Carbon-coated nickel-based super-hydrophobic catalyst, preparation method and application thereof

Abstract

The application discloses a carbon-coated nickel-based super-hydrophobic catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts and high-alcohol synthesis. In the application, nickel salt and citric acid are dissolved in water, and then the obtained mixed solution is heated and stirred to obtain a precursor; the precursor is calcined under an inert atmosphere to obtain a carbon-coated nickel-based catalyst; and the carbon-coated nickel-based catalyst is ball-milled with polytetrafluoroethylene to obtain a carbon-coated nickel-based super-hydrophobic catalyst. In the application, the carbon-coated nickel-based catalyst is prepared first, and then coupled with the hydrophobic polymer polytetrafluoroethylene to form a new super-hydrophobic catalyst. The nickel-based catalyst and the polytetrafluoroethylene are ball-mixed, the hydrophobic performance of the nickel-based catalyst is improved, the water "poisoning" phenomenon of the catalyst is relieved, the coupling of low-alcohol to high-alcohol is further promoted, the yield of high-alcohol and the selectivity of C6+ high-alcohol are improved, and the application prospect is wide.

Description

Technical Field

[0001] This invention belongs to the field of catalyst and higher alcohol synthesis technology, and particularly relates to a carbon-coated nickel-based superhydrophobic catalyst, its preparation method and application. Background Technology

[0002] Higher alcohols are widely used as efficient solvents and surfactants in the chemical, pharmaceutical, fragrance, and food industries, significantly improving product stability and solubility and optimizing production processes. Furthermore, higher alcohols are important chemical intermediates used in the synthesis of various high-value-added products, such as fragrances, plasticizers, and fine chemicals. For example, short-chain higher alcohols such as hexanol and heptanol, due to their unique chemical properties, are frequently used in the preparation of fragrances and plastic additives, demonstrating their crucial role in the industrial chain.

[0003] In recent years, the application of higher alcohols in the field of biofuels has received increasing attention. Compared with traditional petroleum-based fuels, bio-based higher alcohols have significant environmental advantages, including lower carbon emissions and higher renewability. Through bioconversion technologies (such as fermentation and esterification), higher alcohols can be efficiently produced from renewable resources such as vegetable oils and sugars, providing a new solution for sustainable development. Studies show that higher alcohols, as biofuel additives, can not only optimize combustion performance but also effectively reduce greenhouse gas emissions, thus demonstrating broad application prospects in the field of clean energy.

[0004] The synthesis of higher alcohols is also a current research focus. Among them, the Guerbet aldol condensation method can achieve carbon chain growth to prepare higher alcohols through carbon-carbon coupling of small molecule alcohols. This process mainly consists of three parts: First, a low-carbon alcohol such as methanol or ethanol undergoes a dehydrogenation reaction at an active site to generate the corresponding aldehyde; second, the aldehyde undergoes an aldol condensation reaction at a basic site, losing one molecule of water to generate an unsaturated aldehyde; finally, the unsaturated aldehyde is hydrogenated to generate the corresponding high-carbon alcohol. The most critical parts of this method are the dehydrogenation and hydrogenation reactions in the first and third steps, and the catalysts used need to have corresponding metal active centers.

[0005] Chinese patent CN114177908A discloses a method for preparing a solid base-coated carbon-coated nickel-based amphiphilic phase transfer catalyst, which enhances mass transfer between oil and water phases and improves the yield of C4+ higher alcohols. However, in the catalytic carbon-carbon coupling reaction of ethanol and aqueous phase to prepare higher alcohols, ethanol molecules tend to undergo self-coupling, significantly limiting the selectivity of the target product. Therefore, to achieve efficient synthesis of high-carbon-number alcohols (C6+), it is necessary to promote a secondary cross-coupling reaction between the product higher alcohol (C4+) and the feedstock ethanol. However, the catalyst prepared in the aforementioned patent exhibits low selectivity (35.0%) for C6+ higher alcohols due to reactant self-coupling when used for the aqueous small-molecule synthesis of higher alcohols.

