Highly efficient hydrophobic methanol catalyst and method for making same

Abstract

This application belongs to the technical field of catalyst preparation, and particularly relates to a highly efficient hydrophobic methanol catalyst and its preparation method. The method includes: preparing raw materials such as copper salt, zinc salt, and aluminum salt, setting a preset total molar ratio of copper, zinc, and aluminum, and separating the zinc salt and aluminum salt according to a deviation of ≤10% from the total molar ratio; preparing first and second salt solutions, an auxiliary agent solution, and an alkaline solution; first establishing a first liquid level in the reactor, and then adding the first salt solution and alkaline solution in parallel at a preset temperature and pH to construct the core phase, followed by the addition of the second salt solution, the auxiliary agent solution, and the alkaline solution to form a coating layer, and aging at a higher temperature; washing, drying, and calcining to prepare a catalyst precursor; preparing a hydrophobic component solution and an oxide precursor solution, mixing and hydrolyzing them to obtain a composite hydrophobic solution; and impregnating and drying the precursor with the solution to obtain the product. This application solves the problem of water-induced deactivation of traditional catalysts and improves CO2 efficiency. 2 Conversion rate and methanol selectivity, reduced deactivation rate, and process adaptability to industrial production.

Description

Highly efficient hydrophobic methanol catalyst and its preparation method Technical Field

[0001] This invention relates to the technical field of catalyst preparation, and in particular to a highly efficient hydrophobic methanol catalyst and its preparation method. Background Technology

[0002] Driven by both energy transition and chemical industry upgrading, carbon dioxide hydrogenation to methanol technology, with its dual advantages of carbon emission reduction and energy conversion, has become a key research and development area in global scientific and industrial fields. Currently, while carbon dioxide hydrogenation catalysts used in industrial applications and research can achieve efficient methanol synthesis, the reaction inevitably generates a large amount of water. As the reaction continues, this water accumulates on the catalyst surface, causing problems such as sintering and agglomeration of active components, collapse of crystal structure, and a sharp increase in crystal particle size. This leads to a sharp decrease in the catalyst's specific surface area, resulting in activity degradation, reduced selectivity, and increased byproducts, severely hindering the industrialization process and economic benefits of this technology.

[0003] Despite extensive research efforts by scientists to improve catalyst performance, such as through metal doping and support optimization to enhance catalyst activity and selectivity, a truly effective solution remains lacking for addressing the water-induced deactivation problem. While some technologies can slow down the deactivation rate to some extent, they fail to fundamentally prevent water damage to the catalyst. Therefore, effectively improving the hydrophobicity of catalysts has become a pressing technical challenge for the industry. Summary of the Invention

[0004] This application provides a highly efficient hydrophobic methanol catalyst and its preparation method, aiming to solve, to some extent, the problem of how to effectively improve the hydrophobicity of the catalyst.

[0005] In a first aspect, this application provides a method for preparing a highly efficient hydrophobic methanol catalyst, characterized by comprising the following steps:

[0006] S100: A copper salt, a first portion of zinc salt satisfying a first molar ratio, and a first portion of aluminum salt are mixed and dissolved in water to form a first salt solution; a second portion of zinc salt and a second portion of aluminum salt satisfying a second molar ratio are mixed and dissolved in water to form a second salt solution, wherein the relative deviations of the first molar ratio, the second molar ratio, and the third molar ratio of zinc salt and aluminum salt are all less than or equal to 10%;

[0007] S200: The alkaline solution formed by the first salt solution and the precipitant is added in parallel flow, and a precipitation reaction is carried out under the first preset temperature and first pH conditions to obtain a precipitate; the auxiliary solution formed by the second salt solution and the auxiliary salt and the alkaline solution are added in parallel flow to the precipitate, and the first preset temperature and first pH are maintained until all raw materials are added, and then the precipitate is aged under the second preset temperature and second pH conditions to obtain a precipitate;

[0008] S300: The precipitate is washed to a preset conductivity, filtered, dried and calcined to obtain a methanol synthesis catalyst precursor.

[0009] S400: The hydrophobic component solution and the oxide precursor solution are stirred and mixed evenly, and then hydrolyzed to obtain a composite hydrophobic solution. The hydrophobic component solution includes long-chain alkyl carboxylic acids or long-chain alkylamines, and the oxide precursor solution includes tetrabutyl titanate or tetrabutyl silicate. The composite hydrophobic solution is a titanium oxide-organic complex solution or a silicon oxide-organic complex solution.

[0010] S500: The methanol synthesis catalyst precursor is stirred and impregnated with the composite hydrophobic aqueous solution, and then dried to obtain a hydrophobic methanol catalyst.

[0011] The long-chain alkyl carboxylic acid is a C6-C18 monocarboxylic acid, and the long-chain alkylamine is a C6-C18 monoprimary amine.

[0012] Furthermore, in the hydrophobic methanol catalyst, the total molar ratio of copper, zinc, and aluminum metal elements is (5~7):(2~3.5):(0.5~1.5);

[0013] Based on the total molar amount of zinc salt, the first portion of zinc salt has a molar percentage of 60-80%, and the second portion of zinc salt has a molar percentage of 20-40%.

[0014] Based on the total molar amount of aluminum salt, the first part of aluminum salt has a molar percentage of 60-80%, and the second part of aluminum salt has a molar percentage of 20-40%.

[0015] Based on the total molar amount of copper, zinc, and aluminum salts, the molar percentage of metal salts in the first salt solution is 70-90%, and the molar percentage of metal salts in the second salt solution is 10-30%.

[0016] Based on the total molar amount of copper salt, zinc salt, aluminum salt, and auxiliary salt, the molar percentage of the auxiliary salt is 0.5% to 5%.

[0017] The concentration of the precipitant in the alkaline solution is 0.8~2 mol / L.

[0018] Further, in step S200, before adding the first salt solution and the alkaline solution in parallel flow, an initial liquid level is established in the reaction vessel; the initial liquid level accounts for 5-15% of the volume of the reaction vessel; the first preset temperature is 50-70℃, the first pH is 6-9, and the precipitation reaction time is 2-6h; the second preset temperature is 50-80℃, the second pH is 6-9, and the aging time is 1-10h.

[0019] Further, in step S300, the preset conductivity is ≤10μS cm-1; drying temperature is 80~130℃, drying time is 6~24h; calcination temperature is 250~450℃, calcination time is 2~6h.

[0020] Further, in step S400, the mixing temperature of the hydrophobic component solution and the oxide precursor solution is 20~30℃, and the mixing time is 5~30min; the hydrolysis temperature is 20~60℃, and the hydrolysis time is 0.5~2h; the amount of water added for hydrolysis is 200~1000μL; the concentration of the hydrophobic component solution is 15~30g / L; and the concentration of the oxide precursor solution is 10~25g / L.

[0021] Further, in step S400, long-chain alkyl carboxylic acids or long-chain alkylamines are dissolved in an alcohol solvent to form a hydrophobic component solution, and tetrabutyl titanate or tetrabutyl silicate is dissolved in an alcohol solvent to form an oxide precursor solution.

[0022] The long-chain alkyl carboxylic acid is selected from at least one of hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, and stearic acid;

[0023] The long-chain alkylamine is selected from at least one of n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, and stearylamine;

[0024] The alcohol solvent is selected from at least one of methanol, ethanol, propanol, n-butanol, and isobutanol.

[0025] Furthermore, in step S500, the stirring and impregnation time is 20~40 min; the drying temperature is 60~70℃.

[0026] Furthermore, the copper salt is selected from at least one of copper chloride, copper acetate, copper nitrate, and copper sulfate;

[0027] The zinc salt is selected from at least one of zinc chloride, zinc acetate, zinc nitrate, and zinc sulfate;

[0028] The aluminum salt is selected from at least one of aluminum chloride, aluminum acetate, aluminum nitrate, aluminum sulfate, aluminum isopropoxide, boehmite, and boehmite.

[0029] The auxiliary salt is selected from at least one of magnesium salts, zirconium salts, cerium salts, manganese salts, strontium salts, lanthanum salts, niobium salts, barium salts, and yttrium salts, wherein: the magnesium salt is magnesium chloride, magnesium acetate, magnesium nitrate, or magnesium sulfate; the zirconium salt is zirconium chloride, zirconium acetate, zirconium nitrate, zirconium sulfate, or zirconium isopropoxide; the cerium salt is cerium chloride, cerium acetate, cerium nitrate, or cerium sulfate; the manganese salt is manganese chloride, manganese acetate, manganese nitrate, or manganese sulfate; the strontium salt is strontium chloride, strontium acetate, strontium nitrate, or strontium sulfate; the lanthanum salt is lanthanum chloride, lanthanum acetate, lanthanum nitrate, or lanthanum sulfate; the niobium salt is niobium chloride or niobium nitrate; the barium salt is barium nitrate, barium sulfate, barium chloride, or barium acetate; and the yttrium salt is yttrium nitrate, yttrium sulfate, yttrium chloride, or yttrium acetate.

[0030] The precipitant is selected from at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, ammonia, potassium carbonate, potassium bicarbonate, and potassium hydroxide.

[0031] Furthermore, in the hydrophobic methanol catalyst, based on the total molar amount of CuO, ZnO, Al2O3 and auxiliary oxides in the catalyst: the molar percentage of CuO is 50-70%, the molar percentage of ZnO is 20-35%, the molar percentage of Al2O3 is 5-15%, and the molar percentage of auxiliary oxides is 0.5-3%.

[0032] Secondly, this application provides a highly efficient hydrophobic methanol catalyst, which is prepared by the above-mentioned method for preparing highly efficient hydrophobic methanol catalyst, wherein the water contact angle of the highly efficient hydrophobic methanol catalyst is ≥150 degrees.

