A nickel-based bimetallic catalyst, its preparation method and applications

Abstract

This invention provides a nickel-based bimetallic catalyst, its preparation method, and its applications. The preparation method includes the following steps: (1) in-situ preparation of a Ni@S-1-C precursor; (2) mixing an M metal salt and the Ni@S-1-C precursor, followed by grinding, melting, and calcination to obtain a NiM@S-1 nickel-based bimetallic catalyst; wherein M is a metal other than nickel. This invention combines in-situ encapsulation and solid-phase melting calcination. The resulting nickel-based bimetallic catalyst exhibits excellent hydrogenolysis activity and aromatic selectivity in the catalytic hydrogenolysis reaction of lower-order mixed phenolic hydroxyl groups, showing broad application prospects.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a nickel-based bimetallic catalyst, its preparation method, and its uses. Background Technology

[0002] Light aromatic hydrocarbons, such as benzene, toluene, and xylene (abbreviated as "BTX"), are important organic chemical raw materials used in the production of resins, rubber, pharmaceuticals, and dyes, and are mainly derived from petroleum. The preparation of non-petroleum-based light aromatic hydrocarbons from low-value phenolic substances, such as phenolic oil from low-temperature coal tar and biomass phenolic oil, through directed catalytic hydrogenolysis of phenolic hydroxyl groups is of great significance.

[0003] However, the strong interaction between the CO bonds in the phenolic hydroxyl groups due to the conjugation effect of the benzene ring, and the extremely complex reaction network of the hydrogenation reaction system of phenolic substances, which involves multiple parallel and serial reactions, make it very difficult to produce aromatics by hydrogenolysis of phenolic hydroxyl groups.

[0004] In existing patents and research papers, phenol or m-cresol are generally chosen as model compounds for phenolic substances. The reported catalysts include noble metal supported catalysts, non-noble metal supported catalysts, and sulfide-based catalysts. Compared to noble metal catalysts, non-noble metal catalysts, especially nickel, exhibit high hydrogenation activity, low cost, and abundant reserves, making them promising for industrial applications.

[0005] However, nickel-based supported catalysts generally suffer from low phenolic hydroxyl hydrogenolysis activity and poor aromatic selectivity due to the uneven distribution and size of the nickel (Ni) active centers on the outer surface of the support, as well as the lack of reported data on catalytic stability. Furthermore, existing NiM bimetallic catalysts still cannot achieve a balance between catalytic activity and aromatic selectivity, exhibiting low phenolic hydroxyl hydrogenolysis activity and low throughput even at high temperatures.

[0006] Therefore, there is an urgent need to develop new, efficient, and stable hydrogenolysis catalysts for phenolic hydroxyl groups. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a nickel-based bimetallic catalyst, its preparation method, and its applications, thereby solving the problems of low hydrogenolysis activity, high reaction temperature, and small throughput of existing nickel-based bimetallic catalysts.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing a nickel-based bimetallic catalyst, the method comprising the following steps: (1) preparing a Ni@S-1-C precursor in situ; (2) mixing a metal salt of M and the Ni@S-1-C precursor, and successively grinding, melting and calcining to obtain a NiM@S-1 nickel-based bimetallic catalyst; wherein, M is a metal other than nickel.

[0010] This invention utilizes Ni@S-1-C precursor and a second metal for melt calcination treatment. Compared with the impregnation method for preparing two bimetallic catalysts, this invention combines in-situ encapsulation with melt calcination. In the early stage, Ni is encapsulated in situ, and then a low-melting-point M metal salt is used for melt calcination to prepare bimetallic nanoparticles and their interactions.

[0011] In this invention, the Ni@S-1-C precursor is the precursor used to prepare the Ni@S-1 catalyst but before reduction, denoted as Ni@S-1-C precursor, where S-1 is pure silicon molecular sieve S-1, and the designation S-1-C indicates that it is a precursor.

[0012] Preferably, the in-situ preparation of Ni@S-1-C precursor in step (1) includes: mixing silicon source, template agent, metallic Ni precursor and water, carrying out crystallization reaction, and the resulting crystallization product is sequentially subjected to solid-liquid separation, washing, drying and calcination to obtain Ni@S-1-C precursor.

[0013] Preferably, the metallic Ni precursor comprises any one or a combination of at least two of nickel nitrate, nickel sulfate, nickel chloride, or metallic nickel ions, wherein typical but non-limiting combinations are the combination of nickel nitrate and nickel sulfate, the combination of nickel chloride and nickel sulfate, and the combination of nickel nitrate and nickel chloride.

[0014] Preferably, the silicon source includes any one or a combination of at least two of tetraethyl orthosilicate, silica, silica sol, or solid silica gel, wherein typical but non-limiting combinations are a combination of tetraethyl orthosilicate and silica, a combination of silica sol and silica, a combination of tetraethyl orthosilicate and silica sol, or a combination of solid silica gel and silica.

