Hydrophobic catalysts for water-hydrogen exchange reactions and methods of making the same

Abstract

The present application provides a kind of hydrophobic catalyst for water-hydrogen exchange reaction, the hydrophobic catalyst includes: carrier, the carrier includes nickel foam and nitrogen-doped carbon layer grown in situ on the surface of the nickel foam, the nitrogen-doped carbon layer has porous structure;Active component, the active component is loaded on the nitrogen-doped carbon layer, the active component includes Pt;And hydrophobic component, the hydrophobic component is grafted on the nitrogen-doped carbon layer, the hydrophobic component includes fluorosilane.The hydrophobic catalyst of the present application has good hydrophobic property and catalytic activity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalysts, in particular to a hydrophobic catalyst for water-hydrogen exchange reaction and a preparation method thereof. BACKGROUND

[0002] Among the many hydrogen isotope separation methods, water-hydrogen exchange reaction has been widely used due to its high separation factor, low energy consumption and low cost. Hydrophobic catalyst is an essential part of water-hydrogen exchange reaction. The hydrophobic catalyst mainly consists of active components and hydrophobic carriers. The hydrophobic catalysts used in current research mainly include Pt / SDB, Pt / C / PTFE and Pt / C / inert carrier (Pt / C / IC) catalysts. Most of these three types of hydrophobic catalysts exist in the form of granular catalysts. However, in industrial large-scale application, regular catalysts have more advantages, such as low gas resistance, strong mass and heat transfer capacity, and easy scaling. Therefore, to realize the large-scale industrial application of hydrophobic catalysts, regular hydrophobic catalysts need to be developed, i.e. using regular carriers to prepare hydrophobic catalysts.

[0003] In the current reported research, the regular carriers used mainly include honeycomb ceramic cordierite, foamed nickel (FN) and foamed silicon carbide (SiC). 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.) reported a method of preparing hydrophobic catalysts using cordierite as the carrier, which was to graft an organic polymer with intrinsic hydrophobicity on the surface of the carrier. However, in this method, the grafting process is complicated and the hydrophobicity is poor. Patent (CN107930621A) disclosed a method of preparing hydrophobic catalysts using foamed silicon carbide (SiC) as the carrier, which was to load polytetrafluoroethylene (PTFE) on the carrier using natural impregnation method to construct a hydrophobic surface and then load the active component Pt. In this method, the dispersion of the active component Pt is poor. In addition, foamed silicon carbide (SiC) and cordierite both belong to ceramic materials, which are heavy in quality and prone to powdering and dropping.

[0004] Therefore, it is still necessary to continue to develop regular hydrophobic catalysts with better comprehensive performance. SUMMARY

[0005] Therefore, the main purpose of the present application is to provide a regular hydrophobic catalyst with good catalytic activity.

[0006] To this end, the present application provides a hydrophobic catalyst for water-hydrogen exchange reaction, comprising: a carrier, the carrier comprising a nickel foam and a nitrogen-doped carbon layer grown in situ on the surface of the nickel foam, the nitrogen-doped carbon layer having a porous structure; an active component, the active component being loaded on the nitrogen-doped carbon layer, the active component comprising Pt; and a hydrophobic component, the hydrophobic component being grafted on the nitrogen-doped carbon layer, the hydrophobic component comprising fluorosilane.

[0007] In some embodiments, the active component is selected from one or more of Pt, Fe-doped Pt, Ir-doped Pt, and Ru-doped Pt.

[0008] In some embodiments, the fluorosilane is selected from one or more of heptadecafluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, heptadecafluorodecyltriethoxysilane, and tridecafluorooctyltriethoxysilane.

[0009] In some embodiments, the loading amount of the active component is 0.1wt%-1.0wt% based on the total weight of the carrier.