[0033] The advantages of this application compared to the prior art are:

[0034] The first step of this application ensures the uniformity of the overall catalyst composition after stepwise precipitation by pre-setting the total molar ratio of copper, zinc, and aluminum, and simultaneously separating the zinc and aluminum salts with a relatively consistent molar ratio (relative deviation ≤10%). This design accommodates minute errors in industrial production and ensures the synergy between the core phase and the coating layer, avoiding defects in the hydrophobic layer coating caused by local structural imbalances. This lays a regular microstructural foundation for the uniform adhesion of the subsequent hydrophobic solution. Simultaneously, the independent preparation design of each solution ensures that all copper salts are concentrated to form the first salt solution of the highly active copper core phase. This also prevents different salts from reacting prematurely to generate impurities, ensuring a clean and contaminant-free catalyst surface and providing effective preconditions for the tight bonding between the hydrophobic layer and the catalyst surface.

[0035] The second step involves a stepwise precipitation process to overcome the limitations of traditional one-time co-precipitation. First, a Cu-Zn-Al core phase is formed, and then a uniform ZnO-Al2O3-additive coating layer is constructed to create a smooth and continuous catalyst surface morphology. This solves the problem of incomplete hydrophobic layer coverage caused by rough surfaces. Subsequent aging further optimizes the surface regularity and improves the uniformity of hydrophobic layer adhesion, thereby ensuring the structural stability of the precursor.

[0036] The third step is to remove Na through washing. + Cl - Impurity ions are removed to prevent the active sites from being occupied or destroyed, thus ensuring catalytic activity and maintaining a clean chemical environment on the catalyst surface. This prevents impurities from affecting the interaction between the hydrophobic components and the surface. After drying and calcination, a stable oxide structure is formed, providing a strong adhesion substrate for the composite hydrophobic solution.

[0037] The fourth step involves an innovative and precise process of "stepwise dissolution-mixing-synergistic hydrolysis": long-chain alkyl carboxylic acids or long-chain alkylamines are dissolved in an alcohol solvent to form a hydrophobic component solution; simultaneously, tetrabutyl titanate or tetrabutyl silicate is dissolved in an alcohol solvent to form an oxide precursor solution. This results in a uniformly dispersed hydrophobic component solution and oxide precursor solution. This stepwise dissolution utilizes the compatibility of the alcohol solvent to ensure the full dissolution of the two types of raw materials and avoid excessively high local concentrations or phase separation. Furthermore, subsequent stirring and mixing achieves molecular-level contact between the two components. Finally, a trace amount of water is added to obtain a composite hydrophobic solution. Because the hydrophobic component solution and the oxide precursor solution undergo synergistic hydrolysis by adding a trace amount of water, the long-chain alkyl hydrophobic groups and the titanium oxide or silicon oxide network are assembled simultaneously. This avoids the runaway reaction that is prone to occur when hydrolyzing a single raw material (such as the oxide precursor hydrolyzing alone to form large particles, or the hydrophobic component hydrolyzing alone failing to form a stable structure). It also allows for precise control of the viscosity and dispersibility of the composite hydrophobic solution, providing a suitable system state for subsequent uniform coating. At the same time, the molecular-level synergistic effect allows the hydrophobic groups and the oxide network to be tightly bound together, laying a solid structural foundation for the strong binding force and long-lasting effect of the hydrophobic layer.

[0038] The fifth step involves stirring and impregnating the composite hydrophobic solution to uniformly coat the surface of the methanol synthesis catalyst precursor. Low-temperature drying prevents the decomposition of hydrophobic groups, ultimately forming a complete and dense superhydrophobic coating on the catalyst surface, resulting in a water contact angle ≥150 degrees. This achieves efficient water repulsion, fundamentally blocking the accumulation and penetration of water on the catalyst surface, and completely solving the problems of water-induced sintering of active components and crystal phase collapse.

[0039] In summary, the entire process revolves around "improving hydrophobicity" as its core principle, with each step building upon the previous one: the initial steps optimize the component uniformity and surface regularity of the catalyst, creating suitable conditions for hydrophobic modification; the subsequent steps directly enhance hydrophobicity and the stability of the hydrophobic layer through innovative hydrophobic system construction and coating processes, ultimately achieving a comprehensive effect of "superhydrophobic resistance to deactivation, high catalytic activity, and stable and controllable process," thus precisely addressing the core technical challenge of "how to improve the hydrophobicity of the catalyst." Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art 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.

[0041] Figure 1 is a schematic flowchart of the preparation method of the high-efficiency hydrophobic methanol catalyst of this application;

[0042] Figure 2 is a schematic diagram of the water contact angle of the catalyst in Example 1 of this application;

[0043] Figure 3 is a schematic diagram of the water contact angle of the catalyst in Comparative Example 1 of this application. Detailed Implementation

[0044] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0045] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0046] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, a~b (i.e., a and b), a~c, b~c, or a~b~c, where a, b, and c can be single or multiple.

[0047] The terms "first" and "second" are used only to describe the purpose and to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the provisions of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0048] The terminology used in the embodiments of this application is for the purpose of describing particular implementations only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the implementations of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0049] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0050] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0051] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0052] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application are available on the market or can be prepared by existing methods.

[0053] Currently, there is still a lack of truly effective solutions to the problem of water-induced deactivation of catalysts. While some technologies can slow down the deactivation rate to some extent, they cannot fundamentally prevent water from damaging the catalyst.

[0054] Referring to Figure 1, to address the aforementioned problems to some extent, the first aspect of this application provides a method for preparing a highly efficient hydrophobic methanol catalyst, characterized by comprising the following steps:

[0055] S100: A copper salt, a first portion of zinc salt satisfying a first molar ratio, and a first portion of aluminum salt are mixed and dissolved in water to form a first salt solution; a second portion of zinc salt and a second portion of aluminum salt satisfying a second molar ratio are mixed and dissolved in water to form a second salt solution, wherein the relative deviations of the first molar ratio, the second molar ratio, and the third molar ratio of zinc salt and aluminum salt are all less than or equal to 10%;

[0056] S200: The alkaline solution formed by the first salt solution and the precipitant is added in parallel flow, and a precipitate is obtained under the conditions of the first preset temperature and the first pH. The auxiliary solution formed by the second salt solution and the auxiliary salt is added in parallel flow to the precipitate, and the first preset temperature and the first pH are maintained until all raw materials are added. Then, the precipitate is aged under the conditions of the second preset temperature and the second pH to obtain the precipitate.

[0057] S300: The precipitate is washed to a preset conductivity, filtered, dried and calcined to obtain a methanol synthesis catalyst precursor.

[0058] S400: The hydrophobic component solution and the oxide precursor solution are stirred and mixed evenly, and then hydrolyzed to obtain a composite hydrophobic solution. The hydrophobic component solution includes long-chain alkyl carboxylic acids or long-chain alkylamines, and the oxide precursor solution includes tetrabutyl titanate or tetrabutyl silicate. The composite hydrophobic solution is a titanium oxide-organic complex solution or a silicon oxide-organic complex solution.

[0059] S600: The methanol synthesis catalyst precursor is stirred and impregnated with the composite hydrophobic aqueous solution, and then dried to obtain a hydrophobic methanol catalyst;

[0060] The long-chain alkyl carboxylic acid is a C6-C18 monocarboxylic acid, and the long-chain alkylamine is a C6-C18 monoprimary amine.

[0061] In this embodiment, for step S100, the proportioning and separation of the core raw materials are first completed to prepare a suitable raw material system for stepwise precipitation. Specifically, copper salt, a first portion of zinc salt, and a first portion of aluminum salt are mixed to prepare a first salt solution, and a second portion of zinc salt and a second portion of aluminum salt are mixed to prepare a second salt solution. Simultaneously, the molar ratio of each portion of zinc salt and aluminum salt is controlled. Specifically, the molar ratio of the first portion of zinc salt to the first portion of aluminum salt is the first molar ratio, the molar ratio of the second portion of zinc salt to the second portion of aluminum salt is the second molar ratio, and the molar ratio of the total molar amount of zinc salt to the total molar amount of aluminum salt is the third molar ratio. The relative deviations of the first molar ratio, the second molar ratio, and the third molar ratio are all less than or equal to 10%. By selecting a raw material system that is compatible with subsequent hydrophobic modification requirements, the use of impurity raw materials that are prone to react with hydrophobic components is avoided, ensuring process compatibility. The preset total molar ratio balances the proportions of active sites (Cu-based), electronically controlled components (ZnO), and structurally supporting components (Al2O3), providing a formula basis for "high activity + high stability". Zinc salt and aluminum salt are simultaneously separated at a basically consistent molar ratio (relative deviation ≤10%), avoiding local Zn / Al ratio imbalance from the source, ensuring the overall composition of the catalyst is uniform, and avoiding incomplete hydrophobic layer coating due to structural defects. This provides raw material guarantee for the subsequent regular formation of the "core-shell" structure (high Cu core phase + ZnO-Al2O3 coating layer), indirectly improving the uniformity of hydrophobic layer coverage.

[0062] For step S200, a stepwise precipitation strategy of "core phase first, then coating layer" is adopted to directionally construct the catalyst's "core-shell" microstructure. The precipitation temperature, pH, and feeding method are controlled to ensure stable precipitation reaction. The aging process refines the precipitate's crystal form and optimizes its surface morphology and structural stability. Specifically, stepwise precipitation overcomes the limitations of traditional one-time co-precipitation: first, the first salt solution and alkaline solution are added to the reaction system in parallel flow, forming a high-Cu-content core phase under preset temperature and pH conditions. Then, the second salt solution, auxiliary solution, and alkaline solution are added in parallel flow, forming a ZnO-Al2O3-auxiliary coating layer under the same temperature and pH conditions. After all raw materials are added, aging refines the crystal form. This distributed precipitation process effectively inhibits the aggregation of Cu active components, improves the dispersion of active sites, and forms a smooth, continuous catalyst surface. This solves the problem of incomplete hydrophobic layer coverage caused by rough surfaces, ensuring the precipitation reaction takes place in a stable alkaline and concentration environment. The precipitate particles are uniform, reducing surface porosity and defects, allowing the hydrophobic layer to adhere tightly to the catalyst surface and improving adhesion. Precise control of temperature and pH ensures that the precipitate has a regular crystal structure, avoids the formation of amorphous precipitate, and improves the structural stability of the catalyst itself. The subsequent aging process promotes the interfacial fusion between precipitate particles, further optimizes the surface regularity, reduces the blind area of ​​hydrophobic layer coating, and indirectly improves the long-term effectiveness of hydrophobicity.

