Bimetallic carbon dioxide capture and methanation catalytic material, preparation method and application thereof

Abstract

This invention relates to the field of photocatalysis technology, and proposes a bimetallic carbon dioxide capture and methanolization catalytic material, its preparation method, and its application. The catalytic material consists of UiO-66 and V-Bi grown in situ on the surface and within the pores of UiO-66. 19 Br3S 27 Distributed load on UiO-66 and V-Bi 19 Br3S 27 The formed S-shaped heterojunction interface and the Au-Er bimetallic active centers on the UiO-66 surface are composed of these active centers. The Au-Er bimetallic active centers are loaded via sequential photodeposition, with a molar ratio of Au to Er of (1-2):(2-1). UiO-66 and V-Bi... 19 Br3S 27 S-shaped heterojunctions were formed by in-situ hydrothermal composite method; V-Bi 19 Br3S 27 Powered by UiO‑66 and Bi 19 Br3S 27 It is obtained by in-situ composite and alkaline etching treatment. It has high adsorption capacity, broad spectral response and excellent charge separation efficiency. It can efficiently activate low concentration CO2 and achieve direct air CO2 capture and highly selective conversion to methanol at room temperature and pressure, which solves the problems of functional fragmentation and low energy efficiency of existing technologies.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis technology, and more specifically, to bimetallic carbon dioxide capture and methanolization catalytic materials, their preparation methods, and applications. Background Technology

[0002] With global carbon emissions continuing to rise, the development of CO2 capture and utilization technologies has become a research hotspot. Catalytically converting CO2 into methanol can both mitigate the greenhouse effect and achieve carbon cycling, offering both environmental and economic benefits.

[0003] Photocatalysis, driven by solar energy, is an ideal pathway for CO2 conversion. However, traditional photocatalysts (such as TiO2) only respond to ultraviolet light and have extremely low utilization rates for visible and infrared light. Furthermore, CO2 molecules are stable with high C=O bond energies, making activation difficult.

[0004] Metal-organic framework material UiO-66 possesses high specific surface area, excellent stability, and strong CO2 adsorption capacity, but has a narrow photoresponse range; bismuth thiohalides Bi 19 Br3S 27 As a one-dimensional nanowire semiconductor, it can extend the spectrum to the infrared region and promote charge separation through vacancy defects, but it suffers from weak CO2 adsorption and difficulty in controlling vacancy defects.

[0005] Therefore, existing technologies face two major bottlenecks. First, traditional materials in the adsorption stage have low adsorption capacity, slow kinetics, or poor stability. Second, the conversion stage suffers from high thermal catalytic energy consumption, narrow photocatalytic spectral response, and difficulty in CO2 activation. There is a lack of an integrated solution that organically combines efficient CO2 capture, broad-spectrum light absorption, and photocatalysis. A novel composite catalyst capable of synergistically achieving direct air CO2 adsorption and conversion is urgently needed. Summary of the Invention

[0006] In view of this, the present invention provides a bimetallic carbon dioxide capture and methanol conversion catalytic material, preparation method and application. The catalytic material has high adsorption capacity, broad spectral response and excellent charge separation efficiency. It can efficiently activate low concentration CO2 and achieve direct air CO2 capture and highly selective conversion to methanol at room temperature and pressure, solving the problems of functional fragmentation and low energy efficiency of the prior art.

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

[0008] In a first aspect, the present invention provides a bimetallic carbon dioxide capture and methanolization catalytic material, said catalytic material being composed of UiO-66 and V-Bi grown in situ on the surface and within the pores of said UiO-66. 19 Br3S 27 Distributed loading on the UiO-66 and the V-Bi 19 Br3S 27The formed S-shaped heterojunction interface and the Au-Er bimetallic active center on the surface of the UiO-66 are composed of the following:

[0009] The Au-Er bimetallic active center is loaded by sequential photodeposition, wherein the molar ratio of Au to Er is (1-2)∶(2-1).

[0010] The UiO-66 and the V-Bi 19 Br3S 27 S-shaped heterojunctions were formed by in-situ hydrothermal composite method;

[0011] The V-Bi 19 Br3S 27 The UiO-66 and Bi 19 Br3S 27 The product is obtained by in-situ composite followed by alkaline etching.

[0012] Furthermore, the CO2 adsorption capacity of the catalytic material is not less than 0.8 mmol / g; the cumulative methanol yield over 2 hours is 750-1250.45 μmol / g.

[0013] Furthermore, the preparation method of the UiO-66 includes the following steps:

[0014] Zirconium oxychloride pentahydrate was mixed with terephthalic acid in a molar ratio of (1-2):1, N,N-dimethylformamide was added as a solvent, and acetic acid was added as a crystallization regulator. The mixture was reacted at a constant temperature of 100-150℃ for 20-25 hours. After washing with DMF, deionized water and anhydrous ethanol in sequence, the mixture was dried under vacuum at 50-80℃ overnight to obtain UiO-66.

[0015] Furthermore, the Bi 19 Br3S 27 The preparation method includes the following steps:

[0016] Bismuth bromide, thiourea, and ethylenediaminetetraacetic acid were mixed at a mass ratio of 5:(4-5):(0.1-0.2), and anhydrous ethanol was used as the solvent. The mixture was stirred at 500-1000 rpm for 0.5-1.5 h at room temperature, and then reacted at a constant temperature of 150-200 °C for 70-75 h. After washing with deionized water and anhydrous ethanol alternately, the mixture was dried at 70-90 °C for 4-5 h to obtain the Bi. 19 Br3S 27 .

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

[0018] S1. Combine the UiO-66 with the Bi19 Br3S 27 UiO-66 / Bi was obtained by in-situ hydrothermal composite method. 19 Br3S 27 ;

[0019] S2. The UiO-66 / Bi 19 Br3S 27 Alkali etching was performed to obtain UiO-66 / V-Bi. 19 Br3S 27 Heterojunction materials;

[0020] S3. The UiO-66 / V-Bi... 19 Br3S 27 The heterojunction material was loaded with Au and Er sequentially by sequential photodeposition to obtain the catalytic material.