[0010] The second aspect of the present application provides a preparation method of a hydrophobic catalyst, comprising the following steps:

[0011] S1, placing a solution comprising a carbon source and a nitrogen source in a reaction kettle with a nickel foam, carrying out a hydrothermal reaction at 120°C-180°C for 4h-18h, and then mixing with an alkali solution to carry out an activation treatment, to obtain a carrier with a nitrogen-doped carbon layer grown in situ on the surface of the nickel foam;

[0012] S2, impregnating the carrier with a precursor solution of an active component, and after drying, carrying out a reduction reaction to obtain a carrier loaded with the active component, wherein the active component comprises Pt;

[0013] S3, impregnating the carrier loaded with the active component in a solution containing a hydrophobic component for 12h-24h, taking out and drying for 6-12h to obtain the hydrophobic catalyst, wherein the hydrophobic component comprises fluorosilane.

[0014] In some embodiments, in step S1, the activation treatment comprises reacting with the alkali solution at 100°C-150°C for 6h-24h, and then calcining at 600°C-800°C for 0.5h-3h under an argon atmosphere.

[0015] In some embodiments, the mass ratio of the nitrogen-doped carbon layer to the alkali in the alkali solution is 1:1-1:3.

[0016] In some embodiments, the base is selected from one or more of KOH or NaOH.

[0017] In some embodiments, in step S1, the carbon source is glucose; and the nitrogen source is urea.

[0018] In some embodiments, in step S2, the precursor solution of the active component is selected from an alcohol solution of chloroplatinic acid, an alcohol solution of ferrous chloride and chloroplatinic acid, an alcohol solution of chloroiridic acid and chloroplatinic acid, an alcohol solution of ruthenium trichloride and chloroplatinic acid, wherein the alcohol is ethanol or ethylene glycol.

[0019] In some embodiments, the concentration of the precursor solution of the active component is 0.1 mol / L-0.3 mol / L.

[0020] In some embodiments, the loading amount of the active component is added in the precursor solution of the active component in an amount of 0.1-1.0 wt% based on the total weight of the carrier with the nitrogen-doped carbon layer grown in situ; and the active component is selected from one or more of Pt, Fe-doped Pt, Ir-doped Pt, Ru-doped Pt.

[0021] In some embodiments, in step S2, the reduction reaction is carried out in an argon atmosphere with hydrogen as the reducing agent, the reaction temperature is 200-300°C, and the reaction time is 6-12h.

[0022] In some embodiments, in step S3, the solution of the hydrophobic component is an ethanol solution of the hydrophobic component; and the concentration of the hydrophobic component solution is 0.1-0.3 wt%.

[0023] In some embodiments, the fluorosilane is selected from one or more of heptadecafluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane.

[0024] In the present application, the porous nickel foam with the nitrogen-doped carbon layer grown in situ is used as the carrier, and a regular hydrophobic catalyst with improved performance is provided, wherein the nitrogen-doped carbon layer provides binding sites for the active component, so that the active component can be uniformly dispersed on the carrier and fully exposed, thereby improving the utilization rate of the active component, improving the catalytic activity of the hydrophobic catalyst, and reducing the waste of noble metals. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 A schematic diagram of the grafting principle of the hydrophobic component in the hydrophobic catalyst of the present application.

[0026] Figure 2XPS test patterns of the platinum-loaded catalyst (hydrophobic treatment before catalyst) prepared in step S2 and the Pt / N-C / FN hydrophobic catalyst (hydrophobic treatment after catalyst) prepared in step S3 in Example 1 of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work under the premise that the embodiments of the present application fall within the scope of protection of the present application.

[0028] Throughout the specification, unless otherwise specifically indicated, the terms used herein are to be understood in the sense commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present application belongs. If there is a conflict, the present specification takes precedence.

[0029] It should be noted that in the embodiments of the present application, the terms "comprise", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the method or device comprising a series of elements not only includes the elements explicitly recited, but also includes other elements not explicitly listed, or further includes the elements inherent in the implementation of the method or device. Without more limitation, the element defined by the sentence "comprises a…" does not exclude the presence of other related elements in the method or device comprising the element.

