Ordered Ni / Co-NiCo heterojunction catalyst and preparation method and application thereof

Abstract

The invention provides an ordered Ni / Co-NiCo heterojunction catalyst, which comprises a carbon sphere skeleton and Ni / Co-NiCo heterojunctions, the carbon sphere skeleton wraps the Ni / Co-NiCo heterojunctions in ordered arrangement, the Ni / Co-NiCo heterojunctions have oxygen vacancies and interfaces, the Ni / Co-NiCo heterojunctions are metal Ni or Co and NiCo alloy species which are orderly arranged in carbon spheres, and Ni / Co-NiCo-C nanoparticles are respectively formed. Compared with the prior art, the ordered Ni / Co-NiCo heterojunction catalyst disclosed by the invention has the characteristics of high activity, high selectivity and recycling without reduction regeneration, and is suitable for directional deoxidation upgrading of lignin oil and derivatives thereof.

Description

Technical Field

[0001] This invention relates to the field of heterojunction catalysts, and in particular to an ordered Ni / Co-NiCo heterojunction catalyst, its preparation method, and its application. Background Technology

[0002] With the rapid growth of fossil fuel consumption, energy supply and environmental issues are becoming increasingly prominent. Promoting the replacement of petroleum-based feedstocks with renewable resources has become an important development direction. Biomass is the only renewable carbon resource in nature. It has a high lignin content and rich aromatic structure, and has the potential to produce fuels and bulk chemicals. However, lignin oil obtained after lignin depolymerization is usually a complex mixture of highly oxygenated aromatic compounds. It has defects such as strong acidity, poor stability and high corrosivity, making it difficult to use directly as a fuel or chemical feedstock. Hydrodeoxygenation (HDO) can selectively remove oxygen-containing functional groups while retaining the aromatic skeleton or directionally generating products such as alkylphenols / cyclohexanols. It is an important path for the high-value upgrading of lignin oil.

[0003] In the existing HDO catalytic system, although noble metal catalysts exhibit high activity, they suffer from high cost and scarce resources. Non-noble metal catalysts (such as Co, Ni and their compounds) have advantages in terms of cost and large-scale application, but they generally face the following technical bottlenecks: (1) Harsh reaction conditions: high temperature / hydrogen pressure is often required to achieve high conversion and selectivity; (2) Insufficient selectivity and resistance to deactivation: side reactions such as over-hydrogenation, aromatic ring saturation, and non-target CO bond breakage are prone to occur; (3) Significant differences between model derivatives and real lignin oil: the excellent catalytic performance of the catalytic system on model compounds is difficult to reproduce in real lignin oil. This is due to factors such as the complex composition of lignin oil, the diversity of oxygen-containing functional groups, competitive adsorption, and carbon deposition / polymerization side reactions; (4) Insufficient catalyst structural stability: metal / metal compound particles are prone to migration, sintering, or being covered by deposits during the reaction, resulting in activity decay.

[0004] In recent years, heterogeneous interface catalysis and defect engineering (such as oxygen vacancies) have been considered effective means to improve the performance of non-noble metal HDO catalysts (ACS Catalysis, 15 (2025) 13831-13845; ENERGY & ENVIRONMENTAL SCIENCE, 14 (2021) 5228-5259; APPLIED CATALYSIS B-ENVIRONMENT AND ENERGY, 325(2023) 122385.). Heterogeneous interfaces can promote hydrogen activation and charge transfer, and defect sites can enhance the selective adsorption and activation of oxygen-containing groups, thereby reducing the reaction energy barrier and improving selectivity (SCIENCE AND TECHNOLOGY OF ADVANCE DMATERIALS, 23 (2022) 587-616.). However, existing heterogeneous interface / defect catalysts still have problems such as complex preparation processes, difficulty in controlling interface structure, difficulty in stably retaining defect sites, and easy sintering or carbon deposition and deactivation during the reaction (MATERIALS). CHEMISTRY FRONTIERS, 5 (2021) 1033-1059. Therefore, there is an urgent need for a heterojunction HDO catalyst with a simple preparation method, controllable in-situ construction of interfaces and defects, and high stability. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an ordered Ni / Co-NiCo heterojunction catalyst that combines high activity, high selectivity and recyclability without the need for reduction and regeneration, making it suitable for the directional deoxygenation upgrading of lignin oil and its derivatives.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An ordered Ni / Co-NiCo heterojunction catalyst comprises a carbon sphere framework and a Ni / Co-NiCo heterojunction. The carbon sphere framework encapsulates the ordered Ni / Co-NiCo heterojunction, which has oxygen vacancies and interfaces. The Ni / Co-NiCo heterojunction consists of metallic Ni or Co alloy species arranged in an orderly manner within the carbon spheres, forming Ni / Co-NiCo@C nanoparticles.

[0007] Compared with the prior art, the ordered Ni / Co-NiCo heterojunction catalyst of the present invention has the following beneficial effects: (1) This scheme provides an in-situ constructed carbon-encapsulated ordered Ni / Co-NiCo heterojunction catalyst, which can achieve high selectivity, high activity and good cycle stability when used for the directional upgrading of aqueous HDO of lignin derivatives, thereby overcoming the problems of insufficient selectivity, easy deactivation of structure and difficulty in migrating model system to real lignin oil of existing non-precious metal HDO catalysts under mild conditions. (2) The catalyst of the present invention is specifically a Ni / Co-NiCo heterojunction catalyst with an ordered arrangement of carbon spheres containing abundant heterojunctions and oxygen vacancy sites. That is, it contains metal heterojunctions, abundant heterojunctions, and oxygen vacancy sites. The present invention encapsulates Ni / Co-NiCo particles in carbon spheres to synergize with metal heterojunction-oxygen vacancy sites. The multifunctional site design generates a synergistic effect of metal heterojunction-oxygen vacancy, which effectively enhances the multi-step catalytic action of lignin derivatives in the direction of hydrogenation-hydrogenolysis-deoxygenation. It can effectively saturate / break the C=C and CO bonds of lignin derivatives and directionally remove oxygen. It can carry out lignin derivatives under relatively mild conditions. This invention enables the targeted hydrodeoxygenation of lignin oil and its derivatives to produce high-value chemicals and liquid fuels. The carbon sphere framework designed in this invention can effectively confine Ni / Co-NiCo heterostructure particles, maintaining a stable synergistic effect of metal-oxygen vacancy sites. This results in a catalyst with excellent stability, preventing leaching or migration and aggregation of active sites during hydrothermal processes, which could lead to catalyst deactivation. This ensures the stability of the catalyst in continuous cycle testing, giving the Ni / Co-NiCo heterostructure catalyst of this invention both high activity and high selectivity, as well as the ability to be recycled without reduction and regeneration. The preparation process is simple and scalable, making it suitable for the targeted deoxygenation upgrading of lignin oil and its derivatives. (3) Compared with the traditional cascade catalysis of liquid acid / base catalysts and supported metal nanoparticles, the catalyst prepared in this invention has a shorter spatial distance between the nano heterojunction particles, the abundant interfaces on the particles and the defect sites. This not only enhances the synergistic effect between the metal-interface-defect sites, but also helps the diffusion, heat transfer and mass transfer of reactants and their intermediates, thereby improving the reaction efficiency.