[0006] Therefore, there is an urgent need for a catalyst that can improve the selectivity of C6+ higher alcohols to solve the above problems. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention proposes a carbon-coated nickel-based superhydrophobic catalyst, its preparation method, and its application.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a method for preparing a carbon-coated nickel-based superhydrophobic catalyst, comprising the following steps:

[0010] S1. Dissolve nickel salt and citric acid in water to obtain a mixed solution; heat and stir the resulting mixed solution to obtain the precursor;

[0011] S2. The precursor is calcined under an inert atmosphere to obtain a carbon-coated nickel-based catalyst;

[0012] S3. The carbon-coated nickel-based catalyst is ball-milled and mixed with polytetrafluoroethylene to obtain the carbon-coated nickel-based superhydrophobic catalyst.

[0013] Technical Principle: This invention first prepares a carbon-coated nickel-based catalyst, and then couples it with the hydrophobic polymer polytetrafluoroethylene (PTFE) to form a new superhydrophobic catalyst. By ball milling and mixing the nickel-based catalyst and PTFE, the hydrophobic properties of the nickel-based catalyst are improved, the water "poisoning" phenomenon of the catalyst is alleviated, thereby promoting the further coupling of lower alcohols to higher alcohols, improving the yield of higher alcohols and the selectivity of C6+ higher alcohols, and has broad application prospects.

[0014] Further, in step S1, the molar ratio of citric acid to nickel salt is 4:(1-4).

[0015] Furthermore, in step S1, the heating and stirring temperature is 40–100°C, and the time is 1–2 hours.

[0016] Furthermore, in step S2, the calcination temperature is 300–600°C, and the calcination time is 1–3 hours.

[0017] Further, in step S3, the mass ratio of the polytetrafluoroethylene to the carbon-coated nickel-based catalyst is 4:(1-4).

[0018] Furthermore, in step S3, the ball-to-material mass ratio in the ball milling mixture is 10:1, the ball milling time is 8 hours, and the ball milling speed is 200 rpm.

[0019] Further, in step S3, the polytetrafluoroethylene is selected from polytetrafluoroethylene micro powder; the particle size of the polytetrafluoroethylene micro powder is 1-15 μm.

[0020] The present invention provides a carbon-coated nickel-based superhydrophobic catalyst prepared by the preparation method described in the above technical solution.

[0021] This invention also provides the application of the carbon-coated nickel-based superhydrophobic catalyst described above in the catalytic aqueous synthesis of higher alcohols from small molecule alcohols.

[0022] Furthermore, the small molecule alcohol is ethanol; the higher alcohol is an alcohol with 4 to 16 carbon atoms.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] 1. This invention synthesizes a carbon-coated nickel-based superhydrophobic catalyst by ball milling a nickel-based catalyst and a hydrophobic polymer PTFE. When this catalyst is applied to the one-step synthesis of C6+ higher alcohols from aqueous ethanol, it exhibits the following advantages: it facilitates the secondary reaction of ethanol and higher alcohol molecules, promotes the secondary growth of carbon chains, improves the conversion rate of ethanol, increases the yield of higher alcohols, and enhances the selectivity for C6+ higher alcohols.

[0025] 2. The inventors discovered that because ethanol has high solubility in aqueous systems, the microenvironment on the catalyst surface can be effectively controlled by constructing a heterogeneous reaction interface using a superhydrophobic catalyst. The superhydrophobic catalyst surface can effectively reduce the local concentration of ethanol. The resulting interfacial concentration gradient difference inhibits the contact probability between homologous ethanol molecules from a kinetic perspective. This makes it more thermodynamically favorable for the cross-coupling pathway between ethanol and higher alcohol molecules, rather than the occurrence of its own homogeneous coupling reaction, thereby improving the yield of higher alcohols and the selectivity for C6+ higher alcohols.

[0026] 3. The carbon-coated nickel-based superhydrophobic catalyst prepared by this invention is a heterogeneous catalyst, which is easy to separate, recover and reuse in the preparation of higher alcohols. Attached Figure Description

[0027] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0028] Figure 1 The XRD patterns are of the carbon-coated nickel-based superhydrophobic catalyst prepared in Example 1 and the carbon-coated nickel-based catalyst prepared in Comparative Example 1.

