Hydrophobic catalysts, methods of making and using the same

Abstract

This application relates to a hydrophobic catalyst, comprising: a hydrophobic support comprising a modified PTFE support having a specific surface area of ​​7.00 m² / g to 12.00 m² / g and / or a porosity of 29% to 35%; and an active metal supported on the hydrophobic support, wherein the active metal has a mass content of 0.25 wt% to 2.0 wt% based on the total mass of the hydrophobic catalyst. Furthermore, this application also relates to the use of the hydrophobic catalyst in a water-hydrogen exchange reaction.

Description

Technical Field

[0001] This application belongs to the field of hydrophobic catalysts, specifically relating to a hydrophobic catalyst, its preparation method, and its uses. Background Technology

[0002] Hydrogen isotope separation has wide and important applications in the nuclear industry. Among the many hydrogen isotope separation methods, the combined water electrolysis-hydrogen liquid-phase catalytic exchange (CECE) method is internationally recognized as the most advanced hydrogen isotope separation technology due to its outstanding advantages such as large separation coefficient, simple operation, and low energy consumption. The hydrophobic catalyst used in the water-hydrogen liquid-phase catalytic exchange reaction is the key to realizing CECE technology.

[0003] Polytetrafluoroethylene (PTFE) supports are commonly used as hydrophobic catalyst supports for water-hydrogen liquid-phase catalytic exchange reactions. However, it is currently difficult to obtain excellent pore structures for these supports, resulting in hydrophobic catalysts with low activity. Therefore, optimizing the pore structure of PTFE supports to obtain hydrophobic catalysts with good catalytic activity has become an urgent technical problem to be solved. Summary of the Invention

[0004] This application is made in view of the above-mentioned issues, and its purpose is to provide a hydrophobic catalyst with good catalytic activity.

[0005] To achieve the above objectives, this application provides a hydrophobic catalyst comprising: a hydrophobic support, the hydrophobic support comprising a modified PTFE support having a specific surface area of ​​7.00 m² / g to 12.00 m² / g and / or a porosity of 29% to 35%; and an active metal supported on the hydrophobic support, wherein the mass content of the active metal is 0.25 wt% to 2.0 wt% based on the total mass of the hydrophobic catalyst.

[0006] In some embodiments, the modified PTFE carrier has a specific surface area of ​​7.49 m² / g to 11.28 m² / g.

[0007] In some embodiments, the modified PTFE carrier has a porosity of 29.65% to 34.48%.

[0008] In some embodiments, the modified PTFE carrier is PTFE modified by one or more modifying materials selected from graphene and graphene oxide, and optionally, the mass ratio of the modifying material to PTFE is (0.02~0.5):100.

[0009] This application also provides a method for preparing a hydrophobic catalyst, the method comprising: S1: PTFE powder, modified materials and pore-forming agents are blended and pressed into a columnar carrier; S2: Curing the columnar carrier at a temperature of 320°C to 350°C to obtain a hydrophobic carrier including a modified PTFE carrier, wherein the modified PTFE carrier has a specific surface area of ​​7.00 m² / g to 12.00 m² / g and / or a porosity of 29% to 35%. S3: Prepare an active metal precursor solution, then immerse a hydrophobic support in the active metal precursor solution, remove it, and perform drying and reduction treatment to obtain a hydrophobic catalyst.

[0010] In some embodiments, the mass ratio of PTFE powder, modifier and pore-forming agent is 100:(0.02~0.5):(10~40).

[0011] In some embodiments, the particle size of the PTFE powder is in the range of 100 nm to 500 μm.

[0012] In some embodiments, the particle size of the pore-forming agent is in the range of 100 nm to 500 μm.

[0013] In some implementations, the diameter of the columnar carrier is in the range of 3 mm to 8 mm.

[0014] In some embodiments, compression molding is performed under pressures of 5 MPa to 10 MPa.

[0015] In some embodiments, the modifying material is selected from one or more of graphene and graphene oxide.

[0016] In some embodiments, the pore-forming agent is selected from one or more of polystyrene, polymethyl methacrylate, and polyvinyl alcohol.

[0017] In some implementations, curing takes 1 to 3 hours.