[0021] Furthermore, the in-situ hydrothermal composite method in step S1 specifically includes the following steps:

[0022] Add the UiO-66 to the Bi 19 Br3S 27 Stirring at room temperature for 1-2 hours, then transferring to a high-pressure reactor lined with polytetrafluoroethylene (PTFE), sealing, and reacting at 150-200℃ for 70-75 hours. After cooling to room temperature, centrifuging to obtain the precipitate, washing with deionized water and anhydrous ethanol alternately at least four times, and drying at 70-90℃ for 4-5 hours, yields the UiO-66 / Bi. 19 Br3S 27 .

[0023] Furthermore, the alkaline etching process in step S2 specifically includes the following steps:

[0024] Take 0.1-0.3 parts by weight of the UiO-66 / Bi 19 Br3S 27 The product was ultrasonically dispersed in 20-40 parts of a 0.4-0.6 mol / L NaOH solution, placed in a water bath at 50-70℃, and stirred at 200-400 rpm for 4-6 min. The solid product was collected by centrifugation, washed at least four times alternately with deionized water and anhydrous ethanol, and dried at 70-90℃ for 4-5 h to obtain the UiO-66 / V-Bi. 19 Br3S 27 Heterojunction materials.

[0025] Furthermore, the sequential optical deposition method in step S3, which loads Au and Er in sequence, specifically includes the following steps:

[0026] S3.1. Prepare a potassium chloroaurate solution with a concentration of 0.9-0.95 mg / mL and an erbium nitrate solution with a concentration of 1.0-2.0 mg / mL;

[0027] S3.2. Distribute 80-120 parts of UiO-66 / V-Bi by weight. 19 Br3S 27 The heterojunction material is added to 40-50 parts of deionized water and ultrasonically treated for 10-20 minutes to form a suspension. Under continuous stirring and light-proof conditions, 1-2 parts of the potassium chloroaurate solution are added dropwise and stirred in a light-proof environment for 20-40 minutes to obtain mixture A.

[0028] S3.3. Place the mixture A under a 300-400W full-spectrum xenon lamp and irradiate it with visible light (λ>420nm), controlling the light intensity to 500-700mW / cm². 2 The reaction was carried out under light for 1.5-2.5 hours, followed by centrifugation, washing with deionized water and anhydrous ethanol at least four times alternately, and drying at 70-90℃ for 4-5 hours to obtain UiO-66 / V-Bi. 19 Br3S 27 @Au;

[0029] S3.4. The UiO-66 / V-Bi 19 Br3S 27 @Au is dispersed in 40-50 parts of deionized water and ultrasonically treated for 10-20 minutes to form a suspension. Under continuous stirring and light protection, 1-2 parts of the potassium chloroaurate solution are added dropwise and stirred in a light-protected environment for 50-70 minutes to obtain mixture B.

[0030] S3.5. Place the mixture B under a 300-400W full-spectrum xenon lamp and irradiate it with visible light (λ>420nm), controlling the light intensity to 500-700mW / cm². 2 The catalyst was subjected to light irradiation for 2.5-3.5 hours, centrifuged, washed at least four times with deionized water and anhydrous ethanol, and dried at 70-90°C for 4-5 hours to obtain the catalyst material.

[0031] Thirdly, based on the same inventive concept, this invention provides the application of the bimetallic carbon dioxide capture and methanolization catalytic material described in the first aspect or the bimetallic carbon dioxide capture and methanolization catalytic material prepared by the preparation method described in the second aspect in direct air capture of carbon dioxide and photocatalytic conversion to methanol.

[0032] Furthermore, the methanol selectivity of the catalyst is 65%-75%.

[0033] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0034] 1. The catalytic material of this invention has a capacity of 0.845 mmol / g during dynamic adsorption of carbon dioxide, with an adsorption equilibrium time of about 1 hour. It can efficiently capture low concentrations of CO2 in the atmosphere and meet the requirements of direct air capture.

[0035] 2. The present invention V-Bi 19 Br3S 27 The double vacancy defect extends the spectral response into the infrared region. Combined with the plasma effect of Au, it enables full-spectrum solar energy utilization, significantly improving the light energy utilization rate.

[0036] 3. The S-type heterojunction and Au-Er bimetallic work synergistically to significantly suppress electron-hole recombination, prolong carrier lifetime, and improve charge utilization efficiency.

[0037] 4. The present invention achieves a methanol yield of 1250.45 μmol / g in 2 hours, with a methanol selectivity of 75%, which is much higher than that of single-component or single-metal modified materials, and the content of by-products is low.

[0038] 5. This invention can operate at normal temperature and pressure, without the need for photosensitizers, sacrificial agents, or high-pressure equipment. It has low energy consumption, is easy to operate, has good cycle stability, and is suitable for large-scale applications. Attached Figure Description

[0039] 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 on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a SEM image of UiO-66 in Embodiment 1 of the present invention;

[0041] Figure 2 UiO-66 / V-Bi in Embodiment 1 of the present invention 19 Br3S 27 SEM image;

[0042] Figure 3 This is a graph showing the direct air adsorption of carbon dioxide by the catalytic material in Example 1 of the present invention.

[0043] Figure 4 The graph shows the methanol yield of different catalysts as a function of reaction time in the embodiments and comparative examples of this invention.

[0044] Figure 5 This is a comparison chart of the product selectivity of different catalysts in the embodiments and comparative examples of the present invention after 2 hours;

[0045] Figure 6 This is a comparison chart of the products of the catalytic material in Example 1 of the present invention over reaction time. Detailed Implementation

[0046] 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, not all, of the embodiments of the present invention. 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.

[0047] 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.

