A bifunctional Ni-Cu bimetallic catalyst, a preparation method and application in catalytic dehydrogenation of organic liquid

Abstract

The application provides a bifunctional Ni-Cu bimetallic catalyst, a preparation method and application in catalytic hydrogenation and dehydrogenation of organic liquid, and belongs to the technical field of catalysts. In the application, a nickel metal salt, a copper metal salt and an N-containing organic ligand are added into a dispersion solvent, then a carrier is added to obtain a catalyst precursor powder, and the catalyst precursor powder is calcined and passivated to obtain the bifunctional Ni-Cu bimetallic catalyst. The catalyst prepared in the application has good catalytic universality, can be applied to hydrogenation and dehydrogenation reactions of organic liquid hydrogen storage materials, especially carbazole hydrogen storage materials, the catalyst has high catalytic activity, high stability and no by-products in the reaction. Moreover, the catalyst prepared in the application can complete reversible catalytic hydrogenation and dehydrogenation of an organic liquid hydrogen storage system, and significantly reduces the cost and complexity of the hydrogen storage system.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more particularly to a bifunctional Ni-Cu bimetallic catalyst, its preparation method, and its application in the catalytic dehydrogenation of organic liquids. Background Technology

[0002] Currently, commercially available catalysts for the dehydrogenation of organic liquid hydrogen storage materials are generally Pd, Ru, and Pt noble metal catalysts. These catalysts possess good catalytic activity, stability, and versatility. However, the high cost of noble metals makes them unsuitable for widespread industrial applications. Therefore, ensuring high catalytic activity and stability of catalysts while reducing or eliminating the use of noble metals is one of the keys to promoting the development of hydrogen energy. Currently widely used commercial catalysts have limited functions, generally only possessing one catalytic function: hydrogenation or dehydrogenation. Patent CN112076748A discloses a Pt / Mo bimetallic supported dehydrogenation catalyst prepared using a co-precipitation method, applicable only to the unidirectional dehydrogenation of methylcyclohexane to toluene. Patent CN113042043A discloses a Ru-based unidirectional hydrogenation catalyst prepared using a liquid-phase reduction method, applicable only to the hydrogenation of benzene to cyclohexane. Patent CN111686718A discloses a Pt supported dehydrogenation catalyst prepared using an impregnation method, applicable only to the unidirectional dehydrogenation of cyclohexane to benzene. In future stationary hydrogen storage facilities, using different catalysts for hydrogen addition and dehydrogenation undoubtedly increases the cost and complexity of the system. To achieve the full-chain promotion of hydrogen energy technology and further reduce the complexity of hydrogen storage systems, reversible catalysts with dual hydrogen addition and dehydrogenation functions are a powerful driving force for the widespread application of hydrogen energy technology.

[0003] Currently, the development of bifunctional catalysts mainly falls into two categories. The first category utilizes the inherent high activity and synergistic catalysis of noble metals to generate reversible catalytic activity. Forberg et al. constructed a novel lignin energy storage system and developed a novel Pd2Ru@SiCN bimetallic catalyst through the pyrolysis of organometallic ligands for the hydrogenation and dehydrogenation reactions of N-heterocyclic compounds. Under mild conditions, this catalyst achieves NECZ-H 12-NECZ exhibits a reversible hydrogenation-dehydrogenation cycle, but achieving full hydrogenation takes up to 36 hours, and catalytic activity declines after three hydrogenation-dehydrogenation cycles. Zhu et al. investigated the synergistic effect between Ru and Pd, finding that the main factors affecting the hydrogenation-dehydrogenation activity of RuPd / Al2O3 catalysts are metal size, dispersion, and surface acidic sites. The hydrogenation-dehydrogenation activity of this series of catalysts shows a linear relationship with the metal loading. Subsequently, Zhu et al. further studied RuPd-based bimetallic bifunctional catalysts, using a double reduction method to improve the degree of electronic interaction between the strongly acidic sites, active sites, and support in the Pd2Ru2 / H2 catalyst. This resulted in better catalytic dehydrogenation activity and recyclability of the catalyst after 10 NPCZ-H 12 -NPCZ showed no significant decrease in activity after dehydrogenation cycling. Theoretical calculations indicate that H8-NPCZ and H4-NPCZ form stable adsorption structures on the catalyst surface, thereby promoting the catalytic reaction. Xue et al. prepared bimetallic nanocluster catalysts with Pd atoms isolating Rh atoms. Combined with DFT calculations, it was shown that the synergistic effect of Pd-Rh nanoclusters is beneficial for hydrogenation and dehydrogenation reactions on the surface of Pd4Rh2 / γ-Al2O3 catalyst.

