Preparation method and application of ammonia heterojunction interface regulated co-mo2c@nc diatomic catalyst

Abstract

The application discloses a preparation method and application of a Co-Mo2C@NC diatomic catalyst regulated by an aminated hetero interface. CoMoO4 nanorod-like crystals are prepared by using cobalt (Co) and molybdenum (Mo) salts as precursors and a hydrothermal method; N-Pot is prepared by using a high-nitrogen and carbon compound, a hydrogen-nitrogen atmosphere and a programmed temperature in-situ topological phase change; and nanometer CoMoO4 is anchored on the N-doped carbon hetero structure of the N-Pot by annealing to prepare the Co-Mo2C@NC diatomic catalyst. The catalyst prepared by the method is used for continuous amination and cyclization of materials containing diol hydroxyl groups, such as ethylene glycol (EG), diethylene glycol (DEG), dihydroxyl amination, cyclization amination, preparation of high-value organic amine products such as ethylenediamine, piperazine, diethylene glycol amine and morpholine, and the like. The production process is continuously operated, and equipment is connected in series to regulate industrial production of different amine derivatives.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a method for preparing and applying a Co-Mo2C@NC diatomic catalyst regulated by an ammoniation heterostructure interface. Background Technology

[0002] Currently, the mass production of ammonia widely employs the Haber Bosch process, using an iron (γ-Fe)-based catalyst to react nitrogen and hydrogen from the air under high temperature and pressure. Researchers, including Nishibayashi Hitoshi, in collaboration with companies such as Idemitsu Kosan and Nissan Chemical, have used molybdenum (Mo) as a catalyst, achieving a synthesis rate seven times faster than γ-Fe iron-based catalysts and increasing the number of uses to 15 times, reaching 60,000. Ammonia plays a vital role in people's diets as a nitrogen source for fertilizers and proteins. Ammonia and organic matter are synthesized into organic amines through catalytic ammoniation. Organic amines are classified into seven major categories: aliphatic amines, alkanolamines, alicyclic amines, aromatic amines, naphthylamines, and other amines. With broad downstream applications and large industrial demand, promoting the development of the organic amine industry is of great importance.

[0003] Ethylene glycol and diethylene glycol are important raw materials for polyester products. In recent years, national policy goals have focused on greening, high-end development, and intelligent manufacturing. With continuous innovation in bioenergy and materials technology, the production capacity of bio-ethylene glycol and diethylene glycol is constantly increasing. In China, the traditional methods for producing ethylene glycol are the petroleum-based ethylene process and coal-based production, with coal-based ethylene glycol showing particularly significant new capacity growth. Ethylene glycol and diethylene glycol can be converted into various amine compounds through amination reactions. These compounds have a wide range of applications. For example: diethylene glycolamine (DGA) is readily biodegradable, has low bioaccumulation, and high biostability, and is used in high-end electronic products such as polymer proton exchange membranes, liquid crystals, and microspheres; morpholine is one of the important cyclic amines used in industry, a raw material for new pesticides and pharmaceuticals, a gas absorbent, a synthetic herbicide, an environmentally friendly solvent for synthetic fibers, an antioxidant, a preservative, a slowing agent, and an antiscalant; bismorpholino diethyl ether is used as a waterborne polyurethane curing agent; ethylenediamine is an important chemical raw material used in the production of insecticides, herbicides, fuels, and curing agents; piperazine, as a pharmaceutical intermediate, is used in the production of fluphenazine, dimethicone, piperazine citric acid, levonorpiperazine, and piperazine ferulic acid; hydroxypiperazine is used to synthesize surfactants, pharmaceuticals and pesticides, and polyurethane curing agents.

[0004] In organic synthesis, single-atom catalysts have played a wide role in applications. However, under normal circumstances, single-atom catalysts have only one active site, which limits their performance and makes them unable to perform catalytic reactions, including amination and cyclic amine reactions, which require both selectivity and versatility.

[0005] Polymeric carbon nitride (CN) is an organic semiconductor material with a fibrous structure bonded together by hydrogen bonds, also known as a heterojunction (N-Pot). Materials with metal atoms fixed by polymeric carbon nitride (CN) have good catalytic properties. Summary of the Invention

[0006] This invention utilizes polymerized carbon nitride as a substrate to prepare diatomic catalysts. It provides a method for preparing and applying Co-Mo2C@NC diatomic catalysts regulated by an ammoniation heterostructure.

[0007] Nano-Co-Mo2C heterostructures were prepared via in-situ topological phase transition and anchored on N-doped carbon (Co-Mo2C@NC). Cobalt (Co) and molybdenum (Mo) incorporated into the CN framework structure entered the N-pot of the carbon nitride framework. This process, utilizing new energy levels, high thermal conductivity, high loading, and abundant heterointerfaces, improved the spatial separation of charge carriers and increased mass transfer, thereby enhancing the catalyst's conversion, selectivity, separation efficiency, and specific surface area, further exhibiting high catalytic activity. Furthermore, it achieved adaptive coordination during the reaction process, demonstrating excellent general performance.