[0048] To address the problems existing in the prior art, according to one aspect of the embodiments of this disclosure, a bimetallic carbon dioxide capture and methanolization catalyst is provided, which is composed of UiO-66 and V-Bi grown in situ on the surface and pores of UiO-66. 19 Br3S 27 Distributed load on UiO-66 and V-Bi 19 Br3S 27 The formed S-shaped heterojunction interface and the Au-Er bimetallic active center on the UiO-66 surface;

[0049] The Au-Er bimetallic active center was loaded by sequential photodeposition, wherein the molar ratio of Au to Er was (1-2)∶(2-1).

[0050] UiO-66 and V-Bi 19 Br3S 27 S-shaped heterojunctions were formed by in-situ hydrothermal composite method;

[0051] V-Bi 19 Br3S 27 Powered by UiO-66 and Bi 19 Br3S 27 The product is obtained by in-situ composite followed by alkaline etching.

[0052] It should be noted that in this technical field, researchers typically employ strategies such as noble metal deposition, dye sensitization, or the construction of type I / II heterojunctions to achieve broad-spectrum responses. These methods are either costly or introduce instability. In particular, combining a MOF, known for its stability but weak photocatalytic activity, with a novel narrow-bandgap semiconductor with defect engineering is generally considered to be merely a simple physical mixture or type I heterojunction. Its main purpose is to utilize the adsorption properties of the MOF, while the photocatalytic function is still primarily undertaken by the semiconductor.

[0053] However, this invention has discovered that, through a specific alkaline etching process and in-situ growth composite method, UiO-66 and V-Bi can be combined... 19 Br3S 27 An S-shaped (stepped) heterojunction is formed between them. This structure not only achieves efficient charge separation, but more importantly, it makes the photocatalytic activity of the composite material, especially its selectivity for methanol, far exceed the superposition of single components or physical mixtures, producing a synergistic enhancement effect. This breaks through the traditional understanding that UiO-66 can only act as an adsorbent and cannot play a key role in charge separation.

[0054] It is worth noting that this invention relates to bismuth thiohalide-based semiconductor materials (Bi). 19 Br3S 27 After alkaline etching, V-Bi rich in double vacancies was obtained. 19 Br3S 27 This treatment altered its properties; the introduction of vacancy defects greatly expanded its light absorption range, enabling it to effectively utilize infrared light, which has lower energy but accounts for the majority of solar energy. The modified Bi... 19 Br3S 27 In the composite material of this invention, it acts as an infrared light absorber, responsible for capturing solar energy and driving chemical reactions.

[0055] It should also be noted that the core challenges facing current carbon dioxide capture and conversion technologies lie in the separation of functions and the inefficient use of energy. Most existing solutions treat adsorption enrichment and catalytic conversion as two separate steps, resulting in complex processes, high energy consumption, and the inability to maintain a sustained high-concentration reaction environment on the surface of the catalytic material. Furthermore, widely studied traditional photocatalytic materials can only utilize a small portion of ultraviolet light from sunlight, remaining ineffective against the dominant visible and infrared light, leading to significant energy waste. In addition, the extremely stable chemical properties of carbon dioxide molecules necessitate efficient breaking of their carbon-oxygen double bonds and precise control of multi-electron reduction pathways to accelerate the reaction rate and improve the selectivity for high-value fuels such as methanol.

[0056] Specifically, at the materials level, high-performance adsorbents themselves lack photocatalytic activity; while promising photothermal materials suffer from weak carbon dioxide adsorption capacity, difficulty in controlling the construction of vacancy defects, and susceptibility to aggregation and deactivation. These materials cannot solve the technical problem of adsorption-conversion. Therefore, the bottleneck in technological development lies in the lack of an innovative material system that can integrate efficient adsorption, broad-spectrum absorption, and highly selective photocatalysis. An ideal catalytic material should be able to actively capture and concentrate carbon dioxide feedstock, fully utilize full-spectrum solar energy, and ultimately efficiently and selectively convert carbon dioxide into the target product at closely synergistic active sites.

[0057] Specifically, the core significance of the bimetallic synergistic effect in this invention lies in the fact that, by constructing an Au-Er active center, it successfully achieves a simultaneous doubling of photogenerated charge separation efficiency and CO2 molecule activation capability. The strong coupling between the plasma effect of Au and the f-electron characteristics of Er not only extends the range of light energy utilization to the visible-infrared region, but more importantly, it forms a highly efficient electron transfer channel at the S-type heterojunction interface. Au acts as an electron pump to rapidly capture and transfer photogenerated electrons, while the Er site strongly adsorbs and polarizes CO2 molecules through its unique empty orbitals. The synergy between the two significantly reduces the C=O bond breaking energy barrier, jointly guiding the reaction pathway towards methanol production. Ultimately, this enables the catalytic material to achieve efficient and highly selective conversion of CO2 to methanol even under the harsh conditions of direct air capture and solar energy drive.

[0058] Furthermore, the Au and Er bimetals introduced by sequential photodeposition do not function in isolation, but form a multi-level, strongly coupled synergistic network with the UiO-66 support and V-Bi19Br3S27 semiconductor. The core of its technical principle lies in the precise electronic and structural linkage between the components, which together constitute an inseparable catalytic system.

[0059] First, Au and V-Bi 19 Br3S 27 The linkage of defect sites is fundamental to constructing efficient electron transport channels. During photodeposition, Au 3+ Ions are preferentially absorbed by V-Bi 19 Br3S 27 The surface photogenerated electrons are reduced and tend to anchor near sulfur and bromine vacancies generated by alkaline etching. These vacancy defects are not only key to extending the light absorption range but also provide stable anchoring sites for Au nanoparticles, forming a strong metal-carrier interaction (SMSI). This strong interaction enables Au nanoparticles to act as efficient electron relays. On the one hand, their surface plasmon resonance (LSPR) effect can enhance the capture of visible light and generate hot electrons; on the other hand, and more importantly, they act as electron pumps, rapidly capturing electrons from V-Bi. 19 Br3S 27 Photogenerated electrons migrate from the conduction band and greatly accelerate the transfer rate of electrons to subsequent reaction sites, effectively preventing electron recombination within the semiconductor.