[0063] For step S300, wash to remove the impurity ions (such as Na + , Cl - ) generated in the precipitation reaction, and dry to remove the moisture in the precipitate to avoid particle cracking during subsequent calcination. Calcination realizes the transformation of metal salts into stable oxide phases, forming the final structure of the catalyst precursor. Specifically, wash to a preset conductivity to thoroughly remove impurity ions, avoiding impurities occupying active sites or damaging the structure of active sites, and at the same time avoiding the interaction between impurities and hydrophobic components, ensuring the binding force between the hydrophobic layer and the catalyst surface, and avoiding the shedding of the hydrophobic layer due to the presence of impurities; during the drying process, slowly remove the moisture to avoid catalyst particle cracking caused by rapid drying, keep the surface regular, ensure that the hydrophobic layer can cover evenly without local bare areas; after calcination, a stable CuO-ZnO-Al2O3-promoter composite oxide structure is formed, which not only ensures the effective exposure of active sites (CuO, reduced to Cu / Cu + ), but also forms a dense and stable structural substrate, making the attachment of the hydrophobic layer more firm and not easily peeled off under high-temperature and high-pressure reaction conditions, improving the water resistance stability.

[0064] For step S400, a stable titanium oxide-organic complex or silicon oxide-organic complex solution (composite hydrophobic solution) is prepared through the "stepwise dissolution - mixing - cooperative hydrolysis" process. Specifically, the precise "stepwise dissolution - mixing - cooperative hydrolysis" process is adopted: dissolve long-chain alkyl carboxylic acid or long-chain alkylamine in an alcohol solvent to form a hydrophobic component solution; at the same time, dissolve tetrabutyl titanate or tetraethyl orthosilicate in an alcohol solvent to form an oxide precursor solution, forming a uniformly dispersed hydrophobic component solution and oxide precursor solution. Such stepwise dissolution not only utilizes the compatibility of the alcohol solvent to ensure the full dissolution of the two types of raw materials, avoiding local high concentration or phase separation, but also realizes the molecular-level contact of the two components through subsequent stirring and mixing. Then add a small amount of water to initiate the cooperative hydrolysis reaction. The molecular-level cooperative mechanism of this process is: tetrabutyl titanate hydrolyzes to generate a primary titanium oxide intermediate containing titanium hydroxyl (-Ti-OH), and tetraethyl orthosilicate hydrolyzes to generate a primary silicon oxide intermediate containing silicon hydroxyl (-Si-OH); at the same time, the carboxyl group (-COOH) of long-chain alkyl carboxylic acid or the amino group (-NH2) of long-chain alkylamine will coordinate with the titanium hydroxyl in the primary titanium oxide intermediate / silicon hydroxyl in the primary silicon oxide intermediate to form stable Ti-O-C / Si-O-C or Ti-N-C / Si-N-C chemical bonds, anchoring the organic ligand in the oxide network, and finally forming a composite hydrophobic solution with a tightly bound "oxide network - organic ligand". During the preparation process, the length of the long-chain alkyl carbon chain is limited (C6~C18), which not only avoids insufficient hydrophobicity caused by too short carbon chains (<C6), but also avoids the problem of active site coverage caused by too long carbon chains (>C18), balancing hydrophobicity and catalytic activity.

[0065] In step S500, the composite hydrophobic solution is uniformly coated on the surface of the catalyst precursor by stirring and impregnation. Low-temperature drying removes the solvent and residual moisture, fixing the hydrophobic layer structure. Specifically, the stirring and impregnation process ensures that the composite hydrophobic solution uniformly covers the surface of the catalyst precursor, without any areas of excessive coating or exposed areas, forming a complete hydrophobic coating. This prevents moisture from penetrating and eroding the active components from exposed areas. Low-temperature drying (avoiding high-temperature damage to hydrophobic groups) thoroughly removes the alcohol solvent and residual moisture while ensuring the structural integrity of the long-chain alkyl hydrophobic groups, ensuring stable hydrophobic performance. The resulting superhydrophobic coating (water contact angle ≥150 degrees) can directly repel the moisture generated in the reaction, fundamentally blocking the accumulation and penetration of moisture on the catalyst surface, completely solving the core technical problem of "moisture causing sintering of active components, crystal phase collapse, and activity degradation".

[0066] In summary, the entire process revolves around "improving hydrophobicity" as its core principle, with each step building upon the previous one: the initial steps optimize the component uniformity and surface regularity of the catalyst, creating suitable conditions for hydrophobic modification; the subsequent steps directly enhance hydrophobicity and the stability of the hydrophobic layer through innovative hydrophobic system construction and coating processes, ultimately achieving a comprehensive effect of "superhydrophobic resistance to deactivation, high catalytic activity, and stable and controllable process," thus precisely addressing the core technical challenge of "how to improve the hydrophobicity of the catalyst."

[0067] Furthermore, in the hydrophobic methanol catalyst, the total molar ratio of copper, zinc, and aluminum metal elements is (5~7):(2~3.5):(0.5~1.5);

[0068] Based on the total molar amount of aluminum salt, the first part of aluminum salt has a molar percentage of 60-80%, and the second part of aluminum salt has a molar percentage of 20-40%.

[0069] Based on the total molar amount of copper, zinc, and aluminum salts, the molar percentage of metal salts in the first salt solution is 70-90%, and the molar percentage of metal salts in the second salt solution is 10-30%.

[0070] Based on the total molar amount of copper salt, zinc salt, aluminum salt, and auxiliary salt, the molar percentage of the auxiliary salt is 0.5% to 5%.

[0071] The concentration of the precipitant in the alkaline solution is 0.8~2 mol / L.

[0072] In this embodiment, firstly, the core purpose of limiting the content of the above-mentioned substances is to precisely control the raw material ratio and solution parameters to achieve a synergistic effect of "core-shell" structure construction, hydrophobic layer bonding, catalytic activity and water resistance stability, ultimately enhancing the core effect of "superhydrophobic and anti-deactivation". Specifically, the total molar ratio of copper, zinc and aluminum in the final catalyst is (5~7):(2~3.5):(0.5~1.5), and the molar content ratio of Cu is set to (5~7). As the core active component of CO2 hydrogenation to methanol, this proportion ensures that sufficient Cu / Cu ratio is formed after reduction. + Active sites provide the foundation for high catalytic activity. Setting the molar ratio of Zn to (2~3.5) allows ZnO and Cu to synergistically regulate the electronic structure and dispersion of Cu, while simultaneously enhancing CO2 adsorption and activation capabilities and preventing Cu particle agglomeration. Setting the molar ratio of Al to (0.5~1.5) allows Al2O3, as a high specific surface area support, to provide stable structural support for the active components, inhibiting particle sintering and optimizing the catalyst surface morphology, thus facilitating the adhesion of the hydrophobic layer. Specifically, this ratio allows the active sites (Cu), synergistic components (ZnO), and supporting support (Al2O3) to form optimal synergy, ensuring both CO2 conversion and methanol selectivity while avoiding excessive Al content leading to active site coverage or insufficient Al content leading to structural collapse.

[0073] Secondly, the molar content of the split portions is limited to avoid an excessively thick core phase or insufficient external coating in the methanol synthesis catalyst precursor. Specifically, in the first portion, the first zinc salt comprises 60-80% of the total zinc salt molar content, and the first aluminum salt comprises 60-80% of the total aluminum salt molar content. This configuration provides sufficient Zn and Al synergistic components to the "copper core phase" in the first salt solution, ensuring a dense core phase structure and uniformly dispersed active sites. In the second portion, the second zinc salt comprises 20-40% of the total zinc salt molar content, and the second aluminum salt comprises 20-40% of the total aluminum salt molar content. This is to form a ZnO-Al2O3-auxiliary coating layer of appropriate thickness, avoiding an excessively thick coating layer that obscures active sites, or an excessively thin layer that fails to provide structural support and hydrophobic adhesion. This configuration is designed to precisely match the splitting ratio with the "core-shell" structure, ensuring sufficient active sites in the core phase while allowing the coating layer to uniformly encapsulate the core phase, reducing surface roughness and defects, ensuring the hydrophobic layer covers the entire area without blind spots, and ensuring the same Zn and Al molar ratio for splitting, thus ensuring the consistency of composition between the core phase and the coating layer, avoiding local electronic structure imbalance, improving the overall stability of the catalyst, and reducing structural damage caused by water erosion.

[0074] Third, the total molar content of metal salts in the first salt solution and the total molar content of metal salts in the second salt solution are limited. The first salt solution (70~90%) contains all copper salts and most of Zn and Al salts. This proportion can ensure that the volume of the "copper core phase" is sufficient to become the main active region of the catalytic reaction. The second salt solution (10~30%) controls the volume of the coating layer to avoid the coating layer being too thick and causing the active sites to be blocked, or too thin and unable to effectively protect the Cu-containing core phase.

[0075] Fourth, the content of auxiliary salts and precipitants is limited. Auxiliary salts are used to dope into the ZnO-Al2O3 lattice to inhibit crystal growth and sintering, and improve the structural stability of the catalyst. The proportion of auxiliary salts should be ≤5% to avoid excessive enrichment of auxiliary salts covering active sites, and ≥0.5% to ensure that the auxiliary salts can play a stabilizing role, achieving "no decrease in activity and improved stability". The concentration of precipitants is limited to 0.8~2 mol / L: too low a concentration will lead to incomplete precipitation and a slow reaction rate, while too high a concentration will cause local overconcentration and the formation of large particle precipitates.