[0029] Figure 2 Water droplet contact angle test diagram of the carbon-coated nickel-based catalyst prepared in Comparative Example 1;

[0030] Figure 3 The image shows the water droplet contact angle of the carbon-coated nickel-based superhydrophobic catalyst prepared in Example 1. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] This invention provides a method for preparing a carbon-coated nickel-based superhydrophobic catalyst, comprising the following steps:

[0034] S1. Dissolve nickel salt and citric acid in water to obtain a mixed solution; heat and stir the resulting mixed solution to obtain the precursor;

[0035] S2. The precursor is calcined under an inert atmosphere to obtain a carbon-coated nickel-based catalyst;

[0036] S3. The carbon-coated nickel-based catalyst is ball-milled and mixed with polytetrafluoroethylene to obtain the carbon-coated nickel-based superhydrophobic catalyst.

[0037] In a preferred embodiment, in step S1, the molar ratio of citric acid to nickel salt is 4:(1-4), more preferably 4:(2-4); the nickel salt is selected from nickel nitrate. In this invention, if the amount of nickel salt used is too small, the number of active sites is insufficient, resulting in low catalytic activity, slow reaction rate, and difficulty in meeting reaction requirements; if the amount of nickel salt used is too large, the active components are prone to aggregation and sintering, reducing the surface area and number of active sites, decreasing catalytic activity and selectivity, and may also change the reaction pathway, increasing the formation of byproducts; controlling the molar ratio of citric acid to nickel salt within the above range is beneficial for obtaining a carbon-coated nickel-based superhydrophobic catalyst with excellent catalytic performance.

[0038] In a preferred embodiment, in step S1, the heating and stirring temperature is 40–100°C, more preferably 40–60°C; the heating and stirring time is 1–2 hours. Citric acid has multiple carboxyl (-COOH) and hydroxyl (-OH) functional groups. During heating and stirring, these functional groups can react with nickel ions (Ni... 2+ A coordination reaction occurs, forming a stable nickel citrate complex, which uniformly disperses nickel ions in the solution, forming a stable sol. As the solvent evaporates, the sol gradually transforms into a gel.

[0039] In a preferred embodiment, in step S2, the calcination temperature is 300–600°C, more preferably 550–600°C; the calcination time is 1–3 hours. At lower calcination temperatures, the active components in the catalyst may not be sufficiently dispersed. As the calcination temperature increases, the diffusion ability of the active component atoms is enhanced, which helps the active components to be uniformly dispersed on the support surface. However, if the calcination temperature is too high, the pore structure of the support may collapse, and sintering may occur between the particles, causing the particles to aggregate and reducing the porosity. This reduces the surface area exposed by the active components, making it difficult for reactants to reach the active sites. Controlling the calcination temperature within the above range is beneficial for obtaining carbon-coated nickel-based superhydrophobic catalysts with excellent catalytic performance.

[0040] In a preferred embodiment, in step S3, the mass ratio of polytetrafluoroethylene (PTFE) to carbon-coated nickel-based catalyst is 4:(1-4), more preferably 4:(2-4). This invention improves the hydrophobic properties of the nickel-based catalyst by coupling it with the hydrophobic polymer PTFE, alleviating the catalyst's water "poisoning" phenomenon, thereby promoting the further coupling of lower alcohols to higher alcohols, increasing the yield of higher alcohols and the selectivity of C6+ higher alcohols. PTFE is used in this invention because it has extremely high chemical stability, reacting almost no with any chemical substances, and remains stable even in strongly alkaline environments. This prevents chemical decomposition or corrosion under strongly alkaline conditions, effectively protecting the active components of the catalyst. Furthermore, PTFE has a wide operating temperature range, maintaining good performance between -196℃ and 260℃ without losing its protective effect at high temperatures. PTFE also possesses good mechanical strength and toughness, maintaining structural integrity even under high temperature and strongly alkaline environments. This helps protect catalyst particles during ball milling, preventing them from breaking or agglomerating due to mechanical impact.

[0041] In a preferred embodiment, in step S3, the ball-to-material mass ratio of the ball milling mixture is 10:1, the ball milling time is 8 hours, and the ball milling speed is 200 rpm. Ball milling significantly affects the crystal structure and phase composition of the carbon-coated nickel-based catalyst, leading to reduced nickel dispersion and increased crystallinity, while simultaneously promoting the loading of carbon and polytetrafluoroethylene in the catalyst.

[0042] In a preferred embodiment, in step S3, the polytetrafluoroethylene is selected from polytetrafluoroethylene micro powder; the particle size of the polytetrafluoroethylene micro powder is 1-15 μm.