[0008] The catalyst obtained by the preparation method is used for the amination synthesis of ethylene glycol and diethylene glycol to obtain high-value-added aliphatic amines and cyclic amines such as ethylenediamine, piperazine, hydroxyethylpiperazine, diethylene glycolamine, and morpholine. The Co-Mo2C@NC diatomic catalyst has high activity and high stability, and exhibits high selectivity for target substances under different reaction conditions. It also has the advantages of mild, continuous and universally applicable reaction conditions.

[0009] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution. One of the objectives of the present invention is to provide: a method for preparing a Co-Mo2C@NC diatomic catalyst with ammoniated heterostructure interface regulation, characterized in that the preparation method includes:

[0010] Prepare rod-shaped crystalline phase of cobalt molybdate (CoMoO4) as catalyst precursor.

[0011] Prepare polymeric carbon nitride (NC) heterosupports.

[0012] Preparation of heterogeneous interface-regulated Co-Mo2C@NC diatomic catalysts.

[0013] To achieve the above objectives, the present invention is implemented as follows:

[0014] A method for preparing a Co-Mo2C@NC diatomic catalyst with ammoniated heterostructure interface includes three steps:

[0015] (1) Preparation of cobalt molybdate (CoMoO4) as a catalyst precursor.

[0016] Soluble cobalt salt and molybdenum salt were weighed separately and prepared into aqueous solutions, which were then thoroughly mixed with polyethylene glycol / aqueous solution. The aqueous solution of polyethylene glycol served as the structure directing agent for synthesizing nanorods. The reactants and structure directing agent were thoroughly mixed and added to a hydrothermal reactor. The reactor was stirred, and the temperature and pressure were controlled for 10-60 minutes. After the reaction was completed, the mixture was cooled to room temperature and depressurized. The resulting ultrafine product was first centrifuged, then washed 3-5 times with distilled water, and dried at 50-100℃ under normal or negative pressure for 10-24 hours to prepare cobalt molybdate (CoMoO4) nanorod materials.

[0017] (2) Preparation of polymerized carbon (NC) heterosupport

[0018] Weigh a precursor with high nitrogen (N) and carbon (C) content and a triazine or mesotriazine compound. In a hydrogen-nitrogen mixed atmosphere, heat the mixture to 400-600℃ using a programmed temperature rise method. Hold the mixture at the final temperature for 6-24 hours to complete the in-situ topological phase transition. Then, allow it to cool naturally to room temperature to obtain a polymer carbon nitride (NC) heterostructure (N-Pot) support.

[0019] (3) Preparation of Co-Mo2C@NC diatomic catalyst

[0020] The cobalt molybdate (CoMoO4) nanomaterials obtained in step (1) were dispersed in anhydrous ethanol, and dicyandiamide (DCDA) was added at a ratio of 1:10 mol as the carbon and nitrogen source for the metal nitrides and carbides. Then, polymerized carbon nitride (NC) heterosupports prepared in step (2) were added according to different molybdenum and cobalt loadings. The mixture was thoroughly mixed, and the temperature was programmed to 500-1000℃ in a hydrogen-nitrogen mixed atmosphere, held at the final temperature for 6-24 hours, and then naturally cooled to room temperature. Further annealing after loading was performed, and the in-situ carbonization and nitridation of the cobalt molybdate nanorods were due to the release of nitrogen-carbon substances (CN) from the thermal decomposition of dicyandiamide. - A certain amount of metal nitrides (MoN and CoN) and molybdenum carbide (Mo2C) are formed and embedded in the polymerized carbon nitride support to obtain the heterogeneous diatomic catalyst Co-Mo2C@NC for ammoniation.

[0021] Furthermore, the soluble cobalt salt in step (1) is one or a mixture of two or more of cobalt chloride, cobalt sulfate, cobalt nitrate, and cobalt acetate.

[0022] Furthermore, the soluble molybdenum salt in step (1) is one or a mixture of two or more of the following: ammonium molybdate, potassium molybdate, sodium molybdate, and ammonium dodecylmolybdate phosphate.

[0023] Furthermore, in step (1), the molar ratio of soluble cobalt salt to molybdenum salt is 1:05 to 2, with 1:1 being the most preferred. The molar concentration of the bimetallic soluble salt in the polyethanol / water solution is 0.01 to 3 mol / L.

[0024] Furthermore, in step (1), the hydrothermal reaction temperature is 120-200℃, the reaction time is 0.5-1h, and the pressure is 0.2-0.6MPa.

[0025] Furthermore, in step (1), the anisotropic agent is polyethylene glycol HO(CH2CH2O). n H: is a polymer of α-hydrogen-ω-hydroxyl (oxy-1,2-ethylenedimethyl) glycol, where the value of n determines the molecular weight of α-polyglycol. It is one or a mixture of two or more of polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol 2000, polyethylene glycol 6000, and polyethylene glycol 12000.

[0026] Furthermore, in step (2), the precursor with high nitrogen (N) / carbon (C) content and / or triazine compound: dicyandiamine (dicyandiamine) melamine

[0027] cyanuric acid Trichloroisocyanuric acid (trichlorotriazine trione) Thiourea urea One or more of the following.