[0008] (4) The Ni / Co-NiCo@C heterostructure of this scheme is suitable for the directional conversion of lignin derivatives and their mixtures into cyclohexanol or cyclohexane liquid fuels under mild aqueous conditions, and can effectively transfer the model substrate system to the upgrading of real lignin oil; (5) Compared with commonly used liquid acid / base catalysts and solid catalysts, the catalyst of the present invention has strong magnetic properties and does not have the problems of strong corrosiveness, difficulty in recycling, and waste liquid discharge that pose significant limitations to practical applications; (6) The raw materials Ni and Co salts of the catalyst are cheap and readily available, non-toxic, green and environmentally friendly, can be reused multiple times, and can also achieve magnetic separation; (7) The catalyst of the present invention has high selectivity under mild conditions. Under aqueous phase conditions of 220~240 °C and 2 MPa H2, it can completely generate cyclohexanol or cyclohexane liquid fuels from real lignin oil through directional HDO, with a yield of 90% based on lignin oil feedstock. Secondly, it has structure-function synergy. The heterojunction interface promotes H2 activation and hydrogen overflow, and the defect sites (such as oxygen vacancies) enhance the adsorption / activation of oxygen-containing functional groups, synergistically reducing the hydrogenation and hydrogenolysis energy barriers. In addition, it has strong applicability to real lignin oil and can transfer the directional deoxygenation ability of the model substrate to the real lignin oil upgrade system to achieve high yield product output. Furthermore, it has good cycle stability. Under optimized conditions, the catalyst does not need to be regenerated / reduced and can maintain high selectivity even after 5 direct cycles, which has industrial application potential.

[0009] Preferably, the exposed Ni / Co-NiCo crystal planes of the Ni / Co-NiCo heterojunction are arranged in an ordered manner; wherein, the main exposed crystal planes of metallic Ni / Co are (111) and (200), the lattice spacing of Ni / Co (111) is 0.203~0.206nm, and the lattice spacing of Ni / C (200) is 0.175~0.177nm; wherein, the main exposed crystal planes of the NiCo alloy are (111) and (101), the lattice spacing of NiCo alloy (111) is 0.215~0.217nm, and the lattice spacing of NiCo alloy (101) is 0.13~0.15nm.

[0010] Preferably, the diameter of the carbon sphere skeleton is 3-30 nm, and the thickness of the carbon layer is 0.300-0.370 nm.

[0011] Another object of the present invention is to provide a method for preparing the above-mentioned ordered Ni / Co-NiCo heterojunction catalyst, comprising the following steps: (1) Preparation of materials: Prepare nickel nitrate, cobalt nitrate, and citric acid according to the specified dosage, and prepare alcohol-water mixed solvent according to the specified dosage; (2) Add the nickel nitrate, cobalt nitrate and citric acid to the alcohol-water mixed solvent, and stir in a water bath at 50-80°C until the solvent evaporates to dryness to obtain a carbon-based catalyst precursor containing nickel and cobalt species; (3) The carbon-based catalyst precursor is placed in a specified atmosphere and calcined at high temperature, wherein the temperature is ≥600℃, the reaction is kept at the temperature for at least 4 hours, and then cooled to obtain an ordered Ni / Co-NiCo heterojunction catalyst.

[0012] Compared with the prior art, the method for preparing an ordered Ni / Co-NiCo heterojunction catalyst of the present invention has the following beneficial effects: (1) The ordered Ni / Co-NiCo heterojunction catalyst encapsulated by carbon spheres prepared by the sol-gel in-situ carbonization method is a Ni / Co-NiCo heterojunction structure. The method uses cobalt salt and nickel salt as metal precursors and organic complexing agent as carbon source for structure-guided assembly. After sol-gel gelation and drying, carbonization is carried out in an inert atmosphere, so that metal species can generate ordered Ni / Co-NiCo@C heterojunction nanoparticles in-situ under the confinement of carbon layer, while introducing abundant heterojunction interfaces and oxygen vacancies. (2) The process of this method is simple and can be scaled up. Sol-gel combination in-situ carbonization can realize the construction of carbon layer confinement and multiphase heterostructure interface in one step.

[0013] Preferably, in step (1), the nickel nitrate and cobalt nitrate are first dissolved in an alcohol-water mixed solvent, and then citric acid is slowly added.

[0014] Preferably, in step (3), the high-temperature calcination is carried out at a heating rate of 5-10°C / min up to 650°C, and the holding time is 4h.

[0015] Another object of the present invention is to provide the application of the above-mentioned ordered Ni / Co-NiCo heterojunction catalyst in the hydrodeoxygenation reaction of lignin-derived oxygen-containing aromatic compounds.

[0016] Another object of the present invention is to provide the application of the above-mentioned ordered Ni / Co-NiCo heterojunction catalyst in the directed hydrodeoxygenation of lignin derivative model materials and lignin oil to prepare high-value chemicals and petroleum fuels.

[0017] Another object of the present invention is to provide the application of the above-mentioned ordered Ni / Co-NiCo heterojunction catalyst in the conversion of lignin derivative model compounds; The conversion of lignin derivative model compounds includes: preparing 40-60 mg of catalyst per 1 mmol of lignin derivative model compound and adding it to an aqueous solvent; reacting at a reaction temperature of 80-260℃ and an initial hydrogen pressure of 0-30 bar for a reaction time of 0.01-36 h (preferably 10 min-36 h) and a stirring speed of 600-800 rpm. After the reaction is complete, wait for the material to cool to room temperature before removing it.

[0018] Another object of the present invention is to provide the application of the above-mentioned ordered Ni / Co-NiCo heterojunction catalyst in the conversion of lignin oil; The conversion of lignin oil includes: lignin oil and catalyst are prepared at a mass ratio of 1:1 to 2 and added together to an aqueous solvent. The reaction is carried out at a reaction temperature of 80 to 260°C and an initial hydrogen pressure of 0 to 30 bar for a reaction time of 0.01 to 36 h (preferably 10 min to 36 h) and a stirring speed of 600 to 800 rpm. After the reaction is complete, wait for the material to cool to room temperature before removing it.

[0019] Preferably, in the above-mentioned conversion methods for lignin-derived model compounds and conversion methods for lignin oil, the reaction temperature is 80–260°C and the reaction time is 10 min–36 h.