[0015] Preferably, the template agent comprises any one or a combination of at least two of triethylamine, tributylamine, diisopropylamine, diisobutylamine, isobutylamine, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetramethylethyldiammonium, or dimethyldiethylammonium hydroxide. Examples of such combinations include combinations of triethylamine and tributylamine, diisopropylamine and diisobutylamine, isobutylamine and tetraethylammonium hydroxide, or tetrapropylammonium hydroxide, tetramethylethyldiammonium, and dimethyldiethylammonium hydroxide.

[0016] Preferably, the temperature of the crystallization reaction in step (1) is 150~180℃, for example, it can be 150℃, 154℃, 157℃, 160℃, 164℃, 167℃, 170℃, 174℃, 177℃ or 180℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0017] Preferably, the crystallization reaction time is 12 to 36 hours, for example, 12 hours, 15 hours, 18 hours, 20 hours, 23 hours, 26 hours, 28 hours, 31 hours, 34 hours, or 36 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0018] Preferably, the roasting temperature is 400~600℃, for example, it can be 400℃, 423℃, 445℃, 467℃, 489℃, 512℃, 534℃, 556℃, 578℃ or 600℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, the roasting time is 2 to 10 hours, for example, 2 hours, 2.9 hours, 3.8 hours, 4.7 hours, 5.6 hours, 6.5 hours, 7.4 hours, 8.3 hours, 9.2 hours or 10 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, the amount of Ni encapsulated in the Ni@S-1-C precursor is such that the Ni content in the NiM@S-1 nickel-based bimetallic catalyst is 1.0~5.0 wt%, for example, it can be 1.0 wt%, 1.5 wt%, 2.0 wt%, 3.0 wt%, 44.0 wt%, or 5.0 wt%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] In this invention, the amount of Ni encapsulated in the Ni@S-1-C precursor is preferably controlled within a reasonable range. When the amount of Ni encapsulated is too low, there is a problem of low hydrogenolysis activity. When the amount of Ni encapsulated is too high, there are problems such as affecting the introduction of the second metal and its interaction.

[0022] This invention does not have special requirements for the mass ratio of various substances such as silicon source, template agent and metallic Ni precursor. The appropriate amount of Ni encapsulation can be obtained by using the mass ratio known to those skilled in the art.

[0023] Preferably, the metal M in the metal salt described in step (2) includes any one or at least two combinations of Fe, Zn, Co, Mo, Mn, Cu, La, Ce, W, Bi, Sm or Ga, wherein typical but non-limiting combinations are combinations of Fe and Zn, combinations of Co and Zn, combinations of Fe and Co, combinations of Mn and Zn, combinations of Fe and Cu, combinations of La and Bi, combinations of La and Ga, and combinations of Ga and Zn.

[0024] Preferably, the anion in the M metal salt includes nitrate.

[0025] Preferably, the encapsulation amount of M in the NiM@S-1 nickel-based bimetallic catalyst is 0.5~20wt%, for example, it can be 0.5wt%, 0.6wt%, 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 5wt%, 7wt%, 9wt%, 10wt%, 12wt%, 14wt%, 15wt%, 17wt%, 19wt%, or 20wt%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0026] In this invention, when the encapsulation amount of M is too low, it is difficult to form good bimetallic nanoparticles with metallic Ni. When the encapsulation amount is too high, there are disadvantages such as masking the active sites of metallic Ni and causing pore blockage.

[0027] Preferably, the grinding time in step (2) is 4 to 8 hours, for example, it can be 4 hours, 4.5 hours, 4.9 hours, 5.4 hours, 5.8 hours, 6.3 hours, 6.7 hours, 7.2 hours, 7.6 hours or 8 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] Preferably, the melting temperature is greater than or equal to the melting point of the M metal salt.

[0029] Preferably, the melting temperature is 0-15°C higher than the melting point of the M metal salt, for example, it can be 0°C, 1°C, 2°C, 4°C, 5°C, 7°C, 8°C, 10°C, 11°C, 12°C, 14°C or 15°C.

[0030] Preferably, the melting time is 4 to 15 hours, for example, it can be 4 hours, 4.2 hours, 4.3 hours, 4.5 hours, 4.8 hours, 5.0 hours, 5.2 hours, 5.3 hours, 5.4 hours, 5.5 hours, 5.6 hours, 6.0 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours or 15 hours.

[0031] Preferably, the calcination temperature is 500~650℃, for example, it can be 500℃, 515℃, 535℃, 550℃, 565℃, 580℃, 600℃, 610℃, 630℃ or 650℃, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0032] Preferably, the calcination time is 4 to 6 hours, for example, 4 hours, 4.3 hours, 4.5 hours, 4.7 hours, 4.9 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours, or 6 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] Preferably, the calcination atmosphere is any one or a combination of at least two of air, oxygen, nitrogen or argon, wherein typical but non-limiting combinations are combinations of air and oxygen, combinations of nitrogen and oxygen, combinations of air and nitrogen, and combinations of argon and oxygen.

[0034] Preferably, the NiM@S-1 nickel-based bimetallic catalyst is reduced before use.