[0030] It should be noted that the terms "first", "second", "third" involved in the embodiments of the present application are only to distinguish similar objects, and do not represent the specific order of the objects. Understandably, "first", "second", "third" can be interchanged in specific order or sequence as allowed. It should be understood that the objects distinguished by "first", "second", "third" can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0031] Foamed nickel has the advantages of light weight, low cost, strong processability, strong mass and heat transfer capacity, etc. Therefore, foamed nickel has greater application potential than ceramic materials and is very suitable for preparing regular hydrophobic catalysts. However, in the prior art, the method for preparing a hydrophobic catalyst using foamed nickel as a carrier is generally to coat Pt / C / PTFE on the foamed nickel by natural impregnation, that is, to load Pt on porous carbon to prepare Pt / C, then to mix Pt / C with polytetrafluoroethylene (PTFE) and triton to prepare a suspension, and finally to load Pt / C / PTFE on the foamed nickel by impregnation to prepare a hydrophobic catalyst. For example, the document "Improved catalysts for hydrogen / deuterium exchange reactions" reports that Pt / C powder is mixed with PTFE, PMMA and triton to prepare a suspension, and Pt / C / PTFE is loaded on stainless steel felt by natural impregnation, and the measured contact angle is 125°. The hydrophobic catalyst prepared by this method has certain defects, such as easy coverage of Pt, easy peeling of Pt / C / PTFE coating, and poor hydrophobicity of PTFE.

[0032] Therefore, the present application provides a hydrophobic catalyst, which comprises: a carrier, the carrier comprising foamed nickel and a nitrogen-doped carbon layer grown in situ on the surface of the foamed nickel, the nitrogen-doped carbon layer having a porous structure; an active component, the active component being loaded on the nitrogen-doped carbon layer, the active component comprising Pt; and a hydrophobic component, the hydrophobic component being grafted on the nitrogen-doped carbon layer, the hydrophobic component comprising fluorosilane.

[0033] In the present application, foamed nickel with a nitrogen-doped carbon layer grown in situ is used as a carrier. On the one hand, since the nitrogen element in the nitrogen-doped carbon layer has a lone pair of electrons, it can coordinate with the active component, has an anchoring effect on the active component, inhibits the agglomeration of the active component, and is beneficial to improving the dispersibility of the active component on the surface of the carrier. On the other hand, the nitrogen-doped carbon layer in the carrier has a porous structure, which is beneficial to improving the specific surface area of the hydrophobic catalyst, thereby providing more binding sites to load the active component, and thus improving the catalytic efficiency of the hydrophobic catalyst. The in-situ growth of the nitrogen-doped carbon layer disperses the active component through its physical properties such as porosity and large specific surface area, and chemical coordination with the active component, so that the active component is highly dispersed on the carrier and has a small particle size, thereby being beneficial to improving the catalytic activity of the catalyst. Further, the active component of the catalyst is closely combined with the foamed nickel carrier, and is not easy to fall off in use, thereby improving the stability and service life of the catalyst. In addition, in the present application, the active component is loaded on the surface of the nitrogen-doped carbon layer, so that the active component is fully exposed, the utilization rate of the active component is improved, and the catalytic activity of the hydrophobic catalyst is improved.

[0034] In the present application, the active component is a catalyst commonly used in water-hydrogen exchange reaction. In the present application, the active component comprises Pt. In some embodiments, the active component is selected from one or more of Pt, Fe-doped Pt, Ir-doped Pt, Ru-doped Pt. The above-mentioned active components have good catalytic performance for water-hydrogen exchange reaction.

[0035] In the present application, the hydrophobic component comprises fluorosilane. The term "fluorosilane" refers to silane containing -CF2 and -CF3 functional groups. By using fluorosilane as the hydrophobic component, the -CF2 and -CF3 functional groups in fluorosilane have very low surface energy, and due to the high roughness of the nitrogen-doped carbon layer grown in situ on the carrier, the combination of high roughness of the carrier and low surface energy of the hydrophobic component makes the catalyst have a super-hydrophobic surface, which is conducive to improving the hydrophobic performance of the hydrophobic catalyst. In addition, the hydrophobic component such as fluorosilane can be grafted on the carrier in the form of chemical bond condensation, which belongs to chemical combination and has high stability, thereby being conducive to improving the service life of the catalyst. In some embodiments, the fluorosilane is selected from one or more of heptadecafluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane; preferably heptadecafluorodecyltrimethoxysilane.

