Hydrophobic catalysts and methods for making the same

Abstract

The application provides a hydrophobic catalyst and a preparation method thereof. The preparation method comprises the following steps: S1, loading carbon on a metal framework by drying a carbon-containing suspension after the carbon-containing suspension is attached to the metal framework, so as to obtain a composite carrier, wherein the carbon-containing suspension comprises powdered carbon dispersed in silica sol and a dispersant; S2, loading an active metal on the composite carrier to obtain an original catalyst; and S3, treating the original catalyst by a modification solution to obtain the hydrophobic catalyst, wherein the modification solution comprises a hydrophobic silane and an organic solvent. The hydrophobic catalyst has good catalytic activity.

Description

Technical Field

[0001] This application relates to the field of hydrophobic catalysts, and more particularly to a hydrophobic catalyst with a metal framework as a support and its preparation method. Background Technology

[0002] With the development of nuclear energy, the treatment of large amounts of tritium-containing wastewater generated by nuclear power plants has become an important issue. Water-hydrogen catalytic exchange is an effective method for separating hydrogen isotopes, offering advantages such as high separation factor, low energy consumption, and environmental friendliness, making it a promising candidate for treating tritium-containing wastewater. In the water-hydrogen catalytic exchange process, to avoid "water poisoning" caused by the active sites being covered by liquid water, a hydrophobic catalyst must be used. Currently, hydrophobic catalysts generally consist of an active component and a support. The support is typically styrene-divinylbenzene copolymer (SDB), polytetrafluoroethylene (PTFE), or ceramics, and is mainly in the form of small particles. Particulate hydrophobic catalysts suffer from excessive gas resistance and are prone to flooding during large-scale industrial applications. In contrast, structured hydrophobic catalysts offer advantages such as low gas resistance, low cost, and strong mass and heat transfer capabilities, making them more advantageous for large-scale industrial applications. Therefore, it is necessary to provide an improved structured hydrophobic catalyst. Summary of the Invention

[0003] In view of this, the main objective of this disclosure is to provide a method for preparing a hydrophobic catalyst, which is simple in process and yields a hydrophobic catalyst with good catalytic activity.

[0004] To achieve the above objectives, this disclosure provides the following technical solution.

[0005] The first aspect of this disclosure provides a method for preparing a hydrophobic catalyst, comprising: S1, attaching a carbon-containing suspension to a metal framework and then drying it to load carbon onto the metal framework, thereby obtaining a composite support, wherein the carbon-containing suspension comprises powdered carbon dispersed in silica sol and a dispersant; S2, loading an active metal onto the composite support to obtain a primary catalyst; and S3, treating the primary catalyst with a modification solution to obtain the hydrophobic catalyst, wherein the modification solution comprises a hydrophobic silane and an organic solvent. This disclosure employs a layer-by-layer loading method, first loading powdered carbon onto a metal framework via silica sol, resulting in a composite support with an increased specific surface area, which is beneficial for subsequent loading of active materials; then further loading an active metal, and after loading the active metal, performing hydrophobic modification with a modification solution including a hydrophobic silane, thereby improving the utilization rate of the active metal while achieving hydrophobic modification, thus enhancing the catalytic activity of the hydrophobic catalyst.

[0006] According to one embodiment of this disclosure, the metal frame is made of any one of nickel, iron, cobalt, copper, magnesium, aluminum, and stainless steel. This allows for the selection of a metal frame based on actual needs, meeting requirements such as corrosion resistance and cost.

[0007] According to one embodiment of this disclosure, the morphology of the metal skeleton is selected from any one of foam, mesh, fiber, and honeycomb. This facilitates the control of fluid resistance through the catalyst and increases the specific surface area of ​​the metal skeleton, which is beneficial for the subsequent loading of active materials.

[0008] According to one embodiment of this disclosure, the powdered carbon has a mass percentage content of 1% to 5% relative to the total mass of the carbon-containing suspension, the dispersant has a mass percentage content of 0.5% to 3%, and the silica in the silica sol has a mass percentage content of 20% to 40% relative to the silica sol. This facilitates the formation of a stable carbon-containing suspension and achieves uniform adhesion.

[0009] According to one embodiment of this disclosure, the powdered carbon is selected from one or more of activated carbon, graphite powder, carbon nanotubes, and carbon black. This is beneficial for increasing the specific surface area of ​​the metal framework.

[0010] According to one embodiment of this disclosure, the average particle size of the powdered carbon is 10 nm to 100 nm. This is beneficial for increasing the specific surface area of ​​the metal framework.

[0011] According to one embodiment of this disclosure, the dispersant is Triton X-100. This is beneficial for the stability of the carbon-containing suspension and for the formation of a more uniformly dispersed adhesion on the metal framework.

[0012] According to one embodiment of this disclosure, in step S1, the drying temperature is 100°C to 120°C, and the time is 1 hour to 3 hours. This facilitates the evaporation of moisture from the silica sol, allowing the silica particles to act as binders.

[0013] According to one embodiment of this disclosure, the mass ratio of the composite carrier to the metal framework is (1.2 to 1.8):1. This is beneficial for increasing the specific surface area of ​​the metal framework, increasing the number of sites for subsequent loading of active substances, and improving the dispersibility of the active substances.