[0004] The second method for preparing bifunctional catalysts involves introducing rare earth elements to modify the catalyst, providing a new pathway for electron transfer and enabling the catalyst to possess reversible catalytic activity. Yang et al. developed a Pd / Al₂O₃-YH₃ catalyst capable of reversibly storing 100% of NECZ in 4 hours at 473 K. Utilizing YH₃ to provide a new hydrogen transfer pathway and the inherently high catalytic activity of Pd / Al₂O₃, the catalyst maintained its performance without degradation over three hydrogen storage cycles. Yu et al. deposited a thin palladium layer on the surface of LaNi₅. Due to the abundant lattice hydrogen bonding sites on the LaNi₅ support, the limitations of H bond sites in traditional catalytic surface hydrogenation and dehydrogenation processes were effectively overcome, promoting the hydrogenation of NECZ and H₂O in the Pd / LaNi₅ catalyst. 12 -NECZ dehydrogenation exhibits excellent catalytic activity. Li Chenggen et al. prepared a CeO2-modified Pd / Al2O3 catalyst and applied it to the reversible addition and dehydrogenation of NPCZ, which could complete the hydrogenation and H+ addition of NPCZ in 180 min. 12 -NPCZ dehydrogenation. The addition of CeO2 forms Pd-O-Ce bonds in the catalyst, which effectively modulates the electronic state of Pd particles in the catalyst, leading to the emergence of new active sites and thus improving the catalytic activity of the catalyst.

[0005] In summary, current reports on bifunctional catalysts mainly focus on noble metals as active components, utilizing the inherent superior electronic structure of noble metals or introducing rare earth elements to alter electron transfer pathways to achieve good reversible catalytic activity. However, the high cost of noble metals and rare earth elements limits broader research into bifunctional catalysts. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a method for preparing a bifunctional Ni-Cu bimetallic catalyst. The method involves loading metallic Ni and Cu onto a support by complexing the metal with organic ligands and by impregnation. The preparation process is mild and requires simple equipment. The resulting catalyst can achieve reversible catalytic hydrogenation and dehydrogenation activity without the use of any precious metals, and can be applied in the dehydrogenation reaction of organic liquid hydrogen storage materials.

[0007] To achieve the above objectives, the preparation method of the bifunctional Ni-Cu bimetallic catalyst of the present invention includes the following steps:

[0008] (1) Weigh out nickel metal salt, copper metal salt and N-containing organic ligand, then add dispersion solvent, heat to 60-100℃, heat under reflux and stir until completely dissolved to obtain a uniformly mixed solution;

[0009] (2) Add the support to the solution prepared in step (1), stir evenly, and dry at 60-80℃ overnight to obtain the catalyst precursor. Grind the precursor powder to obtain the catalyst precursor powder. The amount of support added is 5-30% of the NiCu metal loading in the catalyst.

[0010] (3) The catalyst precursor powder in step (2) is transferred to a tube furnace, and a mixture of inert gas and H2 is introduced into it for calcination for 4 hours. After calcination, it is cooled to room temperature, and then a mixture of inert gas and O2 is introduced into it for passivation for 1 hour to obtain the bifunctional Ni-Cu bimetallic catalyst.

[0011] Further, in step (1), the nickel metal salt is any one of nickel nitrate, nickel chloride, and nickel acetate; the copper metal salt is any one of copper nitrate, copper chloride, and copper acetate; the nitrogen-containing organic ligand is any one of dicyandiamide, 1,10-phenanthroline, 2,2′-bipyridine, and melamine; and the dispersing solvent is any one of water, anhydrous ethanol, anhydrous methanol, and dimethyl sulfoxide.

[0012] Furthermore, in step (1), the molar ratio of nickel metal salt to copper metal salt is 5:1-1:5; the total amount of nickel metal salt and copper metal salt is in a molar ratio of 1:0.5-1:3 to the N-containing organic ligand.