[0018] In some embodiments, the active metal precursor is selected from one or more of chloroplatinic acid, ammonium chloroplatinate, and sodium chloroplatinate.

[0019] In some embodiments, the solvent is selected from one or more of ethanol, acetone, or deionized water.

[0020] In some embodiments, the volume ratio of the hydrophobic support to the active metal precursor solution is 1:1 to 1:3.

[0021] In some embodiments, drying is carried out at 50°C to 65°C for 12 to 24 hours.

[0022] In some implementations, the reduction process includes a pretreatment stage, a reduction stage, and a cooling stage.

[0023] In some embodiments, the pretreatment stage includes heating the reduction furnace to 200°C to 280°C at a rate of 10°C / min under an inert atmosphere with a flow rate of 500 ml / min to 2000 ml / min.

[0024] In some embodiments, the reduction stage includes maintaining the temperature of the reduction furnace at 200°C to 280°C for 8 to 16 hours in a mixed atmosphere of inert gas at a flow rate of 500 ml / min to 2000 ml / min and H2 at a flow rate of 500 ml / min to 2000 ml / min.

[0025] In some implementations, the cooling phase includes allowing the reduction furnace to cool naturally to room temperature under an inert atmosphere with a flow rate of 500 ml / min.

[0026] This application also provides the use of the above-mentioned hydrophobic catalyst in water-hydrogen exchange reactions.

[0027] This application modifies the hydrophobic support by using a modified material, thereby increasing the specific surface area and porosity of the hydrophobic support. This allows the active metal to be uniformly loaded in the support at a high content, resulting in a hydrophobic catalyst with good catalytic activity. Attached Figure Description

[0028] Figure 1 A scanning electron microscope image of the hydrophobic support prepared in Example 1 of this application is shown.

[0029] Figure 2 A scanning electron microscope image of the hydrophobic support prepared in Comparative Example 1 of this application is shown.

[0030] Figure 3 A schematic diagram of the catalyst activity testing apparatus used in the test examples of this application is shown. Detailed Implementation

[0031] The following detailed description discusses exemplary embodiments. The specific embodiments included herein should not be construed as limiting this application. Furthermore, while specific language may be used to describe features, actions, and / or structures in the embodiments described herein, the claims are not limited to the described features, actions, and / or structures. Those skilled in the art will understand that other embodiments, including improvements, are possible within the spirit and scope of this application.

[0032] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0033] PTFE supports, as hydrophobic catalyst supports for water-hydrogen liquid-phase catalytic exchange reactions, exhibit good tolerance and high mechanical strength, allowing for long-term use in harsh environments. Furthermore, since PTFE supports are typically manufactured by pressing PTFE powder, they can be produced in any size, offering good process compatibility. However, currently, it is difficult to obtain excellent pore structures in PTFE supports; the specific surface area and pore uniformity of the supports are poor, preventing the active metal from being uniformly loaded onto the hydrophobic support, resulting in lower catalytic activity of the prepared hydrophobic catalysts.

[0034] In view of this, this application provides a hydrophobic catalyst comprising: a hydrophobic support and an active metal. Further, the hydrophobic support comprises a modified PTFE support having a specific surface area of ​​7.00 m² / g to 12.00 m² / g and / or a porosity of 29% to 35%; the active metal is supported on the hydrophobic support, and the mass content of the active metal is 0.25 wt% to 2.0 wt% based on the total mass of the hydrophobic catalyst.

[0035] In the hydrophobic catalyst of this application, the modified PTFE support can have a high specific surface area, resulting in more loading sites on the surface of the support. This facilitates the uniform dispersion and full exposure of the active metal on the hydrophobic support, thereby giving the hydrophobic catalyst good catalytic activity. Alternatively, the modified PTFE support can have a high porosity, resulting in a good pore structure on the surface of the support. This is beneficial for the loading, dispersion, and exposure of the active metal on the hydrophobic support, allowing the active metal to participate more effectively in the reaction and exert its catalytic effect.

[0036] In this application, the terms "specific surface area" and "porosity" may have the meanings disclosed in the art and can be determined by methods known in the art. For example, a mercury porosimeter can be used to obtain the relevant data using the Washburn equation.