[0036] In some embodiments, the loading amount of the active component is 0.1wt%-1.0wt% based on the total weight of the carrier. The loading amount of the active component exceeding the above range is easy to cause the active component to agglomerate, thereby leading to reduced catalytic activity; the loading amount of the active component being lower than the above range makes the content of the active component too low, thereby leading to low catalytic activity of the catalyst. By making the loading amount of the active component within the above range, it is conducive to improving the catalytic efficiency of the hydrophobic catalyst and having good cost-effectiveness. Exemplarily, the loading amount of the active component can be 0.1wt%, 0.3wt%, 0.5wt%, 0.8wt%, 1.0wt% or a value between any two of them.

[0037] Another aspect of the present application provides a preparation method of a hydrophobic catalyst, the method comprising the following steps:

[0038] S1, placing a solution comprising a carbon source and a nitrogen source in a reaction kettle with foamed nickel, carrying out hydrothermal reaction at 120°C-180°C for 4h-18h, and then mixing with an alkali solution to carry out activation treatment, to obtain a carrier having a nitrogen-doped carbon layer grown in situ on at least part of the surface of the foamed nickel;

[0039] S2, impregnating the carrier with a precursor solution of the active component, and after drying, a reduction reaction is performed to obtain a carrier loaded with the active component, wherein the active component is selected from one or more of Pt, Fe-doped Pt, Ir-doped Pt, Ru-doped Pt;

[0040] S3, impregnating the carrier loaded with the active component in a solution containing a hydrophobic component for 12-24h, and after drying for 6-12h, the hydrophobic catalyst is obtained, wherein the hydrophobic component includes fluorosilane.

[0041] In the present application, step S1 grows nitrogen-doped carbon in situ on the foam nickel by a hydrothermal method, so that the nitrogen-doped carbon layer is tightly combined with the foam nickel substrate, avoiding the use of a binder, which is conducive to improving the stability and service life of the catalyst. The hydrothermal reaction is carried out at 120-180℃ for 4-18h. This is conducive to converting the carbon source and nitrogen source into nitrogen-doped carbon. Illustratively, the temperature of the hydrothermal reaction can be 120℃, 140℃, 160℃, 180℃, or a value between any two of these values; the reaction time can be 4h, 6h, 8h, 10h, 12h, or a value between any two of these values.

[0042] In some embodiments, the carbon source is glucose, and the nitrogen source is urea. The above raw materials are widely available and low in price, which is conducive to saving the preparation cost of the hydrophobic catalyst.

[0043] In some embodiments, in step S1, before the activation treatment is performed, the product obtained by the hydrothermal reaction is subjected to washing and drying treatment. Illustratively, the foam nickel loaded with nitrogen-doped carbon obtained after the hydrothermal reaction is taken out, washed with deionized water for 3-4 times, and then dried at 60-100℃ overnight.

[0044] In step S1, after the completion of the above hydrothermal reaction, the foam nickel in which the nitrogen-doped carbon layer is grown in situ is subjected to activation treatment by an alkaline solution to form a nitrogen-doped carbon layer with a porous structure, which increases the active sites of the carrier surface for binding the active component, improves the loading amount of the active component, and is conducive to the uniform dispersion of the active component on the carrier surface, thereby improving the catalytic activity of the catalyst.

[0045] In some embodiments, the activation treatment comprises reacting the mixture of the product from the hydrothermal reaction and the alkaline solution at 100-150°C for 6-24h, and then calcining at 600-800°C for 0.5-3h under argon atmosphere. By reacting the mixture of the product from the hydrothermal reaction and the alkaline solution at 100-150°C for 6-24h, the alkaline is allowed to react with the nitrogen-doped carbon layer on the foam nickel to form a porous structure, and then calcining at 600-800°C for 0.5-3h under argon atmosphere, the nitrogen-doped carbon layer is activated to facilitate the subsequent loading of active components and grafting of hydrophobic components.

[0046] In some embodiments, the alkaline is selected from one or more of KOH or NaOH. The use of the above-mentioned alkaline allows the alkaline to react with the nitrogen-doped carbon layer on the foam nickel to release gas and form a porous structure.