[0014] According to one embodiment of this disclosure, in step S2, loading an active metal onto the composite support includes: immersing the composite support in a solution containing ions of an active metal element, and evaporating the solvent in the solution to obtain a support loaded with an active metal precursor, wherein the active metal is selected from one or more of Pt, Pd, Ru, Rh, Ir, Fe, Fe-doped Pt, Ru-doped Pt, and Ir-doped Pt; and reducing the support loaded with the active metal precursor to obtain a raw catalyst, wherein the reduction treatment includes reducing the support loaded with the active metal precursor in an atmosphere containing a reducing gas. The above impregnation process utilizes a uniform solution containing ions of an active metal element, which facilitates the adhesion of metal ions to the composite support. The reduction process using a reducing gas facilitates the complete reduction to obtain the active metal.

[0015] According to one embodiment of this disclosure, the solvent of the solution comprising ions containing active metal elements is selected from one or more of ethanol, methanol, water, ethylene glycol, and acetone.

[0016] According to one embodiment of this disclosure, the reducing gas is hydrogen.

[0017] According to one embodiment of this disclosure, the content of the active metal element in the solution comprising ions containing the active metal element is 3 g / L to 10 g / L. This is beneficial for improving the catalytic efficiency of the hydrophobic catalyst and has good cost-effectiveness.

[0018] According to one embodiment of this disclosure, the ratio of the mass of the composite carrier to the volume of the solution containing ions of active metal elements is 0.1 g / mL to 1.0 g / mL.

[0019] According to one embodiment of this disclosure, in S3, treating the original catalyst with the modified solution includes drying the catalyst after attaching the modified solution to it. This simplifies the process and ensures sufficient contact between the original catalyst and the modified solution, thereby improving hydrophobicity.

[0020] According to one embodiment of this disclosure, the organic solvent in the modified solution is ethanol.

[0021] According to one embodiment of this disclosure, the hydrophobic silane comprises a structure with the formula R n SiR' m The silane, n is 1, 2 or 3, m = 4-n, R is a fluorine-substituted C1 to C20 alkyl group, and R' is a C1 to C4 alkoxy group.

[0022] According to one embodiment of this disclosure, R is substituted with 2x-9 to 2x+1 fluorine atoms, based on the number of carbon atoms in R. This further enhances the hydrophobicity.

[0023] According to one embodiment of this disclosure, the hydrophobic silane has a mass percentage content of 0.1% to 0.5% in the modified solution. This facilitates better dispersion of the hydrophobic silane in the organic solvent, thereby allowing it to adhere uniformly to the original catalyst.

[0024] According to one embodiment of this disclosure, prior to S2, the preparation method further includes: loading a nickel cobalt oxide precursor onto the composite support via a hydrothermal method; and calcining the composite support loaded with the nickel cobalt oxide precursor to obtain a nickel cobalt oxide-loaded composite support. The hydrothermal loading of the nickel cobalt oxide precursor onto the first support comprises reacting an aqueous mixture comprising the cobalt source, a nickel source, the composite support, a surfactant, and a nucleating agent in a hydrothermal reactor. The molar ratio of cobalt in the cobalt source to nickel in the nickel source is 2:1. The nickel cobalt oxide further enhances the specific surface area and roughness of the support, which is beneficial for increasing the attachment sites of the active metal in S2. Furthermore, the abundant hydroxyl groups on the nickel cobalt oxide facilitate its reaction with hydrophobic silanes in S3, further improving its hydrophobicity.

[0025] According to one embodiment of this disclosure, the hydrothermal reaction is carried out at a temperature of 110°C to 130°C for 5 to 8 hours. This facilitates the full progress of the hydrothermal reaction, resulting in the formation of a nickel cobalt oxide precursor on the composite support.

[0026] According to one embodiment of this disclosure, the amount of cobalt in the cobalt source is 0.1 mmol to 1 mmol per gram of the composite carrier.

[0027] According to one embodiment of this disclosure, the concentration of cobalt-containing ions in the cobalt source is 0.01 mol / L to 0.1 mol / L relative to the aqueous mixture.

[0028] According to one embodiment of this disclosure, the calcination temperature is 300℃~450℃, and the time is 2.5h~4.5h. This facilitates the conversion of the nickel cobalt oxide precursor into nickel cobalt oxide.

[0029] According to one embodiment of this disclosure, the surfactant is hexadecyltrimethylammonium bromide.

[0030] According to one embodiment of this disclosure, the nucleating agent is urea.

[0031] According to one embodiment of this disclosure, the concentration of the surfactant is 0.005 mol / L to 0.04 mol / L relative to the aqueous mixture, and the concentration of the nucleating agent is 0.02 mol / L to 0.20 mol / L.

[0032] A second aspect of this disclosure provides a hydrophobic catalyst obtained according to the preparation method described in any of the above embodiments. This hydrophobic catalyst exhibits improved catalytic activity and the other advantages described above.

[0033] This disclosure employs a layer-by-layer loading method, first loading powdered carbon onto a metal framework via silica sol, which significantly increases the specific surface area of ​​the metal framework, facilitating subsequent loading of active materials; then further loading of active metal increases the exposure of the active metal and improves its utilization rate; finally, hydrophobic modification is performed using a modification solution including hydrophobic silanes to enhance the catalytic activity of the hydrophobic catalyst.

[0034] In addition to the technical problems solved by this disclosure, the technical features constituting the technical solutions, and the beneficial effects brought about by the technical features of these technical solutions as described above, other technical problems that this disclosure can solve, other technical features contained in the technical solutions, and the beneficial effects brought about by these technical features will be further described in detail in the following specific embodiments. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A scanning electron microscope image of the hydrophobic catalyst of Example 2 is shown.