[0060] Secondly, the introduction of Er creates a crucial bridging and activation linkage between Au nanoparticles and the UiO-66 support. 3+ Au particles have a relatively negative reduction potential, making reduction deposition on the carrier alone quite difficult. In the second photodeposition step, Au particles act as pre-established microcathodes, greatly enriching the electron density at the interface, thus providing a favorable environment for Er.3+ The reduction process provides the driving force, ensuring that Er can be successfully reduced and preferentially deposited around Au particles, forming a close-proximity Au-Er structure. More importantly, Er's f-electron orbitals have unique unfilled characteristics, exhibiting a strong affinity for the lone pair electrons of CO2 molecules. When CO2 molecules are physically adsorbed and enriched by the ultra-high specific surface area of ​​UiO-66, they migrate to the Er active sites at the interface. The Er sites strongly chemically polarize and activate CO2 molecules, significantly weakening their C=O bonds and lowering the initial energy barrier for subsequent hydrogenation reduction.

[0061] Ultimately, Au and Er, as well as their interactions with the support / semiconductor, form a complete adsorption-enrichment-electron transfer-molecular activation-catalytic conversion chain reaction. UiO-66 is responsible for efficiently capturing and concentrating low-concentration CO2, providing sufficient raw materials for the reaction; V-Bi 19 Br3S 27 As the engine of a broad-spectrum response, it is responsible for generating photogenerated charges; the S-shaped heterojunction interface is responsible for achieving efficient spatial separation of charges; and the Au-Er bimetallic center is located at the end of this chain reaction. Au is responsible for rapidly receiving and transferring electrons with strong reducing power, while Er is responsible for strongly adsorbing and activating CO2 molecules. Their synergistic effect ensures that photogenerated electrons can be precisely and efficiently used to attack low-energy CO2 molecules that have been activated by Er, thereby jointly guiding the multi-electron reduction pathway towards the high-selectivity of methanol production. Without Au, the electron transfer rate is limited, and Er is difficult to effectively load; without Er, the CO2 activation ability is insufficient, and the reaction energy barrier is too high; without the enrichment effect of UiO-66 and the charge separation guarantee of the S-shaped heterojunction, the bimetallic center will face insufficient dynamism. Therefore, there is a profound functional complementarity and performance multiplication relationship between the Au and Er bimetallic centers and other components, which together constitute the core technical principle of this invention for achieving efficient and highly selective CO2 capture and conversion, forming an inseparable organic whole.

[0062] In some examples, the CO2 adsorption capacity of the catalyst is not less than 0.8 mmol / g; the cumulative methanol yield over 2 hours is 750-1250.45 μmol / g.

[0063] In some examples, the preparation method of UiO-66 includes the following steps:

[0064] Zirconium oxychloride pentahydrate was mixed with terephthalic acid in a molar ratio of (1-2):1, N,N-dimethylformamide was added as a solvent, and acetic acid was added as a crystallization regulator. The mixture was reacted at a constant temperature of 100-150℃ for 20-25 h. After washing with DMF, deionized water and anhydrous ethanol in sequence, the mixture was dried under vacuum at 50-80℃ overnight to obtain UiO-66.

[0065] In some examples, Bi 19 Br3S 27 The preparation method includes the following steps:

[0066] Bismuth bromide, thiourea, and ethylenediaminetetraacetic acid were mixed at a mass ratio of 5:(4-5):(0.1-0.2), and anhydrous ethanol was used as the solvent. The mixture was stirred at 500-1000 rpm for 0.5-1.5 h at room temperature, and then reacted at a constant temperature of 150-200 °C for 70-75 h. After washing with deionized water and anhydrous ethanol alternately, the mixture was dried at 70-90 °C for 4-5 h to obtain Bi. 19 Br3S 27 .

[0067] According to another aspect of the embodiments of this application, a method for preparing a bimetallic carbon dioxide capture and methanolization catalyst is also provided, comprising the following steps:

[0068] S1. Mix UiO-66 with Bi 19 Br3S 27 UiO-66 / Bi was obtained by in-situ hydrothermal composite method. 19 Br3S 27 ;

[0069] S2. Place UiO-66 / Bi 19 Br3S 27 Alkali etching was performed to obtain UiO-66 / V-Bi. 19 Br3S 27 Heterojunction materials;

[0070] S3. Connect UiO-66 / V-Bi 19 Br3S 27 The heterojunction material was loaded with Au and Er sequentially by sequential photodeposition to obtain the catalytic material.

[0071] In some examples, the in-situ hydrothermal composite method in step S1 specifically includes the following steps:

[0072] Add UiO-66 to Bi 19 Br3S 27 Stirring at room temperature for 1-2 hours, then transfer to a high-pressure reactor lined with polytetrafluoroethylene (PTFE). After sealing, react at 150-200℃ for 70-75 hours. Cool to room temperature, centrifuge to obtain the precipitate, wash with deionized water and anhydrous ethanol alternately at least four times, and dry at 70-90℃ for 4-5 hours to obtain UiO-66 / Bi. 19 Br3S 27 .

[0073] In some examples, the alkaline etching process in step S2 specifically includes the following steps:

[0074] Distribute 0.1-0.3 parts of UiO-66 / Bi by weight. 19 Br3S 27 The product was ultrasonically dispersed in 20-40 parts of 0.4-0.6 mol / L NaOH solution, placed in a water bath at 50-70℃, and stirred at 200-400 rpm for 4-6 min. The solid product was collected by centrifugation, washed at least four times alternately with deionized water and anhydrous ethanol, and dried at 70-90℃ for 4-5 h to obtain UiO-66 / V-Bi. 19 Br3S 27 Heterojunction materials.