[0076] Further, in step S300, before adding the first salt solution and the alkaline solution in parallel flow, an initial liquid level is established in the reaction vessel; the initial liquid level accounts for 5-15% of the volume of the reaction vessel; the first preset temperature is 50-70℃, the first pH is 6-9, and the precipitation reaction time is 2-6h; the second preset temperature is 50-80℃, the second pH is 6-9, and the aging time is 1-10h.

[0077] In this embodiment, the coordinated setting of various parameters in step S200 constructs a stable and controllable process environment for the precipitation reaction and aging process, ultimately serving the core objective of "improving the surface regularity and structural stability of the catalyst, laying the foundation for uniform coating and tight bonding of the hydrophobic layer": Before adding the first salt solution and alkaline solution in parallel flow, an initial liquid level is established in the reaction vessel; the initial liquid level occupies 5-15% of the reaction vessel volume, which can avoid local over-concentration and agglomeration caused by excessively high initial reaction system concentration, and provide a buffer space for concentration and alkalinity balance during parallel feeding; the combination of the first preset temperature of 50-70℃ and the first pH of 6-9... The combination of these parameters allows for precise control of the precipitation reaction rate, ensuring the formation of a regular Cu-Zn-Al core phase and preventing amorphous precipitates or large particle agglomeration. It also creates conditions for the uniform dispersion of active components. A precipitation reaction time of 2–6 hours ensures sufficient core phase formation without excessive growth, guaranteeing a dense distribution of active sites. The combination of a second preset temperature of 50–80℃ and a second pH of 6–9 promotes the perfection of the precipitate's crystal form while preventing structural collapse caused by sudden temperature or pH changes. An aging time of 1–10 hours further promotes interfacial fusion between precipitate particles, reducing surface porosity and defects, resulting in a smoother and denser catalyst surface. The synergistic effect of all these parameters ultimately produces a precipitate with uniform particle size, a regular surface, and a stable structure. This not only clears obstacles for the subsequent uniform coverage of the hydrophobic layer (preventing detachment or incomplete coverage at defect sites) but also enhances the catalyst's structural strength against water erosion, indirectly strengthening the overall effect of superhydrophobicity and anti-deactivation.

[0078] Further, in step S300, the preset conductivity is ≤10μS cm -1 The drying temperature is 80~130℃, and the drying time is 6~24h; the calcination temperature is 250~450℃, and the calcination time is 2~6h.

[0079] In this embodiment, the coordinated setting of various parameters in step S300 is primarily aimed at constructing a "clean, orderly, and stable" structural substrate for the catalyst precursor by precisely controlling the impurity removal, moisture removal, and crystal phase transformation processes. This directly serves the goal of superhydrophobic anti-deactivation: a preset conductivity ≤10μS. cm - The washing standard¹ can thoroughly remove residual Na from the precipitate. + Cl -Impurity ions are removed to prevent impurities from occupying active sites or interfering with the interaction between subsequent hydrophobic components and the catalyst surface, ensuring that the adhesion of the hydrophobic layer remains unaffected. A drying temperature of 80–130℃ and a drying time of 6–24 h slowly removes free water and water of crystallization from the precipitate, avoiding particle cracking and surface roughness caused by rapid drying, thus maintaining the regular morphology of the catalyst precursor. A calcination temperature of 250–450℃ and a calcination time of 2–6 h ensure that the metal salt is completely converted into a stable CuO-ZnO-Al2O3-auxiliary composite oxide phase, guaranteeing effective exposure of the active CuO sites and forming a dense and robust structural framework, reducing surface porosity and defects. All parameters work synergistically to obtain a catalyst precursor with a clean surface, regular morphology, and stable structure. This not only clears obstacles for the uniform coating of the subsequent composite hydrophobic solution, preventing incomplete coverage and easy detachment of the hydrophobic layer at impurities or defects, but also enhances the catalyst's structural strength against water erosion, laying a solid foundation for the long-term effectiveness and catalytic activity stability of the superhydrophobic coating.

[0080] Further, in step S400, the mixing temperature of the hydrophobic component solution and the oxide precursor solution is 20~30℃, and the mixing time is 5~30min; the hydrolysis temperature is 20~60℃, and the hydrolysis time is 0.5~2h; the amount of water added for hydrolysis is 200~1000μL; the concentration of the hydrophobic component solution is 15~30g / L; and the concentration of the oxide precursor solution is 10~25g / L.

[0081] In this embodiment, the synergistic setting of various parameters in step S400 is primarily achieved by precisely controlling the "mixing-hydrolysis" process to prepare a uniformly dispersed and structurally stable composite hydrophobic solution. This lays a crucial foundation for the subsequent uniform coating and tight bonding of the hydrophobic layer. The combination of a stirring temperature of 20-30°C and a time of 5-30 minutes ensures that the hydrophobic component (long-chain alkyl carboxylic acid / amine) achieves molecular-level uniform mixing with the oxide precursor (tetrabutyl titanate / tetrabutyl silicate) without volatilizing or prematurely reacting, thus avoiding phase separation caused by excessively high local concentrations. The combination of a hydrolysis temperature of 20-60°C and a time of 0.5-2 hours precisely controls the hydrolysis rate, ensuring that the long-chain alkyl carboxylic acid is fully dissolved. The simultaneous assembly of hydrophobic groups with the titanium and silicon oxide networks avoids uncontrolled hydrolysis of a single component (such as rapid aggregation of oxide precursors and self-aggregation of hydrophobic components). Precise control of the addition of trace amounts of water (200-1000 μL) is crucial for regulating the degree of hydrolysis, satisfying the requirements of the hydrolysis reaction while preventing excessive water from causing over-hydrolysis and the formation of large particles, ensuring moderate viscosity and good dispersibility of the composite solution. The appropriate ratio of hydrophobic component solution concentration (15-30 g / L) to oxide precursor solution concentration (10-25 g / L) ensures a balanced density of hydrophobic groups and oxide networks in the composite hydrophobic solution, avoiding both insufficient hydrophobic groups leading to weak hydrophobicity and excessively dense oxide networks clogging catalyst pores. All parameters work synergistically to ultimately prepare a composite hydrophobic solution with "densely distributed hydrophobic groups and uniformly supported oxide networks," providing a suitable system state for uniform impregnation and coating in S400, and strengthening the bonding force between the hydrophobic layer and the catalyst surface through molecular-level synergistic assembly, laying a solid foundation for the long-term effectiveness of superhydrophobic properties.

[0082] Further, in step S400, a long-chain alkyl carboxylic acid or a long-chain alkylamine is dissolved in an alcohol solvent to form a hydrophobic component solution, and tetrabutyl titanate or tetrabutyl silicate is dissolved in an alcohol solvent to form an oxide precursor solution; the long-chain alkyl carboxylic acid is selected from at least one of hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanic acid, and stearic acid;

[0083] The long-chain alkylamine is selected from at least one of n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, and stearylamine;

[0084] The alcohol solvent is selected from at least one of methanol, ethanol, propanol, n-butanol, and isobutanol.

[0085] In this embodiment, it is limited to straight-chain monocarboxylic acids with 6 to 18 carbon atoms (such as n-hexanoic acid and stearic acid) and primary amines (such as n-heptylamine and dodecylamine). On the one hand, the straight-chain alkyl structure can ensure the regular arrangement of hydrophobic groups on the catalyst surface, forming a dense hydrophobic interface. The carbon chain length of 6 to 18 not only avoids insufficient hydrophobicity caused by too short carbon chains (<C6) but also prevents the coverage of active sites by too long carbon chains (>C18). On the other hand, the single functional group (-COOH / -NH2) of monocarboxylic acid or amine can precisely interact with the titanium / silicon oxide network (such as coordination and hydrogen bonding), avoiding excessive crosslinking or agglomeration of hydrophobic groups caused by multi-functional groups, and ensuring the binding force between the hydrophobic layer and the catalyst surface. The diversity of specific types (such as full coverage from C6 to C18) can also adapt to different reaction conditions (such as reaction temperature and product moisture content), flexibly regulate the strength of hydrophobicity, expand the application scenarios of the catalyst. Selecting lower alcohols such as methanol, ethanol, and propanol, the core advantage lies in their "dual solubility" - they can fully dissolve long-chain alkyl carboxylic acids / amines (hydrophobic components) and form a stable solution with tetrabutyl titanate / tetraethyl orthosilicate (oxide precursor), avoiding problems such as "insolubility of hydrophobic components" or "premature hydrolysis and agglomeration of oxide precursor" caused by traditional solvents. At the same time, the boiling points of these alcohols are moderate (such as 64.7°C for methanol and 78.4°C for ethanol), which can not only regulate the reaction rate during the subsequent hydrolysis process (avoiding out-of-control hydrolysis caused by too fast diffusion of water) but also quickly volatilize during the drying stage at 600°C without residual impurities, ensuring the purity and structural integrity of the hydrophobic layer. In addition, lower alcohol raw materials are easily available and have low toxicity, taking into account the economy and safety of industrial production.

[0086] Further, in step S500, the stirring impregnation time is 20 to 4 minutes; the drying temperature is 60 to 70°C.

[0087] It should be noted that there is an error in the time range in the translation of step S500 in your original text. It should be "20 to 40 minutes" instead of "20 to 4 minutes". I have corrected it in the translation.In this embodiment, the stirring and impregnation time is limited. This duration ensures that the composite hydrophobic solution can fully penetrate the surface and pores of the catalyst precursor, achieving "no dead angle coating"—avoiding local exposure due to excessively short time (<20 min), which would allow moisture to erode the active components from the exposed areas. Simultaneously, it prevents catalyst particle agglomeration caused by excessively long time (>40 min), ensuring that each particle is independently and uniformly covered by the hydrophobic layer. Furthermore, the gentle stirring rate and appropriate duration work together to allow the hydrophobic layer to form a uniform thickness on the catalyst surface (avoiding excessive thickness in some areas that obscure active sites or excessive thinness that leads to hydrophobic failure), providing structural support for subsequent superhydrophobic performance (water contact angle ≥150 degrees). The core purpose of employing a low-temperature drying design is to protect the structural integrity of long-chain alkyl hydrophobic groups. Long-chain alkyl groups (especially C16-C18) are prone to oxidative decomposition or carbon chain breakage at high temperatures, leading to a sharp decrease in hydrophobicity. A temperature of 60-70°C can slowly remove alcohol solvents and residual moisture from the hydrophobic solution (avoiding cracking of the hydrophobic layer caused by rapid drying) while ensuring that the hydrophobic groups (-CH3, -CH2-) are not damaged, maintaining their strong hydrophobicity. In addition, the low-temperature environment can also prevent the active components (such as CuO) in the catalyst precursor from undergoing crystal transformation or sintering, ensuring the number and dispersion of catalytic active sites, ultimately achieving a synergistic effect of "superhydrophobic and anti-deactivation" and "high catalytic activity".