[0035] Preferably, the reduction temperature is 400~650°C, for example, it can be 400°C, 428°C, 456°C, 484°C, 512°C, 539°C, 567°C, 595°C, 623°C or 650°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the restoration time is 4 to 10 hours, for example, it can be 4 hours, 4.7 hours, 5.4 hours, 6 hours, 6.7 hours, 7.4 hours, 8 hours, 8.7 hours, 9.4 hours or 10 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] Preferably, the reducing atmosphere is a hydrogen atmosphere.

[0038] In a second aspect, the present invention provides a nickel-based bimetallic catalyst, wherein the nickel-based bimetallic catalyst is prepared by the preparation method of the nickel-based bimetallic catalyst described in the first aspect.

[0039] Preferably, the catalyst is NiM@S-1, wherein the Ni content in NiM@S-1 is 1.0~5.0 wt%, for example, it can be 1.0 wt%, 1.2 wt%, 1.3 wt%, 1.5 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2.0 wt%, 2.2 wt%, 2.5 wt%, 2.8 wt%, 3.0 wt%, 4.0 wt%, or 5.0 wt%; and the M content is 0.5~20 wt%, for example, it can be 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 7 wt%, 8 wt%, 10 wt%, 12 wt%, 15 wt%, 18 wt%, or 20 wt%.

[0040] Preferably, M includes any one or at least two combinations of Fe, Zn, Co, Mo, Mn, Cu, La, Ce, W, Bi, Sm, or Ga, wherein typical but non-limiting combinations are combinations of Fe and Zn, combinations of Co and Zn, combinations of Fe and Co, combinations of Fe and Mn, combinations of Cu and Zn, combinations of Ce and Zn, combinations of Ce and Ga, and combinations of Ga and Sm.

[0041] The present invention preferably uses the above-mentioned metal M, which has the advantage of hydrogenation / dehydrogenation performance. Compared with metals such as Ti and V, it is easier for metal Ni to form good bimetallic active sites.

[0042] Preferably, the Ni and M form bimetallic nanoparticles.

[0043] Preferably, the bimetallic nanoparticles have a particle size of 2 to 6 nm, such as 2 nm, 2.5 nm, 2.9 nm, 3.4 nm, 3.8 nm, 4.3 nm, 4.7 nm, 5.2 nm, 5.6 nm or 6 nm, but are not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] Thirdly, the present invention provides the use of the nickel-based bimetallic catalyst described in the second aspect in the hydrogenolysis of phenolic hydroxyl groups to produce aromatics.

[0045] Preferably, the use includes: hydrogenolysis of phenolic hydroxyl-containing organic compounds in the presence of a nickel-based bimetallic catalyst.

[0046] Preferably, the phenolic hydroxyl-containing organic compound is any one or a combination of at least two of phenol, cresol, xylenol, guaiacol, eugenol, vanillin, or hydroquinone. Typical but non-limiting combinations include phenol and cresol, xylenol and cresol, phenol and xylenol, guaiacol and cresol, phenol and guaiacol, vanillin and cresol, hydroquinone and cresol, phenol and hydroquinone, and eugenol and cresol. Specifically, the phenolic hydroxyl-containing organic compound includes phenolic oil from low-temperature coal tar and / or biomass phenolic oil.

[0047] Preferably, the temperature of the hydrogenolysis reaction is 250~350°C, for example, it can be 250°C, 262°C, 273°C, 284°C, 295°C, 306°C, 317°C, 328°C, 339°C or 350°C, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0048] Preferably, the pressure of the hydrogenolysis reaction is 0.1~1.0 MPa, for example, it can be 0.1 MPa, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa or 1.0 MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0049] Preferably, the mass hourly space velocity (HSV) of the phenolic hydroxyl-containing organic compound in the hydrogenolysis reaction is 3-15 h⁻¹. -1 For example, it could be 3h -1 3.8h -1 4.6h - 1. 5.4h -1 6.2h -1 6.9h -1 7.7h -1 8.5h -1 9.3h -1 10h -1 10.5h -1 11h -1 11.5h -1 12h -1 13h -1 14h -1 or 15 hours -1 This includes, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0050] The present invention does not impose any special restrictions on the drying process described above. Any device and method known to those skilled in the art for drying can be used. Adjustments can also be made according to the actual process. For example, it can be air drying, vacuum drying, oven drying, or freeze drying, or a combination of different methods.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] (1) The nickel-based bimetallic catalyst provided by the present invention still has high catalytic activity under the condition of low amount of nickel encapsulation (1.0~5.0wt%Ni), and saves the cost of catalyst;

[0053] (2) The nickel-based bimetallic catalyst provided by the present invention still preferentially catalyzes the hydrogenolysis reaction of phenolic hydroxyl groups at a relatively low reaction temperature (≤300°C), ensuring a high yield of aromatic hydrocarbons. Under preferred conditions, the conversion rate of m-cresol is above 83.3%, and the selectivity of toluene is above 81.0%. Attached Figure Description

[0054] Figure 1 This is a TEM image of the NiCu@S-1 nickel-based bimetallic catalyst obtained in Example 1 of this invention.

