Hydrophobic catalysts, methods of making and using the same

Abstract

This invention relates to a hydrophobic catalyst, comprising: a hydrophobic support, the hydrophobic support comprising a ceramic matrix and a hydrophobic coating on the surface of the ceramic matrix, the hydrophobic coating comprising modified graphene oxide; an active metal supported on the hydrophobic support; wherein the ceramic matrix has a particle size greater than 5 mm, and the hydrophobic support has a particle size of 45 μm. 2 / g to 120m 2 / g BET specific surface area. Furthermore, this invention also relates to the use of hydrophobic catalysts in water-hydrogen exchange reactions.

Description

Technical Field

[0001] This invention 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 various hydrogen isotope separation methods, the combined water-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 high separation coefficient, simple operation, and low energy consumption. The hydrophobic catalyst used in the water-hydrogen liquid-phase catalytic exchange reaction is key to realizing CECE technology. Currently, the problem with hydrophobic catalysts used in water-hydrogen liquid-phase catalytic exchange reactions is that it is difficult to simultaneously prepare large-particle-size hydrophobic catalysts for large-capacity systems and maintain high catalytic efficiency.

[0003] Therefore, there is a need for an improved hydrophobic catalyst that can solve or mitigate the problems present in existing hydrophobic catalysts. 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 large particle size and high catalytic efficiency, as well as its preparation method and uses.

[0005] To achieve the above objectives, the first aspect of this application provides a hydrophobic catalyst, comprising: a hydrophobic support, the hydrophobic support comprising a ceramic matrix and a hydrophobic coating located on the surface of the ceramic matrix, the hydrophobic coating comprising modified graphene oxide; Active metals, with active metals loaded on hydrophobic supports; The ceramic matrix has a particle size greater than 5 mm, and the hydrophobic carrier has a particle size of 45 μm. 2 / g to 120m 2 / g BET specific surface area.

[0006] In some embodiments, the modified graphene oxide is modified with a fluorinated siloxane, optionally selected from one or more of the following: tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, and trifluoropropyltrimethoxysilane.

[0007] In some embodiments, the content of active metal is 0.1 wt% to 1 wt% based on the total weight of the hydrophobic catalyst.

[0008] In some embodiments, the ceramic matrix is ​​one or more of the following: a ceramic matrix with three-dimensional channels: silicon dioxide, zirconium oxide, and silicon-based molecular sieves.

[0009] In some embodiments, the hydrophobic coating further includes an adhesive, optionally selected from PVDF.

[0010] In some implementations, the hydrophobic coating has a 100% coverage.

[0011] A second aspect of this application provides a method for preparing a hydrophobic catalyst, comprising: S1: Prepare a solution of the modified material, and then mix the solution of the modified material, graphene oxide and the first solvent to obtain a first mixture; S2: The first mixture is stirred at a temperature of 25°C to 60°C and then dried to obtain modified graphene oxide. S3: Prepare a modified graphene oxide coating solution, then coat the solution onto a ceramic substrate, and after a second drying process, obtain a hydrophobic support. The ceramic substrate has a particle size greater than 5 mm, and the hydrophobic support has a particle size of 45 μm. 2 / g to 120m 2 BET specific surface area per g; S4: Hydrophobic catalysts are prepared by impregnation-gas phase reduction method using hydrophobic supports and active metals.

[0012] In some embodiments, the concentration of the modified material solution is from 0.1 wt% to 0.3 wt%.

[0013] In some embodiments, the modified material includes a fluorosiloxane, optionally selected from one or more of tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, and trifluoropropyltrimethoxysilane.

[0014] In some embodiments, the volume ratio of the modified material solution to the first solvent is 3:1 to 9:1.

[0015] In some embodiments, the amount of graphene oxide added is from 2 mg / ml to 20 mg / ml.

[0016] In some embodiments, the first solvent is selected from deionized water.

[0017] In some implementations, stirring is carried out for 1 to 3 hours.

[0018] In some embodiments, the first drying is carried out at 50°C to 70°C for 1 to 2 hours.

[0019] In some embodiments, the second drying is carried out at room temperature for 12 to 24 hours, followed by a drying process at 40°C to 80°C for 2 to 5 hours.

[0020] In some implementations, the coating-second drying process is repeated 1 to 3 times.

[0021] In some embodiments, the preparation of the modified graphene oxide coating solution includes: S31: Prepare an adhesive solution by dissolving the adhesive in a second solvent; optionally, the adhesive is selected from PVDF; the second solvent is selected from one or more of N-methylpyrrolidone, dimethylformamide, and dimethylacetamide; the adhesive content is 3 wt% to 10 wt% based on the total weight of the adhesive solution; S32: A mixture of binder solution and modified graphene oxide, wherein the content of modified graphene oxide is from 10 wt% to 50 wt% based on the total weight of the coating solution.