[0037] For example, the mass content of the active metal is a value between 0.25 wt%, 0.5 wt%, 0.75 wt%, 1.0 wt%, 1.25 wt%, 1.5 wt%, 1.75 wt%, 2.0 wt%, or any two of these values.

[0038] In this application, the modified PTFE support can be modified by one or more modifying materials selected from graphene and graphene oxide. It is believed that in the preparation process of the modified PTFE support, the modifying material can act as a "skeleton," effectively reducing the formation and collapse of pores during the preparation of the hydrophobic support, generating a dense and uniform pore structure, effectively increasing the specific surface area and / or porosity of the hydrophobic support, so that the active metal loaded on it can be well dispersed, thereby giving the hydrophobic catalyst good catalytic activity.

[0039] Furthermore, the mass ratio of the modified material to PTFE is (0.02~0.5):100. By maintaining the mass ratio of the modified material to PTFE within the above range, the hydrophobicity of PTFE can be maintained while optimizing the pore structure of the hydrophobic carrier. For example, the mass ratio of the modified material to PTFE is a value within the range of 0.02:100, 0.07:100, 0.12:100, 0.17:100, 0.22:100, 0.27:100, 0.32:100, 0.37:100, 0.42:100, 0.47:100, 0.5:100, or any two of these.

[0040] This application also provides a method for preparing the above-mentioned hydrophobic catalyst. The preparation method may include the following steps: S1, S2, and S3.

[0041] Specifically, S1 includes blending and pressing PTFE powder, modifying materials, and pore-forming agents to obtain a columnar support; S2 includes curing the columnar support at a temperature of 320°C to 350°C to obtain a hydrophobic support including a modified PTFE support, wherein the modified PTFE support has a specific surface area of ​​7.00 m² / g to 12.00 m² / g and / or a porosity of 29% to 35%; S3 includes preparing an active metal precursor solution, then immersing the hydrophobic support in the active metal precursor solution, removing it, and performing drying and reduction treatment to obtain a hydrophobic catalyst.

[0042] In the method of this application, PTFE powder, modifying materials, and pore-forming agents are first blended and pressed into columnar supports, which are then cured at a certain temperature. During curing, the columnar supports are in a molten state, and the pore-forming agents decompose into gases during the high-temperature curing process, thereby creating pores in the PTFE. The modified materials blended in act as a "skeleton," helping to reduce the coalescence of gases generated by the decomposition of the pore-forming agents, thus reducing pore coalescence and pore collapse in the supports, which is beneficial to improving the specific surface area and porosity of the supports. As a result, the active metal supported on the supports can be well dispersed, thus giving the prepared hydrophobic catalyst good catalytic activity and improving the utilization rate of the active metal.

[0043] Furthermore, the pore-forming agent is selected from one or more of polystyrene, polymethyl methacrylate, and polyvinyl alcohol.

[0044] Furthermore, in this application, the mass ratio of PTFE powder, modifying material, and pore-forming agent is 100:(0.02~0.5):(10~40). This allows the PTFE support to achieve a suitable pore structure while maintaining its hydrophobicity. Exemplarily, the mass ratio of PTFE powder, modifying material, and pore-forming agent is a value within the range of 100:0.02:10, 100:0.02:40, 100:0.5:10, 100:0.5:40, 100:0.08:30, 100:0.1:20, or any combination thereof.

[0045] Furthermore, the particle size of the PTFE powder is in the range of 100 nm to 500 μm. This allows for uniform mixing of the PTFE powder with the pore-forming agent and modifying materials, while also facilitating compression molding into columnar carriers. For example, the particle size of the PTFE powder can be a value within the range of 100 nm, 100 μm, 300 μm, 500 μm, or any combination thereof.

[0046] In this application, PTFE powder with a single particle size can be selected, or PTFE powder with different particle sizes can be blended. The advantage of nano-sized PTFE powder is that it can be uniformly mixed with modifying materials and pore-forming agents, while the advantage of micron-sized PTFE powder is that it is easier to press into columnar carriers. By blending PTFE powder with different particle sizes, it is beneficial to simultaneously leverage the advantages of both particle sizes. For example, the particle size of a single-sized PTFE powder can be 100nm, 200nm, 300nm, 500nm, 100μm, 300μm, 400μm, 500μm, or any combination thereof; the particle size of the blended PTFE powder can include two or more different PTFE powders, such as PTFE powder with particle sizes of 100nm and 100μm, PTFE powder with particle sizes of 100nm and 200μm, or PTFE powder with particle sizes of 200nm and 200μm.