[0013] Furthermore, the carrier in step (2) is any one of silicon dioxide, aluminum oxide, titanium dioxide, layered graphite, and carbon black.

[0014] Furthermore, the inert gas in step (3) is Ar; the volume content of H2 in the mixed gas A is 10%, and the gas flow rate of the mixed gas A is 70 ml / min; the volume content of O2 in the mixed gas B is 1%, and the gas flow rate of the mixed gas B is 70 ml / min.

[0015] Furthermore, the calcination temperature in step (5) is 500-1000℃.

[0016] Another object of the present invention is to provide a catalyst prepared by the above method, wherein the catalyst uses Ni and Cu metals as active components and has a pore volume of 0.5-1.1 cm³. 3 / g, specific surface area is 400-1000m² 2 / g, the NiCu metal loading in the catalyst is 5-30%, and the particle size of the catalyst metal particles is 3-7nm.

[0017] The present invention also provides an application of the above-mentioned catalyst, which can be used for hydrogenation and dehydrogenation of organic liquid hydrogen storage materials;

[0018] When used in hydrogenation tests of organic liquid hydrogen storage materials, the organic liquid hydrogen storage material is any one of aziridine carbazole, aziridine carbazole, toluene, dibenzyltoluene, 1-methylindole, and 1,2-dimethylindole;

[0019] When used in the dehydrogenation test of organic liquid hydrogen storage materials, the organic liquid hydrogen storage material is any one of perhydronitropropylcarbazole, perhydronitroethylcarbazole, methylcyclohexane, perhydronitrodibenzyltoluene, perhydronitro1-methylindole, and perhydronitro1,2-dimethylindole.

[0020] Furthermore, when the catalyst is used in the hydrogenation test of organic liquid hydrogen storage material, the specific method is as follows: the catalyst and organic liquid hydrogen storage material are mixed at a mass ratio of 1:1, and then cyclohexane is added as a solvent. The reaction pressure is 6-8 MPa, the reaction temperature is 130-150℃, and the rotation speed is 600-700 rpm / min.

[0021] When the catalyst is used in the hydrogenation test of organic liquid hydrogen storage material, the specific method is as follows: the catalyst and organic liquid hydrogen storage material are mixed at a mass ratio of 1:1, and then mesitylene is added as a solvent. The reaction pressure is atmospheric pressure, the reaction temperature is 180-200℃, and the rotation speed is 180-220 rpm / min.

[0022] The catalyst prepared by this invention has the following mechanism of action:

[0023] First, the catalyst prepared in this invention possesses a favorable physical structure. Firstly, it utilizes a support with a high specific surface area to load the active metal. This high specific surface area positively impacts the catalytic activity of the active component and the adsorption of reactants and gases. Secondly, it employs a method of impregnating a metal with a nitrogen-containing organic ligand complex. Due to the dual confinement effect of nitrogen coordination and the support pores, the active metal component is anchored within the regular pores of the support, resulting in excellent metal dispersion. The smaller particle size directly corresponds to better catalytic activity. Thirdly, the added dicyandiamide, after high-temperature pyrolysis, leaves a nitrogen-doped carbon layer with defect sites on the support surface. The high defect site density of the carbon layer on the catalyst surface facilitates the physical and chemical adsorption of reactants and hydrogen, and spatially constructs channels for electron transfer, further enhancing the catalyst's catalytic activity.