[0020] Another object of the present invention is to provide the application of the above-mentioned ordered Ni / Co-NiCo heterojunction catalyst in the preparation of lignin oil by catalytic reduction method; The preparation of lignin oil by catalytic reduction includes: Plants were pulverized into powder with an average particle size ≤40 mesh. Plant powder and Ni / C catalyst were weighed out at a mass ratio of 1-4:0.2 and added to methanol solvent. The mixture was stirred in a hydrogen atmosphere at an initial hydrogen pressure of 2-4 MPa and a temperature of 180-230℃ for 5-10 hours. After the reaction is complete and the material has cooled to room temperature, all the substances in the reactor are removed and filtered to separate the solid residue (carbohydrates and Ni / C). Methanol was removed by vacuum distillation at 50-70℃ to obtain a viscous substance. The lignin oil component of viscous substances was extracted using a two-phase ethyl acetate / water solvent extraction method. Lignin oil exists in the ethyl acetate phase. Lignin oil is obtained by vacuum distillation of ethyl acetate at 60-80℃.

[0021] Compared with existing technologies, the application of the ordered Ni / Co-NiCo heterojunction catalyst of this invention belongs to the field of non-precious metal catalysis technology, enabling the high-value utilization of biomass / lignin resources, especially in the directed hydrodeoxygenation (HDO) of lignin derivatives under mild aqueous conditions to prepare high-value chemicals and liquid fuels. Based on the above catalyst structure design, this invention has developed a catalytic system and conversion process suitable for this catalyst, which can achieve the saturation of C=C, C=O and CO linkages and the directed removal of oxygen-containing groups in different lignin derivatives and their real lignin oils under relatively mild reaction conditions. This invention can realize multiple steps of multiple reactions on a single monolithic catalyst, effectively avoiding product separation and intermediate purification in multiple reaction steps, solving the problems of time-consuming and energy-intensive processes, simplifying the steps, and facilitating technology scale-up, providing a promising strategy for the efficient utilization of lignin. Attached Figure Description

[0022] Figure 1 The scanning electron microscope shows the Ni / Co-NiCo@C structure morphology formed by the 1Ni1Co@C prepared in Example 1. Figures 2A to 2C These are the XRD patterns of the catalysts prepared in Examples 1, 4 to 8 of this invention; Figure 3 This is the H2-TPR diagram (A) of the catalysts prepared in Examples 1, 4 to 8 of this invention; Figure 4 This is the EPR diagram (B) of the catalysts prepared in Examples 1, 4 to 6 of this invention; Figure 5 These are XPS spectra of the catalysts prepared in Examples 1, 4 to 6 of this invention; Figure 6 The results of Examples 9, 17 to 20 are illustrated; Figure 7 The results of Examples 9, 21 to 24 are illustrated; Figure 8 The results of Examples 25 to 34 are illustrated; Figure 9 The results of Examples 9, 35-38 are illustrated below; Figure 10 The reaction processes in Examples 39 to 66 are illustrated. Figure 11 The reaction process of Examples 67 and 68 is illustrated; Figure 12 The test results are illustrated. Figure 13 A schematic diagram of the reaction process and molecular structure involved in the preparation of the catalyst. Detailed Implementation

[0023] The embodiments of the present invention are described below with reference to the accompanying drawings: The preparation method of the ordered Ni / Co-NiCo heterojunction catalyst of the present invention includes the following steps: (1) Preparation of materials: Prepare nickel nitrate, cobalt nitrate, and citric acid according to the specified dosage, and prepare alcohol-water mixed solvent according to the specified dosage; (2) Add the nickel nitrate, cobalt nitrate and citric acid to the alcohol-water mixed solvent, and stir in a water bath at 50-80°C until the solvent evaporates to dryness to obtain a carbon-based catalyst precursor containing nickel and cobalt species; (3) The carbon-based catalyst precursor is placed in a specified atmosphere and calcined at high temperature, wherein the temperature is ≥600℃, the reaction is kept at the temperature for at least 4 hours, and then cooled to obtain an ordered Ni / Co-NiCo heterojunction catalyst.

[0024] In step (1), the nickel nitrate and cobalt nitrate are first dissolved in an alcohol-water mixed solvent, and then citric acid is slowly added.

[0025] In one embodiment, in step (1), nickel nitrate, cobalt nitrate, and citric acid are prepared in a specified molar ratio of 1:0.1 to 3:1 to 2; the volume ratio of the solvent methanol / ethanol / isopropanol to water is 0 to 3:1.

[0026] In one embodiment, in step (1), the molar ratio of nickel nitrate, cobalt nitrate and citric acid is 1:0.1 to 3:2; and the volume ratio of ethanol to water is 0 to 1:1.

[0027] In one embodiment, in step (1), the molar ratio of nickel nitrate, cobalt nitrate, and citric acid is 1:1 to 2:1 to 2; and the volume ratio of solvent methanol / ethanol / isopropanol to water is 1:1.

[0028] In step (2), the mixture is prepared by adding 0-6.35 mmol nickel nitrate, 0-6.35 mmol cobalt nitrate and 12.7-25.4 mmol citric acid to 40 mL of mixed solvent.

[0029] In one embodiment, in step (2), the nickel nitrate, cobalt nitrate, and citric acid are added to the alcohol-water mixed solvent at a concentration ratio of 0.158 mol to 0.476 mol of metal salt per 1 L of alcohol-water mixed solvent, and at a concentration ratio of 0.317 to 11.9 mol of citric acid per 1 L of solvent.

[0030] In one embodiment, in step (2), the solvent in the mixed solution in the water bath is evaporated at a temperature of 50 to 80°C to obtain a carbon-based catalyst precursor containing nickel and cobalt species; the ambient temperature T is 25°C ≤ T ≤ 50°C, and the stirring time is 0.5 to 8 hours.

[0031] In one embodiment, in step (3), the atmosphere is specified as a continuous flow of nitrogen gas containing 8-12% VOL hydrogen, wherein the gas flow rate is 30 ml / min.

[0032] In one embodiment, in step (3), a nitrogen gas flow containing 10% VOL hydrogen is used, the gas delivery flow rate is 30 ml / min, the high-temperature calcination operation is set to a heating rate of 10°C / min up to 650°C, and the holding time is set to 4 to 6 hours.

[0033] In one embodiment, in step (3), the high-temperature calcination is carried out at a heating rate of 5-10°C / min up to 650°C, and the holding time is 4h.

[0034] In one embodiment, in step (3), the high-temperature calcination operation is carried out at a heating rate of 8 to 12°C / min up to 600 to 900°C, and the holding time is 4 to 6 hours.