[0075] In some examples, the sequential photodeposition method in step S3, which loads Au and Er in sequence, specifically includes the following steps:

[0076] S3.1. Prepare a potassium chloroaurate solution with a concentration of 0.9-0.95 mg / mL and an erbium nitrate solution with a concentration of 1.0-2.0 mg / mL;

[0077] S3.2. Distribute 80-120 parts of UiO-66 / V-Bi by weight. 19 Br3S 27 The heterojunction material is added to 40-50 parts of deionized water and ultrasonically treated for 10-20 minutes to form a suspension. Under continuous stirring and light-proof conditions, 1-2 parts of potassium chloroaurate solution are added dropwise and stirred in a light-proof environment for 20-40 minutes to obtain mixture A.

[0078] S3.3. Place mixture A under a 300-400W full-spectrum xenon lamp and irradiate it with visible light (λ>420nm), controlling the light intensity to 500-700mW / cm². 2 The reaction was carried out under light for 1.5-2.5 hours, followed by centrifugation, washing with deionized water and anhydrous ethanol at least four times alternately, and drying at 70-90℃ for 4-5 hours to obtain UiO-66 / V-Bi. 19 Br3S 27 @Au;

[0079] S3.4. Connect UiO-66 / V-Bi 19 Br3S 27 @Au is dispersed in 40-50 parts of deionized water and ultrasonically treated for 10-20 minutes to form a suspension. Under continuous stirring and light protection, 1-2 parts of potassium chloroaurate solution are added dropwise and stirred in a light-protected environment for 50-70 minutes to obtain mixture B.

[0080] S3.5. Place mixture B under a 300-400W full-spectrum xenon lamp and irradiate it with visible light (λ>420nm), controlling the light intensity to 500-700mW / cm². 2The reaction was carried out under light for 2.5-3.5 hours, followed by centrifugation, washing with deionized water and anhydrous ethanol at least four times, and drying at 70-90°C for 4-5 hours to obtain the catalyst material.

[0081] According to another aspect of the embodiments of this application, the application of the bimetallic carbon dioxide capture and methanolization catalytic material as described in any of the first aspects or the bimetallic carbon dioxide capture and methanolization catalytic material prepared by the preparation method described in any of the second aspects in direct air capture of carbon dioxide and photocatalytic conversion to methanol is also provided.

[0082] In some examples, the methanol selectivity of the catalyst is 65%-75%.

[0083] 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 generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0084] Example 1

[0085] This embodiment 1 provides a bimetallic carbon dioxide capture and methanolization catalytic material and its preparation method. The preparation method includes the following steps:

[0086] S1. Weigh 53 mg (0.23 mmol) of zirconium oxychloride pentahydrate (ZrOCl2·5H2O) as the metal source and 34 mg (0.23 mmol) of terephthalic acid (H2BDC) as the organic ligand, and place them in a 100 mL beaker. Add 10 mL of N,N-dimethylformamide (DMF) as the solvent and 2 mL of acetic acid as the crystallization regulator. Place the mixture in an ultrasonic cleaner and sonicate for 10 minutes until the solid powder is completely dissolved, obtaining a clear, transparent, colorless solution. Then, transfer this solution to a 50 mL aerator. The sample was placed in a stainless steel high-pressure reactor lined with polytetrafluoroethylene (PTFE) and sealed. It was then placed in a drying oven at 120°C and reacted at a constant temperature for 24 hours. After the reaction was completed, the reactor was allowed to cool naturally to room temperature. The white solid product was obtained by centrifugation. The product was washed three times in sequence with DMF, deionized water and anhydrous ethanol. Finally, the washed sample was placed in a vacuum drying oven at 60°C and dried overnight to obtain pure UiO-66 white powder for later use.

[0087] S2. Weigh bismuth bromide (BiBr3, 5 mmol) as the bismuth and bromine source, thiourea (4.6 mmol) as the sulfur source, and ethylenediaminetetraacetic acid (EDTA, 0.2 g) as the complexing agent and structure-directing agent, and place them together in a 250 mL Erlenmeyer flask. Add 60 mL of anhydrous ethanol as the solvent. Stir the mixture vigorously at 800 rpm for 1 hour at room temperature using a magnetic stirrer. Transfer the mixture to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene. Seal the autoclave and place it in a 180°C drying oven. React at this temperature for 72 hours. After the autoclave has cooled to room temperature, collect the black or dark gray precipitate by centrifugation. Wash the precipitate four times each with deionized water and anhydrous ethanol, alternating between the two. Dry the washed sample in an oven at 80°C for 4 hours to obtain Bi 19 Br3S 27 Nanowire precursors;

[0088] S3. Use 500 mg of UiO-66 powder as a base material and add it to Bi. 19 Br3S 27 The synthetic system consisted of bismuth bromide (BiBr3, 1 mmol), thiourea (0.92 mmol), ethylenediaminetetraacetic acid (0.04 g), and anhydrous ethanol (60 mL). All the raw materials were placed in a 250 mL Erlenmeyer flask and vigorously stirred in air at room temperature for 1 hour. The suspension was then transferred to a 100 mL polytetrafluoroethylene-lined high-pressure reactor, sealed, and reacted in an oven at 180 °C for 72 hours. After the reaction was completed and cooled, the precipitate was collected by centrifugation and purified by washing four times with deionized water and ethanol. The final product was dried at 80 °C for 4 hours to obtain UiO-66 / Bi. 19 Br3S 27 ;

[0089] S4. Weigh 0.2 g of UiO-66 / Bi 19 Br3S 27 The mixture was ultrasonically dispersed in a beaker containing 30 mL of 0.5 mol / L sodium hydroxide solution. The beaker was placed in a 60°C water bath and reacted for 5 minutes with magnetic stirring (300 rpm). After the reaction, the mixture was immediately centrifuged to collect the solid product. This product was washed four times with deionized water and anhydrous ethanol. The washed sample was then dried in a vacuum drying oven at 80°C for 4 hours. The resulting product was denoted as UiO-66 / V-Bi. 19 Br3S 27 ;

[0090] S5. Weigh 9.45 mg of potassium chloroaurate (KAuCl4), dissolve it in a 10 mL volumetric flask, dilute to volume with deionized water, and shake well before use. The concentration of this solution is 0.945 mg / mL (calculated as KAuCl4). Weigh 11.08 mg of erbium nitrate (Er(NO3)3·6H2O), dissolve it in a 10 mL volumetric flask, dilute to volume with deionized water, and shake well before use. The concentration of this solution is 1.108 mg / mL.