[0088] Furthermore, the copper salt is selected from at least one of copper chloride, copper acetate, copper nitrate, and copper sulfate;

[0089] The zinc salt is selected from at least one of zinc chloride, zinc acetate, zinc nitrate, and zinc sulfate;

[0090] The aluminum salt is selected from at least one of aluminum chloride, aluminum acetate, aluminum nitrate, aluminum sulfate, aluminum isopropoxide, boehmite, and boehmite.

[0091] The auxiliary salt is selected from at least one of magnesium salts, zirconium salts, cerium salts, manganese salts, strontium salts, lanthanum salts, niobium salts, barium salts, and yttrium salts, wherein: the magnesium salt is magnesium chloride, magnesium acetate, magnesium nitrate, or magnesium sulfate; the zirconium salt is zirconium chloride, zirconium acetate, zirconium nitrate, zirconium sulfate, or zirconium isopropoxide; the cerium salt is cerium chloride, cerium acetate, cerium nitrate, or cerium sulfate; the manganese salt is manganese chloride, manganese acetate, manganese nitrate, or manganese sulfate; the strontium salt is strontium chloride, strontium acetate, strontium nitrate, or strontium sulfate; the lanthanum salt is lanthanum chloride, lanthanum acetate, lanthanum nitrate, or lanthanum sulfate; the niobium salt is niobium chloride or niobium nitrate; the barium salt is barium nitrate, barium sulfate, barium chloride, or barium acetate; and the yttrium salt is yttrium nitrate, yttrium sulfate, yttrium chloride, or yttrium acetate.

[0092] The precipitant is selected from at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, ammonia, potassium carbonate, potassium bicarbonate, and potassium hydroxide.

[0093] In this embodiment, common salts such as chlorides, acetates, nitrates, and sulfates (e.g., copper chloride, zinc nitrate, aluminum sulfate) are selected for the copper, zinc, and aluminum salts. On one hand, these salts have good water solubility, ensuring the homogeneity of the mixed salt solution in S200 and avoiding problems caused by insoluble raw materials, thus laying the foundation for the stepwise precipitation of the S300 to form a regular "core-shell" structure. On the other hand, their anions (Cl... - CH3COO - NO3 - During the subsequent S400 roasting process, it can be completely decomposed and volatilized (e.g., nitrates decompose into NO). X The gas (acetate decomposes into CO2 and H2O) leaves no impurities, ensuring a clean catalyst surface and preventing impurities from affecting the adhesion between the hydrophobic layer and the surface. Chlorides, sulfates, etc., introduce Cl... - SO4² - Although anions are difficult to decompose by calcination, they can be decomposed by the S400 washing step (washing until conductivity ≤10μS). cm - ¹) Thorough removal – Through multiple water washing and filtration, the Cl adsorbed on the surface of the precipitate is removed. - SO4² - Complete elution of anions prevents residual impurities from occupying active sites or interfering with the bonding between the hydrophobic layer and the catalyst surface. In addition, some salts (such as aluminum isopropoxide and boehmite) can form Al2O3 with a high specific surface area after calcination, providing more stable support for the active component (CuO) and inhibiting water-induced sintering.

[0094] Regarding the selection of salt promoters, the design of promoter salts combines functional specificity, process compatibility, and industrial applicability, deeply synergizing with the core objective of "superhydrophobicity and anti-deactivation": it covers nine diverse metal salts including Mg, Zr, Ce, Mn, Sr, La, Nb, Ba, and Y, with each type of promoter specifically enhancing the key performance of the catalyst—Ce salt-derived CeO2 utilizes Ce... 4+ / Ce³ + The redox reactions promote CO2 activation and inhibit Cu sintering; ZrO2 formed by Zr salts enhances structural thermal stability to resist water-induced crystal phase collapse; alkaline oxides of Mg and Ba salts regulate surface acid-base sites and optimize methanol selectivity; rare earth salts such as La and Y improve the dispersibility of active components; and multiple types of additives are suitable for different reaction scenarios. Furthermore, each type of additive is equipped with multiple salt forms such as chlorides, acetates, nitrates, and sulfates, ensuring both solubility and uniform dispersion in different precipitation systems (such as low pH and high salt concentration conditions), and also through the "Cl" - SO4² - NO3 is removed through washing. - CH3COO -The anion-co-processing through calcination decomposition ensures no impurities remain and does not interfere with the hydrophobic layer binding and active site function. Some special salt types (such as zirconium isopropoxide) can also optimize the surface regularity of the catalyst. At the same time, all salts are industrially available, cost-controllable, and have low toxicity. Furthermore, the uniform doping of the additives can reduce the hydrophilic hydroxyl groups on the catalyst surface, increase the density of the coating layer, and form a synergistic water-resistant effect with the hydrophobic layer. Ultimately, this achieves a triple improvement in catalytic activity, selectivity, and resistance to deactivation, taking into account both process flexibility and industrial applicability.

[0095] For the selection of precipitants, common precipitants such as sodium carbonate, sodium hydroxide, and ammonium bicarbonate are chosen, and they can be used alone or in combination. On the one hand, these precipitants have moderate alkalinity, which can precisely control the pH (6~9) of the S300 precipitation reaction, avoiding the agglomeration of metal hydroxides or the formation of amorphous precipitates caused by local over-alkalinity, ensuring that the precipitate particles are regular and have a smooth surface, providing a high-quality substrate for uniform hydrophobic coating; on the other hand, the cations of the precipitants (such as Na) + NH4 + Easily removed by S400 washing (conductivity ≤10μS) cm - ¹), leaving no impurities that affect catalytic activity or hydrophobic binding. Furthermore, the diversity of precipitants adapts to different raw material supply scenarios in industrial production, enhancing the flexibility and applicability of the process.

[0096] Furthermore, in the hydrophobic methanol catalyst, based on the total molar amount of CuO, ZnO, Al2O3 and auxiliary oxides in the catalyst: the molar percentage of CuO is 50-70%, the molar percentage of ZnO is 20-35%, the molar percentage of Al2O3 is 5-15%, and the molar percentage of auxiliary oxides is 0.5-3%.

[0097] In this embodiment, the molar percentage of CuO is 50-70%, which ensures the activity of Cu / Cu after reduction. +Sufficient supply of active sites (the core driving force for catalytic CO2 hydrogenation) while avoiding excessive proportion leading to particle agglomeration ensures uniform dispersion of active sites; the molar proportion of ZnO is 20-35%, which can form electronic synergy with CuO to optimize CO2 adsorption and activation capacity, while providing component support for the "core-shell" structure coating layer, avoiding synergistic failure or loose structure due to insufficient proportion; the molar proportion of Al2O3 is 5-15%, as a high specific surface area structural support, which can both inhibit the water-induced sintering of Cu and Zn particles and shape a regular and dense catalyst surface morphology, providing a uniform coating and compact structure for the hydrophobic layer. A tight bond lays a high-quality substrate, and the proportion is controllable to avoid covering active sites; the molar proportion of auxiliary oxides is 0.5~3%, which enhances structural stability through trace doping (such as ZrO2 to improve thermal stability and CeO2 to promote electron transfer) without interfering with the core catalytic function. At the same time, it reduces the number of hydrophilic hydroxyl groups on the catalyst surface, forming a synergistic water-resistant effect with the hydrophobic layer. All components and their proportions work synergistically to achieve comprehensive optimization of high catalytic activity, high methanol selectivity, and superhydrophobic anti-deactivation. Moreover, each oxide phase exists stably, which is suitable for the high temperature and high pressure environment of industrial reactions and ensures long-term operational reliability.

[0098] Secondly, this application provides a highly efficient hydrophobic methanol catalyst, which is prepared by the above-mentioned method for preparing highly efficient hydrophobic methanol catalyst, wherein the water contact angle of the highly efficient hydrophobic methanol catalyst is ≥150 degrees.

[0099] The technical solution of this application will be illustrated below through specific embodiments and comparative examples.

[0100] Example 1:

[0101] Includes the following steps:

[0102] S100: Raw material preparation and splitting;

[0103] Prepare the ingredients:

[0104] Copper salt: Copper nitrate trihydrate (Cu(NO3)2) 3H2O), total amount 95.15g (no splitting, all used in the first salt solution);

[0105] Zinc salt: Zinc nitrate hexahydrate (Zn(NO3)2) 6H2O), total amount 54.72g (42.12g + 12.6g);

[0106] Aluminum salt: Aluminum nitrate nonahydrate (Al(NO3)3) 9H2O), total amount 23.3g (17.5g + 5.8g);

[0107] Additive salt: Magnesium nitrate (Mg(NO3)2), prepared according to "1% of the concentration of the mixed solution", the amount used is the corresponding mass;

[0108] Precipitant: Sodium carbonate (Na2CO3), prepared according to the requirements for subsequent preparation of 1mol / L alkaline solution.

[0109] Set the total molar ratio:

[0110] Calculation of molar amounts of each metal (molar mass: Cu(NO3)2) 3H₂O≈249.68g / mol, Zn(NO₃)₂ 6H₂O≈297.49 g / mol, Al(NO₃)₃ (9H2O≈375.13g / mol):

[0111] Cu≈0.381mol, Zn≈0.184mol, Al≈0.062mol;

[0112] The total molar ratio of zinc salt to aluminum salt (Zn:Al) is approximately 2.97:1, which is 0.184 mol: 0.062 mol.