[0037] Figure 2 The contact angle test diagram of the hydrophobic catalyst of Example 2 is shown.

[0038] Figure 3 The curves of the total volumetric mass transfer coefficient Kya versus gas velocity are shown for Examples 1, 2 and Comparative Example 1. Detailed Implementation

[0039] The technical solution of this disclosure will be clearly and completely described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] Throughout this specification, unless otherwise specified, the terminology used herein shall 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. In the event of any conflict, this specification shall prevail.

[0041] It should be noted that, in this disclosure, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a method or apparatus that comprises a list of elements includes not only the elements expressly stated, but also other elements not expressly listed, or elements inherent to implementing the method or apparatus. Without further limitations, an element defined by the phrase "containing..." does not exclude the presence of other related elements in the method or apparatus that includes that element.

[0042] Except in any operational instance, or where otherwise indicated, all figures used in the specification and claims to represent amounts of components, reaction conditions, etc., should be understood to be modified in all cases by the term "approximately". Unless otherwise indicated, the numerical parameters set forth in the following specification and appended claims are approximate values ​​and may vary depending on the desired properties to be obtained from this disclosure. Although the numerical ranges and parameters set forth in this disclosure are approximate, the values ​​set forth in the specific embodiments are reported as precisely as possible.

[0043] The above steps are only for clarity. In practice, they can be combined into one step or some steps can be broken down into multiple steps. As long as they include the same logical relationship, they are all within the scope of protection of this patent.

[0044] Terminology Definition

[0045] As used herein, the term "contact angle" refers to the angle between the solid-liquid interface, through the liquid interior, and at the gas-liquid interface at the solid-liquid-gas three-phase junction. The size of the contact angle reflects the strength of the interaction between the liquid and the solid, and is an important parameter for the affinity or repulsion of a solid surface to a liquid. In this application, the "contact angle" is directly obtained by placing a drop of deionized water on the surface of the solid to be tested using a contact angle measuring instrument to test its spreadability. The larger the contact angle, the stronger the hydrophobicity.

[0046] The term "alkyl" includes both branched and straight-chain saturated aliphatic hydrocarbon groups and has a specified number of carbon atoms, for example, 1 to 12 carbon atoms. As used herein, the term "C1-C20 alkyl" refers to an alkyl group having 1 to 20 carbon atoms, such as C1-C18, C1-C10, or C1-C8 alkyl. Examples of alkyl groups include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, 3-methylbutyl, tert-butyl, n-pentyl, sec-pentyl, hexyl, heptyl, octyl, isooctyl, nonyl, decyl, dodecyl, hexadecyl, etc.

[0047] In this document, unless otherwise stated, numerical ranges such as “1 to 20” or “1 to 20” refer to every integer within a given range; for example, “1 to 20 carbon atoms” means that an alkyl group can consist of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 20 carbon atoms. However, there are some exceptions that will be obvious to those skilled in the art. In particular, when a range is given herein to represent molar ratios, diameters or dimensions, pH, time periods, concentrations, osmotic pressures, or temperatures, the range also includes all decimals falling within that range, including both upper and lower limits.

[0048] In the currently reported studies, some hydrophobic catalysts using regular supports have been disclosed. The supports are mainly cordierite, nickel foam (FN), and silicon carbide foam (SiC). These hydrophobic catalysts have advantages such as regular shape and low gas resistance. The literature (Xu M, Zhang S, Wang T, et al. De novo design of a Pt nanocatalyst on a conjugated microporous polymer-coated honeycomb carrier for oxidation of hydrogen isotopes[J].ACS Applied Materials & Interfaces,2022,14(6):7826-7835.) involves a hydrophobic catalyst using cordierite as a support. It discloses grafting an intrinsically hydrophobic organic polymer onto the cordierite surface. The grafting process is relatively complicated, and the hydrophobicity provided by the organic polymer is poor. CN107930621A discloses a hydrophobic catalyst using foamed silicon carbide as a support. In this method, PTFE is first coated onto the foamed SiC using an impregnation method, and then the active component Pt is loaded. However, PTFE is a hydrophobic material, which is detrimental to the dispersion of Pt, thus negatively impacting the catalyst's activity. Furthermore, both foamed SiC and cordierite are ceramic materials, which are heavy, have poor processability, and are prone to powdering. CN104226311A relates to a hydrophobic catalyst using foamed nickel as a support. In this method, the active component Pt is first loaded onto porous carbon to form Pt / C. Then, Pt / C is mixed with PTFE and Triton to form an emulsion. Finally, Pt / C / PTFE is impregnated onto the foamed nickel to obtain the hydrophobic catalyst. This preparation method is simple, and foamed nickel has advantages such as strong processability and high mass and heat transfer capabilities. However, Pt is easily covered by PTFE, resulting in low Pt utilization, which is detrimental to the catalytic reaction. Therefore, it is still necessary to continue developing well-structured hydrophobic catalysts with excellent performance.

[0049] Based on this, this application provides a hydrophobic catalyst and a method for preparing the same. The following provides a more detailed description of this application and its optional embodiments.