[0022] In some embodiments, the impregnation-vapor phase reduction method includes an impregnation treatment, a third drying, and a reduction treatment; The impregnation process includes: impregnating a hydrophobic support in a precursor solution of an active metal to obtain a semi-finished catalyst; wherein, optionally, the volume ratio of the hydrophobic support to the precursor solution of the active metal is 1:1 to 1:3. The third drying process includes drying the semi-finished catalyst at a temperature of 50°C to 65°C for 12 to 24 hours. The reduction process includes a pretreatment stage, a reduction stage, and a cooling stage.

[0023] In some embodiments, the pretreatment stage includes raising the temperature of the reduction furnace from room temperature to 200°C to 280°C at a rate of 10°C / min in an inert atmosphere 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 in an inert gas atmosphere with a flow rate of 500 ml / min.

[0026] The third aspect of this application provides the use of the above-mentioned hydrophobic catalyst in water-hydrogen exchange reactions.

[0027] In this application, because the ceramic matrix has a particle size greater than 5 mm, the hydrophobic catalyst including the ceramic matrix is ​​relatively large, which is advantageous for use in high-capacity systems. Furthermore, since the hydrophobic coating includes modified graphene oxide, the high specific surface area of ​​the graphene oxide effectively increases the specific surface area of ​​the support, allowing the active metal to be uniformly loaded in the support and enabling more active metal to deposit on the surface of the hydrophobic support, thereby improving catalytic efficiency. Therefore, the hydrophobic catalyst prepared in this application maintains high catalytic efficiency while having a large particle size. 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 schematic diagram of the hydrophobic catalyst activity testing apparatus used in the test examples of this application is shown. Detailed Implementation

[0030] The following detailed description discusses exemplary embodiments. The specific embodiments included herein should not be construed as limiting the invention. 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 within the spirit and scope of the invention.

[0031] 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 invention pertains.

[0032] Currently available hydrophobic catalysts can be broadly classified into three categories: Pt / SDB, Pt / C / PTFE, and Pt / C / IC. Pt / SDB catalysts directly support Pt particles on a polymeric SDB support, exhibiting excellent hydrophobicity and catalytic performance. However, they are difficult to prepare into large-particle sizes, making them unsuitable for large-scale systems and applications in the detritium removal process for tritium-containing wastewater requiring large-scale treatment. Pt / C / PTFE catalysts are prepared by blending PTFE powder with Pt / C, allowing for the production of catalysts of any size. However, the Pt particles are largely masked by PTFE, resulting in low Pt utilization and catalytic efficiency. Pt / C / IC catalysts use PTFE as a binder and hydrophobic agent to coat Pt / C onto an inert support. The preparation process is complex, and a large number of Pt particles are also masked by PTFE, leading to low Pt utilization and catalytic efficiency.

[0033] Therefore, this application provides a hydrophobic catalyst, comprising: a hydrophobic support, the hydrophobic support comprising a ceramic matrix and a hydrophobic coating located on the surface of the ceramic matrix, the hydrophobic coating comprising modified graphene oxide; Active metals, with active metals loaded on hydrophobic supports; The ceramic matrix has a particle size greater than 5 mm, and the hydrophobic carrier has a particle size of 45 μm. 2 / g to 120m 2 / g BET specific surface area.

[0034] Large-scale tritium-containing wastewater treatment involves large-volume treatment, large-diameter reaction columns, high gas velocities, and large liquid flow rates. In this device, small-particle catalysts can cause flooding due to high gas resistance. Severe flooding can cause liquid to overflow from the top of the column, resulting in a sharp drop in separation efficiency, making the reaction difficult to proceed, or even damaging the reaction device. Therefore, large-size catalysts must be used.

[0035] In this application, a low-cost and easily prepared ceramic matrix is ​​used as the support. Because the ceramic matrix has a particle size greater than 5 mm, the hydrophobic catalyst incorporating the ceramic matrix is ​​relatively large. This helps to reduce the reaction resistance drop in large-scale tritium-containing wastewater treatment devices, thereby mitigating flooding and improving the water-hydrogen exchange reaction. catalytic efficiency Furthermore, since the hydrophobic coating includes modified graphene oxide, the high specific surface area of ​​the graphene oxide can effectively increase the specific surface area of ​​the support, especially the specific surface area of ​​the hydrophobic catalyst surface. This allows the active metal to be uniformly loaded on the support and for more active metal to be deposited on the catalyst surface. Because the diffusion of reactants takes time, the active metal on the catalyst surface can preferentially participate in the reaction, thereby improving catalytic efficiency. Therefore, the hydrophobic catalyst prepared in this application can maintain high catalytic efficiency while having a large particle size.