[0024] Secondly, the catalyst prepared in this invention exhibits excellent interactions among its components. The nitrogen produced after calcination of the N-containing organic ligands takes various forms (pyridine nitrogen, pyrrole nitrogen, graphitic substituted nitrogen, metal-coordinated nitrogen, etc.), endowing the catalyst surface with tunable acidity / basicity and microscopic electronic structure. This method successfully modifies the surface properties of the catalyst support, enhances the interaction between the active metal and the support, reduces the d-band centers and electron density of Ni, and improves the reversible catalytic activity of the catalyst. Furthermore, there is a good interaction between the two active metals, Ni and Cu. When Ni with partially filled d-bands combines with Cu with fully filled d-bands, the formation of NiCu sites leads to interactions in both geometry and electrons. This results in NiCu becoming a new active species. A specific amount of Cu can enhance the dehydrogenation activity of Ni, lower the reaction energy barrier for catalytic dehydrogenation, and promote the generation of reversible catalytic activity.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] This invention utilizes an organic ligand complexation and impregnation method to support Ni and Cu metals on a support, followed by high-temperature calcination and reduction to obtain the catalyst. The preparation process is mild, requires simple equipment, and is suitable for large-scale production. The catalyst prepared by this invention exhibits reversible catalytic hydrogenation and dehydrogenation activity without the use of any precious metals, and is cost-effective. The catalyst prepared by this invention possesses good catalytic versatility and can be applied to the addition and dehydrogenation reactions of organic liquid hydrogen storage materials, especially carbazole-based hydrogen storage materials. The catalyst exhibits high catalytic activity, strong stability, and no byproducts. Furthermore, the catalyst prepared by this invention completes reversible catalytic addition and dehydrogenation in an organic liquid hydrogen storage system, significantly reducing the cost and complexity of the hydrogen storage system. Attached Figure Description

[0027] Figure 1 The physical adsorption-desorption curves of the catalyst prepared in Example 1;

[0028] Figure 2 The pore size distribution diagram is shown for the catalyst prepared in Example 1.

[0029] Figure 3 Transmission electron microscope image of the catalyst prepared in Example 1;

[0030] Figure 4 The particle size distribution diagram is shown for the catalyst prepared in Example 1.

[0031] Figure 5 The catalyst prepared in Example 1 is a component of the hydrogenation reaction of aziridine carbazole;

[0032] Figure 6 Results for the hydrogenation performance of a commercial 5wt% Ru / Al2O3 supported catalyst;

[0033] Figure 7 The catalyst prepared in Example 1 is a component for the dehydrogenation reaction of aziridine carbazole;

[0034] Figure 8 Results for the dehydrogenation performance of a commercial 5wt% Pd / Al2O3 supported catalyst;

[0035] Figure 9 The results of cyclic hydrogenation and dehydrogenation of organic liquid hydrogen storage materials using the catalyst prepared in Example 1;

[0036] Figure 10 The XRD test results are for the catalysts prepared in Examples 1-4;

[0037] Figure 11 The X-ray diffraction test results are for the catalysts prepared in Examples 1 and 10-13. Detailed Implementation

[0038] This invention provides a bifunctional Ni-Cu bimetallic catalyst, its preparation method, and its application. The preparation method of the catalyst includes the following steps:

[0039] (1) Weigh out nickel metal salt, copper metal salt and N-containing organic ligand, then add dispersion solvent, heat to 60-100℃, heat under reflux and stir until completely dissolved to obtain a uniformly mixed solution;

[0040] (2) Add the carrier to the solution prepared in step (1), stir evenly, dry at 60-80℃ overnight to obtain the catalyst precursor, and grind to obtain the catalyst precursor powder;

[0041] (3) The catalyst precursor powder in step (2) is transferred to a tube furnace, and a mixture of inert gas and H2 is introduced into it for calcination for 4 hours. After calcination, it is cooled to room temperature, and then a mixture of inert gas and O2 is introduced into it for passivation for 1 hour to obtain the bifunctional Ni-Cu bimetallic catalyst.

[0042] The nickel metal salt is any one of nickel nitrate, nickel chloride, and nickel acetate; the copper metal salt is any one of copper nitrate, copper chloride, and copper acetate; the nitrogen-containing organic ligand is any one of dicyandiamide, 1,10-phenanthroline, 2,2′-bipyridine, and melamine; and the dispersing solvent is any one of water, anhydrous ethanol, anhydrous methanol, and dimethyl sulfoxide.

[0043] The catalyst of this invention is used for hydrogenation and dehydrogenation of organic liquid hydrogen storage materials, as well as for the cyclic hydrogenation and dehydrogenation of organic liquid hydrogen storage materials;

[0044] When used in hydrogenation and cyclic hydrogenation tests of organic liquid hydrogen storage materials, the organic liquid hydrogen storage material is any one of aziridine carbazole, aziridine carbazole, toluene, dibenzyltoluene, 1-methylindole, and 1,2-dimethylindole.