[0028] Furthermore, in step (2), the hydrogen-nitrogen mixture of different nitrogen- and carbon-containing organic compounds is pyrolyzed in an atmosphere of 10% H2 to 90% N2, heated to 500 to 1000°C, held at the final temperature for 2 to 24 hours, and then naturally cooled to room temperature to obtain heterostructures of polymerized carbon nitride (NC) with different structures. Preferably, the temperature is programmed to 650°C and held at 650°C for 24 hours.

[0029] Furthermore, in step (2), the different structures of polymerized carbon nitride (NC) heterosupports include: α-C3N4, β-C3N4, g-C3N4, cubic-C3N4, non-cubic-C3N4, and tris-triazine-C3N4.

[0030] Furthermore, in step (3), cobalt molybdate (CoMoO4) and dicyandiamide The molar ratio is 1:10, preferably 1:3mol. During annealing and pyrolysis, a Co-Mo2C bimetallic compound can be generated, and the bimetal can be embedded in the polymer carbon nitride framework N-Pot (heterogeneous structure).

[0031] Compared with the prior art, the present invention has the following characteristics:

[0032] (1) Cobalt molybdate nanorod-shaped crystalline phase was prepared by hydrothermal method using soluble cobalt (Co) salt and molybdenum (Mo) salt as precursors, polyethylene glycol of a certain molecular weight as a directing agent, and water as solvent. The cobalt molybdate (CoMoO4) crystalline phase has molybdenum (Mo) and cobalt (Co) chemical bonds and composition ratio. In-situ pyrolysis with dicyandiamide generates metal nitrides (MoN or CoN) and molybdenum carbide (Mo2C). Simultaneously, excess dicyandiamide releases nitrogen / carbon substances (CN) during pyrolysis. - The bimetallic catalyst Co-Mo2C@NC, which is uniformly dispersed and formed in situ, is macroscopically a stacked rod-like structure and microscopically a tunable heterogeneous interface (α-C3N4, β-C3N4, g-C3N4, etc.) of polymeric carbon nitride (NC). The confined catalyst also has the pore effect of selective adsorption, which improves the activity of the catalyst.

[0033] (2) Carbon nitride (NC), a support polymer, is an organic semiconductor material widely used in the field of catalysts due to its excellent chemical stability and unique electronic structure. This invention obtains structural phases with different geometric configurations by adjusting the surface and atomic arrangement of CN.

[0034] Polymerized carbon nitride (NC) is obtained by pyrolyzing a high-nitrogen-content precursor through a network structure of triazine or tri-s-triazine linked by a tertiary amine phase at different temperatures under the protection of a mixed H2-N2 gas.

[0035] Further regulation of the polymeric carbon nitride (NC) framework structure can be achieved, thereby obtaining better electron-hole pairs, ion exchange sites, loading, specific surface area, lattice strength, etc. When loaded with the bimetallic catalyst Co-Mo2C, the content of active bimetals can be easily controlled. After programmed temperature rise and calcination (or annealing) in a hydrogen-nitrogen mixed atmosphere, a highly loaded and highly active heterogeneous interface-regulated Co-Mo2C@NC biatomic catalyst is obtained.

[0036] (3) Introducing bimetallic atoms into the polycarbon nitride (NC) framework allows for the control of its physicochemical properties. The incorporated metal elements enter the N-Pot of the NC framework, facilitating the establishment of new energy levels, improving the spatial separation of charge carriers, increasing mass transfer, and lowering the energy barrier for activation during amination reactions. The positions of C / N vacancies and the types and quantities of incorporated bimetallic elements are easily controlled, significantly influencing the catalytic performance of the Co-Mo2C@NC catalyst and the selectivity of target substances. This enables the amination and cycloamination of alcohol hydroxyl groups; achieves both selectivity and diversity; and allows for the control of reaction performance with multiple substrates without damage to the catalyst.

[0037] The catalyst is characterized by selectivity, high activity, and high stability, and operates under mild reaction conditions. It is used for the catalytic reactions of continuous amination and cycloamination of ethylene glycol and diethylene glycol, and for the selective production of ethylenediamine, piperazine, diethylene glycolamine, and morpholine, demonstrating its versatility.

[0038] An application of Co-Mo2C@NC diatomic catalysis regulated by an ammoniation heterostructure, the specific steps of which are as follows:

[0039] (1) Use hydrogen to reduce the above catalyst at a pressure of 0.1-1.0 MPa for 1-3 hours and a hydrogen flow rate of 100-600 ml / min.

[0040] (2) The reduced catalyst was reacted with different raw materials, ethylene glycol (EG) and diethylene glycol (DEG), and hydrogen in a multi-stage continuous fixed-bed reactor under different operating parameters. The products produced by the different raw materials were:

[0041] Ethylene glycol (EG): ethanolamine, ethylenediamine, piperazine, hydroxyethylpiperazine;

[0042] Diethylene glycol (DEG): diethylene glycolamine, morpholine, bismorpholine ethyl ether.