[0036] In this application, there are no particular restrictions on the particle size of the ceramic matrix. A suitable particle size can be selected according to the reaction scale, as long as it is greater than 5 mm.

[0037] In this application, the active metal may include Pt.

[0038] In some embodiments, the hydrophobic carrier may have a thickness of 45m. 2 / g to 120m 2 The BET specific surface area is / g. A BET specific surface area of ​​the hydrophobic support within the above range indicates a high BET specific surface area. A higher specific surface area facilitates the uniform dispersion of the active metal, thereby improving catalytic efficiency. For example, the BET specific surface area of ​​the hydrophobic support can be 45m². 2 / g、55m2 / g、65m 2 / g、75m 2 / g、85m 2 / g、95m 2 / g, 105m 2 / g、115m 2 / g、120m 2 / g or a range between any two of them.

[0039] In this application, the term "BET specific surface area" may have the meaning disclosed in the art and may be determined by methods known in the art. For example, the BET specific surface area may be calculated using the BET (Brunauer Emmett Teller) method by measuring the adsorption and desorption isotherms of a hydrophobic support by nitrogen adsorption using a specific surface area and porosity analyzer.

[0040] In some embodiments, the modified graphene oxide can be modified with fluorinated siloxanes. After hydrolysis, the Si-O bonds of the fluorinated siloxanes can undergo a condensation reaction with the hydroxyl groups of the graphene oxide, allowing the fluorinated siloxane molecular chains to chemically bond with the graphene oxide. The fluorine groups impart hydrophobicity to the graphene oxide. Furthermore, graphene oxide itself possesses an ultra-high specific surface area; after hydrophobic modification, a high-roughness, high-specific-surface-area hydrophobic structure can be formed, allowing more hydrophobic molecules to be grafted onto it, thus giving the hydrophobic carrier even better hydrophobicity.

[0041] In some embodiments, the fluorosiloxane may be selected from one or more of the following: tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, and trifluoropropyltrimethoxysilane.

[0042] In some embodiments, the content of the active metal may be from 0.1 wt% to 1 wt% based on the total weight of the hydrophobic catalyst. Exemplarily, the content of the active metal may be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, or a value within a range of any two thereof, based on the total weight of the hydrophobic catalyst.

[0043] In some embodiments, the ceramic matrix may be one or more of the following: a ceramic matrix with three-dimensional channels: silica, zirconium oxide, and silicon-based molecular sieves.

[0044] The term "three-dimensional pores" refers to a continuous pore system that runs through the interior of a ceramic matrix, interconnects with each other in three-dimensional space, and forms a network structure.

[0045] In some embodiments, the hydrophobic coating also includes an adhesive. By using the adhesive, the hydrophobic coating can be adhered to the ceramic substrate, thereby hydrophobizing the ceramic substrate.

[0046] In some implementations, the adhesive may be selected from PVDF.

[0047] In this application, the hydrophobic coating has a coverage of 100%. Typically, 100% coverage can be achieved when coating is performed by immersion, and the use of the term "coating" inherently implies a coverage of 100%.

[0048] To avoid being constrained by theoretical limitations, the thickness of the hydrophobic coating in this application is approximately less than 150 μm. This essentially ensures the hydrophobicity of the carrier, avoids wasting graphene and increasing costs, and prevents graphene accumulation that could lead to increased agglomeration probability and loss of the high specific surface area advantage.

[0049] This application also provides a method for preparing a hydrophobic catalyst, comprising: S1: Prepare a solution of the modified material, and then mix the solution of the modified material, graphene oxide and the first solvent to obtain a first mixture; S2: The first mixture is stirred at a temperature of 25°C to 60°C and then dried to obtain modified graphene oxide. S3: Prepare a modified graphene oxide coating solution, then coat the solution onto a ceramic substrate, and after a second drying process, obtain a hydrophobic support. The ceramic substrate has a particle size greater than 5 mm, and the hydrophobic support has a particle size of 45 μm. 2 / g to 120m 2 BET specific surface area per g; S4: Hydrophobic catalysts are prepared by impregnation-gas phase reduction method using hydrophobic supports and active metals.

[0050] In the method of this application, the use of a ceramic matrix with a particle size greater than 5 mm results in a hydrophobic catalyst with a relatively large particle size, which is advantageous for use in high-capacity systems. Furthermore, by coating the ceramic matrix with a modified graphene oxide coating solution, the high specific surface area of ​​the graphene oxide increases the surface area of ​​the support, allowing the active metal to be uniformly loaded onto the support and enabling more active metal to deposit on the catalyst surface, thereby improving catalytic efficiency.

[0051] In this application, step S1 is first performed: a solution of the modified material is prepared, and then the solution of the modified material, graphene oxide and a first solvent are mixed to obtain a first mixture.