[0091] S6. Weigh 100 mg of UiO-66 / V-Bi 19 Br3S 27 The powder was placed in a transparent quartz reactor, and 50 mL of deionized water was added. The reactor was then ultrasonically treated for 15 minutes in an ultrasonic cleaner. Under continuous magnetic stirring, two 1 mL pipettes were used to transfer a total of 2 mL of KAuCl4 solution, which was then slowly and dropwise added to the solution. After the addition was complete, stirring was continued in the dark for 30 minutes. Subsequently, the reactor was placed on a magnetic stirrer, and the suspension was irradiated from above with a 300W full-spectrum xenon lamp (equipped with a cutoff filter that only allows visible light with λ>420 nm to pass through). The photo-reaction was carried out for 2 hours with continuous stirring, and the light intensity was controlled at 600 mW / cm². 2 After the reaction was completed, the solid product was obtained by centrifugation and washed four times alternately with deionized water and anhydrous ethanol. The washed sample was then dried in a vacuum drying oven at 80°C for 4 hours to obtain the intermediate product, denoted as UiO-66 / V-Bi. 19 Br3S 27 @Au.

[0092] S7. Connect UiO-66 / V-Bi 19 Br3S 27 The sample was placed in a quartz reactor, and 50 mL of deionized water was added. The mixture was sonicated for 15 minutes to form a homogeneous suspension. Under continuous magnetic stirring and in the dark, two 1 mL pipettes were used to transfer a total of 2 mL of Er(NO3)3 solution, which was then slowly and dropwise added to the suspension. After the addition was complete, stirring was continued in the dark for 60 minutes. Then, with continued stirring, the suspension was irradiated with the same xenon lamp source (λ>420 nm) as described above. The photoreaction was carried out for 3 hours, with the light intensity controlled at 600 mW / cm². 2 After the reaction was completed, the solid product was obtained by centrifugation and washed four times alternately with deionized water and anhydrous ethanol. The washed sample was then dried in a vacuum drying oven at 80°C for 4 hours to finally obtain the bimetallic modified target catalyst material, denoted as UiO-66 / V-Bi. 19 Br3S 27 @Au1Er1(UVB-Au1Er1)

[0093] It should be noted that in this embodiment, the molar ratio of Au to Er is 1:1.

[0094] Example 2

[0095] Example 2 provides a bimetallic carbon dioxide capture and methanolization catalyst and its preparation method, which is basically the same as Example 1, except that the molar ratio of Au to Er is 1:2. Specifically, 22.17 mg of erbium nitrate is weighed, dissolved in a 10 mL volumetric flask, and diluted to volume with deionized water. The solution concentration is 2.217 mg / mL, and the product is denoted as UiO-66 / V-Bi. 19 Br3S 27 @Au1Er2 (UVB-Au1Er2).

[0096] Example 3

[0097] Example 3 provides a bimetallic carbon dioxide capture and methanolization catalyst and its preparation method, which is basically the same as Example 1, except that the molar ratio of Au to Er is 2:1. Specifically, 18.89 mg of potassium chloroaurate is weighed, dissolved in a 10 mL volumetric flask, and diluted to volume with deionized water. The solution concentration is 1.89 mg / mL, and the product is denoted as UiO-66 / V-Bi. 19 Br3S 27 @Au2Er1 (UVB-Au2Er1).

[0098] Comparative Example 1

[0099] Comparative Example 1 provides a catalytic material and its preparation method, which are basically the same as those in Example 1, except that metal loading was not performed, and the prepared product is UiO-66 / V-Bi. 19 Br3S 27 (UVB).

[0100] Comparative Example 2

[0101] Comparative Example 2 provides a catalytic material and its preparation method, which are basically the same as those in Example 1, except that metal Er was not loaded, and the prepared product is UiO-66 / V-Bi. 19 Br3S 27 @Au (UVB-Au).

[0102] Comparative Example 3

[0103] Comparative Example 3 provides a catalytic material and its preparation method, which are basically the same as those in Example 1, except that Au metal loading was not performed, and the prepared product is UiO-66 / V-Bi. 19Br3S 27 @Er (UVB-Er).

[0104] Comparative Example 4

[0105] Comparative Example 4 provides a catalytic material and its preparation method, which are basically the same as those in Example 1, except that the pure UiO-66 basic framework is used as the catalytic material in this comparative example.

[0106] The UiO-66 and UiO-66 / V-Bi prepared in Example 1 19 Br3S 27 The SEM images obtained by scanning electron microscopy are as follows: Figure 1 and Figure 2 As shown, by Figure 1 As can be seen, the SEM image of UiO-66 shows a standard octahedron, indicating the successful synthesis of the metal-organic framework UiO-66.

[0107] pass Figure 2 It can be seen that V-Bi 19 Br3S 27 The in-situ growth of nanowires on the UiO-66 surface indicates that V-Bi 19 Br3S 27 Successfully combined with UiO-66.