[0043] The reaction temperature was set to 120–260℃, the reaction pressure was set to 1.0–7.0 MPa, and the hydrogen to ammonia flow rate ratio was 20–10:1 ml / min.

[0044] Furthermore, the molar ratio of ethylene glycol (EG) and / or diethylene glycol (DEG) to hydrogen and ammonia is 1:10 to 60:1 to 20.

[0045] Furthermore, the reaction gases include hydrogen and ammonia. Under a hydrogen atmosphere, diol hydroxyl groups are catalyzed and mono- or di-substituted with amino groups, and the monoamines and diamines undergo recyclization reactions to generate cyclic aliphatic amines. In excess gas, the reaction heat is circulated out to stabilize the reaction temperature of the series continuous fixed-bed reactor.

[0046] Furthermore, products made from different raw materials are separated into corresponding high-purity monomers through distillation. Attached Figure Description

[0047] Figure 1 SEM images (a, b) of the nano-cobalt molybdate prepared in Example 1.

[0048] Figure 2 STEM and EDS images of the Co-Mo2C@NC diatomic catalyst from Example 1 are shown.

[0049] Figure 3: TEM image of the Co-Mo2C@NC diatomic catalyst prepared in Example 1; "@" indicates coating, meaning: cobalt-molybdenum carbide nanoparticles are the core, in the center; different interfaces of polymerized carbon nitride are the shell, on the outer layer. Detailed Implementation

[0050] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following description.

[0051] This invention presents a method for preparing and applying an ammonified heterointerface-controlled Co-Mo2C@NC diatomic catalyst using nanorod-shaped cobalt molybdate (CoMoO4) as a precursor.

[0052] Example 1

[0053] 1. Catalyst Preparation

[0054] (1) Preparation of cobalt molybdate (CoMoO4) as catalyst precursor

[0055] 50 mmol of cobalt nitrate hexahydrate Co(NO3)2·6H2O (14.6 g) red crystalline powder and 50 mmol of ammonium molybdate tetrahydrate (NH4)2MoO4·4H2O (13.4 g) white crystalline powder were dissolved in 200 ml of 50% polyethylene glycol (PEG-600) aqueous solution. After stirring to form a homogeneous mixture, the mixture was transferred to a PTFE-lined high-pressure reactor (500 ml) and subjected to a hydrothermal reaction at 160 °C and 0.4 MPa for 30 min with stirring. After the reaction was completed, the mixture was cooled to room temperature, the pressure was released, and the mixture was centrifuged. The residue was washed 3-5 times with distilled water and dried at 100 °C under normal pressure for 10 h to obtain 10.9 g of pale blue cobalt molybdate (CoMoO4). See attached electron micrograph of cobalt molybdate. Figure 1 .

[0056] (2) Preparation of polycarbon nitride (NC) heterosupport

[0057] 600g of cyanuric acid was weighed and heated to 450℃ at a heating rate of 5℃ / min in a 10% (H2) and 90% (N2) atmosphere. The temperature was maintained at 450℃ for calcination for 4 hours, followed by natural cooling to obtain 430g of polymerized carbon nitride heterosupport. At the high temperature of 450℃, the generated carbon nitride retains the triazine conjugated structure, and hydrogen bonds promote the adsorption of metal ions by electrons and holes.

[0058] (3) Preparation of Co-Mo2C@NC diatomic catalyst

[0059] 10.9g of nano-cobalt molybdate, 4.2g of dicyandiamide, and 10g of the polymerized carbon nitride prepared in step (2) above were added to 60ml of anhydrous ethanol. After ultrasonic dispersion, the mixture was heated to 650℃ at a heating rate of 5℃ / min in a 10% (H2) and 90% (N2) atmosphere, and calcined at 650℃ for 4h to complete the in-situ carbonization and nitridation of the active metal ions in cobalt molybdate. The nitrogen-carbon substances (CN) released by the thermal decomposition of dicyandiamide were also obtained. - The resulting metal nitrides (MoN and CoN) and molybdenum carbide (Mo2C) were embedded in a polymeric carbon nitride support, and the annealing process was completed by natural cooling and secondary calcination. A total of 19.6 g of the diatomic catalyst Co-Mo2C@NC was obtained, containing 24.5% molybdenum and 15.1% cobalt. It was named CHJ-Ⅰ. STEM and EDS images are attached. Figure 2 Appendix Figure 3 .

[0060] 1. Application of CHJ-Ⅰ catalyst

[0061] 40g of CHJ-Ⅰ catalyst was ground, compressed, crushed, and sieved to obtain catalyst particles of 40-60 mesh. These particles were divided into two equal parts and loaded into the isothermal zones of tubes A and B in a fixed-bed reactor. Reactors A and B were connected in series, each with its own condenser, storage tank, and separate parameter setting system. Hydrogen gas was used at a flow rate of 300 ml / min at 260℃ to reduce the CHJ-Ⅰ catalyst in tubes A and B for 6 hours. After cooling, under different reaction pressures, temperatures, hydrogen-ammonia, ammonia-ethanol ratios, and liquid hourly space velocity (LHSV), ethylene glycol and diethylene glycol, containing hydroxyl groups, were pumped into reactors A and B at different speeds and pressures using a high-pressure constant flow pump. The resulting reaction solutions were quantitatively analyzed using a calibrated gas chromatograph. The conversion rate of the hydroxyl groups (ethylene glycol and diethylene glycol) in reactor A was 100%. In reactor B, corresponding cyclic amine derivatives were generated. Specific operating parameters, reaction product components, and selectivity are shown in Table 1.