[0052] In this application, the concentration of the modified material solution can be from 0.1 wt% to 0.3 wt%. Exemplarily, the concentration of the modified material solution can be 0.1 wt%, 0.2 wt%, 0.3 wt%, or a value within a range of any two of these.

[0053] In this application, the modified material includes fluorosiloxanes. By using fluorosiloxanes as the modified material, after hydrolysis, the Si-O bonds of the fluorosiloxanes can undergo a condensation reaction with the hydroxyl groups of graphene oxide, allowing the fluorosiloxane molecular chains to be chemically bonded to graphene oxide, thus giving it hydrophobic properties.

[0054] In this application, the fluorosiloxane may be selected from one or more of tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, and trifluoropropyltrimethoxysilane.

[0055] In this application, the volume ratio of the modified material solution to the first solvent can be from 3:1 to 9:1. This facilitates the complete hydrolysis of the fluorinated siloxane, thereby benefiting the hydrophobic modification of graphene oxide. Exemplarily, the volume ratio of the modified material solution to the first solvent can be 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or a value within a range of any two of these.

[0056] In this application, the first solvent can be deionized water. This facilitates the complete hydrolysis of fluorinated siloxanes.

[0057] In this application, the amount of graphene oxide added can be from 2 mg / ml to 20 mg / ml. Therefore, the amount of graphene oxide is within a suitable range, allowing for good dispersion, which is beneficial for the hydrophobic modification of graphene oxide. Exemplarily, the amount of graphene oxide added can be 2 mg / ml, 4 mg / ml, 6 mg / ml, 8 mg / ml, 10 mg / ml, 12 mg / ml, 14 mg / ml, 16 mg / ml, 18 mg / ml, 20 mg / ml, or a value within a range of any two of these.

[0058] Next, step S2 is performed: the first mixture is stirred at a temperature of 25°C to 60°C, and after a first drying, modified graphene oxide is obtained. For example, stirring can be carried out at temperatures between 25°C, 35°C, 45°C, 55°C, 60°C, or any combination thereof.

[0059] In this application, stirring can be performed for 1 to 3 hours. This is beneficial for the hydrophobic modification of graphene oxide. Exemplarily, stirring can be performed for 1 hour, 2 hours, 3 hours, or a range consisting of any two of these.

[0060] In this application, the first drying can be carried out at 50°C to 70°C for 1 to 2 hours.

[0061] Next, step S3 is performed: a modified graphene oxide coating solution is prepared, and then the coating solution is coated onto a ceramic substrate. After a second drying process, a hydrophobic support is obtained, wherein the ceramic substrate has a particle size greater than 5 mm, and the hydrophobic support has a particle size of 45 μm. 2 / g to 120m 2 / g BET specific surface area.

[0062] In this application, the preparation of the modified graphene oxide coating solution includes: S31: Prepare an adhesive solution by dissolving the adhesive in a second solvent; optionally, the adhesive is selected from PVDF; the second solvent is selected from one or more of N-methylpyrrolidone, dimethylformamide, and dimethylacetamide; the adhesive content can be from 3 wt% to 10 wt% based on the total weight of the adhesive solution. By controlling the adhesive content within the above range, the masking effect of the adhesive on the graphene oxide coating is reduced while ensuring uniform adhesion of the modified graphene oxide coating liquid to the hydrophobic carrier. For example, the adhesive content can be a value within the range of 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, or any combination thereof, based on the total weight of the adhesive solution.

[0063] S32: A mixed binder solution and modified graphene oxide are used, wherein the content of modified graphene oxide can be from 10 wt% to 50 wt% based on the total weight of the coating solution. By controlling the content of modified graphene oxide within the above range, it is beneficial to increase the specific surface area of ​​the hydrophobic carrier while reducing the aggregation of graphene oxide. For example, the content of modified graphene oxide, based on the total weight of the coating solution, can be a value between 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 35 wt%, 40 wt%, 45 wt%, 50 wt%, or any combination thereof.

[0064] In this application, there are no particular limitations on the method of coating the modified graphene oxide coating liquid onto the ceramic substrate, such as dip coating, brush coating or spray gun coating.

[0065] In this application, there is no particular limitation on the amount of coating liquid applied to the ceramic substrate. For example, the amount of coating liquid applied to the ceramic substrate can be 0.025% to 0.1% of the weight of the ceramic substrate. Thus, while imparting hydrophobicity to the ceramic substrate and increasing the specific surface area of ​​the ceramic substrate, it is beneficial to reduce the increase in the probability of agglomeration caused by graphene accumulation and the loss of the advantage of high specific surface area.

[0066] In this application, the second drying can be carried out at 25°C for 12 to 24 hours, followed by a drying process at 40°C to 80°C for 2 to 5 hours.