[0108] To better understand the present invention, the performance of the catalytic materials in the examples and comparative examples was evaluated, and the evaluation steps are as follows:

[0109] (1) Dynamic CO2 adsorption performance test

[0110] The catalytic material was loaded into a fixed-bed reactor equipped with a quartz window. Before starting the adsorption test, high-purity dry argon gas at a flow rate of 150 mL / min was introduced into the reactor at a constant temperature of 25°C and continuously purged for 30 minutes. After pretreatment, the gas source was switched to simulated air at a flow rate of 100 mL / min (CO2 concentration of approximately 400-500 ppm), and the humidity of the inlet gas was precisely controlled to simulate the real atmospheric environment. Throughout the adsorption process, a high-sensitivity, fast-response infrared gas analyzer (sensitivity: 0.001% vol, response time ≤ 90 seconds) was used to monitor and record the CO2 concentration in the reactor outlet gas flow in real time and continuously. By calculating the integral of the CO2 concentration difference between the inlet and outlet over time, the dynamic CO2 adsorption capacity and adsorption kinetic curve of the composite catalytic material under simulated atmospheric conditions were calculated.

[0111] (2) Photocatalytic conversion of CO2

[0112] Subsequently, the catalytic material after direct air adsorption of carbon dioxide was used to achieve photocatalytic carbon dioxide reduction to prepare high-value-added products. This conversion process was carried out in a 500 mL quartz glass photocatalytic reactor. The photocatalytic material was placed in the reactor, and under light irradiation, the enriched CO2 and proton source H2O were converted into high-value-added chemicals such as methanol, thus realizing the integration of the entire process from capture to conversion.

[0113] The specific photocatalytic scheme adopts the following standardized experimental procedure for testing and product analysis:

[0114] (I) Dispersion of catalytic materials and construction of reaction system

[0115] Weigh 20.0 mg of catalytic material powder and place it in a photocatalytic reactor (a jacketed reaction tank with a quartz window). Then, add 20 mL of ultrapure water to the reactor as a reaction medium and proton source. After sealing the reactor, place it in an ultrasonic cleaner for ultrasonic treatment for 10 minutes to ensure that the catalytic material powder is fully dispersed in the aqueous phase and forms a uniform and stable suspension, thereby maximizing its light absorption and reactive surface area.

[0116] (ii) Reactor purging and atmosphere control

[0117] Before starting the photocatalytic reaction, it is necessary to eliminate the potential interference of impurity gases in the reaction system on the catalytic process. High-purity argon gas (99.999% purity) is continuously introduced into the system through the gas inlet of the reactor and purged for 10 minutes. This step can effectively drive away the impurity gases dissolved in the reactor headspace and liquid phase, laying the foundation for the subsequent construction of a pure CO2 reaction atmosphere.

[0118] (III) CO2 saturation and reaction initialization

[0119] After purging, the inlet gas is switched to high-purity carbon dioxide gas with a concentration of 99.99% and introduced into the reactor at a constant flow rate for 15 minutes to fully saturate the system with CO2. After purging, the circulating water bath system is turned on to precisely control and maintain the temperature of the circulating water in the reactor jacket at 60°C. This temperature setting is intended to promote the mass transfer and dissolution of CO2 in the aqueous phase, while providing a mild thermal environment to assist the photocatalytic reaction and avoid local overheating caused by light source irradiation.

[0120] (iv) Photoreaction and Product Analysis

[0121] After the system stabilized, a 300 W full-spectrum xenon lamp was turned on, and a photometer was used for calibration to stabilize the light intensity illuminating the reactor window at 600 mW / cm². 2The reaction begins when the light source is turned on. During the photo-induced reaction, 1.0 mL of gaseous product is precisely extracted from the headspace of the reactor every 0.5 hours using an airtight injection needle.

[0122] The gaseous products were immediately injected into two coupled gas chromatographs for analysis.

[0123] The first gas chromatograph is equipped with a thermal conductivity detector (TCD) for the quantitative analysis of inorganic gas products such as hydrogen, carbon monoxide, and oxygen.

[0124] The second gas chromatograph is equipped with a flame ionization detector (FID) and a methanation converter for highly sensitive detection and quantification of hydrocarbon gaseous products such as methane and ethylene.

[0125] For liquid-phase products, especially formaldehyde that may be generated, a highly sensitive acetylacetone colorimetric method is used for quantitative determination. This method is based on the reaction of formaldehyde with acetylacetone in the presence of ammonium salt to form yellow 3,5-diacetyl-1,4-dihydrorutidine. Its absorbance is measured at a specific wavelength (412 nm) using a UV-Vis spectrophotometer and compared with a standard curve, thereby achieving accurate determination of formaldehyde concentration in the liquid phase.

[0126] Using the above testing methods, the adsorption curve data of the catalytic material prepared in Example 1 for direct air adsorption of carbon dioxide were obtained. Figure 3 As shown, the adsorption process basically reaches equilibrium in about 0.15 hours, exhibiting a relatively fast adsorption process and a high adsorption capacity of 0.845 mmol / g, demonstrating good carbon dioxide adsorption efficiency.

[0127] The product yield and methanol selectivity of each catalyst after two hours of reaction, obtained using the above testing methods, are shown in Table 1.

[0128] Table 1. Product yield and methanol selectivity of each catalyst after two hours of reaction.

[0129]

[0130] Table 2 shows the methanol production data of each catalyst during the reaction process within 2 hours:

[0131] Table 2. Methanol yield of each catalyst during the reaction process within 2 hours.

[0132]

[0133] Combination Figure 4 and Figure 5 It can be seen that UiO-66 and V-Bi 19 Br3S 27The composite material exhibits improved activity. Further doping with Er increases the yield of methanol and formaldehyde, but reduces selectivity. Au single-atom doping significantly increases formaldehyde yield while decreasing methanol yield. Compared to the two single-metal doped materials and the matrix material, the AuEr bimetallic doped catalytic material shows significantly improved activity and a three-fold increase in methanol yield. The highest methanol yield (1245.45 μmol / g) is achieved with a 1:2 Au:Er molar ratio, along with a methanol selectivity of 75%. This indicates that a 1:2 Au:Er molar ratio is optimal.