[0045] When used in dehydrogenation and cyclic dehydrogenation tests of organic liquid hydrogen storage materials, the organic liquid hydrogen storage material is any one of perhydronitropropylcarbazole, perhydronitroethylcarbazole, methylcyclohexane, perhydronitrodibenzyltoluene, perhydronitro1-methylindole, and perhydronitro1,2-dimethylindole.

[0046] The present invention will be further described below with reference to the embodiments.

[0047] Example 1

[0048] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, comprising the following steps:

[0049] (1) Weigh out 0.9290 g of nickel nitrate hexahydrate Ni(NO3)2·6H2O, 0.1845 g of copper nitrate hydrate Cu(NO3)2·xH2O, and 0.7025 g of dihydrodiamine C2H4N4. Then add 10 ml of water as a dispersing solvent. Heat the mixture in an oil bath at 60 °C in a fume hood and stir under reflux for 20 min to obtain a homogeneous solution. (Cu:Ni mass ratio = 1:3; total molar amount of metal: molar amount of dihydrodiamine = 1:2)

[0050] (2) Add 1.000g of silicon dioxide to the solution prepared in step (1), stir until it becomes a paste and is uniformly blue-green, dry it in an oven at 60°C (overnight) for 8 hours to obtain the catalyst precursor, grind it to obtain the catalyst precursor powder (blue-green powder).

[0051] (3) The catalyst precursor powder in step (2) is transferred to a tube furnace, and Ar / H2 mixed gas A (H2 volume content is 10%, gas flow rate is 70 ml / min) is introduced. After calcination at 600°C for 4 h, it is placed to cool to room temperature. Then, Ar / O2 mixed gas B (O2 volume content is 1%, gas flow rate is 70 ml / min) is introduced to passivate for 1 h to obtain the bifunctional Ni-Cu bimetallic catalyst (Cu theoretical loading is 5%, Ni theoretical loading is 15%, and total metal theoretical loading is 20%).

[0052] The physical adsorption-desorption curve of the catalyst is as follows: Figure 1 As shown, the aperture distribution is as follows Figure 2 As shown, from Figure 1 It can be seen that the specific surface area of ​​the novel NiCu catalyst is 569.2212 m². 2 / g, the hysteresis loop of the curve shows a sudden change, which is due to the pore-forming effect of dicyandiamide causing a significant change in the pore structure of the catalyst. Figure 2 This further explains the changes in the catalyst's pore structure. The catalyst's pore size distribution exhibits a bimodal distribution, with the appearance of pores around 4 nm in size. From... Figure 2 As can be seen, the pore volume is 0.72 cm. 3 / g, with a pore size of 5.53nm.

[0053] The transmission electron microscope image of the catalyst is shown below. Figure 3 As shown, from Figure 3 As can be seen, almost all catalyst particles are uniformly anchored within the ordered pores of the support. The particle size distribution of the catalyst is shown in the figure. Figure 4 As shown, from Figure 4 It can be seen that the particle size of this new catalyst is mostly 4nm, and the particle size is stable between 4-7nm.

[0054] Hydrogenation experiments were conducted on organic liquid hydrogen storage materials using the catalyst prepared in Example 1 and a commercially available Ru / Al2O3 supported catalyst (purchased from Shaanxi Kaida Chemical Co., Ltd., analytical grade AR).

[0055] Take 0.2g of the catalyst prepared in Example 1, use 2.0g of aziridine carbazole as the hydrogen storage material, add 40ml of cyclohexane as the solvent, and react at a pressure of 7MPa, a temperature of 150℃, a rotation speed of 600rpm / min, and a reaction time of 25min to achieve complete hydrogenation of aziridine carbazole without any other byproducts. The hydrogenation reaction components of aziridine carbazole prepared by this catalyst are as follows: Figure 5 As shown, from Figure 5 It can be seen that the NiCu bimetallic catalyst completes hydrogenation in 25 minutes.

[0056] 0.2 g of a commercial 5 wt% Ru / Al₂O₃ supported catalyst, 2 g of aziridine carbazole, and 40 ml of n-hexane solvent were placed in a reactor. The hydrogenation performance was tested under the following conditions: reaction pressure 7 MPa, reaction temperature 150 °C, and reaction speed 600 rpm / min. The results are as follows: Figure 6 .from Figure 6 It can be seen that complete hydrogenation can be achieved after 50 minutes of reaction. Compared with the hydrogenation data of the catalyst in Example 1, the hydrogenation performance of the commercial 5wt% noble metal Ru catalyst is actually inferior to that of the novel catalyst supported on non-noble metal NiCu. This clearly demonstrates that the novel NiCu catalyst can improve the catalytic hydrogenation performance of the catalyst without using the noble metal Ru, and has great potential for industrial application.

