Heteroatomic molecular sieve catalysts and use in the reaction of carbon dioxide and water

Abstract

This invention discloses a heteroatom molecular sieve catalyst and its application in the reaction of carbon dioxide and water, relating to the field of catalysts and their applications. The prepared heteroatom molecular sieve is used as a photocatalyst for the reduction of carbon dioxide by water, solving the technical problems existing in the prior art. Specifically: Si source, OSDA1, OSDA2, Ti source, F source, and H2O are mixed in a certain proportion and statically crystallized at 373-423K for 4 to 17 days to synthesize Ti-ION / MFI mixed crystal TIM hydrothermally; the TIM material prepared by S1 is compounded with oxides of indium, cobalt, tin, manganese, cerium, iron, nickel, and copper by microwave-assisted evaporation and impregnation method; specifically: 1g of TIM is dispersed in an ethanol solution, and 5%-25% by weight of metal oxide is added. After thorough stirring and mixing, the mixture is treated in a temperature-controlled microwave reactor until completely dry, and then the material is calcined in air at 723K to obtain X-TIM material, where X is the corresponding metal.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a heteroatom molecular sieve catalyst and its application in the reaction of carbon dioxide and water. Background Technology

[0002] With the continuous advancement of science and technology, photocatalysis technology has developed rapidly. Researchers have discovered that by designing and synthesizing photocatalysts with specific structures and properties, carbon dioxide and water can be converted into valuable chemicals and fuels, such as methanol and methane, under light conditions. This discovery provides a new approach and technological means for solving environmental and energy problems.

[0003] Existing catalysts suffer from poor selectivity, low catalytic efficiency, and insufficient stability in carbon dioxide reduction reactions, necessitating the development of novel catalysts to improve the selectivity and efficiency of the reaction.

[0004] Molecular sieves possess a uniform microporous structure with pores of uniform diameter. These pores adsorb molecules smaller than their diameter into the interior of the pores, exhibiting preferential adsorption capacity for polar and unsaturated molecules. Therefore, they can separate molecules with different degrees of polarity, saturation, size, and boiling point, effectively "sieving" molecules, hence the name molecular sieve. Due to their high adsorption capacity and strong thermal stability, which are advantages not found in other adsorbents, molecular sieves have found wide applications.

[0005] Introducing heteroatoms into the molecular sieve framework is one of the important ways to improve the catalytic performance of molecular sieves. Heteroatom molecular sieves refer to molecular sieves containing other elements, formed by replacing some of the silicon, aluminum, or phosphorus in the molecular sieve framework with other elements. Introducing heteroatoms into the molecular sieve framework does not significantly change its structure, but it significantly modulates the physicochemical properties of the molecular sieve, breaking through the limitations of pure molecular sieves in catalysis and other applications. At the same time, the catalytic properties of heteroatoms themselves are conducive to achieving multifunctional catalysis by molecular sieves, thereby broadening the application fields and increasing the application value of molecular sieves.

[0006] In the prior art, CN114433171B discloses a carbon dioxide reduction photocatalyst and its preparation method and application. The preparation method includes the following steps: dissolving bismuth salt and cesium salt in dimethyl sulfoxide, adding molecular sieves, mixing, grinding, and impregnating, and then heating and holding at a set temperature for a set time to form a molecular sieve@Cs3Bi2Br9 composite. The prepared molecular sieve@Cs3Bi2Br9 photocatalyst has good photogenerated carrier separation and transfer efficiency, and can achieve photocatalytic reduction of CO2 when irradiated with light.

[0007] CN119098211A discloses the preparation of a molecular sieve-supported metal catalyst and its application in the catalytic coupling of carbon dioxide and higher-carbon alkanes to produce high-octane gasoline. The catalyst preparation method is as follows: Beta molecular sieve, ZSM-5 molecular sieve, and Y molecular sieve are thoroughly dried to obtain a catalyst support; then, using a metal salt as a precursor, the catalyst is obtained through equal-volume impregnation, drying, calcination, and reduction to obtain a heterogeneous catalyst. This series of catalysts exhibits good catalytic activity and selectivity in the coupling conversion of carbon dioxide and higher-carbon alkanes to produce high-octane gasoline, achieving high yields of gasoline products. Furthermore, the carbon dioxide atmosphere promotes the formation of high-octane aromatic components, effectively increasing the octane number of the gasoline.