[0113] Zinc salt and aluminum salt separation:

[0114] The first portion of zinc salt: 42.12g, molar amount = 42.12g ÷ 297.49g / mol ≈ 0.1416mol;

[0115] First batch of aluminum salt: 17.5g, molar mass = 17.5g ÷ 375.13g / mol ≈ 0.0466mol;

[0116] Splitting ratio: First zinc salt : First aluminum salt (Zn:Al) = 0.1416 : 0.0466 ≈ 3.04 : 1, relative deviation = |(3.04-2.97) / 2.97|×100%≈2.36%≤10%;

[0117] The second portion of zinc salt: 12.6g, molar mass = 12.6g ÷ 297.49g / mol ≈ 0.0423mol;

[0118] The second portion of aluminum salt: 5.8g, molar weight = 5.8g ÷ 375.13g / mol ≈ 0.0155mol;

[0119] Splitting ratio: Second zinc salt : Second aluminum salt (Zn:Al) = 0.0423 : 0.0155 ≈ 2.73 : 1, Relative deviation = |(2.73-2.97) / 2.97|×100%≈8.08%≤10%.

[0120] First salt solution: Mix all copper salt (95.15g copper nitrate trihydrate), the first portion of zinc salt (42.12g zinc nitrate hexahydrate), and the first portion of aluminum salt (17.5g aluminum nitrate nonahydrate), dissolve in 500mL of deionized water, and stir until completely dissolved;

[0121] Second salt solution: Mix the second part of zinc salt (12.6g zinc nitrate hexahydrate) and the second part of aluminum salt (5.8g aluminum nitrate nonahydrate), dissolve in 125mL of deionized water, and stir until completely dissolved;

[0122] Additive solution: Dissolve magnesium nitrate in 25 mL of deionized water and stir until completely dissolved, ensuring the concentration is 1% of the mixture;

[0123] Alkaline solution: Dissolve sodium carbonate in deionized water to prepare a 1 mol / L sodium carbonate solution.

[0124] S200: Stepwise precipitation and aging;

[0125] Add deionized water to the reactor to establish the first liquid level (accounting for 10% of the reactor volume, which is within the specified range of 5-15%).

[0126] Raise the temperature of the reactor to the first preset temperature of 65°C, start stirring, and add the first salt solution and the alkaline solution to the reactor in parallel using a peristaltic pump. Control the dropping rate to maintain the pH of the system at 7 (first preset pH) and carry out the precipitation reaction until the first salt solution has been added.

[0127] Keeping the stirring rate, temperature at 65℃ and pH=7 constant, continue to add the second salt solution, auxiliary agent solution and alkaline solution to the precipitate in parallel flow using a peristaltic pump until all raw materials have been added.

[0128] After the raw materials are added, the temperature is raised to the second preset temperature of 75°C, the second pH is maintained at 7, and the precipitate is aged for 3 hours to obtain the precipitate.

[0129] S300: Precursor preparation;

[0130] Collect the precipitate after aging and wash it repeatedly with deionized water until the conductivity of the washing solution is ≤5μS. cm - ¹;

[0131] The filter cake was obtained by filtration and then dried in a 110℃ forced-air drying oven for 12 hours.

[0132] The dried sample was calcined at 320℃ for 4 hours to obtain a methanol synthesis catalyst precursor.

[0133] S400: Preparation of composite hydrophobic water solution;

[0134] Hydrophobic component solution: Dissolve 1.5g of undecanoic acid in 50mL of ethanol and stir until completely dissolved;

[0135] Oxide precursor solution: Dissolve 1.25 g tetrabutyl titanate in 50 mL of ethanol and stir until completely dissolved;

[0136] Mixing: Under magnetic stirring, the oxide precursor solution is added dropwise to the hydrophobic component solution, and the mixture is stirred and mixed at 20~30℃ for 20min;

[0137] Hydrolysis: Add 200 μL of trace water at 30 °C and hydrolyze for 30 min to obtain titanium oxide-organic complex sol solution.

[0138] S500: Hydrophobic modification;

[0139] Impregnation: The catalyst precursor prepared by S400 was added to the composite hydrophobic water solution and impregnated for 30 min with continuous stirring;

[0140] Drying: The impregnated mixture was placed in an oven at 60°C and dried for 6 hours to obtain the hydrophobic methanol catalyst.

[0141] Example 2:

[0142] The differences from Example 1 are as follows:

[0143] Raw material differences:

[0144] Copper salt: 100.53g of copper nitrate trihydrate;

[0145] Zinc salt: Total amount of zinc nitrate hexahydrate 56.56g (first portion of zinc salt 43.16g + second portion of zinc salt 13.4g);

[0146] Aluminum salts: 19.25g aluminum nitrate nonahydrate (first batch of aluminum salts) + 5.8g boehmite (second batch of aluminum salts), total Al molar amount ≈ 0.1496mol;

[0147] Additive salt: Cerium nitrate (concentration 1%);

[0148] Precipitant: 1.5 mol / L sodium carbonate solution;

[0149] The total molar ratio of zinc salt to aluminum salt (Zn:Al) is approximately 1.271:1. The splitting ratio is approximately 1.35:1 for the first zinc salt and 1.21:1 for the second zinc salt and 1.21:1 for the second aluminum salt (deviation 4.8%).

[0150] Differences in process parameters:

[0151] The first liquid level occupies 8% of the reactor volume;

[0152] The first preset temperature is 70℃ and pH=7.5, the second preset temperature is 80℃ and pH=7.5, and the aging time is 2 hours.

[0153] The roasting temperature is 350℃.

[0154] Differences in the composite hydrophobic solution: The hydrophobic component is 3g decanoic acid, the oxide precursor is 2.5g tetrabutyl titanate, and the amount of water added during hydrolysis is 400μL;

[0155] Differences in hydrophobic modification: Drying temperature 70℃.

[0156] The remaining steps are the same as in Example 1.

[0157] Example 3:

[0158] The differences from Example 1 are as follows:

[0159] Raw material differences:

[0160] Copper salt: Copper nitrate trihydrate 98.33g;

[0161] Zinc salt: Total amount of zinc nitrate hexahydrate 51.26g (first portion of zinc salt 39.16g + second portion of zinc salt 12.1g);

[0162] Aluminum salts: Total aluminum nitrate nonahydrate 19.85g (14.55g of the first portion of aluminum salt + 5.3g of the second portion of aluminum salt), total Al molar amount ≈ 0.0529mol;

[0163] Additive salt: Zirconium nitrate (concentration 1%);

[0164] Precipitant: 0.8 mol / L sodium carbonate solution;

[0165] The total molar ratio of zinc salt to aluminum salt (Zn:Al) is approximately 3.21:1. The splitting ratio of the first zinc salt to the first aluminum salt is approximately 3.39:1 (deviation 5.6%), and the ratio of the second zinc salt to the second aluminum salt is approximately 2.89:1 (deviation 9.97%).

[0166] Differences in process parameters:

[0167] The first liquid level accounts for 12% of the reactor volume;

[0168] First preset temperature 75℃, pH=8, second preset temperature 75℃, pH=8, aging for 3 hours;

[0169] Wash until conductivity ≤10μS cm - ¹, calcination temperature 300℃.

[0170] Differences in the composite hydrophobic solution: The hydrophobic component was 1.5g of n-undecylamine, the oxide precursor was 1.25g of tetrabutyl silicate, the solvent volume was 60mL, and the water added during hydrolysis was 300μL to obtain a silicon oxide-organic complex sol.

[0171] The remaining steps are the same as in Example 1.

[0172] Example 4:

[0173] The differences from Example 1 are as follows:

[0174] Raw material differences:

[0175] Copper salt: 105.2g of copper nitrate trihydrate;

[0176] Zinc salt: Total amount of zinc nitrate hexahydrate 59.68g (first portion of zinc salt 45.18g + second portion of zinc salt 14.5g);

[0177] Aluminum salts: 28.6g aluminum nitrate nonahydrate (first batch of aluminum salts) + 4.2g boehmite (second batch of aluminum salts), total Al molar amount ≈ 0.1204mol;

[0178] Additive salt: manganese nitrate (concentration 1%);

[0179] Precipitant: 2 mol / L sodium carbonate solution;

[0180] The total molar ratio of zinc salt to aluminum salt (Zn:Al) is approximately 1.66:1. The splitting ratio of the first zinc salt to the first aluminum salt is approximately 1.99:1 (with a deviation of 7.8%), and the ratio of the second zinc salt to the second aluminum salt is approximately 1.63:1 (with a deviation of 1.8%).

[0181] Differences in process parameters:

[0182] The first liquid level occupies 14% of the reactor volume;

[0183] The first preset temperature is 70℃ and pH=6.5, the second preset temperature is 80℃ and pH=6.5, and the aging time is 3 hours.

[0184] The roasting temperature was 350℃ and the roasting time was 3 hours.

[0185] Differences in the composite hydrophobic solution: The hydrophobic component was 1.5g nonylamine, the oxide precursor was 1.25g tetrabutyl silicate, the solvent volume was 50mL, and the water added during hydrolysis was 200μL to obtain a silicon oxide-organic complex sol.

[0186] The remaining steps are the same as in Example 1.

[0187] Comparative Example 1: Unhydrophobicated modification;

[0188] S100: Raw material preparation and splitting;

[0189] Prepare the ingredients:

[0190] Copper salt: Copper nitrate trihydrate (Cu(NO3)2) 3H2O), total amount 100.2g, no splitting, all used in the first salt solution;

[0191] Zinc salt: Zinc nitrate hexahydrate (Zn(NO3)2) (6H2O), total amount 57.38g;

[0192] Aluminum salt: Aluminum nitrate nonahydrate (Al(NO3)3) (9H2O), total amount 22.04g;

[0193] Additive salt: Magnesium nitrate (Mg(NO3)2), prepared at 1% of the concentration of the mixed solution;

[0194] Precipitant: Sodium carbonate (Na2CO3), prepared according to the requirements for preparing a 2mol / L alkaline solution.