[0043] The present invention provides a carbon-coated nickel-based superhydrophobic catalyst prepared by the preparation method described in the above technical solution.

[0044] This invention also provides the application of the carbon-coated nickel-based superhydrophobic catalyst described above in the catalytic aqueous synthesis of higher alcohols from small molecule alcohols.

[0045] In a preferred embodiment, the small molecule alcohol is ethanol; the higher alcohol is an alcohol with 4 to 16 carbon atoms.

[0046] In a preferred embodiment, the application of the carbon-coated nickel-based superhydrophobic catalyst in the catalytic synthesis of higher alcohols from small molecule alcohols in aqueous phase includes the following steps: placing the carbon-coated nickel-based superhydrophobic catalyst, sodium hydroxide, ethanol, and water in a reaction vessel at a mass ratio of 1:1:(10-40):(10-40). After leak testing of the reaction vessel, the air inside the vessel is replaced with high-purity hydrogen. Then, the reaction is carried out continuously for 10 hours at a reaction temperature of 200°C, an initial pressure of 0.1 MPa, and a stirring speed of 1500 rpm. After standing and centrifugation, the oil phase and the aqueous phase are obtained respectively.

[0047] In this embodiment of the invention, room temperature refers to "25±2℃".

[0048] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0049] Example 1

[0050] A method for preparing a carbon-coated nickel-based superhydrophobic catalyst, the specific steps of which are as follows:

[0051] S1. Add nickel nitrate and citric acid to deionized water at a molar ratio of 1:4 and stir to form a homogeneous solution; stir the resulting homogeneous solution at 40°C for 2 hours and dry to obtain the precursor;

[0052] S2. The precursor obtained in step S1 is placed in a nitrogen atmosphere and calcined at 550°C for 2 hours to obtain a carbon-coated nickel-based catalyst.

[0053] S3. The carbon-coated nickel-based catalyst and PTFE micro powder obtained in step S2 are ball-milled and mixed at a mass ratio of 1:4 to obtain a carbon-coated nickel-based superhydrophobic catalyst, denoted as Ni@C-PTFE; wherein the mass ratio of ball to material in the ball milling is 10:1, the ball milling time is 8h, the ball milling speed is 200rpm, and the particle size of the PTFE micro powder is 1μm.

[0054] Example 2

[0055] A method for preparing a carbon-coated nickel-based superhydrophobic catalyst, comprising the following steps:

[0056] S1. Add nickel nitrate and citric acid to deionized water in a molar ratio of 4:4 and stir to form a homogeneous solution; stir the resulting homogeneous solution at 40°C for 2 hours and dry to obtain the precursor;

[0057] S2. Same as Example 1;

[0058] S3. The carbon-coated nickel-based catalyst and PTFE micro powder obtained in step S2 are ball-milled and mixed at a mass ratio of 4:4 to obtain a carbon-coated nickel-based superhydrophobic catalyst, denoted as Ni@C-PTFE; the mass ratio of ball to material in the ball milling is 10:1, the ball milling time is 8 hours, the ball milling speed is 200 rpm, and the particle size of the PTFE micro powder is 1 μm.

[0059] Example 3

[0060] A method for preparing a carbon-coated nickel-based superhydrophobic catalyst, comprising the following steps:

[0061] S1. Add nickel nitrate and citric acid to deionized water at a molar ratio of 3:4 and stir to form a homogeneous solution; stir the resulting homogeneous solution at 40°C for 2 hours and dry to obtain the precursor;

[0062] S2. Same as Example 1;

[0063] S3. The carbon-coated nickel-based catalyst and PTFE micro powder obtained in step S2 are ball-milled and mixed at a mass ratio of 3:4 to obtain a carbon-coated nickel-based superhydrophobic catalyst, denoted as Ni@C-PTFE; wherein the mass ratio of ball to material in the ball milling is 10:1, the ball milling time is 8h, the ball milling speed is 200rpm, and the particle size of the PTFE micro powder is 1μm.