[0035] Compared with the prior art, the method for preparing an ordered Ni / Co-NiCo heterojunction catalyst of the present invention has the following beneficial effects: (1) The ordered Ni / Co-NiCo heterojunction catalyst encapsulated by carbon spheres prepared by the sol-gel in-situ carbonization method is a Ni / Co-NiCo heterojunction structure. The method uses cobalt salt and nickel salt as metal precursors and organic complexing agent as carbon source for structure-guided assembly. After sol-gel gelation and drying, carbonization is carried out in an inert atmosphere, so that metal species can generate ordered Ni / Co-NiCo@C heterojunction nanoparticles in-situ under the confinement of carbon layer, while introducing abundant heterojunction interfaces and oxygen vacancies. (2) The process of this method is simple and can be scaled up. Sol-gel combination in-situ carbonization can realize the construction of carbon layer confinement and multiphase heterostructure interface in one step.

[0036] An ordered Ni / Co-NiCo heterojunction catalyst comprises a carbon sphere framework and a Ni / Co-NiCo heterojunction. The carbon sphere framework encapsulates the ordered Ni / Co-NiCo heterojunction, which has oxygen vacancies and interfaces. The Ni / Co-NiCo heterojunction consists of metallic Ni or Co alloy species arranged in an orderly manner within the carbon spheres, forming Ni / Co-NiCo@C nanoparticles.

[0037] For ease of understanding, metals Ni or Co will be referred to as Ni / Co below.

[0038] The exposed Ni / Co-NiCo crystal planes of the Ni / Co-NiCo heterojunction are arranged in an ordered manner; wherein, the main exposed crystal planes of metallic Ni / Co are (111) and (200), the lattice spacing of Ni / Co (111) is 0.203~0.206nm, and the lattice spacing of Ni / C (200) is 0.175~0.177nm; wherein, the main exposed crystal planes of the NiCo alloy are (111) and (101), the lattice spacing of NiCo alloy (111) is 0.215~0.217nm, and the lattice spacing of NiCo alloy (101) is 0.13~0.15nm.

[0039] The diameter of the carbon sphere skeleton is 3-30 nm, and the thickness of the carbon layer is 0.300-0.370 nm.

[0040] Compared with the prior art, the ordered Ni / Co-NiCo heterojunction catalyst of the present invention has the following beneficial effects: (1) This scheme provides an in-situ constructed carbon-encapsulated ordered Ni / Co-NiCo heterojunction catalyst, which can achieve high selectivity, high activity and good cycle stability when used for the directional upgrading of aqueous HDO of lignin derivatives, thereby overcoming the problems of insufficient selectivity, easy deactivation of structure and difficulty in migrating model system to real lignin oil of existing non-precious metal HDO catalysts under mild conditions. (2) The catalyst of the present invention is specifically a Ni / Co-NiCo heterojunction catalyst with an ordered arrangement of carbon spheres containing abundant heterojunctions and oxygen vacancy sites. That is, it contains metal heterojunctions, abundant heterojunctions, and oxygen vacancy sites. The present invention encapsulates Ni / Co-NiCo particles in carbon spheres to synergize with metal heterojunction-oxygen vacancy sites. The multifunctional site design generates a synergistic effect of metal heterojunction-oxygen vacancy, which effectively enhances the multi-step catalytic action of lignin derivatives in the direction of hydrogenation-hydrogenolysis-deoxygenation. It can effectively saturate / break the C=C and CO bonds of lignin derivatives and directionally remove oxygen. It can carry out lignin derivatives under relatively mild conditions. This invention enables the targeted hydrodeoxygenation of lignin oil and its derivatives to produce high-value chemicals and liquid fuels. The carbon sphere framework designed in this invention can effectively confine Ni / Co-NiCo heterostructure particles, maintaining a stable synergistic effect of metal-oxygen vacancy sites. This results in a catalyst with excellent stability, preventing leaching or migration and aggregation of active sites during hydrothermal processes, which could lead to catalyst deactivation. This ensures the stability of the catalyst in continuous cycle testing, giving the Ni / Co-NiCo heterostructure catalyst of this invention both high activity and high selectivity, as well as the ability to be recycled without reduction and regeneration. The preparation process is simple and scalable, making it suitable for the targeted deoxygenation upgrading of lignin oil and its derivatives. (3) Compared with the traditional cascade catalysis of liquid acid / base catalysts and supported metal nanoparticles, the catalyst prepared in this invention has a shorter spatial distance between the nano heterojunction particles, the abundant interfaces on the particles and the defect sites. This not only enhances the synergistic effect between the metal-interface-defect sites, but also helps the diffusion, heat transfer and mass transfer of reactants and their intermediates, thereby improving the reaction efficiency.

[0041] (4) The Ni / Co-NiCo@C heterostructure of this scheme is suitable for the directional conversion of lignin derivatives and their mixtures into cyclohexanol or cyclohexane liquid fuels under mild aqueous conditions, and can effectively transfer the model substrate system to the upgrading of real lignin oil; (5) Compared with commonly used liquid acid / base catalysts and solid catalysts, the catalyst of the present invention has strong magnetic properties and does not have the problems of strong corrosiveness, difficulty in recycling, and waste liquid discharge that pose significant limitations to practical applications; (6) The raw materials Ni and Co salts of the catalyst are cheap and readily available, non-toxic, green and environmentally friendly, can be reused multiple times, and can also achieve magnetic separation. (7) The catalyst of the present invention has high selectivity under mild conditions. Under aqueous phase conditions of 220~240 °C and 2 MPa H2, it can completely generate cyclohexanol or cyclohexane liquid fuels from real lignin oil through directional HDO, with a yield of 90% based on lignin oil feedstock. Secondly, it has structure-function synergy. The heterojunction interface promotes H2 activation and hydrogen overflow, and the defect sites (such as oxygen vacancies) enhance the adsorption / activation of oxygen-containing functional groups, synergistically reducing the hydrogenation and hydrogenolysis energy barriers. In addition, it has strong applicability to real lignin oil and can transfer the directional deoxygenation ability of the model substrate to the real lignin oil upgrade system to achieve high yield product output. Furthermore, it has good cycle stability. Under optimized conditions, the catalyst does not need to be regenerated / reduced and can maintain high selectivity even after 5 direct cycles, which has industrial application potential.

[0042] Another object of the present invention is to provide the application of the above-mentioned ordered Ni / Co-NiCo heterojunction catalyst in the hydrodeoxygenation (HDO) reaction of lignin-derived oxygen-containing aromatic compounds.

[0043] Another object of the present invention is to provide the application of the above-mentioned ordered Ni / Co-NiCo heterojunction catalyst in the directed hydrodeoxygenation of lignin derivative model materials and lignin oil to prepare high-value chemicals and petroleum fuels.

[0044] The lignin-derived model compound is diphenyl ether; phenol, guaiacol, eugenol, vanillin, 4-propylguaiacol; one or more of vanillin, eugenol, and vanillic acid in any proportion; the lignin oil is derived from plants.