[0055] Figure 2 This is a TEM image of the NiCu@S-1 nickel-based bimetallic catalyst obtained in Example 2 of the present invention.

[0056] Figure 3 This is a TEM image of the NiMo@S-1 nickel-based bimetallic catalyst obtained in Example 4 of the present invention.

[0057] Figure 4 This is a TEM image of the Mo / Silicalite-1 catalyst obtained in Comparative Example 3 of this invention.

[0058] Figure 5 This is a TEM image of the Ni@S-1 nickel-based catalyst obtained in Comparative Example 4 of this invention. Detailed Implementation

[0059] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0060] Example 1

[0061] This embodiment provides a method for preparing a nickel-based bimetallic catalyst, the method comprising the following steps:

[0062] (1) In-situ preparation of Ni@S-1-C precursor; Ni@Si-1 nanoparticles with a diameter of 3-6 nm were synthesized according to the method reported in Example 1 of ZL201910092758.5; the specific steps are as follows:

[0063] (a) Tetraethyl orthosilicate (TEOS), tetrapropylammonium hydroxide (TPAOH), nickel nitrate (Ni(NO3)2·6H2O), ethylenediamine (EDA) and deionized water were placed in a 500 mL beaker and stirred in a 70°C water bath for 5 h to obtain a gel. The molar ratio of SiO2, TPAOH and H2O in the obtained gel was 1:0.3:50.

[0064] (b) The gel was transferred to a hydrothermal crystallization vessel and crystallized at 170°C for 48 h.

[0065] (c) After the temperature of the hydrothermal crystallization vessel drops to room temperature, the product is filtered, washed, dried, and transferred to a muffle furnace for calcination at 550°C for 10 hours to obtain Ni@S-1-C prepared by hydrothermal method.

[0066] (2) Mix copper nitrate trihydrate (Cu(NO3)2·3H2O) and Ni@S-1-C precursor, grind them sequentially for 6 hours, transfer them to an oven, the oven temperature is slightly higher than the melting point of copper nitrate trihydrate (114.5°C), set to 120°C, the treatment time is 15 hours, and calcined at 550°C in air for 6 hours to obtain NiCu@S-1 nickel-based bimetallic catalyst with 2.0wt% Ni and 10.5wt% Cu and 2~6nm.

[0067] Example 2

[0068] This embodiment provides a method for preparing a nickel-based bimetallic catalyst, the method comprising the following steps:

[0069] (1) In-situ preparation of Ni@S-1-C precursor; Ni@S-1 nanoparticles with a diameter of 3-5 nm were synthesized according to the method reported in Example 1 of ZL201910092758.5; the specific steps are as follows:

[0070] (a) Tetraethyl orthosilicate (TEOS), tetrapropylammonium hydroxide (TPAOH), nickel nitrate (Ni(NO3)2·6H2O), ethylenediamine (EDA) and deionized water were placed in a 500 mL beaker and stirred in a 70°C water bath for 2 h to obtain a gel. The molar ratio of SiO2, TPAOH and H2O in the obtained gel was 1:0.5:60.

[0071] (b) The gel was transferred to a hydrothermal crystallization vessel and crystallized at 180°C for 24 h.

[0072] (c) After the temperature of the hydrothermal crystallization vessel drops to room temperature, the product is filtered, washed, dried, and transferred to a muffle furnace for calcination at 600°C for 2 hours to obtain Ni@S-1-C prepared by hydrothermal method.

[0073] (2) Mix copper nitrate trihydrate (Cu(NO3)2·3H2O) and Ni@S-1-C precursor, grind them sequentially for 4 hours, transfer them to an oven, the oven temperature is slightly higher than the melting point of copper nitrate trihydrate (114.5°C), set to 120°C, the treatment time is 6 hours, and calcined at 500°C in air for 4 hours to obtain NiCu@S-1 nickel-based bimetallic catalyst with 1.5wt% Ni and 6.4wt% Cu and 2~5nm.

[0074] Example 3

[0075] This embodiment provides a method for preparing a nickel-based bimetallic catalyst, the method comprising the following steps:

[0076] (1) In-situ preparation of Ni@S-1-C precursor; Ni@Si-1 nanoparticles with a diameter of 3-6 nm were synthesized according to the method reported in Example 1 of ZL201910092758.5; the specific steps are as follows:

[0077] (a) Tetraethyl orthosilicate (TEOS), tetrapropylammonium hydroxide (TPAOH), nickel nitrate (Ni(NO3)2·6H2O), ethylenediamine (EDA) and deionized water were placed in a 500 mL beaker and stirred in a 78°C water bath for 6 h to obtain a gel. The molar ratio of SiO2, TPAOH and H2O in the obtained gel was 1:0.3:40.

[0078] (b) The gel was transferred to a hydrothermal crystallization vessel and crystallized at 150°C for 72 h.

