on the light source (300W xenon lamp, full spectrum light, equipped with AM1.5G filter to simulate sunlight, light intensity adjusted to 600mWcm²). -2 At the same time, timing begins, and continuous stirring and constant temperature are maintained during the light exposure period (the temperature of the reaction tank is controlled at 60℃ by circulating water bath).

[0138] S2.4. Sampling and monitoring of product gases:

[0139] S2.4.1. At 0.5, 1, 1.5, and 2 hours after irradiation, 0.5 mL of gas is drawn from the headspace using a gas-tight syringe and injected into a gas chromatograph to detect methanol (in a sealed system, due to constant pressure and temperature, the liquid and gas phases reach equilibrium, so the methanol content can be calculated from the methanol content in the vapor) and carbon monoxide. The gas is then analyzed using a gas chromatograph (equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD)). The yield and productivity are calculated based on the peak area of ​​the product.

[0140] S2.4.2. After the reaction is complete, collect the liquid containing the mixed catalyst, centrifuge to separate the supernatant, and further analyze the bulk products. The concentration of formaldehyde (HCHO) in the liquid product is quantitatively determined by colorimetry, as follows:

[0141] First, 15g of ammonium acetate, 0.3mL of acetic acid, and 0.2mL of 2,4-pentanedione were dissolved in water to prepare a 100mL aqueous solution as a colorimetric reagent. 0.5mL of the colorimetric reagent was mixed with 2.0mL of water and 0.5mL of the test liquid. The mixed solution was kept at 35℃ in a water bath and monitored using a UV-Vis absorption spectrometer until the absorption intensity at 412nm no longer increased. The concentration of HCHO in the product was determined by a standard curve. The catalyst was dried and recovered for future use.

[0142] As attached Figure 4 The methanol yield of the main product over time is shown in the graph. The methanol yield data of Examples 1-2 and Comparative Examples 1-2 are shown in the table below:

[0143]

[0144] Depend on Figure 4 As shown in the table, the methanol yield increased continuously over time within 2 hours. Different loading rates affected the product yield, but overall it increased continuously over time. In contrast, the yield of the control example was very low.

[0145] Please refer to Figure 5-6 , Figure 5-6 The table below shows the yields of all products after two hours of use for each example and comparative catalyst. CO (carbon monoxide) and CH3OH (methanol) were detected directly by gas chromatography, while HCHO (formaldehyde) was detected using the colorimetric method mentioned earlier. Specific data are shown in the table below.

[0146]

[0147] Depend on Figure 5 As shown in the table, in Examples 1-2 and Comparative Examples 1-2, small amounts of formaldehyde (approximately 150 μmol / g) and carbon monoxide (approximately 20 μmol / g) were observed after two hours, while methanol selectivity was high. The yields of the different examples varied slightly, but the overall trend was similar. Example 1 showed the best performance because the Ru loading in the composite catalyst was adjusted; excess Ru atoms lead to aggregation, reducing its utilization and thus decreasing activity. In contrast, the comparative examples showed significant yield reductions and did not exhibit obvious photocatalytic performance.

[0148] To further investigate the effect of different composite ratios of photocatalytic materials on photocatalytic performance, performance tests were also conducted on Examples 3-5 and Comparative Example 1. The data in the table are compared with... Figure 6 As can be seen, in Example 3, with the increase of Ru loading, the excess of Ru atoms leads to aggregation, reducing its utilization rate and increasing costs. In addition, the introduction of COF material was also adjusted. When the amount of COF is too small, the light-harvesting ability and CO2 adsorption ability decrease, resulting in insufficient substrate for multi-electron reduction and performance degradation. When the amount of COF is too large, excessive COF will bury Ru particles deep within the framework, burying active sites, resulting in insufficient electron conductivity, and preventing distant Ru sites from obtaining enough electrons to drive the six-electron reduction process. Simple physical composites also did not exhibit significant performance improvements because the physical composite components are only connected by weak van der Waals forces. Different components are prone to phase separation (detachment) during the reaction; physical composites merely pile materials together, while chemical composites functionalize and integrate materials.

[0149] The products catalyzed by the catalysts in Examples 1-2 and Comparative Examples 1-2 were summarized and compared, and a product distribution map was obtained. Figure 7 As shown, by Figure 7As can be seen, the overall product yield of the examples is significantly higher than that of the comparative examples, and the methanol selectivity of Example 1 can reach 82%.