[0050] Preparation method of hydrophobic catalyst

[0051] This application provides a method for preparing a hydrophobic catalyst, comprising: S1, attaching a carbon-containing suspension to a metal framework and then drying it to load carbon onto the metal framework to obtain a composite support, wherein the carbon-containing suspension comprises powdered carbon dispersed in silica sol and a dispersant; S2, loading an active metal onto the composite support to obtain a primary catalyst; and S3, treating the primary catalyst with a modification solution to obtain the hydrophobic catalyst, wherein the modification solution comprises a hydrophobic silane and an organic solvent.

[0052] This disclosure employs a layer-by-layer loading method. First, powdered carbon is loaded onto a metal framework using silica sol, resulting in a composite support with an increased specific surface area, which is beneficial for subsequent loading of active materials. Then, active metal is further loaded. Compared to methods where carbon powder of active metal is directly attached to the metal framework using polytetrafluoroethylene (PTFE) as a binder, in which some of the active metal is covered by PTFE, this invention avoids the active metal being covered, increasing its exposure. Furthermore, after loading the active metal, hydrophobic modification is performed using a modification solution including hydrophobic silanes. This achieves hydrophobic modification while also preventing the active metal from being covered, thereby improving the utilization rate of the active metal and enhancing the catalytic activity of the hydrophobic catalyst.

[0053] According to some implementation methods, the metal frame is made of any one of nickel, iron, cobalt, copper, magnesium, aluminum, and stainless steel. This allows for the selection of the metal frame based on the specific purpose, meeting requirements such as corrosion resistance and cost. Preferably, the metal frame is made of nickel.

[0054] According to some embodiments, the morphology of the metal framework is selected from any one of foam, mesh, fiber, and honeycomb. This facilitates the control of fluid resistance through the catalyst and increases the specific surface area of ​​the metal framework, which is beneficial for the subsequent loading of active materials. Preferably, the metal framework is in the form of foam.

[0055] According to some embodiments, the mass percentage of the powdered carbon relative to the total mass of the carbon-containing suspension is 1% to 5%, the mass percentage of the dispersant is 0.5% to 3%, and the mass percentage of silica in the silica sol is 20% to 40%. This facilitates the formation of a stable carbon-containing suspension and achieves uniform adhesion. Exemplarily, the mass percentage of the powdered carbon relative to the total mass of the carbon-containing suspension is 1%, 2%, 3%, 4%, 5%, or any value within a range of two such values, but is not limited thereto. Exemplarily, the mass percentage of the dispersant relative to the total mass of the carbon-containing suspension is 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or any value within a range of two such values, but is not limited thereto. For example, the mass percentage of silicon dioxide in the silica sol relative to the silica sol is 20%, 25%, 30%, 35%, 40%, or any value within a range of two such values, but is not limited thereto.

[0056] According to some embodiments, the powdered carbon is selected from one or more of activated carbon, graphite powder, carbon nanotubes, and carbon black. This is beneficial for increasing the specific surface area of ​​the metal framework.

[0057] According to some embodiments, the average particle size of the powdered carbon is 10 nm to 100 nm. This is beneficial for increasing the specific surface area of ​​the metal framework. Exemplarily, the average particle size of the powdered carbon is a value between 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or any two of these values, but is not limited thereto.

[0058] According to some embodiments, the dispersant is Triton X-100. This is beneficial for the stability of the carbon-containing suspension and for the formation of a more uniform dispersion on the metal skeleton.

[0059] According to some implementation methods, in S1, the drying temperature is 100°C to 120°C, and the time is 1 hour to 3 hours. This facilitates the evaporation of moisture from the silica sol, allowing the silica particles to act as binders.

[0060] According to some embodiments, the mass ratio of the composite carrier to the metal framework is (1.2 to 1.8):1. Exemplarily, the mass ratio of the composite carrier to the metal framework is 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, or any value within a range of two such values, but is not limited thereto. This is beneficial for increasing the specific surface area of ​​the metal framework, increasing the sites for subsequent loading of active substances, and improving the dispersibility of the active substances.

[0061] According to some embodiments, prior to S2, the preparation method further includes loading a nickel cobalt oxide precursor onto the composite support via a hydrothermal method; and calcining the composite support loaded with the nickel cobalt oxide precursor to obtain a composite support loaded with nickel cobalt oxide (NiCo2O4). Loading the nickel cobalt oxide precursor onto the first support via a hydrothermal method includes reacting an aqueous mixture comprising a nickel source and a cobalt source, the composite support, a surfactant, and a nucleating agent in a hydrothermal reactor. The molar ratio of cobalt in the cobalt source to nickel in the nickel source is 2:1. The nickel cobalt oxide can further increase the specific surface area and roughness of the support, which is beneficial for increasing the attachment sites of the active metal in S2. Furthermore, the nickel cobalt oxide contains abundant hydroxyl groups, which is beneficial for reaction with hydrophobic silanes in S3, further improving hydrophobicity. Exemplarily, the cobalt source is a cobalt salt such as cobalt acetate, cobalt chloride, or cobalt nitrate, or its hydrate, but is not limited thereto. Exemplarily, the nickel source is a nickel salt such as nickel acetate, nickel chloride, or nickel nitrate, or its hydrate, but is not limited thereto.

[0062] According to some embodiments, the hydrothermal reaction is carried out at a temperature of 110°C to 130°C for 5 to 8 hours. This facilitates the full progress of the hydrothermal reaction, forming a nickel cobalt oxide precursor on the composite support.