[0047] In this application, the particle size of the pore-forming agent is in the range of 100 nm to 500 μm. This facilitates obtaining a pore structure suitable for water-hydrogen exchange reactions. Exemplarily, the particle size of the pore-forming agent can be a value within the range of 100 nm, 200 nm, 300 nm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, or any combination thereof.

[0048] In this application, a single-size pore-forming agent can be selected, or pore-forming agents of different sizes can be compounded. Compounding pore-forming agents of different sizes can obtain multi-level pores. Larger pores facilitate the diffusion of reactant gases, while smaller pores increase the specific surface area of ​​the hydrophobic support, thereby promoting uniform dispersion of the active metal. For example, the particle size of the single-size pore-forming agent can be 100 nm, 100 μm, 200 nm, 300 nm, 200 μm, 300 μm, 400 μm, or 500 μm; the particle size of the compounded pore-forming agent can include two or more pore-forming agents of different sizes, such as pore-forming agents with particle sizes of 200 nm and 100 μm, pore-forming agents with particle sizes of 100 nm and 100 μm, pore-forming agents with particle sizes of 100 nm and 200 μm, or pore-forming agents with particle sizes of 100 nm and 500 μm.

[0049] In this application, the diameter of the columnar support can be in the range of 3 mm to 8 mm. This is more conducive to carrying out the water-hydrogen exchange reaction. For example, in S1, the diameter of the columnar support is a value between 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, or any combination thereof.

[0050] In this application, compression molding can be performed under a pressure of 5 MPa to 10 MPa. This is beneficial for increasing the compaction density of the columnar carrier. Exemplarily, in S1, the compression molding pressure is a value between 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, or any two of these values.

[0051] Furthermore, in this application, the curing in step S2 can be carried out at a temperature between 320°C and 350°C. Curing at this temperature facilitates the complete decomposition of the pore-forming agent into gas. Exemplarily, the curing temperature can be a value between 320°C, 330°C, 340°C, 350°C, or any combination thereof.

[0052] Furthermore, the curing in step S2 is carried out for 1 to 3 hours. By controlling the curing time within the above range, it is beneficial for the pore-forming agent to fully vaporize, thereby improving the specific surface area and porosity of the carrier. For example, the curing time can be a value between 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, or any combination thereof.

[0053] Furthermore, in this application, by controlling the conditions of steps S1 and S2, the obtained modified PTFE support has a specific surface area of ​​7.00 m² / g to 12.00 m² / g and / or a porosity of 29% to 35%, more particularly a specific surface area of ​​7.49 m² / g to 11.28 m² / g and / or a porosity of 29.65% to 34.48%.

[0054] Next, in step S3 of this application, an active metal precursor solution is prepared. There is no particular requirement for this preparation; conventional methods in the art can be used.

[0055] There are no particular restrictions on the concentration of the precursor solution of the active metal, as long as it facilitates the uniform dispersion of the active component on the carrier surface. For example, the concentration of the precursor solution of the active metal can be from 0.01 mol / L to 0.031 mol / L, such as 0.01 mol / L, 0.015 mol / L, 0.02 mol / L, 0.025 mol / L, 0.031 mol / L, or any value within the range of two of these.

[0056] There are no particular restrictions on the materials used as precursors for the active metal; those conventionally used in the art can be used. For example, when the active metal is Pt, one or more of chloroplatinic acid (H₂PtCl₆·6H₂O), ammonium chloroplatinate, and sodium chloroplatinate can be selected. When other active metals are selected, those skilled in the art will know the corresponding precursors.

[0057] In this application, the solvent for preparing the precursor solution may be selected from one or more of ethanol, acetone or deionized water, but is not limited thereto.

[0058] In this application, the volume ratio of the hydrophobic support to the precursor solution can be from 1:1 to 1:3. This facilitates sufficient impregnation and loading of the hydrophobic support by the precursor solution, thereby ensuring uniform deposition of the active metal precursor on the hydrophobic support, while also effectively controlling costs. Exemplarily, the volume ratio of the hydrophobic support to the precursor solution is a value within the range of 1:1, 1:2, 1:3, or any combination thereof.