[0150] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0151] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A catalytic material for capturing carbon dioxide from flue gas and methanolization, characterized in that, The catalytic material is composed of a triazine covalent organic framework, molybdenum disulfide grown in situ on the surface and in the pores of the triazine covalent organic framework, and ruthenium single atoms dispersed and loaded on the hierarchical structure interface formed by the triazine covalent organic framework and the molybdenum disulfide and on the surface of the triazine covalent organic framework. The triazine covalent organic framework is prepared by a solvothermal method via Schiff base condensation reaction of 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer and 1,2-acenaphthoquinone. The molybdenum disulfide and ruthenium single atoms are in situ composited on the surface and within the pores of the triazine-based covalent organic framework via a one-step hydrothermal method to form a heterojunction.

2. The catalytic material according to claim 1, characterized in that, The preparation method of the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer includes the following steps: 4-Aminobenzonitrile was placed in an ice-water bath, and trifluoromethanesulfonic acid was added dropwise. The internal temperature was controlled to be no higher than 5°C. After reacting for 0.5-1.5 h, the mixture was stirred at room temperature for 20-25 h under a nitrogen atmosphere. The mixture was then quenched in ice water, and the pH was neutralized to neutral with 2M sodium hydroxide solution. After filtration, washing, and vacuum drying at 50-60°C for 10-15 h, the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer was obtained.

3. The catalytic material according to claim 2, characterized in that, The molar ratio of 4-aminobenzonitrile to trifluoromethanesulfonic acid is (2-3):(8-9).

4. The catalytic material according to claim 1, characterized in that, The preparation method of the triazine-based covalent organic framework includes the following steps: The 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer and 1,2-acenaphthoquinone were dissolved in a mixture of dioxane, acetonitrile, and glacial acetic acid, and ultrasonically dispersed for 10-15 min. The mixture was subjected to a cycle of freezing, vacuuming, and thawing for degassing, which was repeated at least 3 times. The mixture was then sealed under nitrogen protection and solvothermal reacted at 100-150 °C for 70-75 h. After washing, Soxhlet extraction, and vacuum drying at 100-150 °C for 10-15 h, the triazine-based covalent organic framework was obtained.

5. The catalytic material according to claim 4, characterized in that, The molar ratio of the 2,4,6-tris(4-aminophenyl)-1,3,5-triazine monomer to the 1,2-acenaphthoquinone is 1:(1-2); the molar ratio of the dioxane, the acetonitrile, and the glacial acetic acid is (4-6):(4-6):

1.

6. A method for preparing a flue gas carbon dioxide capture and methanolization catalyst according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Dissolve ammonium molybdate tetrahydrate and thiourea in deionized water and stir at room temperature for 20-40 min to obtain a homogeneous precursor solution; S2. Add ruthenium trichloride hydrate and triazine covalent organic framework powder to the homogeneous solution of the precursor, and stir at room temperature for 5-8 hours to obtain a mixture; S3. The mixture is transferred to a high-pressure reactor with a polytetrafluoroethylene liner and sealed at 200-240°C for 15-20 hours to obtain a black precipitate; S4. The black precipitate is separated by centrifugation or filtration, washed at least 3 times with deionized water and anhydrous ethanol alternately, dried at 50-80℃ for 5-7 hours, and ground to obtain MoS2-Ru-COF black solid powder, which is the catalyst material.

7. The method according to claim 6, characterized in that, The mass ratio of the ammonium molybdate tetrahydrate to the thiourea is 1:(2-4).

8. The method according to claim 6, characterized in that, The amount of ruthenium trichloride hydrate added is 20wt%-40wt% of the total solid mass; the amount of triazine-based covalent organic framework powder added is 10wt%-50wt% of the total solid mass.

9. The application of any one of the flue gas carbon dioxide capture and methanolization catalysts according to claims 1-5 in integrated flue gas carbon dioxide capture and conversion to methanol.

10. The application according to claim 9, characterized in that, The selectivity of the photocatalytic reduction of carbon dioxide to methanol by the catalytic material is ≤82%, and the cumulative methanol yield within 2 hours is ≤715umol / g.

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