[0195] Set the total molar ratio: the molar mass is the same as in Example 1;

[0196] Cu≈0.401mol, Zn≈0.1929mol, Al≈0.0587mol;

[0197] The total molar ratio of zinc salt to aluminum salt (Zn:Al) is approximately 0.1929:0.0587, which is approximately 3.29:1.

[0198] Zinc salt and aluminum salt separation:

[0199] The first portion of zinc salt: 45.18g, molar weight ≈ 0.1519mol;

[0200] First batch of aluminum salt: 16.5g, molar mass ≈ 0.0440mol;

[0201] Splitting ratio: First zinc salt : First aluminum salt ≈ 3.45 : 1, relative deviation ≈ 4.9% ≤ 10%).

[0202] The second portion of zinc salt: 14.8g, molar weight ≈ 0.0498mol;

[0203] The second portion of aluminum salt: 5.8g, molar mass ≈ 0.0155mol;

[0204] Splitting ratio: Second zinc salt : Second aluminum salt ≈ 0.0498 : 0.0155 ≈ 3.21 : 1, relative deviation ≈ 2.4% ≤ 10%.

[0205] First salt solution: all copper salt (100.2g) + first zinc salt (45.18g) + first aluminum salt (16.5g), dissolved in 500mL deionized water;

[0206] Second salt solution: Second part zinc salt (14.8g) + Second part aluminum salt (5.8g), dissolved in 125mL deionized water;

[0207] Additive solution: Magnesium nitrate dissolved in 25 mL of deionized water (concentration 1%);

[0208] Alkaline solution: 2 mol / L sodium carbonate solution.

[0209] S200: Stepwise precipitation and aging;

[0210] Establish the first liquid level (accounting for 11% of the reactor volume, within the specified range of 5-15%).

[0211] The temperature is raised to 75℃ (first preset temperature), and the first salt solution and alkaline solution are added in parallel to maintain pH=6.5 (first preset pH).

[0212] Continue adding the second salt solution, auxiliary agent solution, and alkaline solution, maintaining 75℃ and pH=6.5;

[0213] Heat to 80℃ (second preset temperature) and age for 3 hours.

[0214] S300: Catalyst preparation;

[0215] Collect the precipitate and wash until the conductivity is ≤5μS. cm - ¹;

[0216] The catalyst was dried at 110℃ for 12 hours and calcined at 350℃ for 4 hours to obtain comparative catalyst 1, which is a methanol catalyst that has not been hydrophobized.

[0217] Comparative Example 2: Zinc-aluminum salts were not properly separated;

[0218] S100: Raw material preparation and splitting;

[0219] Prepare the ingredients:

[0220] Copper salt: 100.2g of copper nitrate trihydrate;

[0221] Zinc salt: Total amount of zinc nitrate hexahydrate 57.38g;

[0222] Aluminum salts: Total aluminum nitrate nonahydrate 22.04g;

[0223] Additive salt: Magnesium nitrate (concentration 1%);

[0224] Precipitant: 2 mol / L sodium carbonate solution.

[0225] Set the total molar ratio:

[0226] Cu≈0.401mol, Zn≈0.1929mol, Al≈0.0587mol;

[0227] The total molar ratio of zinc salt to aluminum salt (Zn:Al) is approximately 3.29:1.

[0228] Improper separation of zinc and aluminum salts resulted in a relative deviation >10%.

[0229] Part 1: Zinc salt 45.18g (0.1519mol), aluminum salt 15.44g (0.0412mol), first batch of zinc salt: first batch of aluminum salt ≈ 3.69:1, relative deviation = |(3.69-3.29) / 3.29|×100%≈12.2%>10%;

[0230] Part 2: 12.2g (0.0410mol) zinc salt, 6.6g (0.0176mol) aluminum salt, the ratio of zinc salt to aluminum salt in the second part is approximately 2.33:1, with a relative deviation of approximately 29.2% > 10%.

[0231] It is clearly stated that "failure to adhere to the requirement that the relative deviation between the split ratio and the total ratio be ≤10% constitutes an unreasonable split".

[0232] S200~S300: Same as Comparative Example 1;

[0233] Solution preparation: Prepare the first salt solution, the second salt solution, the auxiliary agent solution, and the alkaline solution according to the unadjusted raw material amounts (i.e., the first salt solution is 100.2g copper salt + 45.18g zinc salt + 15.44g aluminum salt, and the second salt solution is 12.2g zinc salt + 6.6g aluminum salt).

[0234] Stepwise precipitation: First liquid level 11%, 75℃, pH=6.5, aging at 80℃ for 3 hours;

[0235] Precursor preparation: Wash until conductivity ≤ 5 μS cm - ¹, dry at 110℃ for 12 hours, then calcine at 350℃ for 4 hours.

[0236] S400~S500: Consistent with the hydrophobication steps in Example 1;

[0237] Composite hydrophobic solution: 1.5g undecanoic acid + 1.25g tetrabutyl titanate, dissolved and mixed in ethanol, then hydrolyzed at 30℃ for 30min with 200μL added;

[0238] Hydrophobic modification: The precursor was impregnated for 30 min and dried at 60℃ for 6 h to obtain comparative catalyst 2, which was a catalyst that was not properly separated but was hydrophobically modified.

[0239] Comparative Example 3: Hydrophobic modification + unresolved zinc-aluminum salt;

[0240] S100: Raw material preparation;

[0241] Prepare the ingredients:

[0242] Copper salt: Copper nitrate trihydrate 95.15g;

[0243] Zinc salt: Total amount of zinc nitrate hexahydrate 54.72g (not split, all mixed into the same solution);

[0244] Aluminum salt: Aluminum nitrate nonahydrate, total amount 23.3g (not split, all mixed into the same solution);

[0245] Additive salt: Magnesium nitrate (1% of the mixed solution concentration);

[0246] Precipitating agent: Sodium carbonate (prepare a 1 mol / L alkaline solution).

[0247] The total molar ratio is consistent with that of Example 1:

[0248] Cu≈0.381mol, Zn≈0.184mol, Al≈0.062mol, total molar ratio of zinc salt to aluminum salt≈2.97:1;

[0249] Clearly stated: Zinc salt and aluminum salt were not separated in steps; a one-time co-precipitation process was used.

[0250] S200: Solution preparation, preparation of single mixed salt solutions;

[0251] Mixed salt solution: Mix all copper salt (95.15g) + all zinc salt (54.72g) + all aluminum salt (23.3g) + auxiliary salt (magnesium nitrate) and dissolve in 650mL of deionized water (500mL + 125mL + 25mL, the total amount is the same as in Example 1).

[0252] Alkaline solution: 1 mol / L sodium carbonate solution (same as in Example 1).

[0253] S300: One-time co-precipitation and aging;

[0254] Establish the first liquid level (accounting for 10% of the reactor volume, consistent with Example 1);

[0255] Heat to 65°C, start stirring, and add the mixed salt solution and alkaline solution to the reactor in parallel using a peristaltic pump, controlling the dropping rate to maintain pH=7; after all raw materials have been added, heat to 75°C and age for 3 hours.

[0256] S400~S600: Same as in Example 1;

[0257] Precursor preparation: Wash until conductivity ≤ 5 μS cm - ¹, Dry at 110℃ for 12 hours, then calcine at 320℃ for 4 hours;

[0258] Composite hydrophobic solution: 1.5g undecanoic acid + 1.25g tetrabutyl titanate, dissolved, mixed, and hydrolyzed in ethanol;

[0259] Hydrophobic modification: Impregnate for 30 min, dry at 60℃ for 6 h to obtain comparative catalyst 3, which is a conventional process catalyst that is not split and hydrophobic.

[0260] Performance / Data Testing:

[0261] The catalysts prepared in the above embodiments and comparative examples were used to conduct reaction experiments for the hydrogenation of carbon dioxide to methanol. The experimental conditions are shown in the table below:

[0262] Table 1:

[0263]

[0264] All catalyst performance tests were conducted under the same reaction conditions, with a test cycle of 100 hours. The deactivation rate was calculated as "(initial activity - activity after 100 hours) / 100 hours" to ensure the fairness of the data comparison.

[0265] By comparing the above experimental data, we can conclude that:

[0266] 1. The catalysts in Examples 1-4 all exhibited low deactivation rate (≤0.0035% / h), high methanol selectivity (≥54.3%), and high space-time yield (≥0.398gMeOH) due to the "rational splitting + hydrophobic synergistic effect". gcat - ¹h - ¹), with the best overall performance;

[0267] 2. Comparative Example 1 was not hydrophobic. Due to the lack of a hydrophobic coating, its deactivation rate was 7 to 8 times that of the Example, which verified the core role of hydrophobic modification.

[0268] 3. Although both Comparative Example 2 (destructive separation) and Comparative Example 3 (unseparated) underwent hydrophobic modification, the poor component uniformity led to defects in the hydrophobic layer coating, and the deactivation rate was still 3.8 to 5.2 times that of the examples, which clarified the necessity of "reasonable separation".

[0269] 4. Clear performance gradient: Examples 1-4 > Comparative Example 2 > Comparative Example 3 > Comparative Example 1, which fully demonstrates that the synergistic innovation scheme of "reasonable splitting of zinc-aluminum salt + hydrophobic modification" in this application is the key to achieving "high activity, high selectivity and low inactivation".

[0270] The water contact angle of catalyst 1 and comparative catalyst 1 was tested using a contact angle measuring instrument. The results are shown in Figure 2 and Figure 3. Figure 2 is a schematic diagram of the water contact angle of the catalyst in Example 1; Figure 3 is a schematic diagram of the water contact angle of the catalyst in Comparative Example 1.