[0059] Subsequently, the impregnated hydrophobic carrier can be dried at 50°C to 65°C for 12 to 24 hours. This facilitates the complete evaporation of the solvent.

[0060] Next, the dried hydrophobic support is reduced, thereby reducing the active metal precursor loaded on the hydrophobic support to the active metal.

[0061] In this application, there are no particular restrictions on the restoration process, and those conventionally used in the art can be used.

[0062] For example, the reduction process may include a pretreatment stage, a reduction stage, and a cooling stage.

[0063] Furthermore, the pretreatment stage can be carried out by raising the temperature of the reduction furnace to 200°C to 280°C at a heating rate of 10°C / min under an inert atmosphere with a flow rate of 500 ml / min to 2000 ml / min. The reduction stage can be carried out by maintaining the temperature of the reduction furnace at 200°C to 280°C for 8 to 16 hours under a mixed atmosphere of inert gas and H2 with a flow rate of 500 ml / min to 2000 ml / min. This facilitates the complete reduction of the active metal precursor to the active metal. For example, the reduction can be carried out at temperatures ranging from 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, or any combination thereof. Furthermore, the restoration time can be, for example, a value between 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, or any two of these ranges.

[0064] Furthermore, during the cooling stage, the temperature of the reduction furnace can be naturally reduced to room temperature under an inert atmosphere with a flow rate of 500 ml / min.

[0065] In this application, the active metal is directly loaded onto the hydrophobic support by the impregnation-vapor phase reduction method, which can effectively prevent the active metal from being covered by the hydrophobic coating and improve the utilization rate of the active metal.

[0066] The present application is described in more detail below through embodiments. It should be understood that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art or in accordance with the product instructions. Where the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be obtained commercially.

[0067] Example 1 20g of PTFE powder, 0.008g of modified graphene, and 2g of pore-forming agent were blended and stirred for 2 hours at room temperature. The PTFE powder contained 50wt% particles with a diameter of 100nm and the remaining 50wt% particles with a diameter of 100μm. The pore-forming agent was PMMA with a particle size of 100μm. The blend was then pressed into cylindrical supports with a diameter of 3mm under a pressure of 5MPa. The cylindrical supports were placed in a muffle furnace and cured at 320℃ for 2 hours to obtain approximately 20g of hydrophobic support.

[0068] The precursor of the active metal, chloroplatinic acid (H₂PtCl₆·6H₂O), was dissolved in ethanol to obtain a precursor solution of the active metal with a concentration of 0.013 mol / L. 20 g of the above hydrophobic support was impregnated in 40 mL of the above active metal precursor solution. It was then dried at 50 °C for 12 hours. Next, it was placed in a tubular reduction furnace and reduced using hydrogen as the reducing gas. First, the furnace was heated to 240 °C at a heating rate of 10 °C / min under an Ar atmosphere with a flow rate of 500 mL / min. Then, the temperature was maintained at 240 °C for 8 hours under a mixed atmosphere of Ar and H₂ at a flow rate of 500 mL / min. Finally, the H₂ was turned off, and the furnace was allowed to cool naturally to room temperature under an Ar atmosphere with a flow rate of 500 mL / min. The reduction was then complete, yielding approximately 20 g of hydrophobic catalyst.

[0069] The mass of active metal Pt can be calculated based on the concentration and amount of the chloroplatinic acid precursor solution, and then it can be calculated that the mass content of active metal Pt is 0.5 wt% based on the total mass of the hydrophobic catalyst.

[0070] In this embodiment, after the hydrophobic support was prepared, it was scanned using a scanning electron microscope (ZEISS Sigma 300, Germany) to obtain... Figure 1 .from Figure 1 It can be seen that the prepared hydrophobic carrier has many pores and the pore size is relatively uniform.

[0071] Parameter characterization Specific surface area Using a mercury porosimeter (MicroActive AutoPore V 9600 from Micromeritics, USA), the non-wetting property of mercury was utilized to establish a quantitative relationship between external pressure P and the radius of pores that can be penetrated, based on the classical Washburn equation. Assuming the pores are cylindrical, the specific surface area was estimated based on the mercury penetration data.