[0064] Example 4

[0065] A method for preparing a carbon-coated nickel-based superhydrophobic catalyst, comprising the following steps:

[0066] S1. Add nickel nitrate and citric acid to deionized water at a molar ratio of 2:4 and stir to form a homogeneous solution; stir the resulting homogeneous solution at 40°C for 2 hours and dry to obtain the precursor;

[0067] S2. Same as Example 1;

[0068] S3. The carbon-coated nickel-based catalyst and PTFE micro powder obtained in step S2 are ball-milled and mixed at a mass ratio of 2:4 to obtain a carbon-coated nickel-based superhydrophobic catalyst, denoted as Ni@C-PTFE; wherein the mass ratio of ball to material in the ball milling is 10:1, the ball milling time is 8h, the ball milling speed is 200rpm, and the particle size of the PTFE micro powder is 1μm.

[0069] Example 5

[0070] A method for preparing a carbon-coated nickel-based superhydrophobic catalyst differs from Example 1 in that, in step S2, the precursor obtained in step S1 is calcined at 400°C for 2 hours under a nitrogen atmosphere, while the rest is the same as in Example 1.

[0071] Example 6

[0072] A method for preparing a carbon-coated nickel-based superhydrophobic catalyst differs from Example 1 in that, in step S2, the precursor obtained in step S1 is calcined at 450°C for 2 hours under a nitrogen atmosphere, while the rest is the same as in Example 1.

[0073] Example 7

[0074] A method for preparing a carbon-coated nickel-based superhydrophobic catalyst differs from Example 1 in that, in step S2, the precursor obtained in step S1 is calcined at 500°C for 2 hours under a nitrogen atmosphere, while the rest is the same as in Example 1.

[0075] Example 8

[0076] A method for preparing a carbon-coated nickel-based superhydrophobic catalyst differs from Example 1 in that, in step S2, the precursor obtained in step S1 is calcined at 600°C for 2 hours under a nitrogen atmosphere, while the rest is the same as in Example 1.

[0077] Comparative Example 1

[0078] A method for preparing a carbon-coated nickel-based catalyst, the specific steps of which are as follows:

[0079] S1. Dissolve nickel nitrate and citric acid in deionized water at a molar ratio of 1:4 and stir until homogeneous to form a homogeneous solution;

[0080] S2. Stir the homogeneous solution obtained in step S1 at 40°C for 2 hours, then dry it to obtain the precursor;

[0081] S3. The precursor obtained in step S2 is calcined at 550°C for 2 hours under a nitrogen atmosphere to obtain a carbon-coated nickel-based catalyst, denoted as Ni@C.

[0082] Comparative Example 2

[0083] A method for preparing a carbon-coated nickel-based hydrophobic catalyst differs from Example 1 in that PTFE in step S3 is replaced with polydimethylsiloxane, while the rest is the same as in Example 1.

[0084] Test characterization

[0085] The catalysts prepared in Examples 1-8 and Comparative Examples 1-2 were added to a 70 mL high-pressure reactor and co-catalyzed with a homogeneous base to produce higher alcohols via carbon-carbon coupling of ethanol. Specifically, 0.5 g of the catalysts prepared in Examples 1-8 and Comparative Examples 1-2, 0.5 g of NaOH, 10 g of ethanol, and 10 g of water were added to the high-pressure reactor. After leak testing, the air in the reactor was replaced with high-purity hydrogen. The reaction was carried out continuously for 10 h at a reaction temperature of 200 °C, an initial pressure of 0.1 MPa, and a stirring speed of 1500 rpm. After the reaction, the reaction system was allowed to cool to room temperature, and the gaseous product was collected using a gas bag. The solid-liquid mixture in the reactor was then removed. The solid-liquid mixture was separated by centrifugation and filtration to obtain the liquid product and the solid catalyst. After standing, the liquid product naturally separated into two phases: an oil phase and an aqueous phase. The gaseous product, aqueous phase, and oil phase were all qualitatively and quantitatively analyzed by gas chromatography. The analytical results are shown in Table 1.