[0047] In some embodiments, the ratio of the mass of the nitrogen-doped carbon layer loaded on the foam nickel to the mass of the alkaline in the alkaline solution is 1:1-1:3. By having the ratio of the mass of the nitrogen-doped carbon layer to the mass of the alkaline within the above-mentioned range, the alkaline is allowed to react with the nitrogen-doped carbon sufficiently. Illustratively, the mass of the nitrogen-doped carbon layer in-situ grown on the foam nickel can be obtained by the difference method, i.e. weighing the mass of the foam nickel before the hydrothermal reaction, denoted as M0, and then weighing the mass of the foam nickel with the porous nitrogen-doped carbon layer after step S1, denoted as M1, and the mass of the nitrogen-doped carbon layer on the foam nickel M is the difference between M1 and M0.

[0048] In some embodiments, after the activation treatment, the foam nickel with the in-situ grown porous nitrogen-doped carbon layer is subjected to a washing and drying treatment. Illustratively, the foam nickel with the in-situ grown porous nitrogen-doped carbon layer is rinsed with deionized water and dried at 100-150°C under vacuum for 12-24h.

[0049] In the present application, step S2 comprises attaching the active component precursor to the carrier with the porous nitrogen-doped carbon layer by impregnation, and after drying, a reduction reaction is performed to obtain the carrier loaded with the active component. In this way, the active component is fully exposed on the surface of the carrier.

[0050] In some embodiments, the active component precursor solution is selected from an alcohol solution of chloroplatinic acid, an alcohol solution of ferrous chloride and chloroplatinic acid, an alcohol solution of chloroiridic acid and chloroplatinic acid, and an alcohol solution of ruthenium trichloride and chloroplatinic acid, wherein the alcohol is selected from ethanol or ethylene glycol. The above-mentioned active component precursor solutions can obtain active metals with catalytic activity on the surface of the carrier through a reduction reaction.

[0051] In some embodiments, the concentration of the active component precursor solution is 0.1-0.3 mol / L. By having the concentration of the active component precursor solution in the above range, the active component can be uniformly dispersed on the surface of the carrier, thereby improving the catalytic activity of the hydrophobic catalyst. Illustratively, the concentration of the active component precursor solution can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, or a value between any two of these values.

[0052] In some embodiments, the loading amount of the active component is 0.1-1.0 wt% in the active component precursor solution, based on the total weight of the carrier with the nitrogen-doped carbon layer grown in situ. In this way, the loading amount of the active component can be regulated, thereby improving the catalytic efficiency of the hydrophobic catalyst.

[0053] In some embodiments, the active component is selected from one or more of Pt, Fe-doped Pt, Ir-doped Pt, and Ru-doped Pt.

[0054] In some embodiments, the reduction reaction is performed in an argon atmosphere using hydrogen as the reducing agent.

[0055] In some embodiments, the flow rate of argon gas during the reduction reaction is 400-1000 mL / min.

[0056] In some embodiments, the reduction reaction comprises, after the introduction of argon, heating to the reaction temperature at a heating rate of 5-15 ℃ / min under an argon atmosphere, and then introducing hydrogen to start the reduction reaction.

[0057] In some embodiments, the flow rate ratio of argon to hydrogen is 1:1-1:3. Illustratively, the flow rate ratio of argon to hydrogen can be 1:1, 1:2, 1:3, or a value between any two of these ratios.

[0058] In some embodiments, the reaction temperature of the reduction reaction is 200-300 ℃, and the reaction time is 6-12 h. By having the reduction reaction meet the above conditions, the content of the metal element in the active component can be increased, and the particle size of the active component can be reduced, thereby improving the catalytic activity of the catalyst.

[0059] In the present application, step S3 forms a grafted hydrophobic layer on the carrier loaded with the active component by the method of impregnation, thereby reducing the surface energy of the carrier. In this way, the hydrophobic catalyst has good hydrophobic properties, and the active component is not covered, which facilitates the full exposure of the active component and improves the catalytic activity of the hydrophobic catalyst. By sufficient impregnation for 12-24 h, a large amount of hydrophobic components can be grafted onto the carrier, thereby improving the hydrophobic properties of the hydrophobic catalyst.