[0063] According to some embodiments, the amount of cobalt in the cobalt source is 0.1 mmol to 1 mmol per gram of the composite carrier. Exemplarily, the amount of cobalt per gram of the composite carrier is 0.1 mmol, 0.2 mmol, 0.4 mmol, 0.6 mmol, 0.8 mmol, 0.10 mmol, or a value within a range of any two of these values, but is not limited thereto.

[0064] According to some embodiments, the concentration of cobalt-containing ions in the cobalt source relative to the aqueous mixture is 0.01 mol / L to 0.1 mol / L. Exemplarily, the concentration of cobalt-containing ions in the nickel cobalt oxide precursor relative to the aqueous mixture is 0.01 mol / L, 0.02 mol / L, 0.40 mol / L, 0.06 mol / L, 0.08 mol / L, 0.10 mol / L, or a value within a range of any two of these values, but is not limited thereto.

[0065] According to some embodiments, the calcination temperature is 300℃~450℃, and the time is 2.5h~4.5h. This facilitates the conversion of the nickel cobalt oxide precursor into nickel cobalt oxide.

[0066] According to some embodiments, the surfactant is hexadecyltrimethylammonium bromide.

[0067] According to some implementation methods, the nucleating agent is urea.

[0068] According to some embodiments, the concentration of the surfactant relative to the aqueous mixture is 0.005 mol / L to 0.04 mol / L, and the concentration of the nucleating agent is 0.02 mol / L to 0.20 mol / L. Exemplarily, the concentration of the surfactant relative to the aqueous mixture is 0.005 mol / L, 0.010 mol / L, 0.015 mol / L, 0.020 mol / L, 0.025 mol / L, 0.030 mol / L, 0.035 mol / L, 0.040 mol / L, or a value within a range of any two values, but is not limited thereto. For example, the concentration of the nucleating agent relative to the aqueous mixture is 0.02 mol / L, 0.04 mol / L, 0.06 mol / L, 0.08 mol / L, 0.10 mol / L, 0.12 mol / L, 0.14 mol / L, 0.16 mol / L, 0.18 mol / L, 0.20 mol / L, or any range of two such values, but is not limited thereto.

[0069] According to some embodiments, in S2, loading the active metal onto the composite support includes immersing the composite support in a solution containing ions of the active metal element, and evaporating the solvent in the solution containing the ions of the active metal element to obtain a support loaded with an active metal precursor, wherein the active metal is selected from one or more of Pt, Pd, Ru, Rh, Ir, Fe, Fe-doped Pt, Ru-doped Pt, and Ir-doped Pt; and reducing the support loaded with the active metal precursor to obtain the original catalyst, wherein the reduction treatment includes reducing the support loaded with the active metal precursor in an atmosphere containing a reducing gas. The above impregnation process utilizes a uniform solution containing ions of the active metal element, which facilitates the adhesion of metal ions to the composite support. The above reduction process using a reducing gas facilitates the complete reduction to obtain the active metal.

[0070] According to some embodiments, the solvent of the solution comprising ions of an active metal element is selected from one or more of ethanol, methanol, water, ethylene glycol, and acetone.

[0071] According to some implementation methods, the reducing gas is hydrogen.

[0072] According to some embodiments, the content of the active metal element in the solution containing ions of the active metal element is 3 g / L to 10 g / L. This is beneficial for improving the catalytic efficiency of the hydrophobic catalyst and has good cost-effectiveness. Exemplarily, the content of the active metal element in the solution containing ions of the active metal element is 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L, 10 g / L, or a value within a range of any two of these values, but is not limited thereto.

[0073] According to some embodiments, the mass ratio of the composite carrier to the volume of the solution containing ions of the active metal element is 0.1 g / mL to 1.0 g / mL. Exemplarily, the mass ratio of the composite carrier to the volume of the solution containing ions of the active metal element is a value between 0.1 g / mL, 0.3 g / mL, 0.5 g / mL, 0.7 g / mL, 1.0 g / mL, or any two of these values, but is not limited thereto.

[0074] This disclosure does not impose any particular limitation on the treatment of the original catalyst by a modified solution, and those skilled in the art can perform the treatment according to methods known in the art.

[0075] According to some embodiments, treating the original catalyst with a modification solution involves attaching the modification solution to the original catalyst and then drying it. For example, the original catalyst is immersed in the modification solution, then removed and dried. This simplifies the process and ensures sufficient contact between the original catalyst and the modification solution, thereby improving hydrophobicity.

[0076] According to some embodiments, the organic solvent in the modified solution is ethanol.

[0077] According to some embodiments, the hydrophobic silane includes the structural formula R n SiR' m The silane has n = 1, 2, or 3, m = 4-n, R is a fluorine-substituted C1-C20 alkyl group, and R' is a C1-C4 alkoxy group. According to some embodiments, R is substituted with 2x-9 to 2x+1 fluorine atoms, based on R having x carbon atoms. This further enhances hydrophobicity.

[0078] According to some embodiments, the hydrophobic silane includes one or more of heptadecafluorodecyltrimethoxysilane (FD-TMS), perfluorodecyltriethoxysilane, and tridecafluorooctyltriethoxysilane.

[0079] According to some embodiments, the mass percentage of the hydrophobic silane in the modified solution is 0.1% to 0.5%. This facilitates better dispersion of the hydrophobic silane in the organic solvent, thereby allowing it to uniformly adhere to the original catalyst. Exemplarily, the mass percentage of the hydrophobic silane in the modified solution is 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or any value within a range of two such values, but is not limited thereto.