[0045] The lignin oil is preferably prepared by the following method: The preparation of lignin oil B by catalytic reduction includes the following steps: Plants were pulverized into powder with an average particle size ≤40 mesh. Plant powder and Ni / C catalyst were weighed out at a mass ratio of 1-4:0.2 and added to methanol solvent. The mixture was stirred and reacted in a hydrogen atmosphere at an initial hydrogen pressure of 2-4 MPa and a temperature of 180-230°C for 5-10 hours. After the reaction is complete, the material is cooled to room temperature. All the substances in the reactor are removed and filtered to separate the solid residue (carbohydrates and Ni / C). Methanol is removed by vacuum distillation at 50-70℃ to obtain a viscous substance. The viscous substance is extracted with a two-phase ethyl acetate / water solvent to extract the lignin oil component. The lignin oil in the ethyl acetate phase is then distilled under vacuum at 60-80℃ to obtain lignin oil B.

[0046] The process involves pulverizing the plant material into powder with an average particle size of ≤40 mesh, reacting at a temperature of 190℃, and for a reaction time of 6 hours.

[0047] The alcohol solvent is methanol.

[0048] Example 1 (1) Dissolve 6.35 mmol of Ni(NO3)2·6H2O and 6.35 mmol of Ni(NO3)2·6H2O in a mixture of 15.0 mL and 15 mL of ethanol and stir until completely dissolved. Then, slowly add 25.4 mmol of citric acid monohydrate to the above solution and stir to dissolve to obtain the pre-prepared solution.

[0049] (2) The pre-prepared solution was stirred at a water bath temperature of 70°C until the solvent evaporated to dryness, to obtain a carbon-based catalyst precursor containing nickel and cobalt species; (3) The carbon-based catalyst precursor was ground and loaded into a quartz tube, then placed in a tube furnace. Subsequently, the temperature was raised to 650℃ at a rate of 5℃ / min and held for 4h. Then, it was cooled naturally. The entire calcination and cooling process was carried out in a N2 gas flow of 30mL / min. The obtained sample was labeled as 1Ni1Co@C.

[0050] Example 2 Compared with Example 1, the amount of cobalt nitrate hexahydrate used was 0.635 mmol, and the amount of hydrated citric acid used was 13.97 mmol, to prepare the 1Ni0.1Co@C catalyst; the rest of the operation was the same as in Example 1.

[0051] Example 3 Compared with Example 1, the amount of cobalt nitrate hexahydrate used was 1.59 mmol, and the amount of hydrated citric acid used was 15.88 mmol, to prepare the 1Ni0.25Co@C catalyst; the rest of the operation was the same as in Example 1.

[0052] Example 4 Compared with Example 1, the amount of cobalt nitrate hexahydrate used was 3.18 mmol, and the amount of hydrated citric acid used was 19.6 mmol, to prepare the 1Ni0.5Co@C catalyst; the remaining operations were the same as in Example 1.

[0053] Example 5 Compared with Example 1, the amount of cobalt nitrate hexahydrate used was 12.7 mmol, and the amount of hydrated citric acid used was 38.1 mmol, to prepare the 1Ni2Co@C catalyst; the remaining operations were the same as in Example 1.

[0054] Example 6 Compared with Example 1, the amount of cobalt nitrate hexahydrate used was 19.05 mmol, and the amount of hydrated citric acid used was 50.8 mmol, to prepare the 1Ni3Co@C catalyst; the remaining operations were the same as in Example 1.

[0055] Example 7 Compared with Example 1, the amount of cobalt nitrate hexahydrate used was 0, and the amount of hydrated citric acid used was 12.7 mmol, to prepare the Ni@C catalyst; the remaining operations were the same as in Example 1.

[0056] Example 8 Compared with Example 1, the amount of nickel nitrate hexahydrate used was 0, and the amount of hydrated citric acid used was 12.7 mmol, to prepare the Ni@C catalyst; the remaining operations were the same as in Example 1.

[0057] Example 9 A method for converting lignin-derived model compounds: Using 50 mg of the catalyst 1Ni1Co@C prepared in Example 4 as the catalyst, 1 mmol (124.14 mg) of the typical lignin-derived monomer "guaiacol" as the substrate, 10 ml of water as the solvent, the reaction temperature was 120 °C, the reaction time was 36 h, the initial hydrogen pressure was 20 bar, and the stirring speed was 700 rpm.

[0058] After the reaction was completed, the material was cooled to room temperature, and the liquid product was extracted three times with ethyl acetate (10 mL ethyl acetate each time). The extracted ethyl acetate phase was qualitatively detected by gas chromatography-mass spectrometry and quantitatively analyzed by gas chromatography to calculate the substrate conversion rate and product selectivity.

[0059] Examples 10 to 16 Compared with Example 9, 50 mg of the samples prepared in Examples 1 to 8 were used as catalysts; the rest of the operations were the same as in Example 9.

[0060] Table 1: Results of Examples 9-16 Example 17 Compared with Example 9, the reaction temperature was 160°C and the reaction time was 9 hours; the rest of the operation was the same as in Example 9.

[0061] Example 18 Compared with Example 9, the reaction temperature was 180°C, the reaction time was 9 hours, and the rest of the operation was the same as in Example 9.

[0062] Example 19 Compared with Example 9, the reaction temperature was 200°C, the reaction time was 9 hours, and the rest of the operation was the same as in Example 9.

[0063] Example 20 Compared with Example 9, the reaction temperature was 220°C, the reaction time was 9 hours, and the rest of the operation was the same as in Example 9.

[0064] Example 21 Compared with Example 9, the reaction hydrogen pressure was 0.5 MPa, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0065] Example 22 Compared with Example 9, the reaction hydrogen pressure was 1.0 MPa, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0066] Example 23 Compared with Example 9, the reaction hydrogen pressure was 1.5 MPa, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0067] Example 24 Compared with Example 9, the reaction hydrogen pressure was 2.5 MPa, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0068] Example 25 Compared with Example 9, the reaction time was 1 / 6 h, and the rest of the operation was the same as in Example 9.

[0069] Example 26 Compared with Example 9, the reaction time was 1 / 3 h, and the rest of the operation was the same as in Example 9.

[0070] Example 27 Compared with Example 9, the reaction time was 0.5 h, and the rest of the operation was the same as in Example 9.

[0071] Example 28 Compared with Example 9, the reaction time was 1 hour, and the rest of the operation was the same as in Example 9.

[0072] Example 29 Compared with Example 9, the reaction time was 2 hours, and the rest of the operation was the same as in Example 9.

[0073] Example 30 Compared with Example 9, the reaction time was 3 hours, and the rest of the operation was the same as in Example 9.

[0074] Example 31 Compared with Example 9, the reaction time was 4 hours, and the rest of the operation was the same as in Example 9.