[0060] In some embodiments, the solution of the hydrophobic component is an ethanol solution of the hydrophobic component. In this way, the hydrophobic component is uniformly dispersed in the solution, so that as much hydrophobic component as possible reacts with the hydroxyl groups on the surface of the carrier to reduce the surface energy of the carrier to achieve a super-hydrophobic state, thereby improving the hydrophobicity of the catalyst without covering the active component, thereby improving the catalytic activity.

[0061] In some embodiments, the concentration of the solution of the hydrophobic component is 0.1wt%-0.3wt%. By using a solution of the hydrophobic component with the above concentration, a hydrophobic layer is formed on the carrier loaded with the active component, thereby improving the hydrophobicity of the catalyst. Illustratively, the concentration of the solution of the hydrophobic component can be 0.1wt%, 0.2wt%, 0.3wt% or a value between any two of the above values.

[0062] In some embodiments, the fluoro-silane is selected from one or more of heptadecafluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane. The fluoro-silane reagent hydrolyzes itself to form Si-OH, and then the obtained Si-OH hydrolyzes and dehydrates and condenses with the -OH on the surface of the carrier to graft the fluoro-silane reagent to the surface of the carrier. Illustratively, the grafting reaction mechanism of heptadecafluorodecyltrimethoxysilane with the carrier is shown in Figure 1 The fluoro-silane reagent hydrolyzes itself to form Si-OH, and then the obtained Si-OH hydrolyzes and dehydrates and condenses with the -OH on the surface of the carrier to graft the fluoro-silane reagent to the surface of the carrier. Illustratively, the grafting reaction mechanism of heptadecafluorodecyltrimethoxysilane with the carrier is shown in

[0063] In some embodiments, the carrier after impregnation is taken out and dried at 80-100°C. The drying can be carried out in a manner known to those skilled in the art, which is not specifically limited in the present application.

[0064] The technical solutions of the present application will be further illustrated by specific examples below.

[0065] Example

[0066] Example 1

[0067] Step S1: The foamed nickel was respectively placed in deionized water and anhydrous ethanol and ultrasonically cleaned for 20 min. After cleaning, it was placed in an oven and dried at 60°C for 1 h.

[0068] 4 g glucose and 4 g urea were dissolved in 30 ml deionized water, and then the solution was transferred into a Teflon-lined autoclave with foamed nickel. Hydrothermal reaction was carried out at 180 °C for 8 h. After the reaction, the foamed nickel was taken out and washed with deionized water for 3 times, and dried at 80 °C overnight to obtain a foamed nickel carrier with a nitrogen-doped carbon layer (denoted as N-C / FN). The mass of the nitrogen-doped carbon (denoted as N-C) in the N-C / FN was determined by the difference method. KOH was weighed according to the mass ratio of N-C to KOH being 1:2, and deionized water was used to prepare a solution. The N-C / FN was immersed in the KOH solution and then placed in an oven. Reaction was carried out at 120 °C for 12 h. After the reaction, the N-C / FN was placed in a tube furnace and calcined at 700 °C in an argon (Ar) atmosphere for 1 h. Finally, the N-C / FN was washed with deionized water and placed in a vacuum oven to dry at 150 °C for 24 h to obtain a porous N-C / FN.

[0069] Step S2: 5 g of the porous N-C / FN was immersed in 50 ml of 0.03 mol / L chloroplatinic acid hexahydrate ethanol solution at room temperature. After the solvent was completely volatilized, it was placed in an oven and dried at 70 °C for 12 h. Then it was placed in a tube furnace. The temperature was raised to 220 °C at a rate of 10 °C / min in an argon atmosphere (flow rate of 500 ml / min). After reaching the temperature, H2was introduced (flow rate of 500 ml / min) for reduction. Reduction was carried out at 220 °C for 8 h. After the reduction was completed, the introduction of H2was stopped, and the furnace was cooled overnight under Ar (flow rate of 500 ml / min) protection. Finally, a platinum-loaded catalyst (denoted as Pt / N-C / FN) was prepared.

[0070] Step S3: The Pt / N-C / FN was completely immersed in a 0.2 wt% heptadecafluorodecyltrimethoxysilane (FD-TMS) ethanol solution for 12 h. After being taken out, it was dried at 80 °C for 6 h to obtain a Pt / N-C / FN hydrophobic catalyst.