[0080] Hydrophobic catalyst

[0081] A second aspect of this application provides a hydrophobic catalyst, prepared according to the method described in any of the above embodiments. This hydrophobic catalyst exhibits improved catalytic activity and the other advantages mentioned above.

[0082] Example

[0083] The following describes embodiments of this application. 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 are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. All reagents or instruments without specified manufacturers are conventional products that can be obtained commercially.

[0084] Example 1

[0085] Supported carbon

[0086] 2g of silica sol (purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with a solid content of 29%–31%), 0.5mL of Triton X-100, 1g of activated carbon (purchased from Fuzhou Yihuan Carbon Co., Ltd., with an average particle size of 30nm–80nm), and 30mL of deionized water were mixed under magnetic stirring to prepare a carbon-containing suspension, wherein the powdered carbon contained 3% by mass relative to the total mass of the carbon-containing suspension.

[0087] 0.26g of nickel foam (purchased from Kunshan Zhangpu Town Baiyida Electronic New Materials Business Department, disc-shaped, with a bottom diameter of 27mm, a thickness of 2mm, a porosity of 75ppi, and a specific surface area of ​​1m²) was used. 2 The product (g) was immersed in the above carbon-containing suspension, then removed and dried in an oven at 100°C for 1 hour. The above process was repeated until the mass ratio of the dried product to the initial nickel foam was 1.5:1, resulting in 0.385 g of composite carrier.

[0088] nickel cobalt oxide support

[0089] Under magnetic stirring, 2 mmol Co(NO3)2·6H2O, 1 mmol NiCl2·6H2O, 0.8 mmol hexadecyltrimethylammonium bromide (CTAB), and 3.6 mmol urea were dissolved in 40 mL of deionized water. The solution and 10 pieces of the above composite support (total 3.85 g) were transferred to a Teflon-lined reactor and placed in an oven. The reactor was reacted at 120 °C for 6 h. After the reaction was completed, the nickel foam was removed, washed with deionized water and ethanol, dried, and then calcined in a muffle furnace at 350 °C for 3 h to obtain 10 pieces of NiCo2O4-loaded composite support (total 4.07 g), of which NiCo2O4 accounted for 5% of the total mass.

[0090] Load Pt

[0091] At room temperature, a 0.407 g piece of the above-mentioned NiCo2O4-supported composite support was impregnated in 1.5 mL of a 0.03 mol / L ethanol solution of chloroplatinic acid hexahydrate (H2PtCl6·6H2O). After the ethanol completely evaporated, it was dried in an oven at 60 °C for 12 h. Then, it was placed in a tube furnace and heated from room temperature to 220 °C at a rate of 10 °C / min under a N2 atmosphere (flow rate of 500 mL / min). After reaching this temperature, H2 (flow rate of 500 mL / min) was introduced for reduction at 220 °C for 8 h. After the reduction was completed, the H2 supply was stopped, and the catalyst was cooled overnight under N2 (flow rate of 500 mL / min) protection to obtain 0.410 g of the original catalyst.

[0092] Hydrophobic treatment

[0093] The original catalyst was immersed in 5 mL of 0.2 wt% heptadecafluorodecyltrimethoxysilane (FD-TMS) ethanol solution for 24 h, then removed and dried overnight at 80 °C to obtain 0.412 g of hydrophobic catalyst.

[0094] Specific surface area test

[0095] Using a specific surface area and porosity analyzer (Micromeritics ASAP 2460, USA), the adsorption and desorption isotherms of the above-mentioned composite support and the NiCo2O4-supported composite support were measured by nitrogen adsorption method. The specific surface area was calculated using the BET (Brunauer-Emmett-Teller) method, and the specific surface area of ​​the composite support was 52 m². 2 / g, the specific surface area of ​​the composite support loaded with NiCo2O4 is 123m². 2 / g. It can be seen that compared to a specific surface area of ​​1m², 2 / g raw material foamed nickel, the loading of activated carbon significantly increased the specific surface area of ​​the foamed nickel substrate and provided more sites for the subsequent growth of NiCo2O4; the loading of NiCo2O4 further significantly improved the specific surface area and roughness, thereby increasing the sites for loading metal Pt.

[0096] Example 2

[0097] The hydrophobic catalyst was prepared using the same method as in Example 1, except that the step of supporting NiCo2O4 was not performed.

[0098] Comparative Example 1

[0099] The hydrophobic catalyst was prepared using the same method as in Example 1, except that the carbon loading step was not performed.

[0100] Comparative Example 2

[0101] The hydrophobic catalyst was prepared using the same method as in Example 1, except that the carbon support was achieved through hydrothermal carbonization, using glucose as the carbon source to grow C on nickel foam, followed by activation treatment. The specific experimental steps of the above carbon support method are as follows:

[0102] (1) Loading C: Ten 0.27g disc-shaped nickel foam pieces (total 2.70g) were placed in a deionized water and ethanol solution and ultrasonically cleaned for 20min to remove surface impurities. Under magnetic stirring, 4g of d-glucose was added to a beaker containing 30mL of deionized water. The solution and the above 10 nickel foam pieces were then placed in a 50mL Teflon-lined reactor. The reactor was placed in an oven and reacted at 180℃ for 8h. After the reaction, the nickel foam pieces were taken out and washed several times with deionized water, and then dried in an oven to obtain 10 nickel foam pieces with carbon (C) loaded on the surface (total 3.00g, 0.3g per piece). The mass of C loaded on the surface of each nickel foam piece was 0.03g.