[0075] Example 32 Compared with Example 9, the reaction time was 5 hours, and the rest of the operation was the same as in Example 9.

[0076] Example 33 Compared with Example 9, the reaction time was 6 hours, and the rest of the operation was the same as in Example 9.

[0077] Example 34 Compared with Example 9, the reaction time was 7 hours, and the rest of the operation was the same as in Example 9.

[0078] Example 35 Compared with Example 9, the reaction time was 4 hours, the reaction solvent was decahydronaphthalene, and the rest of the operation was the same as in Example 9.

[0079] Example 36 Compared with Example 9, the reaction time was 4 hours, the reaction solvent was isopropanol, and the rest of the operation was the same as in Example 9.

[0080] Example 37 Compared with Example 9, the reaction time was 4 hours, the reaction solvent was methanol, and the rest of the operation was the same as in Example 9.

[0081] Example 38 Compared with Example 9, the reaction time was 4 hours, the reaction solvent was dioxane, and the rest of the operation was the same as in Example 9.

[0082] Example 39 Compared with Example 9, the reaction raw material was 1 mmol vanillin, the reaction time was 0 min (Note: after the reaction temperature was raised to 200°C, the heating was stopped, that is, the time at 200°C was 0 min), and the rest of the operation was the same as in Example 9.

[0083] Example 40 Compared with Example 9, the reaction raw material was 1 mmol vanillin, the reaction time was 15 min, and the rest of the operation was the same as in Example 9.

[0084] Example 41 Compared with Example 9, the reaction raw material was 1 mmol vanillin, the reaction time was 4 h, and the rest of the operation was the same as in Example 9.

[0085] Example 42 Compared with Example 9, the reaction raw material was 1 mmol vanillin, the reaction temperature was 240°C, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0086] Example 43 Compared with Example 9, the reaction raw material was 1 mmol of eugenol, the reaction time was 15 min, and the rest of the operation was the same as in Example 9.

[0087] Example 44 Compared with Example 9, the reaction raw material was 1 mmol of eugenol, the reaction time was 4 h, and the rest of the operation was the same as in Example 9.

[0088] Example 45 Compared with Example 9, the reaction raw material was 1 mmol of eugenol, the reaction time was 4 h, the reaction temperature was 220 °C, and the rest of the operation was the same as in Example 9.

[0089] Example 46 Compared with Example 9, the reaction raw material was 1 mmol of eugenol, the reaction time was 9 h, the reaction temperature was 240 °C, and the rest of the operation was the same as in Example 9.

[0090] Example 47 Compared with Example 9, the reaction raw material was 1 mmol vanillic acid, the reaction time was 15 min, and the rest of the operation was the same as in Example 9.

[0091] Example 48 Compared with Example 9, the reaction raw material was 1 mmol vanillic acid, the reaction time was 4 h, and the rest of the operation was the same as in Example 9.

[0092] Example 49 Compared with Example 9, the reaction raw material was 1 mmol vanillic acid, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0093] Example 50 Compared with Example 9, the reaction raw material was 1 mmol vanillic acid, the reaction temperature was 240°C, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0094] Example 51 Compared with Example 9, the reaction raw material was 1 mmol vanillin, the reaction time was 15 min, and the rest of the operation was the same as in Example 9.

[0095] Example 52 Compared with Example 9, the reaction raw material was 1 mmol vanillin, the reaction time was 2 h, and the rest of the operation was the same as in Example 9.

[0096] Example 53 Compared with Example 9, the reaction raw material was 1 mmol vanillin, the reaction time was 4 h, and the rest of the operation was the same as in Example 9.

[0097] Example 54 Compared with Example 9, the reaction raw material was 1 mmol vanillin, the reaction temperature was 220°C, the reaction time was 4 h, and the rest of the operation was the same as in Example 9.

[0098] Example 55 Compared with Example 9, the reaction raw material was 1 mmol of diphenyl ether, the reaction time was 4 h, and the rest of the operation was the same as in Example 9.

[0099] Example 56 Compared with Example 9, the reaction raw material was 1 mmol of diphenyl ether, the reaction temperature was 220°C, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0100] Example 57 Compared with Example 9, the reaction raw material was 1 mmol of 4-propylguaiacol, the reaction time was 4 h, and the rest of the operation was the same as in Example 9.

[0101] Example 58 Compared with Example 9, the reaction raw material was 1 mmol of 4-propylguaiacol, the reaction temperature was 220°C, the reaction time was 4 h, and the rest of the operation was the same as in Example 9.

[0102] Example 59 Compared with Example 9, the reaction raw material was 1 mmol of 4-propylguaiacol, the reaction temperature was 240°C, the reaction time was 9 h, and the rest of the operation was the same as in Example 9.

[0103] Example 60 A method for converting lignin mixed model compounds: Using 100 mg of the product Ni / Co-NiCo@C obtained in Example 1 as a catalyst, and 0.4 mmol (37.64 mg) of phenol, 0.4 mmol (49.66 mg) of guaiacol, 0.4 mmol (61.66 mg) of vanillin, 0.4 mmol (60.86 mg) of vanillin and 0.4 mmol (67.62 mg) of vanillic acid as a mixed substrate, and 20 ml of isopropanol as a solvent, the reaction was carried out at 240 °C for 4 h, with an initial hydrogen pressure of 20 bar and a stirring speed of 700 rpm.

[0104] After the reaction was completed, the material was cooled to room temperature, and the liquid product was extracted three times with ethyl acetate (10 mL ethyl acetate each time). The extracted ethyl acetate phase was qualitatively detected by gas chromatography-mass spectrometry and quantitatively analyzed by gas chromatography to calculate the substrate conversion rate and product selectivity.

[0105] Example 61 Compared with Example 60, the reaction time was 36 hours; the rest of the operation was the same as in Example 60.

[0106] Example 62 Compared with Example 60, the reaction temperature was 250°C; the rest of the operation was the same as in Example 60.

[0107] Example 63 Compared with Example 60, the reaction temperature was 250°C; the reaction time was 24 hours; and the rest of the operation was the same as in Example 60.

[0108] Example 64 Compared with Example 60, the reaction temperature was 250°C; the reaction time was 24 hours; and the rest of the operation was the same as in Example 60.

[0109] Example 65 Compared with Example 60, the reaction temperature was 260°C and the reaction time was 4 hours; the rest of the operation was the same as in Example 60.

[0110] Example 66 Compared with Example 60, the reaction temperature was 260°C and the reaction time was 24 hours; the rest of the operation was the same as in Example 60.