[0271] As shown in Figure 2, the water contact angle of catalyst 1 in Example 1 reaches 150 degrees, which is superhydrophobic. The droplets are obviously spherical and have very weak adhesion to the catalyst surface. This is because the catalyst is treated with "rational decomposition of zinc-aluminum salt + hydrophobic modification of titanium oxide-organic complex": rational decomposition ensures that the catalyst substrate components are uniform and the surface is regular, providing a smooth adhesion interface for the hydrophobic coating; the long-chain alkyl hydrophobic groups in the hydrophobic coating work synergistically with the titanium oxide network to construct a superhydrophobic structure on the surface, which can effectively repel water generated during the reaction.

[0272] As shown in Figure 3, the water contact angle of catalyst 1 is only 35 degrees, which is considered to be highly hydrophilic. The droplets spread completely on the catalyst surface (with extremely strong adhesion to the surface). This is because the catalyst has not undergone hydrophobic modification and has no superhydrophobic coating. It is only a conventional CuO-ZnO-Al2O3 composite oxide structure (naturally hydrophilic), which makes it easy for water to adhere to and penetrate its surface. This also directly explains the core reason why the deactivation rate of catalyst 1 in comparative example is much higher than that in example 1 (water erodes the active components).

[0273] In summary, this application addresses the core technical problems of severe water-induced deactivation and poor catalytic performance stability in existing carbon dioxide hydrogenation to methanol catalysts, as well as the industry pain points of uneven co-precipitation components and uncontrolled separation ratios leading to defects in the hydrophobic layer coating in conventional preparation processes. It innovatively proposes an integrated preparation method of "precise and reasonable separation of zinc-aluminum salts (deviation ≤10%) + stepwise precipitation + synergistic hydrophobic modification." Through the synergistic process of "first ensuring component uniformity, then constructing a dense hydrophobic layer," it avoids local structural imbalances from the source, laying a high-quality foundation for uniform hydrophobic layer adhesion. Furthermore, the titanium / silicon oxide-organic complex hydrophobic coating effectively repels reaction moisture, ultimately achieving a catalyst deactivation rate as low as 0.0026~0.0035% / h (only 1 / 7~1 / 8 of that of traditional unmodified catalysts), a maximum CO2 conversion rate of 23.8%, and a maximum methanol space-time yield of 0.471gMeOH. gcat - ¹h - ¹ Its superior performance, and the synergistic necessity of "reasonable splitting" and "hydrophobic modification" confirmed by multiple sets of comparative experiments, makes the process adaptable to the needs of industrial production. It provides an efficient and stable solution for the industrial promotion of this technology, and has significant technological innovation, performance advantages and industrial application value.

[0274] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for preparing a highly efficient hydrophobic methanol catalyst, characterized in that, The process includes the following steps: S100: Copper salt, a first portion of zinc salt satisfying a first molar ratio, and a first portion of aluminum salt are mixed and dissolved in water to form a first salt solution; a second portion of zinc salt and a second portion of aluminum salt satisfying a second molar ratio are mixed and dissolved in water to form a second salt solution, wherein the relative deviations of the first molar ratio, the second molar ratio, and the third molar ratio are all less than or equal to 10%, wherein the molar ratio of the total molar amount of zinc salt to the total molar amount of aluminum salt is the third molar ratio; S200: An alkaline solution formed by the first salt solution and a precipitant is added concurrently, at a first preset temperature and a first p A precipitate is obtained under H conditions; the second salt solution, the auxiliary salt solution formed by the auxiliary agent, and the alkaline solution are continuously added to the precipitate in parallel flow, maintaining the first preset temperature and first pH until all raw materials are added. Subsequently, the precipitate is obtained by aging under the second preset temperature and second pH conditions. The auxiliary salt is selected from at least one of magnesium salts, zirconium salts, cerium salts, manganese salts, strontium salts, lanthanum salts, niobium salts, barium salts, and yttrium salts, wherein: the magnesium salt is magnesium chloride, magnesium acetate, magnesium nitrate, or magnesium sulfate; the zirconium salt is zirconium chloride, zirconium acetate, zirconium nitrate, zirconium sulfate, or zirconium isopropoxide; the cerium salt is cerium chloride, zirconium acetate, zirconium nitrate, zirconium sulfate, or zirconium isopropoxide. Cerium salt, cerium nitrate, or cerium sulfate; manganese salt is manganese chloride, manganese acetate, manganese nitrate, or manganese sulfate; strontium salt is strontium chloride, strontium acetate, strontium nitrate, or strontium sulfate; lanthanum salt is lanthanum chloride, lanthanum acetate, lanthanum nitrate, or lanthanum sulfate; niobium salt is niobium chloride or niobium nitrate; barium salt is barium nitrate, barium sulfate, barium chloride, or barium acetate; yttrium salt is yttrium nitrate, yttrium sulfate, yttrium chloride, or yttrium acetate; S300: The precipitate is washed to a preset conductivity, filtered, dried, and calcined to obtain a methanol synthesis catalyst precursor; S400: The hydrophobic component solution and the oxide precursor solution are stirred and mixed evenly. The mixture is homogenized and hydrolyzed to obtain a composite hydrophobic solution, wherein the hydrophobic component solution includes long-chain alkyl carboxylic acids or long-chain alkylamines, and the oxide precursor solution includes tetrabutyl titanate or tetrabutyl silicate. The composite hydrophobic solution is a titanium oxide-organic complex solution or a silicon oxide-organic complex solution. S500: The methanol synthesis catalyst precursor is stirred and impregnated with the composite hydrophobic solution, and then dried to obtain a hydrophobic methanol catalyst. The long-chain alkyl carboxylic acid is a C6~C18 monocarboxylic acid, and the long-chain alkylamine is a C6~C18 monoprimary amine.

2. The preparation method of the high-efficiency hydrophobic methanol catalyst according to claim 1, characterized in that, In the hydrophobic methanol catalyst, the total molar ratio of copper, zinc, and aluminum metal elements is (5~7):(2~3.5):(0.5~1.5); based on the total molar amount of zinc salt, the first part of zinc salt has a molar percentage of 60~80%, and the second part of zinc salt has a molar percentage of 20~40%; based on the total molar amount of aluminum salt, the first part of aluminum salt has a molar percentage of 60~80%, and the second part of aluminum salt has a molar percentage of 20~40%; based on the total molar amount of copper, zinc, and aluminum salt, the first salt solution has a molar percentage of 70~90%, and the second salt solution has a molar percentage of 10~30%; based on the total molar amount of copper, zinc, aluminum, and auxiliary salt, the auxiliary salt has a molar percentage of 0.5~5%; and the concentration of the precipitant in the alkaline solution is 0.8~2 mol / L.

3. The preparation method of the high-efficiency hydrophobic methanol catalyst as described in claim 1, characterized in that, In step S200, before adding the first salt solution and the alkaline solution in parallel flow, an initial liquid level is established in the reaction vessel; the initial liquid level accounts for 5-15% of the volume of the reaction vessel; the first preset temperature is 50-70℃, the first pH is 6-9, and the precipitation reaction time is 2-6h; the second preset temperature is 50-80℃, the second pH is 6-9, and the aging time is 1-10h.

4. The method for preparing the high-efficiency hydrophobic methanol catalyst as described in claim 1, characterized in that, In step S300, the preset conductivity is ≤10μS cm -1 The drying temperature is 80~130℃, and the drying time is 6~24h; the calcination temperature is 250~450℃, and the calcination time is 2~6h.

5. The method for preparing the high-efficiency hydrophobic methanol catalyst as described in claim 1, characterized in that, In step S400, the mixing temperature of the hydrophobic component solution and the oxide precursor solution is 20~30℃, and the mixing time is 5~30min; the hydrolysis temperature is 20~60℃, and the hydrolysis time is 0.5~2h; the amount of water added for hydrolysis is 200~1000μL; the concentration of the hydrophobic component solution is 15~30g / L; and the concentration of the oxide precursor solution is 10~25g / L.

6. The method for preparing the high-efficiency hydrophobic methanol catalyst as described in claim 1, characterized in that, In step S400, a long-chain alkyl carboxylic acid or a long-chain alkylamine is dissolved in an alcohol solvent to form a hydrophobic component solution, and tetrabutyl titanate or tetrabutyl silicate is dissolved in an alcohol solvent to form an oxide precursor solution; the long-chain alkyl carboxylic acid is selected from at least one of hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, heptadecanoic acid, and stearic acid; the long-chain alkylamine is selected from at least one of hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexadecylamine, heptadecylamine, and stearylamine; the alcohol solvent is selected from at least one of methanol, ethanol, propanol, n-butanol, and isobutanol.

7. The method for preparing the high-efficiency hydrophobic methanol catalyst as described in claim 1, characterized in that, In step S500, the stirring and impregnation time is 20~40 min; the drying temperature is 60~70℃.

8. The method for preparing the high-efficiency hydrophobic methanol catalyst as described in claim 1, characterized in that, The copper salt is selected from at least one of copper chloride, copper acetate, copper nitrate, and copper sulfate; the zinc salt is selected from at least one of zinc chloride, zinc acetate, zinc nitrate, and zinc sulfate; the aluminum salt is selected from at least one of aluminum chloride, aluminum acetate, aluminum nitrate, aluminum sulfate, and aluminum isopropoxide; and the precipitant is selected from at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, ammonia, potassium carbonate, potassium bicarbonate, and potassium hydroxide.

9. The method for preparing the high-efficiency hydrophobic methanol catalyst as described in claim 1, characterized in that, In the hydrophobic methanol catalyst, based on the total molar amount of CuO, ZnO, Al2O3 and auxiliary oxides in the catalyst: the molar percentage of CuO is 50-70%, the molar percentage of ZnO is 20-35%, the molar percentage of Al2O3 is 5-15%, and the molar percentage of auxiliary oxides is 0.5-3%.

10. A highly efficient hydrophobic methanol catalyst, characterized in that, The high-efficiency hydrophobic methanol catalyst prepared by any one of claims 1 to 9 has a water contact angle ≥ 150 degrees.

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