[0079] (c) After the temperature of the hydrothermal crystallization vessel drops to room temperature, the product is filtered, washed, dried, and transferred to a muffle furnace for calcination at 450°C for 10 hours to obtain Ni@S-1-C prepared by hydrothermal method.

[0080] (2) Cobalt nitrate hexahydrate (Co(NO3)2•6H2O) and Ni@S-1-C precursor were mixed and ground sequentially for 8 hours. The mixture was then transferred to an oven at a temperature slightly higher than the melting point of cobalt nitrate hexahydrate (105°C), set to 110°C, and processed for 6 hours. The mixture was then calcined at 650°C for 4 hours in a nitrogen atmosphere to obtain a 2~3 nm NiCo@S-1 nickel-based bimetallic catalyst with 1.5 wt% Ni and 4.4 wt% Co.

[0081] Example 4

[0082] This embodiment provides a method for preparing a nickel-based bimetallic catalyst, the method comprising the following steps:

[0083] (1) In-situ preparation of Ni@S-1-C precursor; Ni@Si-1 nanoparticles with a size of 4~7 nm were synthesized according to the method reported in ZL201910092758.5; the specific steps are as follows:

[0084] (a) Silica sol, tetrapropylammonium hydroxide (TPAOH), nickel nitrate (Ni(NO3)2·6H2O), ethylenediamine (EDA) and deionized water were placed in a 500 mL beaker and stirred in a 75°C water bath for 5 h to obtain a gel. The molar ratio of SiO2, TPAOH and H2O in the obtained gel was 1:0.3:45.

[0085] (b) The gel was transferred to a hydrothermal crystallization vessel and crystallized at 155°C for 40 h.

[0086] (c) After the temperature of the hydrothermal crystallization vessel drops to room temperature, the product is filtered, washed, dried, and transferred to a muffle furnace for calcination at 450°C for 8 hours to obtain Ni@S-1-C prepared by hydrothermal method.

[0087] (2) Mix ammonium molybdate and Ni@S-1-C precursor, grind them sequentially for 7 hours, transfer them to an oven, set the oven temperature slightly higher than the melting point of ammonium molybdate (105°C) to 130°C, process for 8 hours, and then melt and calcine at 600°C for 5 hours in a nitrogen atmosphere to obtain a 2~4 nm NiMo@S-1 nickel-based bimetallic catalyst with 2.0 wt% Ni and 9.6 wt% Mo.

[0088] Example 5

[0089] This embodiment provides a method for preparing a nickel-based bimetallic catalyst, the method comprising the following steps:

[0090] (1) In-situ preparation of Ni@S-1-C precursor; Ni@Si-1 nanoparticles with a size of 4~7 nm were synthesized according to the method reported in ZL201910092758.5; the specific steps are as follows:

[0091] (a) Silica sol, tetrapropylammonium hydroxide (TPAOH), nickel nitrate (Ni(NO3)2·6H2O), ethylenediamine (EDA) and deionized water were placed in a 500 mL beaker and stirred in a 70°C water bath for 5 h to obtain a gel. The molar ratio of SiO2, TPAOH and H2O in the obtained gel was 1:0.3:50.

[0092] (b) The gel was transferred to a hydrothermal crystallization vessel and crystallized at 170°C for 45 h.

[0093] (c) After the temperature of the hydrothermal crystallization vessel drops to room temperature, the product is filtered, washed, dried, and transferred to a muffle furnace for calcination at 550°C for 8 hours to obtain Ni@S-1-C prepared by hydrothermal method.

[0094] (2) Cerium nitrate hexahydrate and Ni@S-1-C precursor were mixed and ground sequentially for 4 hours. The mixture was then transferred to an oven at a temperature slightly higher than the melting point of cerium nitrate hexahydrate (96°C), set to 100°C, and processed for 6 hours. The mixture was then melted and calcined at 550°C in air for 6 hours to obtain a NiCe@S-1 nickel-based bimetallic catalyst with 2.0wt% Ni and 2.2wt% Ce and a wavelength of 2~3 nm.

[0095] Example 6

[0096] This embodiment provides a method for preparing a nickel-based bimetallic catalyst. The preparation method is the same as in Example 1, except that the Ni content in the nickel-based bimetallic catalyst is 6wt%, and will not be repeated here.

[0097] Example 7

[0098] This embodiment provides a method for preparing a nickel-based bimetallic catalyst. Except for the Ni content in the nickel-based bimetallic catalyst being 0.1 wt%, the preparation method is the same as in Example 1, and will not be repeated here.

[0099] Example 8

[0100] This embodiment provides a method for preparing a nickel-based bimetallic catalyst. Except for the Cu content in the NiCu@S-1 nickel-based bimetallic catalyst being 0.1 wt%, the preparation method is the same as in Example 1, and will not be repeated here.

[0101] Example 9

[0102] This embodiment provides a method for preparing a nickel-based bimetallic catalyst. Except for the Cu content of 25wt% in the NiCu@S-1 nickel-based bimetallic catalyst, the preparation method is the same as in Example 1, and will not be repeated here.