[0062] Table 1:

[0063]

[0064] Example 2

[0065] 1. Catalyst Preparation

[0066] (1) Preparation of cobalt molybdate (CoMoO4) as catalyst precursor

[0067] 12.5 g of 50 mmol cobalt acetate tetrahydrate Co(CH3COO)2·4H2O (deep red monoclinic prismatic crystals) and 12.1 g of 50 mmol sodium molybdate dihydrate (Na2Mo4·2H2O) (white crystalline powder) were dissolved in 200 ml of 50% polyethylene glycol (PEG-800) aqueous solution. After stirring to form a homogeneous mixture, the mixture was transferred to a PTFE-lined high-pressure reactor (500 ml). The mixture was subjected to hydrothermal reaction at 160 °C and 0.4 MPa for 30 min with stirring. After the reaction was completed, the mixture was cooled to room temperature, the pressure was released, and the mixture was centrifuged. The mixture was washed 3-5 times with distilled water and dried at 100 °C and atmospheric pressure for 10 h to obtain 10.2 g of light blue cobalt molybdate (CoMoO4).

[0068] (2) Preparation of polycarbon nitride (NC) heterosupport

[0069] 600g of melamine was weighed and heated to 450℃ in a 10% (H2) and 90% (N2) atmosphere at a heating rate of 5℃ / min. The temperature was maintained at 450℃ for calcination for 4h, and then cooled naturally to obtain 440g of polymerized carbon nitride heterosupport.

[0070] (3) Preparation of Co-Mo2C@NC diatomic catalyst

[0071] 10.9 g of nano-cobalt molybdate, 3.9 g of dicyandiamide, and 9.8 g of polymerized carbon nitride obtained in step (2) above were added to 50 ml of anhydrous ethanol. After ultrasonic dispersion, the mixture was heated to 650 °C at a heating rate of 5 °C / min in a 10% (H2) and 90% (N2) atmosphere, and calcined at 650 °C for 4 h to complete the in-situ carbonization and nitridation of active metal ions in cobalt molybdate. The nitrogen-carbon substances (CN) released by the thermal decomposition of dicyandiamide were also observed. - The resulting metal nitrides (MoN and CoN) and molybdenum carbide (Mo2C) were embedded in a polymeric carbon nitride support, and the annealing process was completed by natural cooling and secondary calcination. A total of 19.1 g of the diatomic catalyst Co-Mo2C@NC was obtained, containing 24.2% molybdenum and 15.0% cobalt. It was named CHJ-Ⅱ.

[0072] 2. The role of CHJ-II catalyst

[0073] 40g of CHJ-II catalyst was ground, compressed, crushed, and sieved to obtain catalyst particles of 40-60 mesh. These particles were divided into two equal parts and loaded into the isothermal zones of tubes A and B in a fixed-bed reactor. Reactors A and B were connected in series, each with its own condenser, storage tank, and separate parameter setting system. Hydrogen gas was used at a flow rate of 300 ml / min at 260℃ to reduce the CHJ-II catalyst in tubes A and B for 6 hours. After cooling, under different reaction pressures, temperatures, hydrogen-ammonia, ammonia-ethanol ratios, and liquid hourly space velocity (LHSV), ethylene glycol and diethylene glycol, containing hydroxyl groups, were pumped into reactors A and B at different speeds and pressures using a high-pressure constant flow pump. The resulting reaction solutions were quantitatively analyzed using a calibrated gas chromatograph. The conversion rate of the hydroxyl groups (ethylene glycol and diethylene glycol) in reactor A was 100%. In reactor B, corresponding cyclic amine derivatives were generated. Specific operating parameters, reaction product components, and selectivity are shown in Table 2.

[0074] Table 2:

[0075]

[0076] Example 3

[0077] 1. Catalyst Preparation

[0078] (1) Preparation of cobalt molybdate (CoMoO4) as catalyst precursor

[0079] 11.9 g of red monoclinic crystals (50 mmol cobalt chloride hexahydrate, CoCl2·6H2O) and 11.9 g of white crystalline powder (50 mmol potassium molybdate, K2Mo4) were dissolved in 200 ml of 50% polyethylene glycol (PEG-400) aqueous solution. After stirring to form a homogeneous mixture, the mixture was transferred to a PTFE-lined high-pressure reactor (500 ml). The mixture was subjected to a hydrothermal reaction at 160 °C and 0.4 MPa for 30 min with stirring. After the reaction was completed, the mixture was cooled to room temperature, the pressure was released, and the mixture was centrifuged. The mixture was washed 3-5 times with distilled water and dried at 100 °C and atmospheric pressure for 10 h to obtain 10.9 g of light blue cobalt molybdate (CoMoO4).