[0057] Dehydrogenation experiments were conducted on organic liquid hydrogen storage materials using the catalyst prepared in Example 1 and a commercially available 5 wt% Pd / Al2O3 supported catalyst (purchased from Shaanxi Kaida Chemical Co., Ltd., analytical grade AR).

[0058] Using 0.2g of the catalyst prepared in Example 1, 2.0g of perhydropropylcarbazole as the hydrogen storage material, and 3.0g of mesitylene as the solvent, the reaction pressure was atmospheric pressure, the reaction temperature was 190℃, the rotation speed was 200 rpm / min, and the reaction time was 120 min to achieve complete dehydrogenation of perhydropropylcarbazole without any other byproducts. The components of the dehydrogenation reaction of this novel catalyst for perhydropropylcarbazole are as follows: Figure 7 As shown.

[0059] 0.2 g of commercially available 5 wt% Pd / Al₂O₃ supported catalyst, 2 g of perhydropropylcarbazole, and 3.0 g of mesitylene were used. The dehydrogenation performance was tested under atmospheric pressure, a reaction temperature of 190 °C, and a reaction speed of 200 rpm / min. The reaction results are as follows: Figure 8 As shown, from Figure 8 As can be seen, complete dehydrogenation can be achieved after 120 minutes of reaction. Compared with the dehydrogenation data of Example 1, the hydrogenation performance of the commercial 5wt% noble metal Pd catalyst is basically the same as that of the novel catalyst supported on non-noble metal NiCu. This fully demonstrates that the novel NiCu catalyst can improve the catalytic hydrogenation performance of the catalyst without using the noble metal Ru, and has great potential for industrial application.

[0060] Cyclic hydrogenation and dehydrogenation experiments were conducted using the catalyst prepared in Example 1 on organic liquid hydrogen storage materials:

[0061] The hydrogenation process in each cycle of the hydrogenation experiment is the same as that in the hydrogenation experiment described above.

[0062] The cyclic dehydrogenation experiment was performed in the same manner as the previous dehydrogenation experiment, with a reaction time of 120 minutes to achieve complete dehydrogenation of fully hydrogenated propylcarbazole without any other byproducts. Cyclic test data are as follows: Figure 9 As shown in the figure (the rising curve represents the hydrogenation process, and the falling curve represents the dehydrogenation process). From Figure 9 It can be seen that the catalyst can complete 5 addition-dehydrogenation cycles without significant performance degradation, indicating that the catalyst has good stability and can be used multiple times.

[0063] Example 2

[0064] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0065] The difference is that the calcination temperature in step (3) of Example 2 is 500℃.

[0066] Example 3

[0067] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0068] The difference is that the calcination temperature in step (3) of Example 3 is 700℃.

[0069] Example 4

[0070] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0071] The difference is that the calcination temperature in step (3) of Example 4 is 800℃.

[0072] Example 5

[0073] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0074] The difference is that the calcination temperature in step (3) of Example 5 is 900℃.

[0075] Example 6

[0076] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0077] The difference is that the calcination temperature in step (3) of Example 6 is 1000℃.

[0078] Inductively coupled plasma atomic emission spectrometry (ICP-AES) was performed on the catalysts prepared in Examples 1-6 to determine the actual loading of the active metal in the catalysts. The data obtained are shown in Table 1.

[0079] Table 1

[0080]

[0081] The catalysts prepared in Examples 1-4 were subjected to XRD tests to determine the degree of crystallinity of the metal components in the catalysts. The data obtained are as follows: Figure 10 As shown. From Figure 10 It can be seen that as the calcination stability increases, the metal diffraction peaks gradually become larger, and the metal components show some agglomeration. However, the peaks are still not sharp, and the catalyst particles at low temperatures are well dispersed in the catalyst.

[0082] Example 7

[0083] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0084] The difference is that in step (1) of Example 7, the amount of dihydrodiamine added is changed so that the total molar amount of metal: molar amount of dihydrodiamine = 1:3.