[0072] The specific surface area calculation results of the hydrophobic carrier prepared in Example 1 are summarized in Table 1 below.

[0073] Porosity Using a mercury porosimeter (MicroActive AutoPore V 9600 from Micromeritics, USA), the non-wetting property of mercury was utilized to establish a quantitative relationship between external pressure P and the radius of pores that can be penetrated using the classic Washburn equation. The porosity can then be calculated by dividing the pore volume by the carrier volume.

[0074] The porosity results of the hydrophobic carrier prepared in Example 1 are summarized in Table 1 below.

[0075] Example 2 20g of PTFE powder, 0.016g of modified graphene, and 5g of pore-forming agent were blended and stirred for 2 hours at room temperature. The PTFE powder had a particle size of 300μm. The pore-forming agent consisted of 80wt% PMMA with a particle size of 100μm and 20wt% PS with a particle size of 200nm. The blend was then pressed into columnar carriers with a diameter of 5mm under a pressure of 7MPa. The columnar carriers were placed in a muffle furnace and cured at 350℃ for 3 hours to obtain approximately 20g of hydrophobic carrier.

[0076] The precursor of the active metal, chloroplatinic acid (H₂PtCl₆·6H₂O), was dissolved in ethanol to obtain a precursor solution of the active metal with a concentration of 0.021 mol / L. 10 g of the above hydrophobic support was impregnated in 20 mL of the above active metal precursor solution. It was then dried at 50 °C for 12 hours. Next, it was placed in a tubular reduction furnace and reduced using hydrogen as the reducing gas. First, the furnace was heated to 260 °C at a heating rate of 10 °C / min under an Ar atmosphere with a flow rate of 500 mL / min. Then, the temperature was maintained at 260 °C for 12 hours under a mixed atmosphere of Ar at a flow rate of 500 mL / min and H₂ at a flow rate of 1000 mL / min. Finally, the H₂ was turned off, and the furnace was allowed to cool naturally to room temperature under an Ar atmosphere with a flow rate of 500 mL / min. The reduction was then complete, yielding approximately 10 g of hydrophobic catalyst.

[0077] The mass of active metal Pt can be calculated based on the concentration and amount of the chloroplatinic acid precursor solution. Therefore, it can be calculated that the mass content of active metal Pt is approximately 0.8 wt% based on the total mass of the hydrophobic catalyst.

[0078] The specific surface area and porosity of the hydrophobic carrier prepared in Example 2 were measured according to the above method, and the results are summarized in Table 1 below.

[0079] Example 3 20g of PTFE powder, 0.012g of modified graphene, and 6g of pore-forming agent were blended and stirred for 2 hours at room temperature. The PTFE powder had a particle size of 100μm, and the pore-forming agent consisted of 50wt% PMMA with a particle size of 100μm and the other 50wt% PS with a particle size of 100nm. The blend was then pressed into a columnar carrier with a diameter of 3mm under a pressure of 8MPa. The columnar carrier was placed in a muffle furnace and cured at 330℃ for 2 hours to obtain approximately 20g of hydrophobic carrier.

[0080] The precursor of the active metal, chloroplatinic acid (H₂PtCl₆·6H₂O), was dissolved in ethanol to obtain a precursor solution of the active metal with a concentration of 0.026 mol / L. 20 g of the above hydrophobic support was impregnated in 40 mL of the above precursor solution. It was then dried at 50 °C for 12 hours. Next, it was placed in a tubular reduction furnace and reduced using hydrogen as the reducing gas. First, the furnace was heated to 240 °C at a heating rate of 10 °C / min under an Ar atmosphere with a flow rate of 500 mL / min. Then, the temperature was maintained at 240 °C for 12 hours under a mixed atmosphere of Ar at a flow rate of 500 mL / min and H₂ at a flow rate of 1000 mL / min. Finally, the H₂ was turned off, and the furnace was allowed to cool naturally to room temperature under an Ar atmosphere with a flow rate of 500 mL / min. The reduction was then complete, yielding approximately 20 g of hydrophobic catalyst.