[0080] (2) Preparation of polycarbon nitride (NC) heterosupport

[0081] 600g of dicyandiamide was weighed and heated to 450℃ in a 10% (H2) and 90% (N2) atmosphere at a heating rate of 5℃ / min. The temperature was maintained at 450℃ for calcination for 4h, and then cooled naturally to obtain 390g of polymerized carbon nitride heterosupport.

[0082] (3) Preparation of Co-Mo2C@NC diatomic catalyst

[0083] 10.9 g of nano-cobalt molybdate, 4.2 g of dicyandiamide, and 10 g of polymerized carbon nitride prepared in step (2) above were added to 60 ml of anhydrous ethanol. After ultrasonic dispersion, the mixture was heated to 650 °C at a heating rate of 5 °C / min in a 10% (H2) and 90% (N2) atmosphere, and calcined at 650 °C for 4 h to complete the in-situ carbonization and nitridation of active metal ions in cobalt molybdate. The nitrogen-carbon substances (CN) released by the thermal decomposition of dicyandiamide were also observed. - The resulting metal nitrides (MoN and CoN) and molybdenum carbide (Mo2C) were embedded in a polymeric carbon nitride support, and the annealing process was completed by natural cooling and secondary calcination. A total of 19.6 g of the diatomic catalyst Co-Mo2C@NC was obtained. It contained 24.5% molybdenum and 15.1% cobalt. It was named CHJ-Ⅲ.

[0084] 2. The role of CHJ-Ⅲ catalyst

[0085] 40g of CHJ-Ⅲ catalyst was ground, compressed, crushed, and sieved to obtain catalyst particles of 40-60 mesh. These particles were divided into two equal parts and loaded into the isothermal zones of tubes A and B in a fixed-bed reactor. Reactors A and B were connected in series, each with its own condenser, storage tank, and separate parameter setting system. Hydrogen gas was used at a flow rate of 300 ml / min at 260℃ to reduce the CHJ-Ⅲ catalyst in tubes A and B for 6 hours. After cooling, under different reaction pressures, temperatures, hydrogen-ammonia, ammonia-ethanol ratios, and liquid hourly space velocity (LHSV), ethylene glycol and diethylene glycol, containing hydroxyl groups, were pumped into reactors A and B at different speeds and pressures using a high-pressure constant flow pump. The resulting reaction solutions were quantitatively analyzed using a calibrated gas chromatograph. The conversion rate of the hydroxyl groups (ethylene glycol and diethylene glycol) in reactor A was 100%. In reactor B, corresponding cyclic amine derivatives were generated. Specific operating parameters, reaction product components, and selectivity are shown in Table 3.

[0086] Table 3:

[0087]

[0088] Example 4

[0089] 1. Catalyst Preparation

[0090] ① Weigh out 10.9g of commercially available cobalt molybdate (CoMoO4) AR grade;

[0091] ②Weigh out 12.0g of amorphous polymeric carbon nitride purchased from the market.

[0092] Add to 60 ml of anhydrous ethanol. After ultrasonic dispersion, heat to 650 °C at a heating rate of 5 °C / min in a 10% (H2) and 90% (N2) atmosphere, maintain at 650 °C for 4 h, and allow to cool naturally to obtain 19.6 g of the diatomic catalyst Co-Mo2C@NC, containing 24.5% molybdenum and 15.1% cobalt. Named: CHJ-Ⅳ.

[0093] 2. Application of CHJ-Ⅳ catalyst

[0094] 40g of CHJ-Ⅳ catalyst was ground, pressed, crushed and sieved to obtain catalyst particles of 40-60 mesh. The particles were divided into two parts and filled into the isothermal zones of tubes A and B of the fixed-bed reactor. The A and B tube reactors were connected in series and each had its own condenser, storage tank and separate parameter setting system. Using hydrogen gas at a flow rate of 300 ml / min, the CHJ-Ⅳ catalyst in tubes A and B was reduced for 6 h at 260 °C. After cooling, under different reaction pressures, temperatures, hydrogen-ammonia, ammonia-ethanol ratios, and liquid hourly space velocity (LHSV), ethylene glycol and diethylene glycol, two alcohol-containing materials, were pumped into reactors A and B at different speeds and pressures using a high-pressure constant flow pump. The resulting reaction solutions were quantitatively analyzed using a calibrated gas chromatograph. The conversion rates of ethylene glycol and diethylene glycol in reactor A were both below 70%. No corresponding cyclic amine derivatives were generated in reactor B. Specific operating parameters, reaction product components, and selectivity are shown in Table 4.

[0095] Table 4:

[0096]

[0097] Example 5

[0098] 1. Catalyst Preparation

[0099] ① Weigh out 2.9g of nano cobalt powder (Co) and 5.4g of nano molybdenum carbide (Mo2C) purchased from the market;

[0100] ② Weigh out 11.6g of amorphous polymeric carbon nitride purchased from the market.