[0085] Example 8

[0086] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0087] The difference is that in step (1) of Example 8, the amount of dihydrodiamine added is changed so that the total molar amount of metal: molar amount of dihydrodiamine = 1:1.

[0088] Example 9

[0089] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0090] The difference is that in step (1) of Example 9, the amount of dihydrodiamine added is changed so that the total molar amount of metal: molar amount of dihydrodiamine = 1:0.5.

[0091] Example 10

[0092] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0093] The difference is that in step (1) of Example 10, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the mass ratio of Cu:Ni is 1:1.

[0094] Example 11

[0095] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0096] The difference is that in step (1) of Example 11, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the mass ratio of Cu:Ni is 1:2.

[0097] Example 12

[0098] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0099] The difference is that in step (1) of Example 12, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the mass ratio of Cu:Ni is 1:4.

[0100] Example 13

[0101] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0102] The difference is that in step (1) of Example 13, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the mass ratio of Cu:Ni is 1:5.

[0103] Example 14

[0104] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0105] The difference is that in step (1) of Example 14, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the mass ratio of Cu:Ni is 2:1.

[0106] Example 15

[0107] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0108] The difference is that in step (1) of Example 15, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the Cu:Ni mass ratio is 3:1.

[0109] Example 16

[0110] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0111] The difference is that in step (1) of Example 16, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the Cu:Ni mass ratio is 4:1.

[0112] Example 17

[0113] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0114] The difference is that in step (1) of Example 17, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the Cu:Ni mass ratio is 5:1.

[0115] The catalysts prepared in Examples 10-13 were subjected to inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine the actual loading of the active metal in the catalysts. The data obtained are shown in Table 2.

[0116] Table 2

[0117]

[0118] As can be seen from Table 2, the total loading of active metal NiCu in the catalyst is basically constant between 14wt% and 16wt%, which is consistent with the theoretical value.

[0119] The catalysts prepared in Examples 1 and 10-13 were tested using X-ray diffraction techniques, and the data obtained are as follows: Figure 11 As shown. From Figure 11 It can be seen that the characteristic peaks of the active metal components in the catalyst are not sharp, indicating that there is basically no agglomeration, the metal components are uniformly distributed, and the dispersion is high.

[0120] Example 18

[0121] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0122] The difference is that in step (1) of Example 18, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added was changed so that the total loading of nickel and copper metal was 5%.

[0123] Example 19

[0124] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0125] The difference is that in step (1) of Example 19, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the total loading of nickel and copper metal is 10%.

[0126] Example 20

[0127] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0128] The difference is that in step (1) of Example 20, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added was changed so that the total loading of nickel and copper metal was 15%, and the catalyst was denoted as 15Cu1Ni3 / CN-SiO2-600.

[0129] Example 21

[0130] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0131] The difference is that in step (1) of Example 21, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the total loading of nickel and copper metal is 20%.

[0132] Example 22

[0133] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0134] The difference is that in step (1) of Example 22, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the total loading of nickel and copper metal is 25%, and the catalyst is denoted as 25Cu1Ni3 / CN-SiO2-600.

[0135] Example 23

[0136] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0137] The difference is that in step (1) of Example 23, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the total loading of nickel and copper metal is 30%.

[0138] Example 24

[0139] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0140] The difference is that in step (1) of Example 24, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added was changed so that the total loading of nickel and copper metal was 35%.

[0141] Example 25

[0142] A method for preparing a bifunctional Ni-Cu bimetallic catalyst, the steps of which are as described in Example 1:

[0143] The difference is that in step (1) of Example 25, the amount of nickel nitrate hexahydrate and copper nitrate hydrate added is changed so that the total loading of nickel and copper metal is 40%.

[0144] The catalysts prepared in Examples 20 and 22 were subjected to inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine the actual loading of the active metal in the catalysts. The data obtained are shown in Table 3.

[0145] Table 3

[0146] Example Actual Cu loading (wt%) Actual Ni loading (wt%) Total actual metal loading (wt%) Example 20 2.56 9.85 12.41 Example 22 4.08 14.85 18.93

[0147] Table 3 shows that the total loading of active metal NiCu in the catalyst is in good agreement with the theoretical data.