[0103] (2) Activation treatment of carbon loaded on the surface of dried nickel foam using KOH: A 0.01 g / mL KOH solution was prepared according to a C to KOH mass ratio of 1:2. The two solutions were mixed and placed in an oven, reacted at 120 °C for 12 h. The resulting nickel foam was then placed in a tube furnace and activated under a nitrogen (N2) atmosphere. The temperature was increased from room temperature to 700 °C at a rate of 5 °C / min and held at 700 °C for 1 h. After activation, the nickel foam was washed with deionized water and finally placed in a vacuum oven and dried at 150 °C for 24 h to obtain nickel foam loaded with porous carbon, with a specific surface area of ​​26 m². 2 / g, which is significantly lower than the specific surface area of ​​the composite carrier in Example 1.

[0104] Morphology of hydrophobic catalysts

[0105] The hydrophobic catalyst of Example 1 was observed using a Sigma 300 scanning electron microscope from ZEISS GmbH, Germany. The scanning electron microscope image is shown below. Figure 1 As shown, the loads on the metal skeleton are evenly distributed, dispersed and without agglomeration.

[0106] Contact angle test

[0107] The surfaces of the hydrophobic catalysts in the above embodiments and comparative examples were tested using an SDC-350 contact angle meter from Dongguan Dingsheng Instrument Co., Ltd., China. A drop of deionized water was added to the surface to be tested, and the contact angle of the droplet was read. The contact angle test diagram for the hydrophobic catalyst in Embodiment 1 is shown below. Figure 2 As shown, the contact angle is as high as 161.2°, achieving superhydrophobic performance.

[0108] Catalytic activity test

[0109] The catalytic activity of the aforementioned hydrophobic catalysts was tested using a co-current hydrogen isotope liquid-phase catalytic exchange apparatus. Before the catalytic reaction began, the apparatus was preheated with 60°C constant-temperature water to the catalytic column (containing 23 mL of the aforementioned hydrophobic catalyst) and the packed column. Then, N2 was introduced to purge the air from the apparatus. H2 was introduced at a flow rate of 0.5 L / min from the bottom of the water vapor saturator, carrying water vapor from saturated light and heavy water at 60°C into the catalytic column, where a water-hydrogen exchange reaction occurred on the hydrophobic catalyst. The deuterium abundance of the gas samples at the inlet and outlet of the catalytic column was measured using a mass spectrometer (Thermofisher, MAT253). The deuterium density of the water sample in the condensate after the reaction was measured using a densitometer. The catalytic exchange efficiency η and the overall volumetric mass transfer coefficient Kya were calculated using the following formulas.

[0110]

[0111] Where X represents the percentage of deuterium atoms in the gas condensate after the isotopic transposition reaction; Y0 represents the percentage of deuterium atoms at the inlet of the catalytic column, Y t Y* represents the percentage of deuterium atoms at the catalytic column outlet; Y* represents the percentage of deuterium atoms in the gas at the catalytic column inlet and outlet at equilibrium; α represents the hydrogen-deuterium phase exchange separation coefficient, which is 1.046 at 60℃; G represents the gas flow rate (m³ / s). 3 / s), V is the catalyst bed volume (m³ / s), 3 The curves of the overall volumetric mass transfer coefficient Kya versus gas velocity in Examples 1-2 and Comparative Example 1 are shown below. Figure 3 As shown.

[0112] The contact angle and the total volumetric mass transfer coefficient Kya at a gas velocity of 0.5 L / min of the hydrophobic catalysts prepared in Examples 1-2 and Comparative Examples 1-2 are shown in Table 1 below.

[0113] Table 1

[0114]

[0115]

[0116] The " / " indicates that no corresponding performance test data was generated.

[0117] The above results indicate that, according to the present invention, layer-by-layer loading of powdered carbon, active metal, and hydrophobic silane onto a metal framework can improve the utilization rate of the active metal while achieving hydrophobic modification. Compared to Comparative Example 1, which has a carbon layer without silica sol loading, and Comparative Example 2, which has a carbon layer loaded by hydrothermal carbonization, Examples 1 and 2 of this disclosure significantly improve the catalytic activity of the hydrophobic catalyst, with a total volumetric mass transfer coefficient reaching 15 × 10⁻⁶. -2 s -1 In particular, loading nickel cobalt oxide after loading powdered carbon and before loading an active metal can further improve hydrophobicity and catalytic activity.

[0118] The above descriptions are merely some specific embodiments of this disclosure, intended to illustrate this disclosure, and are not intended to limit the scope of protection claimed in this application. Any modifications or substitutions made using the present application specification under the inventive concept of this disclosure, or direct / indirect applications in other related technical fields, are included within the scope of protection claimed in this application.

Claims

1. A method for preparing a hydrophobic catalyst, comprising: S1, carbon is loaded onto the metal skeleton by attaching a carbon-containing suspension to the metal skeleton and then drying it to obtain a composite carrier, wherein the carbon-containing suspension includes powdered carbon dispersed in silica sol and a dispersant. S2, loading the active metal onto the composite support to obtain the original catalyst; the active metal is selected from one or more of Pt, Pd, Ru, Rh, Ir, Fe, Fe-doped Pt, Ru-doped Pt, and Ir-doped Pt; and S3, the original catalyst is treated with a modified solution to obtain the hydrophobic catalyst, wherein the modified solution includes a hydrophobic silane and an organic solvent.