[0067] In this application, the coating-second drying process can be repeated 1 to 3 times. This allows for control over the uniformity of the hydrophobic coating.

[0068] Next, proceed to step S4: prepare a hydrophobic catalyst using a hydrophobic support and an active metal via an impregnation-gas phase reduction method.

[0069] In this application, the impregnation-vapor phase reduction method includes impregnation treatment, third drying, and reduction treatment; The impregnation process includes impregnating a hydrophobic support in a precursor solution of an active metal to obtain a semi-finished catalyst.

[0070] In this application, the volume ratio of the hydrophobic support to the active metal precursor solution can be from 1:1 to 1:3. This facilitates sufficient impregnation and loading of the hydrophobic support by the active metal precursor solution, thereby ensuring uniform deposition of the active metal precursor on the hydrophobic support. Exemplarily, the volume ratio of the hydrophobic support to the active metal precursor solution can be 1:1, 1:2, 1:3, or a value within a range of any two thereof.

[0071] This application does not impose any particular limitation 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 0.005 mol / L to 0.025 mol / L, such as 0.005 mol / L, 0.01 mol / L, 0.015 mol / L, 0.02 mol / L, 0.025 mol / L, or any value within a range of two of these.

[0072] This application does not impose any 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.

[0073] In this application, the precursor solution of the active metal can be one or more of an ethanol solution, acetone solution, or deionized water solution of the active metal precursor, but is not limited thereto.

[0074] A third drying process is then carried out, which may include drying the semi-finished catalyst at a temperature of 50°C to 65°C for 12 to 24 hours. This facilitates the full evaporation of the solvent.

[0075] Next, the dried semi-finished catalyst is reduced, thereby reducing the active metal precursor supported on the hydrophobic support to the active metal.

[0076] In this application, there are no particular restrictions on the restoration process, and those conventionally used in the art can be used.

[0077] For example, the reduction process may include a pretreatment stage, a reduction stage, and a cooling stage.

[0078] Furthermore, the pretreatment stage can be carried out by increasing the temperature of the reduction furnace from room temperature 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.

[0079] Furthermore, 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 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. 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. The reduction time can be, for example, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, or any combination thereof.

[0080] Furthermore, the cooling stage can be carried out by allowing the reduction furnace to cool naturally to room temperature in an inert gas atmosphere with a flow rate of 500 ml / min.

[0081] In this application, the active metal is directly loaded onto the hydrophobic carrier by the impregnation-vapor phase reduction method, which can effectively prevent the active metal from being covered by the hydrophobic coating, improve the utilization rate of the active metal, and thus control the cost.

[0082] In this application, there are no special restrictions on the equipment used for the reduction process; for example, a tubular reduction furnace can be used.

[0083] In this application, there are no special restrictions on the inert gas used in the reduction process; for example, Ar, He, etc., can be used.

[0084] The present invention will be described in more detail below through embodiments. It should be understood that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this 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 according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0085] Example 1 Preparation of hydrophobic catalysts S1: Prepare an ethanol solution of 0.2 wt% tridecafluorooctyltrimethoxysilane, mix the above solution with deionized water at a volume ratio of 5:1, and add 10 mg / ml of graphene oxide to obtain a mixed solution. S2: The above mixture was continuously stirred at 45°C for 2 hours under magnetic stirring. After being filtered and rinsed with deionized water, it was placed in an oven and dried at 50°C for 2 hours to obtain modified graphene oxide. S3: Dissolve PVDF in dimethylformamide at 60℃ to prepare a 5wt% PVDF solution. Mix the above solution with modified graphene oxide to obtain a 10wt% modified graphene oxide coating solution. Coat the ceramic substrate (zirconia ceramic, particle size 5mm) with the coating solution, the amount of coating solution coated on the ceramic substrate being 0.05% of the weight of the ceramic substrate. After drying at room temperature for 12 hours, place it in an oven and continue drying at 50℃ for 2 hours to obtain a hydrophobic carrier; S4: Dissolve the precursor chloroplatinic acid (H2PtCl6·6H2O) in ethanol to prepare a 0.0065 mol / L chloroplatinic acid precursor solution. Impregnate 10 mL of a hydrophobic support (corresponding to a mass of 5 g) in 20 mL of the chloroplatinic acid precursor solution to obtain a semi-finished catalyst. Dry the semi-finished catalyst at 50 °C for 12 hours and then place it in a tubular reduction furnace. Reduce using hydrogen as the reducing gas. First, under an Ar atmosphere with a flow rate of 500 mL / min, heat the reduction furnace to 240 °C at a heating rate of 10 °C / min; then, under a mixed atmosphere of Ar and H2 with a flow rate of 500 mL / min, maintain the temperature of the reduction furnace at 240 °C for 8 hours; finally, turn off the H2 and allow the temperature of the reduction furnace to naturally cool to room temperature under an Ar atmosphere with a flow rate of 500 mL / min, thus completing the reduction. Approximately 10 mL of hydrophobic catalyst was obtained. 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 0.5 wt% based on the total mass of the hydrophobic catalyst.