[0148] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a bifunctional Ni-Cu bimetallic catalyst, characterized in that, Includes the following steps: (1) Weigh out nickel metal salt, copper metal salt and N-containing organic ligand, then add dispersion solvent, heat to 60-100℃, heat under reflux and stir until completely dissolved to obtain a uniformly mixed solution; (2) Add the carrier to the solution prepared in step (1), stir evenly, dry at 60-80℃ overnight to obtain the catalyst precursor, and grind to obtain the catalyst precursor powder; (3) The catalyst precursor powder in step (2) is transferred to a tube furnace, and a mixture of inert gas and H2 is introduced into it for calcination for 4 hours. After calcination, it is cooled to room temperature, and then a mixture of inert gas and O2 is introduced into it for passivation for 1 hour to obtain the bifunctional Ni-Cu bimetallic catalyst. The molar ratio of nickel metal salt and copper metal salt in step (1) is 5:1-1:5; the molar ratio of the total amount of nickel metal salt and copper metal salt to the N-containing organic ligand is 1:0.5-1:

3.

2. The method for preparing the bifunctional Ni-Cu bimetallic catalyst according to claim 1, characterized in that, In step (1), the nickel metal salt is any one of nickel nitrate, nickel chloride, and nickel acetate; the copper metal salt is any one of copper nitrate, copper chloride, and copper acetate; the nitrogen-containing organic ligand is any one of dicyandiamide, 1,10-phenanthroline, 2,2'-bipyridine, and melamine; and the dispersing solvent is any one of water, anhydrous ethanol, anhydrous methanol, and dimethyl sulfoxide.

3. The method for preparing the bifunctional Ni-Cu bimetallic catalyst according to claim 1, characterized in that, The carrier in step (2) is any one of silicon dioxide, aluminum oxide, titanium dioxide, layered graphite and carbon black.

4. The method for preparing the bifunctional Ni-Cu bimetallic catalyst according to claim 1, characterized in that, In step (3), the inert gas is Ar; the volume content of H2 in the mixed gas A is 10%, and the gas flow rate of the mixed gas A is 70 ml / min; the volume content of O2 in the mixed gas B is 1%, and the gas flow rate of the mixed gas B is 70 ml / min.

5. The method for preparing the bifunctional Ni-Cu bimetallic catalyst according to claim 1, characterized in that, The calcination temperature in step (3) is 500-1000℃.

6. The catalyst prepared by the method for preparing the bifunctional Ni-Cu bimetallic catalyst according to any one of claims 1 to 5, characterized in that, The catalyst uses Ni and Cu metals as active components, and the catalyst pore volume is 0.5-1.1 cm³. 3 / g, specific surface area is 400-1000 m² 2 / g, the NiCu metal loading in the catalyst is 5-30%, and the particle size of the catalyst metal particles is 3-7nm.

7. The application of the catalyst according to claim 6, characterized in that, The catalyst can be used for the hydrogenation and dehydrogenation of organic liquid hydrogen storage materials; When used for hydrogenation of organic liquid hydrogen storage materials, the organic liquid hydrogen storage material is any one of aziridine carbazole, aziridine carbazole, toluene, dibenzyltoluene, 1-methylindole, and 1,2-dimethylindole; When used for dehydrogenation of organic liquid hydrogen storage materials, the organic liquid hydrogen storage material is any one of perhydronitropropylcarbazole, perhydronitroethylcarbazole, methylcyclohexane, perhydronitrodibenzyltoluene, perhydronitro1-methylindole, and perhydronitro1,2-dimethylindole.

8. The application of the catalyst according to claim 7, characterized in that, When the catalyst is used for hydrogenation of organic liquid hydrogen storage materials, the specific method is as follows: the catalyst and organic liquid hydrogen storage materials are mixed at a mass ratio of 1:1, and then cyclohexane is added as a solvent. The reaction pressure is 6-8 MPa, the reaction temperature is 130-150℃, and the rotation speed is 600-700 rpm / min. When the catalyst is used for hydrogenation of organic liquid hydrogen storage materials, the specific method is as follows: the catalyst and organic liquid hydrogen storage materials are mixed at a mass ratio of 1:1, and then mesitylene is added as a solvent. The reaction pressure is atmospheric pressure, the reaction temperature is 180-200℃, and the rotation speed is 180-220 rpm / min.

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