2. The preparation method according to claim 1, characterized in that, The metal skeleton is made of any one of nickel, iron, cobalt, copper, magnesium, aluminum, or stainless steel.

3. The preparation method according to claim 1, characterized in that, The shape of the metal skeleton is selected from any one of foam, wire mesh, fiber, and honeycomb.

4. The preparation method according to claim 1, characterized in that, The powdered carbon has a mass percentage of 1% to 5% relative to the total mass of the carbon-containing suspension, the dispersant has a mass percentage of 0.5% to 3%, and the silica in the silica sol has a mass percentage of 20% to 40% relative to the silica sol.

5. The preparation method according to claim 1, characterized in that, The powdered carbon is selected from one or more of activated carbon, graphite powder, carbon nanotubes, and carbon black.

6. The preparation method according to claim 1, characterized in that, The average particle size of the powdered carbon is 10 nm to 100 nm.

7. The preparation method according to claim 1, characterized in that, The dispersant is Triton X-100.

8. The preparation method according to claim 1, characterized in that, In S1, the drying temperature is 100℃~120℃ and the time is 1h~3h.

9. The preparation method according to claim 1, characterized in that, In S1, the mass ratio of the composite carrier to the metal skeleton is (1.2 to 1.8):

1.

10. The preparation method according to claim 1, characterized in that, In S2, loading the active metal onto the composite support includes: The composite support is immersed in a solution containing ions of an active metal element, and the solvent in the solution containing ions of the active metal element is evaporated to obtain a support loaded with an active metal precursor. The active metal is selected from one or more of Pt, Pd, Ru, Rh, Ir, Fe, Fe-doped Pt, Ru-doped Pt, and Ir-doped Pt. The support loaded with the active metal precursor is subjected to a reduction treatment to obtain the original catalyst, wherein the reduction treatment includes reducing the support loaded with the active metal precursor in an atmosphere containing a reducing gas.

11. The preparation method according to claim 10, characterized in that, The solvent of the solution containing ions of active metal elements is selected from one or more of ethanol, methanol, water, ethylene glycol, and acetone.

12. The preparation method according to claim 10, characterized in that, The reducing gas is hydrogen.

13. The preparation method according to claim 10, characterized in that, In the solution containing ions of an active metal element, the content of the active metal element is 3 g / L to 10 g / L.

14. The preparation method according to claim 10, characterized in that, The mass ratio of the composite carrier to the volume of the solution containing ions of active metal elements is 0.1 g / mL to 1.0 g / mL.

15. The preparation method according to claim 1, characterized in that, In S3, treating the original catalyst with a modified solution includes drying the catalyst after attaching the modified solution to it.

16. The preparation method according to claim 1, characterized in that, In S3, the organic solvent in the modified solution is ethanol.

17. The preparation method according to claim 1, characterized in that, In S3, the hydrophobic silane includes the structure R n SiR' m The silane, n is 1, 2 or 3, m = 4-n, R is a fluorine-substituted C1 to C20 alkyl group, and R' is a C1 to C4 alkoxy group.

18. The preparation method according to claim 17, characterized in that, Assuming R has x carbon atoms, R can be substituted with 2x-9 to 2x+1 fluorine atoms.

19. The preparation method according to claim 1, characterized in that, In the modified solution, the hydrophobic silane has a mass percentage content of 0.1% to 0.5%.

20. The preparation method according to claim 1, characterized in that, Prior to S2, the preparation method further includes: The nickel cobalt oxide precursor was loaded onto the composite support via a hydrothermal method; and The composite support for the nickel cobalt oxide precursor is calcined to obtain the composite support for nickel cobalt oxide. The process of loading the nickel cobalt oxide precursor onto the composite support via a hydrothermal method includes reacting an aqueous mixture comprising a cobalt source, a nickel source, the composite support, a surfactant, and a nucleating agent in a hydrothermal reactor, wherein the molar ratio of cobalt in the cobalt source to nickel in the nickel source is 2:

1.

21. The preparation method according to claim 20, characterized in that, The hydrothermal reaction is carried out at a temperature of 110℃ to 130℃ for a duration of 5 hours to 8 hours.

22. The preparation method according to claim 20, characterized in that, The amount of cobalt in the cobalt source is 0.1 mmol to 1 mmol per gram of the composite carrier.

23. The preparation method according to claim 20, characterized in that, The concentration of cobalt-containing ions in the cobalt source is 0.01 mol / L to 0.1 mol / L relative to the aqueous mixture.

24. The preparation method according to claim 20, characterized in that, The calcination temperature is 300℃~450℃, and the time is 2.5h~4.5h.

25. The preparation method according to claim 20, characterized in that, The surfactant is hexadecyltrimethylammonium bromide.

26. The preparation method according to claim 20, characterized in that, The nucleating agent is urea.

27. The preparation method according to claim 20, characterized in that, The concentration of the surfactant is 0.005 mol / L to 0.04 mol / L relative to the aqueous mixture, and the concentration of the nucleating agent is 0.02 mol / L to 0.20 mol / L.

28. A hydrophobic catalyst obtained by the preparation method according to any one of claims 1 to 27.

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