[0103] Example 10

[0104] This embodiment provides a method for preparing a nickel-based bimetallic catalyst. The preparation method is the same as in Example 1, except that Cu is replaced with Ti in the NiCu@S-1 nickel-based bimetallic catalyst and the corresponding precursor is replaced with titanium tetrachloride. Therefore, it will not be described again here.

[0105] Comparative Example 1

[0106] This comparative example provides a method for preparing a nickel-based bimetallic catalyst. The preparation method is the same as that in Example 1, except that the Ni@S-1-C precursor is replaced with the Ni@ZSM-5 precursor (for the specific preparation method, please refer to Example 1 in CN111250152B, and the packaging amount is the same as in Example 1). It will not be repeated here.

[0107] Comparative Example 2

[0108] This comparative example provides a method for preparing a Cu / S-1 catalyst, the method comprising:

[0109] (a) Place 26.0 g of tetraethyl orthosilicate (TEOS), 10.1 g of tetrapropylammonium hydroxide (TPAOH) and 56.0 g of deionized water in a 500 mL beaker and stir in a 70°C water bath for 6 h; then transfer to a hydrothermal reactor and crystallize at 170°C for 12 h; after cooling, remove, filter, wash and dry, and then transfer to a muffle furnace at 550°C for calcination for 8 h to obtain S-1 molecular sieve for later use;

[0110] (b) The calcined S-1 molecular sieve and copper nitrate (Cu(NO3)2•3H2O) were placed in a mortar and ground for 2 hours; then the ground mixture was transferred to a muffle furnace at 550°C and calcined for 6 hours to obtain the calcined Cu / S-1 catalyst.

[0111] Comparative Example 3

[0112] This comparative example provides a method for preparing a Mo / Silicalite-1 catalyst, the method comprising:

[0113] (a) S-1 molecular sieve was prepared according to the method described in Comparative Example 2;

[0114] (b) The calcined S-1 molecular sieve and molybdenum oxide (MoO3) were mixed and ground for 4 hours; then transferred to a muffle furnace at 600°C for calcination for 8 hours to obtain the Mo / S-1 catalyst.

[0115] Comparative Example 4

[0116] This comparative example provides a method for preparing a nickel-based bimetallic catalyst. The preparation method is the same as that in Example 1 except that step (2) is omitted, and will not be repeated here.

[0117] Comparative Example 5

[0118] This comparative example provides a method for preparing a nickel-based bimetallic catalyst. The preparation method is the same as in Example 1 except that step (2) is replaced by impregnation with a second metal. It will not be repeated here.

[0119] Specifically, the Ni@S-1 precursor was impregnated with a 1 mol / L solution of copper nitrate trihydrate (Cu(NO3)2•3H2O) for 4 h, and then melt-calcined at 550 °C for 6 h in air to obtain a NiCu@S-1 nickel-based bimetallic catalyst with a diameter of 3~30 nm.

[0120] Comparative Example 6

[0121] This comparative example provides a method for preparing a nickel-based bimetallic catalyst. Except for the in-situ encapsulation of Cu in step (1) and the addition of nickel nitrate in step (2), the preparation method is the same as that in Example 1, and will not be repeated here.

[0122] Figure 1 This is a TEM image of the NiCu@S-1 nickel-based bimetallic catalyst obtained in Example 1; Figure 2 This is a TEM image of the NiCu@S-1 nickel-based bimetallic catalyst obtained in Example 2. Figure 3 This is a TEM image of the NiMo@S-1 nickel-based bimetallic catalyst obtained in Example 4. Figure 4 This is a TEM image of the Mo / Silicalite-1 catalyst obtained in Comparative Example 3. Figure 5 This is a TEM image of the Ni@S-1 nickel-based catalyst obtained in Comparative Example 4. From... Figures 1-5 It can be seen that the preparation method of the nickel-based bimetallic catalyst provided by the present invention can effectively control the particle size and uniform distribution of NiM bimetallic nanoparticles.

[0123] Application Example 1

[0124] This application example provides a hydrodeoxygenation reaction of m-cresol, which includes the following:

[0125] The catalyst prepared in Example 1 with a mesh size of 20-40 was placed in the middle of a fixed-bed reaction tube, and the upper and lower sections of the reaction tube were filled with quartz sand, using m-cresol as the raw material.

[0126] Before feeding, the catalyst prepared in Example 1 was reduced online (using a hydrogen atmosphere) at a reduction temperature of 500°C for 10 hours; then the temperature was lowered to 300°C, the reaction pressure was set to 0.25 MPa, and the m-cresol mass hourly space velocity was set to 6 h⁻¹. -1 The feeding and reaction process begins.

[0127] Application Example 2

[0128] This application example provides a hydrodeoxygenation reaction of m-cresol, which includes the following:

[0129] The catalyst prepared in Example 2 with a mesh size of 20-40 was placed in the middle of a fixed-bed reaction tube, and the upper and lower sections of the reaction tube were filled with quartz sand, using m-cresol as the raw material.