[0111] Table 2: Results of Examples 39-66 Example 67 A method for preparing and converting lignin oil: (1) Preparation of lignin oil by catalytic reduction method Poplar wood was pulverized into powder with an average particle size ≤40 mesh. Approximately 2.0 g of poplar powder, 0.25 g of Ni / C catalyst, and 40 mL of methanol were added to a 70 mL high-pressure reactor and mechanically stirred. After multiple H2 degassing processes, the reactor was initially charged with H2 at a pressure of 2 MPa. The reaction was then carried out at 190℃ for 6 h. After the reaction was complete and the material was cooled to room temperature, all substances in the reactor were removed and filtered to separate the solid residue (carbohydrates and Ni / C). Methanol was removed by vacuum distillation at 50℃ to obtain a viscous substance. The viscous substance was then extracted with a two-phase ethyl acetate / water (40 mL:40 mL) solvent to extract the lignin oil component. The lignin oil in the ethyl acetate phase was then distilled under vacuum at 65℃ to obtain lignin oil B.

[0112] (2) The lignin oil components in the ethyl acetate phase were qualitatively analyzed by gas chromatography-mass spectrometry (GS–MS), and quantitatively analyzed by gas chromatography (GC) with n-dodecane as an internal standard. The yield of the HDO product was estimated by dividing the mass of the HDO product by the mass of the lignin oil. The detectable components and their proportions in the lignin oil after qualitative and quantitative analysis were: 4-ethylguaiacol (7wt%), 4-propylguaiacol (20wt%), 4-propyleugenol (29wt%), 4-propanol guaiacol (28wt%), and other substances (16wt%).

[0113] (3) Take 0.1 g of lignin oil, 0.1 g of catalyst, 20 mL of water, and react at 220 °C and 20 MPa H2 for 24 h. After the reaction is complete, the material is cooled to room temperature. The liquid product is extracted three times with ethyl acetate (20 mL of ethyl acetate each time). The ethyl acetate phase after extraction is qualitatively detected by gas chromatography-mass spectrometry and quantitatively analyzed by gas chromatography. The substrate conversion rate and product selectivity are calculated.

[0114] Example 68 Compared with Example 67, the reaction temperature in step (3) is 240°C and the reaction time is 24h; the rest of the operation is the same as in Example 67.

[0115] Characterization test 1. The catalyst prepared in Example 1 was analyzed by high-resolution transmission electron microscopy (HRTEM) using electron microscopy and transmission electron microscopy. The results are as follows: Figure 1 As shown, the diameter of the carbon sphere skeleton is 3-30 nm, and the thickness of the carbon layer is 0.300-0.370 nm; the Ni / Co-NiCo heterojunction is encapsulated by carbon; the exposed crystal planes of the Ni / Co-NiCo heterojunction are arranged in an ordered manner; The main exposed crystal planes of metallic Ni / Co are (111) and (200). The lattice spacing of Ni / Co (111) is 0.203–0.206 nm, and the lattice spacing of Ni / C (200) is 0.175–0.177 nm; The main exposed crystal planes of the NiCo alloy are (111) and (101). The lattice spacing of NiCo alloy (111) is 0.215–0.217 nm, and the lattice spacing of NiCo alloy (101) is 0.13–0.15 nm.

[0116] (2) The species and dispersion of the catalysts prepared in Examples 1, 4 to 8 were characterized by XRD, and the results are as follows: Figures 2A to 2CAs shown, the catalyst contains three species: Ni / Co, NiCo alloy, and C, which are consistent with the nanoparticle species present in HRTEM.

[0117] (3) The temperature-programmed reduction characteristics of the catalysts prepared in Examples 1, 4 to 8 were analyzed by H2-TPR characterization. The results are as follows: Figure 3 As shown, for Ni@C (Example 7), the peaks around 262°C and 527°C in the spectrum are attributed to Ni with a highly dispersed surface. 2+ Species and large Ni 2+ Species reduction; Co@C (Example 8) peaks at 415℃ and 650℃, respectively, represent Co 3+ →Co 2+ and Co 2+ →Co 0 The reduction peaks were observed in xNiyCo@C from Examples 1 and 4-6. The reduction peaks in Ni / Co metal and NiCo alloys were also observed, and the degree to which the reduction peaks shifted towards lower temperatures was related to the Co content.

[0118] (4) The oxygen vacancies of the catalysts prepared in Examples 1, 4 to 6 were determined by electron paramagnetic resonance (EPR).

[0119] The results are as follows Figure 4 As shown, all xNiyCo@C catalysts exhibit significant oxygen vacancies (G factor = 2.03 is a typical oxygen vacancy signal). Oxygen vacancies can promote C... 芳香环 The activation and breaking of -O bonds is facilitated by a higher concentration of oxygen vacancies.

[0120] (5) The electronic state properties of the catalysts prepared in Examples 1, 4 to 6 were analyzed by XPS spectroscopy.

[0121] The results are as follows Figure 5 As shown, with the increase of the Co / Ni molar ratio, Ni 0 The peak shifts more noticeably towards lower binding energies. Figure 5 (Top left image), while Co 0 The peak shifts more noticeably toward higher binding energy. Figure 5 (See the top right figure), which shows that electrons transfer from Co to Ni due to Ni-Co interactions. Furthermore, for the 1Ni1Co@C and 1Ni2Co@C samples, Ni 2p... 3 / 2 2+ and Ni2p 1 / 2 2+ and Co 2p 3 / 2 3+ and Co 2p 1 / 2 3+The satellite peaks almost disappeared, which is mainly related to the formation of more stable and ordered Ni / Co-NiCo and NiCo-Co-Co3C interface particles.

[0122] Loop test The catalyst used in Example 31 can be used directly after being dried at room temperature (without reduction and regeneration). It can be recycled 4 times according to the conversion process of Example 31, that is, the total number of catalyst cycles is 5.

[0123] After each round of reaction, the mixture was cooled to room temperature, and the liquid product was collected and qualitatively analyzed using gas chromatography-mass spectrometry (GC-MS). Quantitative analysis was performed using GC to calculate the substrate conversion and product selectivity (results are shown in the figure below). Simultaneously, the leaching concentrations of Ni and Co ions in the reaction solution were detected by ICP-AES using the liquid product (results are shown in the table below).

[0124] Table 3: Test Results The results in the table above show that after five catalytic cycles, the Ni / Co-NiCo@C catalyst prepared in Example 1 of this invention showed no Ni or Co ions leaching into the reaction solution (concentrations were all below the detection limit of the equipment) as determined by ICP-AES. The results in the graph above also show that the activity and yield of cyclohexanol did not decrease significantly, indicating that the Ni-MgO@CN catalyst... x The -700 catalyst maintained its stability and activity throughout the entire cycle test, meaning that the catalyst prepared by this invention can maintain stable catalytic hydrodeoxygenation performance over a long period of time and has excellent durability.