[0086] Table 1

[0087]

[0088]

[0089] As shown in Table 1, the carbon-coated nickel-based superhydrophobic catalysts prepared in Examples 1-8 can be used for the carbon-carbon coupling of ethanol to prepare higher alcohols, improving the selectivity of C6+ alcohols and alleviating the water poisoning phenomenon of the catalyst. The catalyst prepared in Example 4 exhibited the best performance, with high ethanol conversion, organic phase product yield, and selectivity for C6+ higher alcohols in the liquid phase. In Comparative Example 1, because it was not ball-milled with PTFE, the catalyst was affected by water, resulting in lower yields of C6+ higher alcohols, ethanol conversion, and organic phase yield. In Comparative Example 2, replacing PTFE with polydimethylsiloxane may cause the Si-O bonds of PDMS to break under strong alkaline conditions, affecting its structural integrity and thus the stability of the catalyst. Under the combined effects of high temperature and strong alkalinity, the stability of PDMS may be challenged, making it less reliable than PTFE. Therefore, the yields of C6+ higher alcohols, ethanol conversion, and organic phase yield in Comparative Example 2 were all low.

[0090] Figure 1 The images show the XRD patterns of the carbon-coated nickel-based superhydrophobic catalyst prepared in Example 1 and the carbon-coated nickel-based catalyst prepared in Comparative Example 1. Figure 1As can be seen from the data, the carbon-coated nickel-based catalyst prepared in Comparative Example 1 exhibits distinct and sharp diffraction peaks, indicating good crystallinity and dispersion of nickel in this material. This may mean that nickel is successfully loaded and uniformly distributed in the carbon matrix. The carbon-coated nickel-based superhydrophobic catalyst prepared in Example 1 shows multiple diffraction peaks, including peaks for carbon, nickel, and possibly PTFE. The intensity of the nickel diffraction peak increases while the peak width decreases, indicating that the crystallinity of nickel is improved after optimization. This may be due to grain growth and a reduction in lattice defects caused by the optimization process, thereby affecting the crystallinity and dispersion of nickel. Simultaneously, the appearance of diffraction peaks for carbon and PTFE indicates that these components successfully combined with the nickel-based catalyst during the optimization process. In summary, the optimization process significantly affected the crystal structure and phase composition of the carbon-coated nickel-based catalyst, leading to a decrease in nickel dispersion and an increase in crystallinity, while also promoting the loading of carbon and PTFE in the catalyst. Furthermore, the XRD patterns of the carbon-coated nickel-based superhydrophobic catalysts prepared in Examples 2–8 also show peaks for C, PTFE, and elemental Ni.

[0091] Figure 2 Water droplet contact angle test diagram of the carbon-coated nickel-based catalyst prepared for Comparative Example 1. Figure 3 This is a water droplet contact angle test diagram of the carbon-coated nickel-based superhydrophobic catalyst prepared in Example 1. Figure 2 and Figure 3 As can be seen, the introduction of PTFE can improve the hydrophobicity of carbon-coated nickel-based catalysts and reduce the impact of water on the catalyst during the reaction.

[0092] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a carbon-coated nickel-based superhydrophobic catalyst, characterized in that, Includes the following steps: S1. Dissolve nickel salt and citric acid in water to obtain a mixed solution; heat and stir the obtained mixed solution to obtain a precursor; the molar ratio of citric acid to nickel salt is 4:2; the heating and stirring temperature is 40℃ and the time is 2h; S2. The precursor is calcined under an inert atmosphere to obtain a carbon-coated nickel-based catalyst; the calcination temperature is 550°C and the calcination time is 2 hours. S3. The carbon-coated nickel-based catalyst and polytetrafluoroethylene are ball-milled and mixed to obtain the carbon-coated nickel-based superhydrophobic catalyst; the mass ratio of polytetrafluoroethylene to carbon-coated nickel-based catalyst is 4:2; the mass ratio of ball to material in the ball milling mixture is 10:1; the ball milling time is 8 hours; and the ball milling speed is 200 rpm.

2. The method for preparing the carbon-coated nickel-based superhydrophobic catalyst according to claim 1, characterized in that, In step S3, the polytetrafluoroethylene is selected from polytetrafluoroethylene micro powder; the particle size of the polytetrafluoroethylene micro powder is 1-15 μm.

3. A carbon-coated nickel-based superhydrophobic catalyst prepared by the preparation method according to any one of claims 1-2.

4. The application of the carbon-coated nickel-based superhydrophobic catalyst of claim 3 in the catalytic aqueous-phase synthesis of higher alcohols from small molecule alcohols.

5. The application according to claim 4, characterized in that, The small molecule alcohol is ethanol; the higher alcohol is an alcohol with 4 to 16 carbon atoms.

Images