[0008] This application aims to prepare heteroatom molecular sieve catalysts for the reduction reaction of carbon dioxide and water. Summary of the Invention

[0009] The purpose of this invention is to provide a heteroatom molecular sieve catalyst and its application in the reaction of carbon dioxide and water. The prepared heteroatom molecular sieve serves as a photocatalyst for the reduction of carbon dioxide by water, thereby solving the technical problems existing in the prior art.

[0010] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0011] A method for preparing a heteroatom molecular sieve catalyst includes the following steps:

[0012] S1: Si source, OSDA1, OSDA2, Ti source, F source, and H2O are mixed in a ratio of 1:0.15-0.34:0.01-0.03:0.02-0.067:0-0.9:5-60, statically crystallized at 373-423K for 4 to 17 days, and then hydrothermally synthesized Ti-ION / MFI mixed crystal TIM.

[0013] S2: The TIM material prepared in S1 is combined with oxides of indium, cobalt, tin, manganese, cerium, iron, nickel and copper by microwave-assisted evaporation and impregnation.

[0014] Specifically: 1g TIM is dispersed in an ethanol solution, and 5%-25% by weight of metal oxide is added. After thorough mixing, the mixture is processed in a temperature-controlled microwave reactor until completely dry. The material is then calcined in air at 723K to obtain X-TIM material, where X is the corresponding metal.

[0015] Furthermore, the Si source, OSDA1, OSDA2, Ti source, F source, and H2O are configured in a ratio of 1:0.15-0.34:0.01-0.03:0.02-0.067:0-0.9:5-60.

[0016] Furthermore, the Si source, OSDA1, OSDA2, Ti source, F source, and H2O are configured in a ratio of 1:0.28:0.01:0.03:0.3:6.

[0017] Furthermore, the Si source, OSDA1, OSDA2, Ti source, F source, and H2O are configured in a ratio of 1:0.25:0.013:0.06:0.5:12.

[0018] Furthermore, the Si source, OSDA1, OSDA2, Ti source, F source, and H2O are configured in a ratio of 1:0.16:0.02:0.02:0.5:30.

[0019] Furthermore, the Si source is one of SiO2, tetraethyl orthosilicate, fuming silica gel, water glass, or fumed silica.

[0020] Furthermore, the Ti source is tetrabutyl titanate; the F source is NH4F or HF.

[0021] 1,4-phenylenediamine hydroxide-N,N,N,N,N',N',N'-hexapropyldichloro(OSDA1) and tetrapropylammonium hydroxide (OSDA2) are organic structure directing agents.

[0022] Another object of the present invention is to disclose the application of heteroatom molecular sieves as photocatalysts in the water-to-carbon dioxide reduction reaction.

[0023] The application is as follows:

[0024] 20 mg of the X-TIM material prepared above was placed in a 300 ml photoreactor, a 200-3500 nm wavelength full-spectrum light source was used, 10 ml of water was added, and the air in the reactor was completely replaced with carbon dioxide multiple times. The reaction was carried out for 2 hours, and the product was detected by liquid nuclear magnetic resonance.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention discloses a heteroatom molecular sieve catalyst and its application in the reaction of carbon dioxide and water. The prepared heteroatom molecular sieve is used as a photocatalyst to reduce carbon dioxide and water, solving the technical problems existing in the prior art and filling the technical gap.

[0027] The catalyst of this invention comprises Si source, OSDA1, OSDA2, Ti source, F source, and H2O in a ratio of 1:0.15-0.34:0.01-0.03:0.02-0.067:0-0.9:5-60, statically crystallized at 373-423K for 4 to 17 days, and hydrothermally synthesized Ti-ION / MFI mixed crystal TIM. The TIM material prepared by S1 is then composited with oxides of indium, cobalt, tin, manganese, cerium, iron, nickel, and copper using a microwave-assisted evaporation and impregnation method. This process exhibits good performance and is simple, making it suitable for industrial applications.