[0125] Description of the attached image: Figure 1 High-resolution transmission electron microscopy (HRTEM) images (a-c, e) of the catalyst prepared in Example 1; Fast Fourier Transform (FFT) of the representative selected crystal domains marked in (d), showing the ordered Ni / Co-NiCo interplanar spacing; Selected area electron diffraction (SAED) pattern of 1Ni1Co@C (f); High-resolution transmission electron microscopy (HRTEM) images (b, c, d, e) of 1Ni1Co@C; Figures b1 and b2 are magnified views of the orange and yellow dashed boxes in (b), with blue dashed circles representing heterostructures (b and c). Energy dispersive spectroscopy (EDS) image of the selected dark field region of the 1Ni1Co@C catalyst (g). High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image and corresponding elemental mapping images (f-i).

[0126] Figure 2 shows the X-ray diffraction (XRD) patterns of the catalysts prepared in Examples 1, 4 to 8; (A) a view with a 2θ angle in the range of 5 to 80°, (B) an enlarged view selected from (A) with a 2θ angle in the range of 42 to 46°, and (C) an enlarged view selected from (A) with a 2θ angle in the range of 50 to 54°.

[0127] Figure 5 The above are XPS spectra of the catalyst prepared in Example 1 of the present invention; wherein (a) Ni2p3 / 2; (b) Co2p3 / 2; (c) O 1s; (d) C1s.

[0128] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. An ordered Ni / Co-NiCo heterojunction catalyst, characterized in that, It includes a carbon sphere framework and a Ni / Co-NiCo heterojunction. The carbon sphere framework encapsulates the orderly arranged Ni / Co-NiCo heterojunction. The Ni / Co-NiCo heterojunction has oxygen vacancies and interfaces. The Ni / Co-NiCo heterojunction consists of metallic Ni or Co and NiCo alloy species arranged in an orderly manner within the carbon sphere, forming Ni / Co-NiCo@C nanoparticles.

2. The ordered Ni / Co-NiCo heterojunction catalyst according to claim 1, characterized in that, The exposed Ni / Co-NiCo crystal planes of the Ni / Co-NiCo heterojunction are arranged in an ordered manner; Among them, the main exposed crystal planes of metal Ni / Co are (111) and (200), the lattice spacing of Ni / Co (111) is 0.203~0.206nm, and the lattice spacing of Ni / C (200) is 0.175~0.177nm; The main exposed crystal planes of the NiCo alloy are (111) and (101), the lattice spacing of NiCo alloy (111) is 0.215~0.217nm, and the lattice spacing of NiCo alloy (101) is 0.13~0.15nm.

3. The ordered Ni / Co-NiCo heterojunction catalyst according to claim 1, characterized in that, The diameter of the carbon sphere skeleton is 3-30 nm, and the thickness of the carbon layer is 0.300-0.370 nm.

4. The method for preparing the ordered Ni / Co-NiCo heterojunction catalyst according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Preparation of materials: Prepare nickel nitrate, cobalt nitrate, and citric acid according to the specified dosage, and prepare alcohol-water mixed solvent according to the specified dosage; (2) Add the nickel nitrate, cobalt nitrate and citric acid to the alcohol-water mixed solvent, and stir in a water bath at 50-80°C until the solvent evaporates to dryness to obtain a carbon-based catalyst precursor containing nickel and cobalt species; (3) The carbon-based catalyst precursor is placed in a specified atmosphere and calcined at high temperature, wherein the temperature is ≥600℃, the reaction is kept at the temperature for at least 4 hours, and then cooled to obtain an ordered Ni / Co-NiCo heterojunction catalyst.

5. The method for preparing the ordered Ni / Co-NiCo heterojunction catalyst according to claim 4, characterized in that, In step (1), the nickel nitrate and cobalt nitrate are first dissolved in an alcohol-water mixed solvent, and then citric acid is slowly added.

6. The method for preparing the ordered Ni / Co-NiCo heterojunction catalyst according to claim 4, characterized in that, High-temperature calcination involves increasing the temperature at a rate of 5–10°C / min up to 650°C and holding it at that temperature for 4 hours.

7. The application of the ordered Ni / Co-NiCo heterojunction catalyst according to any one of claims 1 to 3, characterized in that, Ordered Ni / Co-NiCo heterojunction catalysts are used in the hydrodeoxygenation reaction of lignin-derived oxygen-containing aromatic compounds; Alternatively, ordered Ni / Co-NiCo heterojunction catalysts can be used in the directed hydrodeoxygenation of lignin derivative model materials and lignin oils to produce high-value chemicals and petroleum fuels.

8. The application of the ordered Ni / Co-NiCo heterojunction catalyst according to any one of claims 1 to 3, characterized in that, Ordered Ni / Co-NiCo heterojunction catalysts are used in the conversion of lignin derivative model compounds; The conversion of lignin derivative model compounds includes: adding 40-60 mg of catalyst per 1 mmol of lignin derivative model compound to an aqueous solvent, reacting at a reaction temperature of 80-260 °C, an initial hydrogen pressure of 0-30 bar, for a reaction time of 0.01-36 h, and a stirring speed of 600-800 rpm. After the reaction is complete, wait for the material to cool to room temperature before removing it.

9. The application of the ordered Ni / Co-NiCo heterojunction catalyst according to any one of claims 1 to 3, characterized in that, Ordered Ni / Co-NiCo heterojunction catalysts are used in the conversion of lignin oil; The conversion of lignin oil includes: lignin oil and catalyst are prepared at a mass ratio of 1:1 to 2 and added together to an aqueous solvent. The reaction is carried out at a reaction temperature of 80 to 260°C, an initial hydrogen pressure of 0 to 30 bar, a reaction time of 0.01 to 36 h, and a stirring speed of 600 to 800 rpm. After the reaction is complete, wait for the material to cool to room temperature before removing it.

10. The application of the ordered Ni / Co-NiCo heterojunction catalyst according to any one of claims 1 to 3, characterized in that, Ordered Ni / Co-NiCo heterojunction catalysts are used in the catalytic reduction method for the preparation of lignin oil; The preparation of lignin oil by catalytic reduction includes: Plants were pulverized into powder with an average particle size ≤40 mesh. Plant powder and Ni / C catalyst were weighed out at a mass ratio of 1-4:0.2 and added to methanol solvent. The mixture was stirred in a hydrogen atmosphere at an initial hydrogen pressure of 2-4 MPa and a temperature of 180-230℃ for 5-10 hours. After the reaction is complete, wait for the material to cool to room temperature, remove all the substances from the reactor and filter them to separate the solid residue. Methanol was removed by vacuum distillation at 50-70℃ to obtain a viscous substance. The lignin oil component of viscous substances was extracted using a two-phase ethyl acetate / water solvent extraction method. Lignin oil exists in the ethyl acetate phase. Lignin oil is obtained by vacuum distillation of ethyl acetate at 60-80℃.

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