[0081] The mass of active metal Pt can be calculated based on the concentration and amount of the chloroplatinic acid precursor solution. Furthermore, it can be calculated that the total mass of the hydrophobic catalyst and the mass content of active metal Pt are approximately 1.0 wt%.

[0082] The specific surface area and porosity of the hydrophobic carrier prepared in Example 3 were measured according to the above method, and the results are summarized in Table 1 below.

[0083] Comparative Example 1 The hydrophobic catalyst was prepared in the same manner as in Example 1, except that 0.008g of the modified material graphene was not used.

[0084] The mass of active metal Pt can be calculated based on the concentration and amount of the chloroplatinic acid precursor solution, and then it can be calculated that the mass content of active metal Pt is 0.5 wt% based on the total mass of the hydrophobic catalyst.

[0085] In this experiment, after preparing the hydrophobic support, the obtained hydrophobic support was scanned using a scanning electron microscope to obtain... Figure 2 Therefore, it can be concluded that, with Figure 1 In contrast, the hydrophobic carrier in Comparative Example 1 has fewer pores and a lower porosity.

[0086] The specific surface area and porosity of the hydrophobic catalyst prepared in Comparative Example 1 were measured according to the above method, and the results are summarized in Table 1 below.

[0087] Test example: Testing catalytic activity Adopting such Figure 3The vapor-gas co-flow exchange apparatus shown has a hydrogen flow rate of 0.5 L / min, a catalyst volume of 10 ml, and a catalytic column diameter of 30 mm. Dilute heavy water circulates in the packed column under the action of a peristaltic pump. The packed column and catalytic column are heated to a constant temperature of 60°C. High-purity hydrogen gas, supplied from a gas cylinder and delivered at a constant pressure and flow rate, passes through the packed column, carrying saturated light and heavy water vapor at this temperature into the catalytic column. The hydrogen gas and the water vapor from the dilute heavy water flow co-currently through the catalytic exchange bed, where a hydrogen isotope exchange reaction occurs under the action of the catalyst. The exchanged gas-vapor mixture is separated by a condenser, and gas and water samples are obtained separately. The water density is measured using a densitometer, and the deuterium abundance of the gas is measured using a mass spectrometer to confirm the isotope separation efficiency.

[0088] The gas-vapor co-flow exchange reaction process is as follows: (1) t = tx 1-y 1-xy The activity of a catalyst is evaluated using its separation efficiency. Following a first-order reaction, the following can be derived: The reaction rate equation is: (2) Where x and y are the concentrations of deuterium in the vapor phase and the gas phase, respectively.

[0089] When x and y are relatively small, we can consider (1-x) and (1-y) to be constants, then we have: (3) When equilibrium is reached Then we have: (4) in , These represent the concentrations of deuterium in the vapor phase and the gas phase, respectively, when equilibrium is reached.

[0090] From material balance, we obtain (5) Substituting equations (2) and (3) into equation (1), we get: (6) The entire reaction process is viewed as a mass transfer process of deuterium between water vapor and hydrogen. As the driving force for mass transfer in this process, It can be considered as the mass transfer coefficient, let Then we get: (7) The integral yields: (8) Then we have: (9) in: (10) (11) (12) F represents the separation efficiency (conversion rate); The volume of the catalyst; The separation coefficient; y is the deuterium concentration in the gaseous condensate after the reaction, determined by a densitometer; y is the deuterium concentration in the gas phase after the reaction, determined by mass spectrometry; G is the gas flow rate; H is the ratio of saturated water vapor partial pressure to atmospheric pressure at the reaction temperature (approximately 0.24 at 60℃).

[0091] The specific surface area and porosity of the hydrophobic supports prepared in Examples 1-3 and Comparative Example 1, as well as the HD separation efficiency of the hydrophobic catalysts, are summarized in Table 1 below.

[0092] Table 1

[0093] As shown in Table 1, Examples 1-3 improved the specific surface area of ​​the hydrophobic support by using the modified material graphene, while reducing pores and thus increasing porosity. This allowed for good dispersion of the active metal Pt supported on the support, resulting in high HD separation efficiency of the prepared hydrophobic catalyst. Conversely, in Comparative Example 1, since no modified material was used to modify the hydrophobic support, the specific surface area of ​​the prepared hydrophobic support and the HD separation efficiency of the hydrophobic catalyst were both inferior to those of Examples 1-3.