[0086] Example 2 Preparation of hydrophobic catalysts S1: Prepare an ethanol solution of 0.25 wt% heptadecafluorodecyltriethoxysilane. Mix the above solution with deionized water at a volume ratio of 9:1. The amount of graphene oxide added is 20 mg / ml to obtain a mixed solution. S2: The above mixture was continuously stirred at 50°C for 2 hours under magnetic stirring. After being filtered and rinsed with deionized water, it was placed in an oven and dried at 45°C for 2 hours to obtain modified graphene oxide. S3: Dissolve PVDF in N-methylpyrrolidone at 60°C to prepare a 5wt% PVDF solution. Mix the above solution with modified graphene oxide to prepare a 20wt% modified graphene oxide coating solution. Coat the ceramic substrate (silicon oxide ceramic, particle size 5mm) with the coating solution, the amount of coating solution on the ceramic substrate being 0.1% of the ceramic substrate weight. Perform a second drying, specifically: after drying at room temperature for 12 hours, place in an oven and continue drying at 60°C for 2 hours. Repeat the coating-second drying process twice to obtain a hydrophobic carrier; S4: Dissolve the precursor chloroplatinic acid (H2PtCl6·6H2O) in ethanol to prepare a 0.01 mol / L chloroplatinic acid precursor solution. Impregnate 10 mL of a hydrophobic support (corresponding to a mass of 4.8 g) in 20 mL of the chloroplatinic acid precursor solution to obtain a semi-finished catalyst. Dry the semi-finished catalyst at 50 °C for 12 hours and then place it in a tubular reduction furnace. Reduce the catalyst using hydrogen as the reducing gas. First, under an Ar atmosphere with a flow rate of 500 mL / min, heat the furnace to 280 °C at a heating rate of 10 °C / min. Then, under a mixed atmosphere of Ar with a flow rate of 500 mL / min and H2 with a flow rate of 1000 mL / min, maintain the furnace temperature at 280 °C for 8 hours. Finally, turn off the H2 and allow the furnace temperature to naturally cool to room temperature under an Ar atmosphere with a flow rate of 500 mL / min, thus completing the reduction. Approximately 10 mL of hydrophobic catalyst was obtained. The mass of active metal Pt can be calculated based on the concentration and amount of the chloroplatinic acid precursor solution. Therefore, the mass content of active metal Pt can be calculated to be approximately 0.8 wt% based on the total mass of the hydrophobic catalyst.

[0087] Comparative Example 1 Preparation of hydrophobic catalysts S1: Dissolve PVDF in dimethylformamide at 60℃ to prepare a 5wt% PVDF solution. Mix the above solution with graphene oxide to obtain a 10wt% graphene oxide coating solution. Coat the ceramic substrate (zirconia ceramic, particle size 5mm) with the coating solution, the amount of coating solution coated on the ceramic substrate being 0.05% of the weight of the ceramic substrate. After drying at room temperature for 12 hours, place it in an oven and continue drying at 50℃ for 2 hours to obtain a hydrophobic carrier; S2: Dissolve the precursor chloroplatinic acid (H2PtCl6·6H2O) in ethanol to prepare a 0.0065 mol / L chloroplatinic acid precursor solution. Impregnate 10 mL of a hydrophobic support (corresponding to a mass of 5 g) in 20 mL of the chloroplatinic acid precursor solution to obtain a semi-finished catalyst. Dry the semi-finished catalyst at 50 °C for 12 hours and then place it in a tubular reduction furnace. Reduce using hydrogen as the reducing gas. First, under an Ar atmosphere with a flow rate of 500 mL / min, heat the reduction furnace to 240 °C at a heating rate of 10 °C / min; then, under a mixed atmosphere of Ar and H2 with a flow rate of 500 mL / min, maintain the temperature of the reduction furnace at 240 °C for 8 hours; then, turn off the H2 and allow the temperature of the reduction furnace to naturally cool to room temperature under an Ar atmosphere with a flow rate of 500 mL / min, thus completing the reduction. Approximately 10 mL of hydrophobic catalyst was obtained. 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 0.5 wt% based on the total mass of the hydrophobic catalyst.