[0130] Before feeding, the catalyst prepared in Example 2 was reduced online (using a hydrogen atmosphere) at a reduction temperature of 650°C for 4 hours; then the temperature was lowered to 250°C, the reaction pressure was set to 0.5 MPa, and the m-cresol mass hourly space velocity was set to 3 h⁻¹. -1 The feeding and reaction process begins.

[0131] Application Example 3

[0132] This application example provides a hydrodeoxygenation reaction of m-cresol, which includes the following:

[0133] The catalyst prepared in Example 3 with a mesh size of 20-40 was placed in the middle of a fixed-bed reaction tube, and the upper and lower sections of the reaction tube were filled with quartz sand, using m-cresol as the raw material.

[0134] Before feeding, the catalyst prepared in Example 3 was reduced online (using a hydrogen atmosphere) at a reduction temperature of 400°C for 10 hours; then the temperature was lowered to 350°C, the reaction pressure was set to 0.1 MPa, and the m-cresol mass hourly space velocity was set to 10 h⁻¹. -1 The feeding and reaction process begins.

[0135] Application Example 4

[0136] This application example provides a hydrodeoxygenation reaction of m-cresol, wherein the specific reaction conditions are the same as those in application example 1, except that the catalyst in example 4 is used.

[0137] Application Example 5

[0138] This application example provides a hydrodeoxygenation reaction of m-cresol, which includes the following:

[0139] The catalyst prepared in Example 5 with a mesh size of 20-40 was placed in the middle of a fixed-bed reaction tube, and the upper and lower sections of the reaction tube were filled with quartz sand, using m-cresol as the raw material.

[0140] Before feeding, the catalyst prepared in Example 5 was reduced online (using a hydrogen atmosphere) at a reduction temperature of 420°C for 10 hours; then the temperature was lowered to 350°C, the reaction pressure was set to 0.2 MPa, and the m-cresol mass hourly space velocity was set to 3 h⁻¹. -1 The feeding and reaction process begins.

[0141] Application Examples 6-10 and Comparative Examples 1-6

[0142] Application Examples 6-10 and Comparative Examples 1-6 provide a m-cresol hydrodeoxygenation reaction. Except for the catalysts used in Examples 6-10 and Comparative Examples 1-6, the m-cresol hydrodeoxygenation reaction is the same as that in Application Example 1, and will not be described again here.

[0143] The conversion rate and selectivity of the above application examples and application comparison examples were calculated, and the test results of the above application examples and application comparison examples are shown in Table 1.

[0144] Table 1

[0145]

[0146] In Table 1, " / " indicates that there is no relevant data.

[0147] The following points can be observed from Table 1:

[0148] (1) As can be seen from Application Examples 1 to 5, the nickel-based bimetallic catalyst prepared by the method of the present invention can make the particle size of NiM bimetal in the range of 2 to 6 nm. Based on the low nickel content, the catalyst has excellent conversion rate and toluene selectivity when applied to the hydrogenolysis reaction of organic compounds containing phenolic hydroxyl groups. The conversion rate of m-cresol is above 83.3% and the toluene selectivity is above 81.0%.

[0149] (2) Comparing Application Example 1 and Application Examples 6-7, it can be seen that in Application Example 6, the amount of nickel encapsulation is high, which leads to a limited amount of the second metal introduced, and the catalyst has a significant pore-blocking effect, which ultimately affects the hydrogenolysis performance of phenol oil; in Application Example 7, nickel is used as the first metal, and the amount of encapsulation is low, which leads to low hydrogenolysis performance of phenol oil. At an encapsulation amount of 0.1 wt%, the catalyst prepared has almost no hydrogenolysis activity. This shows that the present invention preferably controls the amount of nickel encapsulation within a reasonable range in order to have excellent hydrogenolysis performance.

[0150] Comparing Application Example 1 with Application Examples 8-9, it can be seen that the Cu content in Application Example 8 is low, resulting in virtually no hydrogenolysis activity. In contrast, the Cu content in Application Example 9 is far excessive, covering the original Ni active sites, leading to low activity of the resulting catalyst in the hydrogenolysis reaction of phenolic oil. This indicates that the present invention preferably controls the amount of the second metal M and the amount of nickel encapsulation within a reasonable range to further improve the conversion rate and toluene selectivity of the hydrogenolysis reaction of phenolic hydroxyl organic compounds.

[0151] (3) Comparing Application Example 1 and Application Example 10, it can be seen that the second metal M in Application Example 10 is Ti. Metal Ti is easy to insert into the S-1 molecular sieve framework and is difficult to form bimetallic nano-active sites with Ni. Ultimately, the catalyst obtained is low in the hydrogenolysis reaction of phenol oil. This shows that the present invention selects a specific metal M to be combined with metal nickel in order to further improve the catalytic activity and toluene selectivity of the hydrogenolysis reaction of phenol oil.