[0134] pass Figure 6 It can be seen that, Figure 6 The graph shows a comparison of the products of the catalyst material in Example 1 over the reaction time. As can be seen from the graph, the production of methanol and CO increases with time, and the methanol production reaches 1245.45 μmol / g at 2 h.

[0135] 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.

[0136] 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 bimetallic carbon dioxide capture and methanolization catalyst, characterized in that, The catalytic material is composed of UiO-66, V-Bi with sulfur vacancies and bromine vacancies grown in-situ on the surface and in the pores of the UiO-66 19 Br3S 27 , dispersedly loaded on the UiO-66 and the V-Bi 19 Br3S 27 S-type heterojunction interface formed by the V-Bi and the Au-Er bimetallic active center group on the surface of the UiO-66 The Au-Er bimetallic active center is loaded with Au and Er sequentially by sequential photodeposition, wherein the molar ratio of Au to Er is (1-2)∶(2-1). The UiO-66 and the V-Bi 19 Br3S 27 S-type heterojunction is formed by in-situ hydrothermal method The V-Bi 19 Br3S 27 The UiO-66 and Bi 19 Br3S 27 The product is obtained by in-situ composite and alkaline etching.

2. The catalytic material according to claim 1, characterized in that, The Bi 19 Br3S 27 The preparation method includes the following steps: Bismuth bromide, thiourea, and ethylenediaminetetraacetic acid were mixed at a mass ratio of 5:(4-5):(0.1-0.2), and anhydrous ethanol was used as the solvent. The mixture was stirred at 500-1000 rpm for 0.5-1.5 h at room temperature, and then reacted at a constant temperature of 150-200 °C for 70-75 h. After washing with deionized water and anhydrous ethanol alternately, the mixture was dried at 70-90 °C for 4-5 h to obtain the Bi. 19 Br3S 27 .

3. A method for preparing a bimetallic carbon dioxide capture and methanolization catalyst according to any one of claims 1-2, characterized in that, Includes the following steps: S1. Combine the UiO-66 with the Bi 19 Br3S 27 UiO-66 / Bi was obtained by in-situ hydrothermal composite method. 19 Br3S 27 ; S2. The UiO-66 / Bi 19 Br3S 27 Alkali etching was performed to obtain UiO-66 / V-Bi. 19 Br3S 27 Heterojunction materials; S3. The UiO-66 / V-Bi... 19 Br3S 27 The heterojunction material was loaded with Au and Er sequentially by sequential photodeposition to obtain the catalytic material.

4. The method according to claim 3, characterized in that, The in-situ hydrothermal composite method in step S1 specifically includes the following steps: Add the UiO-66 to the Bi 19 Br3S 27 Stirring at room temperature for 1-2 hours, then transferring to a high-pressure reactor lined with polytetrafluoroethylene (PTFE), sealing, and reacting at 150-200℃ for 70-75 hours. After cooling to room temperature, centrifuging to obtain the precipitate, washing with deionized water and anhydrous ethanol alternately at least four times, and drying at 70-90℃ for 4-5 hours, yields the UiO-66 / Bi. 19 Br3S 27 .

5. The method according to claim 3, characterized in that, The alkaline etching process in step S2 specifically includes the following steps: Take 0.1-0.3 parts by weight of the UiO-66 / Bi 19 Br3S 27 The product was ultrasonically dispersed in 20-40 parts of a 0.4-0.6 mol / L NaOH solution, placed in a water bath at 50-70℃, and stirred at 200-400 r / min for 4-6 min. The solid product was collected by centrifugation, washed at least four times alternately with deionized water and anhydrous ethanol, and dried at 70-90℃ for 4-5 h to obtain the UiO-66 / V-Bi. 19 Br3S 27 Heterojunction materials.

6. The method according to claim 3, characterized in that, The sequential optical deposition method in step S3, which loads Au and Er sequentially, specifically includes the following steps: S3.

1. Prepare a potassium chloroaurate solution with a concentration of 0.9-0.95 mg / mL and an erbium nitrate solution with a concentration of 1.0-2.0 mg / mL; S3.

2. Distribute 80-120 parts of UiO-66 / V-Bi by weight. 19 Br3S 27 The heterojunction material is added to 40-50 parts of deionized water and ultrasonically treated for 10-20 minutes to form a suspension. Under continuous stirring and light-proof conditions, 1-2 parts of the potassium chloroaurate solution are added dropwise and stirred in a light-proof environment for 20-40 minutes to obtain mixture A. S3.

3. Place the mixture A under a 300-400W full-spectrum xenon lamp and irradiate it with visible light (λ>420nm), controlling the light intensity to 500-700mW / cm². 2 The reaction was carried out under light for 1.5-2.5 hours, followed by centrifugation, washing with deionized water and anhydrous ethanol at least four times alternately, and drying at 70-90℃ for 4-5 hours to obtain UiO-66 / V-Bi. 19 Br3S 27 @Au; S3.

4. The UiO-66 / V-Bi 19 Br3S 27 @Au is dispersed in 40-50 parts of deionized water and ultrasonically treated for 10-20 minutes to form a suspension. Under continuous stirring and light-proof conditions, 1-2 parts of the erbium nitrate solution are added dropwise and stirred in a light-proof environment for 50-70 minutes to obtain mixture B. S3.

5. Place the mixture B under a 300-400W full-spectrum xenon lamp and irradiate it with visible light (λ>420nm), controlling the light intensity to 500-700mW / cm². 2 The catalyst was subjected to light irradiation for 2.5-3.5 hours, centrifuged, washed at least four times with deionized water and anhydrous ethanol, and dried at 70-90°C for 4-5 hours to obtain the catalyst material.

7. The application of a bimetallic carbon dioxide capture and methanolization catalyst as described in any one of claims 1-2 in direct air capture of carbon dioxide and photocatalytic conversion to methanol.

8. The application according to claim 7, characterized in that, The methanol selectivity of the catalyst is 65%-75%.

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