[0028] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0029] Figure 1 This is a flowchart of the preparation method described in an embodiment of the present invention;

[0030] Figure 2 The xrd plot of the material in the embodiment of the present invention;

[0031] Figure 3 Electron micrographs of the materials used in embodiments of the present invention; Detailed Implementation

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings.

[0033] like Figure 1-3 As shown, where, Figure 1 This is a process flow diagram of the preparation method described in the embodiments of the present invention;

[0034] Synthesis method: One of tetraethyl orthosilicate, fuming silica gel, water glass, or silica is used as the silicon source;

[0035] Tetrabutyl titanate is the titanium source;

[0036] 1,4-phenylenediamine hydroxide-N,N,N,N,N',N',N'-hexapropyldichloro(OSDA1) and tetrapropylammonium hydroxide (OSDA2) are organic structure directing agents;

[0037] NH4F or HF is the F source;

[0038] Ti-ION / MFI mixed crystals (TIM) with different silicon-to-titanium ratios were synthesized hydrothermally at a ratio of 1SiO2:0.15-0.34OSDA1:0.01-0.03OSDA2:0.02-0.067Ti:0-0.9F:5-60H2O.

[0039] The TIM material was composited with oxides of indium, cobalt, tin, manganese, cerium, iron, nickel, and copper using a microwave-assisted evaporation and impregnation method. The specific operation was as follows: 1g of TIM was dispersed in an ethanol solution, and 5%-25% by weight of metal oxides were added. After thorough stirring and mixing, the mixture was processed in a temperature-controlled microwave reactor until completely dry. The material was then calcined in air at 723K to obtain X-TIM material (X is the corresponding metal).

[0040] Based on the above implementation method:

[0041] Example 1

[0042] Synthesis method:

[0043] Select the following raw materials and proportions as silicon source, titanium source, organic structure directing agent and F source;

[0044] Si source, OSDA1, OSDA2, Ti source, F source, and H2O were used in a ratio of 1:0.28:0.01:0.03:0.3:6. The mixture was statically crystallized at 413 K for 12 days to synthesize Ti-ION / MFI mixed crystals (TIM) hydrothermally. The silicon-to-titanium ratio was 43. The relevant characterization results are shown in the XRD scan.

[0045] Tetrabutyl titanate is the titanium source; HF is the F source.

[0046] The TIM material is compounded with oxides of indium, cobalt, tin, manganese, cerium, iron, nickel, and copper. The specific operation is as follows: 1g of TIM is dispersed in an ethanol solution, and 5%-25% by weight of metal oxides are added. After thorough stirring and mixing, the mixture is processed in a temperature-controlled microwave reactor until completely dry. The material is then calcined in air at 723K to obtain X-TIM material (X is the corresponding metal).

[0047] like Figure 2-3 As shown:

[0048] from Figure 2 As can be seen from the data, compared with the standard MFI and ion zeolite structures, the XRD of the TIMM material shows that it is a superposition of the two structures, and there is no obvious anatase signal, indicating that titanium is highly dispersed on the framework.

[0049] from Figure 3 As can be seen from the scan, although it is a mixed crystal, it has a uniform morphology without impurities and presents as a stack of nanosheets;

[0050] Meanwhile, the technical solution of this application has the following preferred embodiments based on the selection of raw material ratios.

[0051] Example 2

[0052] Select the following raw materials and proportions as silicon source, titanium source, organic structure directing agent and F source;

[0053] Si source, OSDA1, OSDA2, Ti source, F source, and H2O were used in a ratio of 1:0.25:0.013:0.06:0.5:12. The mixture was statically crystallized at 423 K for 9 days to obtain TIM material with a silicon-to-titanium ratio of 23. The relevant characterization is shown in the XRD scan.

[0054] In this embodiment, tetrabutyl titanate is the titanium source; HF is the F source.