[0152] (4) In Comparative Example 1, ZSM-5 was selected as the molecular sieve. However, due to the presence of acidic sites in ZSM-5, the hydrogenolysis reaction of phenol oil was inhibited, resulting in poor catalytic performance. In Comparative Example 2, Cu / S-1 catalyst and Mo / S-1 catalyst prepared in Comparative Example 3 were used, but they had almost no catalytic effect on m-cresol. In Comparative Example 4, step (2) was not performed. In Comparative Example 5, the impregnation method was used, resulting in larger particle size of bimetallic particles in the final catalyst and poor catalytic effect. In Comparative Example 6, Cu@S-1-C precursor was prepared first, and then Ni metal was added by melting and calcining. This resulted in larger nickel-copper bimetallic particles and a significant decrease in catalytic performance compared to Application Example 1. This indicates that the catalyst preparation method provided by this invention can more effectively ensure the particle size of nickel-M bimetallic particles in the catalyst, thereby improving catalytic activity and toluene selectivity.

[0153] Compared to single-metal Ni, the NiM bimetallic catalyst provided by this invention exhibits higher aromatic selectivity and catalytic activity in the hydrogenolysis reaction of m-cresol. Based on Ni@S-1-C, a second metal is encapsulated to form the NiM@S-1 bimetallic encapsulated catalyst, which significantly improves the phenol conversion rate and aromatic selectivity. Compared with a single second metal, the effect is even more outstanding.

[0154] The present invention has been illustrated with the above embodiments to illustrate its detailed features, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the selected technical features, additions of auxiliary technical features, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a nickel-based bimetallic catalyst, characterized by, The preparation method comprises the following steps: (1) in-situ preparation of a Ni@S-1-C precursor; the encapsulation amount of Ni in the Ni@S-1-C precursor is such that the content of Ni in the NiM@S-1 nickel-based bimetallic catalyst is 1.0-5.0 wt%; (2) mixing of the M metal salt and the Ni@S-1-C precursor, and sequentially grinding, melting and calcining to obtain the NiM@S-1 nickel-based bimetallic catalyst; the melting temperature is greater than or equal to the melting point of the M metal salt; the metal M in the M metal salt comprises any one or a combination of at least two of Mo, Co, Cu, La or Ce; wherein M is a metal other than nickel; the encapsulation amount of M in the NiM@S-1 nickel-based bimetallic catalyst is 0.5-20 wt%; the in-situ preparation of the Ni@S-1-C precursor in step (1) comprises: mixing of a silicon source, a template agent, a metal Ni precursor and water to perform a crystallization reaction, and sequentially subjecting the obtained crystallization product to solid-liquid separation, washing, drying and calcination to obtain the Ni@S-1-C precursor.

2. The production method according to claim 1, characterized by, the anion in the M metal salt comprises nitrate.

3. The preparation method according to claim 1, characterized in that, the grinding time in step (2) is 4-8 h.

4. The method of claim 1, wherein, the melting temperature is 0-15 °C greater than the melting point of the M metal salt.

5. The preparation method according to claim 1, characterized in that, the calcination temperature is 500-650 °C.

6. The method of claim 1, wherein, the calcination time is 4-6 h.

7. The preparation method according to claim 1, characterized in that, the calcination atmosphere is any one or a combination of at least two of air, oxygen, nitrogen or argon.

8. The method of any one of claims 1 to 7, wherein the method further comprises the step of: the NiM@S-1 nickel-based bimetallic catalyst is reduced before use.

9. The preparation method according to claim 8, characterized in that, the reduction temperature is 400-650 °C.

10. The preparation method according to claim 8, characterized in that, the reduction time is 4-10 h.

11. The preparation method according to claim 8, characterized in that, the reduction atmosphere is a hydrogen atmosphere.

12. A nickel-based bimetallic catalyst characterized in that, the nickel-based bimetallic catalyst is prepared by the preparation method of the nickel-based bimetallic catalyst according to any one of claims 1-11; the catalyst is NiM@S-1, wherein the content of Ni in the NiM@S-1 is 1.0-5.0 wt%, and the content of M is 0.5-20 wt%; M comprises any one or a combination of at least two of Mo, Co, Cu, La or Ce.

13. The nickel-based bimetallic catalyst of claim 12, wherein, Ni and M form bimetallic nanoparticles.

14. The nickel-based bimetallic catalyst of claim 13, wherein, the particle size of the bimetallic nanoparticles ranges from 2 to 6 nm.

15. Use of the nickel-based bimetallic catalyst according to any one of claims 12-14 in the hydrogenolysis of phenolic hydroxyl groups to produce aromatic hydrocarbons.

16. Use according to claim 15, characterized in that, the use comprises: hydrogenolysis of a phenolic hydroxyl-containing organic substance in the presence of a nickel-based bimetallic catalyst.

17. Use according to claim 16, characterized in that, the hydrogenolysis temperature is 250-350 °C.

18. Use according to claim 16, characterized in that, the hydrogenolysis pressure is 0.1-1.0 MPa.

19. Use according to claim 16, characterized in that, The mass space velocity of the phenolic hydroxyl-containing organic matter in the hydrogenolysis reaction is 3-15 h -1 .

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