[0071] The platinum-loaded catalyst prepared in step S2 (before hydrophobic treatment) and the Pt / N-C / FN hydrophobic catalyst prepared in step S3 (after hydrophobic treatment) were subjected to XPS testing. The test results are shown in Figure 2 . Figure 2 Fig. 1(a) is an XPS spectrum of the catalyst before and after hydrophobic treatment; Fig. 1(b) is an XPS C1s high-resolution spectrum of the catalyst before hydrophobic treatment; and Fig. 1(c) is an XPS C1s high-resolution spectrum of the catalyst after hydrophobic treatment.

[0072] As can be seen from Figure 2 (a), compared with the catalyst before hydrophobic treatment, the catalyst after fluorosilane hydrophobic treatment has F KL1 peaks and F1s peaks, and the C1s fine spectrum of the two peaks Figure 2From the FTIR spectra of the hydrophobic catalysts before and after the hydrophobic treatment, it can be known that there are only the related peaks of C-C and C-O before the hydrophobic treatment, and after the hydrophobic treatment, strong peaks of -CF2- and -CF3 appear, and F element and -CF2- and -CF3 are all from the fluorosilane reagent, thus it is proved that the fluorosilane is successfully grafted on the catalyst.

[0073] The hydrophobic catalyst prepared above is subjected to performance testing according to the following method.

[0074] Static contact angle measurement:

[0075] The static contact angle is measured by using a static contact angle measuring instrument SDC-350 (Dongguan Shengding Precision Instrument Co., Ltd.), the hydrophobic catalyst is placed on the stage of the measuring instrument, the stage is moved upward to make it contact with the water droplet dropped from the needle tube, after the two are fully contacted, the stage is moved downward to make the water droplet separate from the needle tube and be placed on the hydrophobic catalyst, and the software attached to the measuring instrument is used to fit the contact angle. The larger the static contact angle is, the better the hydrophobic performance of the catalyst is.

[0076] Measurement of catalytic activity:

[0077] The catalytic activity is tested by using a gas-liquid co-current device made in the laboratory, the device mainly comprises a filler column, a catalytic column and a condenser, deuterated water (D2O) liquid is converted into D2O saturated vapor in the filler column, the D2O saturated vapor and hydrogen enter the catalytic column together, and the water-hydrogen exchange reaction occurs on the catalyst, part of the gas after the reaction is condensed into liquid for collection, and the other part of the gas after the reaction which is not condensed is also collected, the deuterium (D) density in the liquid after the reaction is measured by using a densimeter and the abundance thereof is calculated, and the D abundance in the gas after the reaction is measured by using a mass spectrometer. The total volume mass transfer coefficient (Kya) is used to represent the catalytic activity of the catalyst, and the calculation method is as follows:

[0078]

[0079] In formula (1), F is the column efficiency of the catalytic column, y is the deuterium abundance in the gas phase after the reaction, y0 is the deuterium abundance in the gas phase before the reaction, y ∞ is the deuterium abundance in the gas phase at equilibrium; in formula (2), x ∞ is the deuterium abundance in the liquid phase at equilibrium, the reaction temperature for the activity test is 60°C, the separation factor of H / D exchange at this temperature is 3.134; in formula (3), G is the gas flow rate (m 3 / s), and V is the volume of the catalytic bed (m 3 ). The larger the total volume mass transfer coefficient is, the higher the catalytic activity of the catalyst is.

[0080] Conversion relationship between deuterium density and abundance:

[0081] The deuterium density measured by the densimeter is ρ

[0082] ρD2O = 1.105 g / ml

[0083] p H2O = 0.9985 g / ml

[0084]

[0085] Comparative Example 1

[0086] A hydrophobic catalyst was prepared in a similar manner to Example 1, except that in step S1, no urea was added for the hydrothermal reaction.

[0087] The hydrophobic catalysts prepared in Example 1 and Comparative Example 1 above were subjected to static contact angle measurement and catalytic activity measurement in accordance with the test method of Example 1 above. The test results are shown in Table 1.