[0055] The TIM material is compounded with oxides of indium, cobalt, tin, manganese, cerium, iron, nickel, and copper. The specific operation is as follows: 1g of TIM is dispersed in an ethanol solution, and 5%-25% by weight of metal oxides are added. After thorough stirring and mixing, the mixture is processed in a temperature-controlled microwave reactor until completely dry. The material is then calcined in air at 723K to obtain X-TIM material (X is the corresponding metal).

[0056] Example 3

[0057] Select the following raw materials and proportions as silicon source, titanium source, organic structure directing agent and F source;

[0058] Si source, OSDA1, OSDA2, Ti source, F source, and H2O were used in a ratio of 1:0.16:0.02:0.02:0.5:30. The mixture was statically crystallized at 373 K for 4 days to obtain TIM material with a silicon-to-titanium ratio of 55. The relevant characterization results are shown in the XRD scan.

[0059] In this embodiment, tetrabutyl titanate is the titanium source; NH4F is the F source;

[0060] The TIM material is compounded with oxides of indium, cobalt, tin, manganese, cerium, iron, nickel, and copper. The specific operation is as follows: 1g of TIM is dispersed in an ethanol solution, and 5%-25% by weight of metal oxides are added. After thorough stirring and mixing, the mixture is processed in a temperature-controlled microwave reactor until completely dry. The material is then calcined in air at 723K to obtain X-TIM material (X is the corresponding metal).

[0061] The TIM material prepared by this application in the above embodiments has excellent performance. In the embodiments, the different catalyst synthesis ratio, conditions and raw materials will affect the ratio of MFI and ION in the final TIM mixed crystal material, as well as the thickness of the final nanosheet morphology, and will have a certain impact on the reaction performance.

[0062] Example 4

[0063] Based on the material prepared in Example 1 above, in which Si source, OSDA1, OSDA2, Ti source, F source, and H2O were used in a ratio of 1:0.28:0.01:0.03:0.3:6, statically crystallized at 413K for 12 days, and Ti-ION / MFI mixed crystals (TIM) were synthesized hydrothermally with a silicon-to-titanium ratio of 43, X-TIM material was prepared.

[0064] Reaction conditions: 20 mg of X-TIM catalyst was placed in a 300 ml photocatalytic reactor. A full-spectrum light source with a wavelength of 200-3500 nm was used. 10 ml of water was added. The air in the reactor was completely replaced with carbon dioxide several times. The reaction was carried out for 2 hours, and the product was detected by liquid nuclear magnetic resonance. (Yield unit: micromoles of product / gram of catalyst / hour)

[0065] Comparative samples: Industrial samples X-MFI, X-MOR, and X-MWW, with metal oxides loaded using the same method;

[0066] In this embodiment, the samples prepared according to the methods described in the above embodiments are In-TIM, In-MWW, In-MFI, and In-MOR; the yield results in this embodiment are shown in Table 1:

[0067] Table 1: Yield results of In-loaded samples

[0068] carbon monoxide methane Ethane methanol ethanol In-TIM 6 5 2 42 110 In-MWW 4 2 3 37 60 In-MFI 4 5 6 21 47 In-MOR 1 1 2 10 25

[0069] In this embodiment, the samples prepared according to the method described in the above embodiments are Cu-TIM, Cu-MWW, Cu-MFI, and Cu-MOR; the yield results in this embodiment are shown in Table 2.

[0070] Table 2 Yield results for Cu-loaded samples

[0071] carbon monoxide methane Ethane methanol ethanol Cu-TIM 4 3 3 51 119 Cu-MWW 1 6 5 23 44 Cu-MFI 3 2 3 17 31 Cu-MOR 1 1 1 6 21

[0072] In this embodiment, the samples prepared according to the methods described in the above embodiments are Co-TIM, Co-MWW, Co-MFI, and Co-MOR; the yield results of this embodiment are shown in Table 3.

[0073] Table 3 Yield results for Co-loaded samples

[0074] carbon monoxide methane Ethane methanol ethanol Co-TIM 6 3 2 61 96 Co-MWW 5 5 9 12 16 Co-MFI 5 6 7 32 34 Co-MOR 2 3 2 16 29

[0075] In this embodiment, the samples prepared according to the methods described in the above embodiments are Sn-TIM, Sn-MWW, Sn-MFI, and Sn-MOR; the yield results in this embodiment are shown in Table 4.