[0101] Add to 60 ml of anhydrous ethanol. After ultrasonic dispersion, heat to 650 °C at a heating rate of 5 °C / min in a 10% (H2) and 90% (N2) atmosphere, maintain at 650 °C for 4 h, and allow to cool naturally to obtain 19.6 g of the diatomic catalyst Co-Mo2C@NC, containing 24.5% molybdenum and 15.1% cobalt. Named: CHJ-V.

[0102] 2. Application of CHJ-V catalyst

[0103] 40g of CHJ-V catalyst was ground, compressed, crushed, and sieved to obtain catalyst particles of 40-60 mesh. These particles were divided into two equal parts and loaded into the isothermal zones of tubes A and B in a fixed-bed reactor. Reactors A and B were connected in series, each with its own condenser, storage tank, and separate parameter setting system. Hydrogen gas was used at a flow rate of 300 ml / min at 260℃ to reduce the CHJ-V catalyst in tubes A and B for 6 hours. After cooling, under different reaction pressures, temperatures, hydrogen-ammonia, ammonia-ethanol ratios, and liquid hourly space velocity (LHSV), ethylene glycol and diethylene glycol (containing hydroxyl groups) were pumped into reactors A and B at different speeds and pressures using a high-pressure constant flow pump. The resulting reaction solution was quantitatively analyzed using a calibrated gas chromatograph. No conversion of the hydroxyl groups (ethylene glycol and diethylene glycol) was observed in reactor A or reactor B. Specific operating parameters, reaction product composition, and selectivity are shown in Table 5.

[0104] Table 5:

[0105]

[0106] Examples 4 and 5 are control examples. The catalyst precursor and the support polymeric carbon nitride (NC) were both commercially available. Example 4 involved the in-situ pyrolysis synthesis of bimetals from cobalt molybdate (CoMoO4) on a support; Example 5 involved directly mixing nano-cobalt powder and molybdenum carbide with the support. Under the same operating conditions, gas chromatography analysis of the prepared products showed that the catalyst in Example 4 had the following catalytic effect: for ethylene glycol and diethylene glycol, two different alcohol-containing hydroxyl materials entering reactor A, the conversion rates of the materials were both below 70% under the same reaction conditions; for the material entering reactor B (the product of reactor A), no corresponding alicyclic amines were formed under the same reaction conditions.

[0107] In Example 5, during the application test, ethylene glycol and diethylene glycol, two different materials, were introduced into reactor A. Under the same reaction conditions, neither material reacted in reactors A nor B. Therefore, Example 5, by simply mixing the catalyst components, did not demonstrate catalytic performance.

[0108] The above descriptions are merely some embodiments and are not intended to limit the present invention. Any modifications or equivalent substitutions made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a Co-Mo2C@NC diatomic catalyst with ammoniated heterostructure interface, characterized in that, The preparation method includes the following steps: (1) Preparation of cobalt molybdate (CoMoO4) as catalyst precursor Soluble cobalt salt and molybdenum salt were weighed separately and prepared into aqueous solutions, which were then thoroughly mixed with polyethylene glycol / aqueous solution. The aqueous solution of polyethylene glycol served as the structure directing agent for the synthesis of nanorods. The reactants and structure directing agent were thoroughly mixed and added to a hydrothermal reactor. The mixture was stirred, and the temperature and pressure were controlled for 10-60 min. After the reaction was completed, the mixture was cooled to room temperature and depressurized. The resulting ultrafine product was first centrifuged, then washed 3-5 times with distilled water, and dried at 50-100℃ under normal or negative pressure for 10-24 h to prepare cobalt molybdate CoMoO4 nanorod materials. (2) Preparation of polymeric carbon nitride (NC) heterosupport Weigh a precursor with high nitrogen (N) and carbon (C) content, and / or a triazine compound, and heat it to 400-600℃ in a hydrogen-nitrogen mixed atmosphere. Hold it at the final temperature for 6-24 hours to complete the in-situ topological phase transition, and then cool it naturally to room temperature to obtain a polymerized carbon nitride NC heterosupport. The high nitrogen (N) and carbon (C) precursor and / or triazine compound is selected from one or more of the following: dicyandiamide, melamine, cyanuric acid, trichloroisocyanuric acid, thiourea, and urea; (3) Preparation of Co-Mo2C@NC diatomic catalyst The cobalt molybdate (CoMoO4) nanomaterials obtained in step (1) were dispersed in anhydrous ethanol, and dicyandiamide (DCDA) was added at a molar ratio of 1:10 as the carbon and nitrogen source for the metal nitrides and carbides. Different molybdenum and cobalt loadings were added to the polymerized carbon nitride (NC) heterosupport prepared in step (2). The mixture was homogeneous, heated to 500-1000℃ in a hydrogen-nitrogen mixed atmosphere, held at the final temperature for 6-24 hours, and then naturally cooled to room temperature. Further annealing after loading was carried out. The in-situ carbonization and nitridation of the cobalt molybdate nanorods were due to the release of nitrogen and carbon substances (CN) by the thermal decomposition of dicyandiamide. - A certain amount of metal nitrides MoN and CoN, and molybdenum carbide Mo2C are formed and embedded in the polymerized carbon nitride NC heterostructure to obtain Co-Mo2C@NC, a heterostructured diatomic catalyst for ammoniation.