[0094] Although this disclosure has been described with reference to specific exemplary embodiments thereof, many different variations, modifications, etc. will become apparent to those skilled in the art.

[0095] By studying the accompanying drawings, the disclosure, and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments in the practice of this disclosure.

Claims

1. A hydrophobic catalyst, comprising: A hydrophobic carrier, comprising a modified PTFE carrier having a specific surface area of ​​7.00 m² / g to 12.00 m² / g and / or a porosity of 29% to 35%; and An active metal is supported on the hydrophobic support, wherein the mass content of the active metal is from 0.25 wt% to 2.0 wt% based on the total mass of the hydrophobic catalyst.

2. The hydrophobic catalyst according to claim 1, wherein, The modified PTFE support has a specific surface area of ​​7.49 m² / g to 11.28 m² / g and / or a porosity of 29.65% to 34.48%.

3. The hydrophobic catalyst according to claim 1 or 2, wherein, The modified PTFE carrier is PTFE modified by one or more modifying materials selected from graphene and graphene oxide, and optionally, the mass ratio of the modifying material to PTFE is (0.02~0.5):

100.

4. A method for preparing a hydrophobic catalyst, comprising: S1: PTFE powder, modified materials and pore-forming agents are blended and pressed into a columnar carrier; S2: The columnar carrier is cured at a temperature of 320°C to 350°C to obtain a hydrophobic carrier including a modified PTFE carrier, wherein the modified PTFE carrier has a specific surface area of ​​7.00 m² / g to 12.00 m² / g and / or a porosity of 29% to 35%. S3: Prepare an active metal precursor solution, then immerse the hydrophobic support in the active metal precursor solution, remove it, and perform drying and reduction treatment to obtain the hydrophobic catalyst.

5. The method for preparing the hydrophobic catalyst according to claim 4, wherein, S1 in the method satisfies one or more of the following: The mass ratio of the PTFE powder, the modified material, and the pore-forming agent is 100:(0.02~0.5):(10~40); The particle size of the PTFE powder is in the range of 100 nm to 500 μm; The particle size of the pore-forming agent is in the range of 100 nm to 500 μm; The diameter of the columnar carrier is in the range of 3 mm to 8 mm; The compression molding is performed under a pressure of 5 MPa to 10 MPa. The modified material is selected from one or more of graphene and graphene oxide; The pore-forming agent is selected from one or more of polystyrene, polymethyl methacrylate, and polyvinyl alcohol.

6. The method for preparing the hydrophobic catalyst according to claim 4 or 5, wherein, The method satisfies one or more of the following: The curing process takes 1 to 3 hours. The active metal precursor is selected from one or more of chloroplatinic acid, ammonium chloroplatinate, and sodium chloroplatinate. The solvent is selected from one or more of ethanol, acetone or deionized water; The volume ratio of the hydrophobic support to the active metal precursor solution is 1:1 to 1:

3. The drying process is carried out at 50°C to 65°C for 12 to 24 hours.

7. The method for preparing the hydrophobic catalyst according to any one of claims 4 to 6, wherein, The reduction process includes a pretreatment stage, a reduction stage, and a cooling stage.

8. The method for preparing the hydrophobic catalyst according to claim 7, wherein, The pretreatment stage includes raising the temperature of the reduction furnace to 200°C to 280°C at a rate of 10°C / min under an inert atmosphere with a flow rate of 500 ml / min to 2000 ml / min; and / or The reduction stage includes maintaining the temperature of the reduction furnace at 200°C to 280°C for 8 to 16 hours in a mixed atmosphere of inert gas at a flow rate of 500 ml / min to 2000 ml / min and H2 at a flow rate of 500 ml / min to 2000 ml / min; and / or The cooling stage includes allowing the reduction furnace to cool naturally to room temperature under an inert atmosphere with a flow rate of 500 ml / min.

9. Use of the hydrophobic catalyst according to any one of claims 1 to 3 and the hydrophobic catalyst obtained by the preparation method according to any one of claims 4 to 8 in water-hydrogen exchange reactions.

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