[0076] Table 4 Yield results for Sn-loaded samples

[0077] carbon monoxide methane Ethane methanol ethanol Sn-TIM 8 7 3 30 88 Sn-MWW 9 4 8 17 36 Sn-MFI 12 6 4 14 16 Sn-MOR 10 4 7 9 10

[0078] The above-mentioned X-TIM material prepared by the present invention and comparative samples: industrial samples X-MFI, X-MOR, and X-MWW are used as references. The experimental results show that the X-TIM material prepared by the present invention has better performance than the comparative samples; as a catalyst, it has a higher yield, which is significantly better than the prior art.

[0079] Therefore, this invention discloses a heteroatom molecular sieve catalyst and its application in the reaction of carbon dioxide and water. The prepared heteroatom molecular sieve is used as a photocatalyst to reduce carbon dioxide and water, solving the technical problems existing in the prior art and filling the technical gap.

[0080] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. These embodiments have been selected and specifically described in this specification to better explain the raw materials and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a heteroatom molecular sieve catalyst, characterized in that: Includes the following steps: S1: Si source, OSDA1, OSDA2, Ti source, F source, and H2O are mixed in a ratio of 1:0.15-0.34:0.01-0.03:0.02 ~ 0.067:0-0.9:5-60, statically crystallized at 373-423 K for 4 to 17 days, and then hydrothermally synthesized Ti-ION / MFI mixed crystal TIM. S2: The TIM material prepared in S1 is combined with oxides of indium, cobalt, tin, manganese, cerium, iron, nickel and copper by microwave-assisted evaporation and impregnation method; Specifically: 1g TIM is dispersed in an ethanol solution, and 5%-25% by weight of metal oxide is added. After thorough stirring and mixing, the mixture is processed in a temperature-controlled microwave reactor until completely dry. The material is then calcined in air at 723K to obtain X-TIM material, where X is the corresponding metal. Wherein: OSDA1 is: 1,4-phenylenediamine hydroxide-N,N,N,N,N',N',N'-hexapropyldichloro, and OSDA2 is: tetrapropylammonium hydroxide.

2. The method for preparing the heteroatom molecular sieve catalyst as described in claim 1, characterized in that: The Si source, OSDA1, OSDA2, Ti source, F source, and H2O are in the ratio of 1:0.15-0.34:0.01-0.03:0.02 ~ 0.067:0-0.9:5-60.

3. The method for preparing the heteroatom molecular sieve catalyst as described in claim 2, characterized in that: The Si source, OSDA1, OSDA2, Ti source, F source, and H2O are in the ratio of 1:0.28:0.01:0.03:0.3:

6.

4. The method for preparing the heteroatom molecular sieve catalyst as described in claim 2, characterized in that: The Si source, OSDA1, OSDA2, Ti source, F source, and H2O are in the ratio of 1:0.25:0.013:0.06:0.5:

12.

5. The method for preparing the heteroatom molecular sieve catalyst as described in claim 2, characterized in that: The Si source, OSDA1, OSDA2, Ti source, F source, and H2O are in a ratio of 1:0.16:0.02:0.02:0.5:

30.

6. The method for preparing the heteroatom molecular sieve catalyst as described in claim 1, characterized in that: The Si source is SiO. 2、 One of the following: tetraethyl orthosilicate, fuming silica gel, water glass, or silica gel.

7. The method for preparing the heteroatom molecular sieve catalyst according to claim 1, characterized in that: The Ti source is tetrabutyl titanate; the F source is NH4F or HF.

8. The heteroatom molecular sieve catalyst prepared according to any one of claims 1-7 is used in the photocatalyst or photothermal reaction of water reducing carbon dioxide.

9. The application as described in claim 8, characterized in that: 20 mg of the X-TIM material prepared above was placed in a 300 ml photoreactor, a 200-3500 nm wavelength full-spectrum light source was used, 10 ml of water was added, and the air in the reactor was completely replaced with carbon dioxide multiple times. The reaction was carried out for 2 hours, and the product was detected by liquid nuclear magnetic resonance.

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