[0088] Comparative Example 2 Preparation of hydrophobic catalysts S1: Dissolve PVDF in dimethylformamide at 60℃ to prepare a 5wt% PVDF solution as a coating solution. Coat the ceramic substrate (zirconia ceramic, 5mm) with the coating solution, the amount of coating solution applied to the ceramic substrate being 0.05% of the ceramic substrate's weight. After drying at room temperature for 12 hours, place it in an oven and continue drying at 50℃ for 2 hours to obtain a hydrophobic carrier; S2: Dissolve the precursor chloroplatinic acid (H2PtCl6·6H2O) in ethanol to prepare a 0.0065 mol / L chloroplatinic acid precursor solution. Impregnate 10 mL of a hydrophobic support (corresponding to a mass of 5 g) in 20 mL of the chloroplatinic acid precursor solution to obtain a semi-finished catalyst. Dry the semi-finished catalyst at 50 °C for 12 hours and then place it in a tubular reduction furnace. Reduce using hydrogen as the reducing gas. First, under an Ar atmosphere with a flow rate of 500 mL / min, heat the reduction furnace to 240 °C at a heating rate of 10 °C / min; then, under a mixed atmosphere of Ar and H2 with a flow rate of 500 mL / min, maintain the temperature of the reduction furnace at 240 °C for 8 hours; then, turn off the H2 and allow the temperature of the reduction furnace to naturally cool to room temperature under an Ar atmosphere with a flow rate of 500 mL / min, thus completing the reduction. Approximately 10 mL of hydrophobic catalyst was obtained. 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 0.5 wt% based on the total mass of the hydrophobic catalyst.

[0089] Test case Test Example 1: Morphology Characterization of Hydrophobic Supports The hydrophobic support prepared in Example 1 was observed using a ZEISS Sigma 300 scanning electron microscope (SEM) from Germany. The SEM image is shown below. Figure 1 As shown. From Figure 1 As can be seen, the sheet-like hydrophobically modified graphene oxide is uniformly attached to the surface of the carrier, with no obvious agglomeration and good dispersion, which can be used to construct a hydrophobic coating with high specific surface area for hydrophobic carriers.

[0090] Test Example 2: Measurement of the specific surface area of ​​a hydrophobic carrier BET The adsorption and desorption isotherms of the hydrophobic support prepared in Example 1 were measured using a specific surface area and porosity analyzer (ASAP 2460 from Micromeritics, USA) via nitrogen adsorption. The specific surface area was calculated using the BET (Brunauer Emmett Teller) method. The measurement results are summarized in Table 1 below.

[0091] The BET specific surface area of ​​the hydrophobic carriers prepared in Example 2 and Comparative Examples 1-2 was measured using the same method, and the measurement results are summarized in Table 1 below.

[0092] Test Example 3: Measurement of HD separation efficiency of hydrophobic catalyst Adopting such Figure 2 The 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.

[0093] 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.

[0094] 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.

[0095] 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 gaseous 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℃).

[0096] The HD separation efficiency of the hydrophobic catalysts prepared in Examples 1-2 and Comparative Examples 1-2 was measured, and the measurement results are summarized in Table 1 below.

[0097] Test Example 4: Measurement of the static contact angle of a hydrophobic catalyst: Using the SDC static contact angle measuring instrument The 350° measurement (Dongguan Shengding Precision Instruments Co., Ltd.) involves placing the hydrophobic catalyst on the stage of the measuring instrument. The stage is then moved upwards until it contacts a water droplet from the syringe. After full contact, the stage is moved downwards to allow the water droplet to detach from the syringe and land on the hydrophobic catalyst. The contact angle is then fitted using the instrument's built-in software. A larger static contact angle indicates better hydrophobic properties of the catalyst.

[0098] The static contact angles of the hydrophobic catalysts prepared in Examples 1-2 and Comparative Examples 1-2 were measured, and the results are summarized in Table 1 below.

[0099] Table 1

[0100] As shown in Table 1, adding graphene oxide to the hydrophobic coating increases the specific surface area of ​​the support and the static contact angle of the hydrophobic catalyst. Comparative Example 2, which did not contain graphene oxide, had a significantly lower specific surface area than Comparative Example 1. This is mainly due to the ultra-high specific surface area of ​​graphene oxide, which, when coated on the support surface, provides an additional increase in the specific surface area of ​​the support surface. The increase in the specific surface area of ​​the support before and after graphene oxide modification is basically the same, as shown in Example 1 and Comparative Example 1. Modification of graphene oxide can improve catalyst performance. Comparative Example 1, which used unmodified graphene oxide as a hydrophobic coating, produced a catalyst with inferior performance compared to Example 1, which used modified graphene oxide as a hydrophobic coating. This is because the graphene oxide was modified with fluorosiloxanes. Firstly, fluorosiloxanes possess a certain degree of hydrophobicity, which enhances the hydrophobicity of the catalyst. This enhanced hydrophobicity reduces the time water spends adhering to the surface, allowing active sites to participate in the reaction more efficiently. Secondly, the fluorosiloxanes adhering to the graphene oxide prevent Pt particles from agglomerating, allowing them to disperse better and thus enabling more active sites to participate in the reaction, thereby improving catalytic performance.