[0088] Table 1

[0089]

[0090] From the above results, it can be seen that the hydrophobic catalyst prepared by loading a foam nickel loaded with nitrogen-doped carbon as a carrier, loading a metal active component and hydrophobic treatment with fluorosilane has good hydrophobic performance and catalytic activity. In contrast, the catalytic activity of the hydrophobic catalyst prepared by loading a foam nickel loaded with carbon as a carrier in Comparative Example 1 is poor.

[0091] The above only describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made under the inventive concept of the present application, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A hydrophobic catalyst for water-hydrogen exchange reactions, characterized in that, The hydrophobic catalyst comprises: a carrier, the carrier comprising a nickel foam and a nitrogen-doped carbon layer grown in situ on the surface of the nickel foam, the nitrogen-doped carbon layer having a porous structure; an active component, the active component being loaded on the nitrogen-doped carbon layer, the active component comprising Pt; and a hydrophobic component, the hydrophobic component being grafted on the nitrogen-doped carbon layer, the hydrophobic component comprising fluorosilane.

2. The hydrophobic catalyst of claim 1, wherein, The hydrophobic catalyst comprises one or more of the following features: (1) the active component is selected from one or more of Pt, Fe-doped Pt, Ir-doped Pt, Ru-doped Pt; (2) the fluorosilane is selected from one or more of heptadecafluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane.

3. The hydrophobic catalyst of claim 1 or 2, wherein, The loading amount of the active component is 0.1wt%-1.0wt% based on the total weight of the carrier.

4. A process for the preparation of a hydrophobic catalyst, characterized in that, The method comprises the following steps: S1, placing a solution comprising a carbon source and a nitrogen source in a reaction kettle with a nickel foam, carrying out a hydrothermal reaction at 120℃-180℃ for 4h-18h, then mixing with an alkali solution to carry out activation treatment, to obtain a carrier with a nitrogen-doped carbon layer grown in situ on the surface of the nickel foam; S2, immersing the carrier in a precursor solution of an active component, drying and then carrying out a reduction reaction to obtain a carrier loaded with an active component, wherein the active component comprises Pt; S3, immersing the above carrier loaded with an active component in a solution containing a hydrophobic component for 12h-24h, taking out and drying for 6-12h to obtain the hydrophobic catalyst, wherein the hydrophobic component comprises fluorosilane.

5. The preparation method according to claim 4, characterized in that, In step S1, the activation treatment comprises reacting with the alkali solution at 100℃-150℃ for 6h-24h, and then calcining at 600℃-800℃ for 0.5h-3h under an argon atmosphere.

6. The production method according to claim 4 or 5, wherein, The mass ratio of the mass of the nitrogen-doped carbon layer to the mass of the alkali in the alkali solution is 1:1-1:3; The alkali is selected from one or more of KOH or NaOH.

7. The production method according to claim 4 or 5, wherein In step S1, the carbon source is glucose; the nitrogen source is urea.

8. The production method according to claim 4, wherein In step S2, the precursor solution of the active component is selected from an alcohol solution of chloroplatinic acid, an alcohol solution of ferrous chloride and chloroplatinic acid, an alcohol solution of chloroiridic acid and chloroplatinic acid, an alcohol solution of ruthenium trichloride and chloroplatinic acid, wherein the alcohol is selected from ethanol or ethylene glycol; the concentration of the precursor solution of the active component is 0.1mol / L-0.3mol / L; The loading amount of the active component is 0.1-1.0wt% based on the total weight of the carrier with the nitrogen-doped carbon layer grown in situ; the active component is selected from one or more of Pt, Fe-doped Pt, Ir-doped Pt, Ru-doped Pt.

9. The production method according to claim 4, wherein, In step S2, the reduction reaction is carried out in an argon atmosphere with hydrogen as the reducing agent, The reaction temperature is 200℃-300℃, and the reaction time is 6h-12h.

10. The production method according to claim 4, wherein, In step S3, the solution of the hydrophobic component is an ethanol solution of the hydrophobic component; the concentration of the hydrophobic component solution is 0.1wt%-0.3wt%. The fluorosilane is selected from one or more of heptadecafluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane. The fluorosilane is selected from one or more of heptadecafluorodecyltrimethoxysilane, perfluorodecyltriethoxysilane, heptadecafluorodecyltriethoxysilane, tridecafluorooctyltriethoxysilane.

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