2. The preparation method according to claim 1, characterized in that, In step (1), the soluble cobalt salt is selected from one or more of cobalt chloride, cobalt sulfate, cobalt nitrate, and cobalt acetate; the soluble molybdenum salt is selected from one or more of ammonium molybdate, potassium molybdate, sodium molybdate, and ammonium dodecylmolybdate phosphate; the polyethylene glycol is selected from one or more of polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 800, polyethylene glycol 2000, polyethylene glycol 6000, and polyethylene glycol 12000; and the concentration of the polyethylene glycol / water solution is 0.01–2 mol / L.

3. The preparation method according to claim 1, characterized in that, In step (2), the hydrogen-nitrogen mixture has a hydrogen volume of 10% and a nitrogen volume of 90%. The temperature is increased at a rate of 2-10℃ / min. The temperature is maintained at the final temperature of the temperature increase for 6-24 hours, and then naturally cooled to room temperature.

4. The preparation method according to claim 1, characterized in that, In step (3), the molar ratio of cobalt molybdate CoMoO4 and dicyandiamide is 1:

10. During annealing and pyrolysis, a Co-Mo2C bimetallic compound can be generated, and the bimetallic compound can be embedded in the polymerized carbon nitride NC heterogeneous support.

5. A Co-Mo2C@NC diatomic catalyst regulated by an ammoniation heterostructure interface is prepared according to any one of claims 1-4.

6. The application of the Co-Mo2C@NC diatomic catalyst according to claim 5, characterized in that, It is applied to continuous amination of alcohol hydroxyl groups and tandem ring amination reactions.

7. The application according to claim 6, characterized in that, It can be used to selectively synthesize ethanolamine, ethylenediamine, piperazine, hydroxyethylpiperazine; or diethylene glycolamine, morpholine and bismorpholine ethyl ether by continuous amination and tandem cycloammoniation of the hydroxyl groups of ethylene glycol or diethylene glycol.

8. The application according to claim 7, characterized in that, The specific steps for the continuous amination synthesis of ethylene glycol hydroxyl groups and the selective synthesis of ethanolamine, ethylenediamine, piperazine, and hydroxyethylpiperazine via tandem cycloamine reactions are as follows: The Co-Mo2C@NC diatomic catalyst was ground, pressed, crushed and sieved to obtain small granular catalyst with a mesh size of 40-60 mesh; The reactor is a fixed-bed tubular reactor, consisting of two single tubes connected in series. Each tube has an inner diameter of 20 mm and a length of 300 mm. It allows for independent sampling and setting of control parameters. The catalysts were loaded into the isothermal zone of the fixed-bed reactor, and hydrogen gas at a flow rate of 100-300 ml / min was used to reduce the reaction at 100-300℃ for 6-12 hours. After cooling, ethylene glycol (EG) was fed into the reactor through a high-pressure constant flow pump. Feed: The feed rate is 0.2 ml / min, and the material is ethylene glycol (EG). Reaction conditions in tube A: vaporization temperature 200℃, reaction temperature 180~220℃, pressure 3.0~7.0MPa, molar ratio of hydrogen:ammonia:ethylene glycol 6:8:1, with hydrogen flow rate 300ml / min; Reaction conditions in tube B: vaporization temperature 220℃, reaction temperature 220~240℃, pressure 3.0~7.0MPa, the gas phase outlet of reactor A directly enters the vaporization feed inlet of reactor B; Reactors B all have condensers. The products pass through the condenser, and the separator separates the liquid phase products.

9. The application according to claim 7, characterized in that, The specific steps for the selective synthesis of diethylene glycol amines, morpholine, and bismorpholine ethyl ethers via continuous amination and tandem cyclization of the hydroxyl groups in diethylene glycol are as follows: The Co-Mo2C@NC diatomic catalyst was ground, pressed, crushed and sieved to obtain small granular catalyst with a mesh size of 40-60 mesh; The reactor is a fixed-bed tubular reactor, consisting of two single tubes connected in series. Each tube has an inner diameter of 20 mm and a length of 300 mm. It allows for independent sampling and setting of control parameters. The catalysts were loaded into the isothermal zone of the fixed-bed reactor, and hydrogen gas at a flow rate of 100-300 ml / min was used to reduce the catalysts at 100-300℃ for 6-12 hours. The reactor was then cooled and diethylene glycol (DEG) was fed into the reactor via a high-pressure constant flow pump. Feed: The feed rate is 0.2 ml / min, and the material is diethylene glycol (DEG). Reaction conditions in tube A: vaporization temperature 200℃, reaction temperature 180~220℃, pressure 3.0~7.0MPa, molar ratio of hydrogen:ammonia:diethylene glycol 6:8:1, with hydrogen flow rate 300ml / min; Reaction conditions in tube B: vaporization temperature 220℃, reaction temperature 220~240℃, pressure 3.0~7.0MPa, the gas phase outlet of reactor A directly enters the vaporization feed inlet of reactor B; Both reactors A and B have condensers. The products pass through the condensers, and the separator separates the liquid phase products.

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