[0101] 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.

[0102] 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 ceramic substrate and a hydrophobic coating on the surface of the ceramic substrate, the hydrophobic coating comprising modified graphene oxide; An active metal, wherein the active metal is loaded on the hydrophobic support; The ceramic matrix has a particle size greater than 5 mm, and the hydrophobic carrier has a particle size of 45 μm. 2 / g to 120m 2 / g BET specific surface area.

2. The hydrophobic catalyst according to claim 1, wherein, The modified graphene oxide is modified with a fluorinated siloxane, optionally selected from one or more of the following: tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, and trifluoropropyltrimethoxysilane.

3. The hydrophobic catalyst according to claim 1 or 2, wherein, Based on the total weight of the hydrophobic catalyst, the content of the active metal is from 0.1 wt% to 1 wt%.

4. The hydrophobic catalyst according to any one of claims 1 to 3, wherein, The ceramic matrix is ​​one or more of the following: silicon dioxide, zirconium oxide, and silicon-based molecular sieves, which have three-dimensional channels; and / or The hydrophobic coating further includes an adhesive, optionally selected from PVDF; and / or The hydrophobic coating has a 100% coverage.

5. A method for preparing a hydrophobic catalyst, comprising: S1: Prepare a solution of the modified material, and then mix the solution of the modified material, graphene oxide and the first solvent to obtain a first mixture; S2: The first mixture is stirred at a temperature of 25°C to 60°C and then dried to obtain modified graphene oxide. S3: Prepare a modified graphene oxide coating solution, then coat the coating solution onto a ceramic substrate, and after a second drying process, obtain a hydrophobic carrier, wherein the ceramic substrate has a particle size greater than 5 mm, and the hydrophobic carrier has a particle size of 45 μm. 2 / g to 120m 2 BET specific surface area per g; S4: Using the hydrophobic support and active metal, a hydrophobic catalyst is prepared by impregnation-gas phase reduction method.

6. The method according to claim 5, wherein, The method satisfies one or more of the following: The concentration of the modified material solution is from 0.1 wt% to 0.3 wt%; and / or The modified material includes fluorosiloxanes, optionally selected from one or more of tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, and trifluoropropyltrimethoxysilane; and / or The volume ratio of the modified material solution to the first solvent is 3:1 to 9:1; and / or The amount of graphene oxide added is from 2 mg / ml to 20 mg / ml; and / or The first solvent is selected from deionized water.

7. The method according to claim 5 or 6, wherein, The method satisfies one or more of the following: The stirring is carried out for 1 to 3 hours; and / or The first drying is carried out at 50°C to 70°C for 1 to 2 hours; and / or The second drying process is carried out at room temperature for 12 to 24 hours, followed by a drying process at 40°C to 80°C for 2 to 5 hours; and / or Repeat the coating and second drying process 1 to 3 times.

8. The method according to any one of claims 5 to 7, wherein, The preparation of the modified graphene oxide coating solution includes: S31: Prepare an adhesive solution by dissolving the adhesive in a second solvent; optionally, the adhesive is selected from PVDF; the second solvent is selected from one or more of N-methylpyrrolidone, dimethylformamide, and dimethylacetamide; the adhesive content is 3 wt% to 10 wt% based on the total weight of the adhesive solution. S32: Mix the adhesive solution and the modified graphene oxide, wherein the content of the modified graphene oxide is from 10 wt% to 50 wt% based on the total weight of the coating solution.

9. The method according to any one of claims 5 to 8, wherein, The impregnation-vapor phase reduction method includes impregnation treatment, third drying, and reduction treatment; The impregnation process includes: impregnating the hydrophobic support in the precursor solution of the active metal to obtain a semi-finished catalyst; wherein, optionally, the volume ratio of the hydrophobic support to the precursor solution of the active metal is 1:1 to 1:

3. The third drying process includes drying the semi-finished catalyst at a temperature of 50°C to 65°C for 12 to 24 hours. The reduction process includes a pretreatment stage, a reduction stage, and a cooling stage; Optionally, the pretreatment stage includes: increasing the temperature of the reduction furnace from room temperature 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; Optionally, 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 gas 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. Optionally, the cooling stage includes: allowing the temperature of the reduction furnace to cool naturally to room temperature in an inert gas atmosphere with a flow rate of 500 ml / min.

10. Use of the hydrophobic catalyst according to any one of claims 1 to 4 and the hydrophobic catalyst obtained by the preparation method according to any one of claims 5 to 9 in water-hydrogen exchange reactions.

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