A magnetic Ni x% FeNb2O6 composite catalyst, preparation method and application

Abstract

This invention discloses a magnetic Ni x％ This paper describes the preparation method and application of FeNb2O6 composite catalysts, which fall under the technical field of supported bimetallic oxide catalysts. First, magnetic FeNb2O6 nanocatalysts are prepared via a one-pot hydrothermal method using niobium oxalate hydrate as the niobium source and ferric nitrate as the iron source. Then, magnetic Ni is prepared via a modified deposition precipitation method using nickel nitrate as the nickel source and the magnetic FeNb2O6 nanocatalyst as the support. x％ @FeNb2O6 composite catalyst. The beneficial effect of this invention is that Ni... x％ In the FeNb2O6 composite catalyst, iron, niobium, and nickel species are highly dispersed with no obvious agglomeration, exhibiting high activity and high stability. Furthermore, the catalyst's magnetic properties allow for recovery and reuse, overcoming the shortcomings of traditional metal catalysts such as easy loss and difficulty in recovery after reaction. This Ni... x％ The FeNb2O6 composite catalyst is used for the catalytic hydrogenation conversion of Caragana korshinskii and its related model compounds. Due to its high C-O- bond cleavage activity, it can more effectively promote the depolymerization of Caragana korshinskii organic matter, thereby obtaining bio-oil rich in high-value COH functional groups.

Description

Technical Field

[0001] This invention relates to the field of supported bimetallic oxide catalyst technology, and more particularly to a magnetic Ni x％ @FeNb2O6 composite catalyst, preparation method and application. Background Technology

[0002] The green conversion and efficient utilization of renewable resources to replace traditional fossil fuels have received increasing attention, with biomass being considered a promising energy source that can mitigate global climate change. Therefore, the research prospects for developing green, low-carbon, and efficient biomass conversion technologies to obtain high-value oxygenated organic chemicals and clean liquid fuels are extremely promising.

[0003] In existing technologies, the catalysts used in biomass catalytic hydrogenation conversion processes are mostly non-recoverable. However, monomeric metal oxide catalysts and traditional solid catalysts have low porosity, few active sites, and are extremely unstable. Therefore, to improve their stability and activity, doping with other metal oxides to form bimetallic complexes is an improved option. Commonly used bimetallic oxides have good process stability and sufficient acid-base active centers; loading them with nickel metal can further enhance their activity. However, since high reactivity is related to their unique pore size distribution, to ensure a high yield of Caragana korshinskii-derived solubles, it is necessary to increase the specific surface area of ​​the catalyst to expose more active sites, which significantly increases the cost of the catalyst.

[0004] Since transition metal oxides can effectively activate H2, further inducing the cracking of the >CO- bridging bonds in *Caragana korshinskii*, and to simultaneously achieve heteroatom removal while suppressing aromatic ring hydrogenation, precise control of the conversion of active hydrogen species is required. However, in regulating the reaction, especially at relatively high temperatures, catalysts used in existing technologies are prone to sintering and S / N sensitivity, leading to problems such as large catalyst consumption and high process costs. Furthermore, the catalysts used in existing technologies are difficult to recover or regenerate, hindering their large-scale application and improved economic efficiency.

[0005] In view of this, there is an urgent need to develop a catalyst for the catalytic hydrogenation conversion reaction of Caragana korshinskii and its related model compounds, so as to completely solve the problems of sintering, S / N sensitivity, easy loss of active components and difficulty in recovery. Summary of the Invention

[0006] To address the technical problems of traditional bimetallic oxide catalysts, such as sintering, S / N sensitivity, easy loss of active components, and difficulty in recovery during the reaction process, this invention discloses a magnetic Ni x％ @FeNb2O6 composite catalyst, preparation method and application.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A magnetic Ni x％ The preparation method of the FeNb2O6 composite catalyst is characterized by the following specific steps:

[0009] a. Disperse a certain amount of niobium oxalate hydrate and ferric nitrate in deionized water, stir at room temperature, transfer the mixed solution to a polytetrafluoroethylene-lined hydrothermal reactor, slowly inject a certain amount of ammonia water, adjust the pH, and then place the reactor in a forced-air drying oven for heating and heat preservation.

[0010] b. After the solution obtained in step a is cooled to room temperature, it is centrifuged and then washed several times with deionized water and ethanol. The solid sample is then vacuum dried and then placed in a tube furnace for calcination to obtain the support, namely the magnetic FeNb2O6 nanocatalyst.

[0011] c. A certain amount of nickel nitrate and magnetic FeNb2O6 nanocatalyst were added to deionized water, followed by ammonia. The mixture was then stirred in a water bath, centrifuged, and washed alternately with deionized water and ethanol. The mixture was then dried in a drying oven, and the resulting solid was calcined in a tube furnace to obtain magnetic Ni. x％ @FeNb2O6 composite catalyst.

[0012] Further, in step a, the molar ratio of niobium oxalate hydrate to ferric nitrate is 2:1, the volume ratio of the mixed solution to the volume of the polytetrafluoroethylene-lined hydrothermal reactor is (60-75):100, and the pH is adjusted to 8.

[0013] Furthermore, in steps a and b, the volume ratio of ammonia water to deionized water is (5-20):100; the hydrothermal insulation temperature is 160℃, and the insulation time is 12-18h.

[0014] Furthermore, in step b, the centrifugation speed is 5000 rpm, the centrifugation time is 5-8 min; the vacuum drying temperature is 80℃, the drying time is 8-12 h; the tube furnace heating rate is 3℃ / min, the holding temperature is 600℃, and the holding time is 2 h.

[0015] Further, in step c, the mass ratio of nickel nitrate to magnetic FeNb2O6 nanocatalyst is x:100, where x = 5, 10, 15, and 20, respectively, and the resulting catalysts are Ni 5％ @FeNb2O6, Ni 10％ @FeNb2O6, Ni 15％ @FeNb2O6 and Ni 20％ @FeNb2O6, the volume ratio of ammonia water to deionized water is (5-20):100.

[0016] Further, in step c, the beaker containing the mixed solution is placed in a water bath and stirred at 60°C for 1 hour; the centrifugation speed is 5000 rpm and the centrifugation time is 5–15 minutes; the vacuum drying temperature is 80°C and the drying time is 4–12 hours.

[0017] Furthermore, in step c, the heating rate of the tubular furnace is 3℃ / min, the holding temperature is 460℃, and the holding time is 2h.

[0018] This invention also discloses magnetic Ni x％ Application of @FeNb2O6 composite catalyst in the catalytic hydrogenation conversion of organic matter from Caragana korshinskii and its related model compounds. For example, its application in the catalytic hydrogenation conversion of related model compounds from Caragana korshinskii, and its application in the catalytic hydrogenation conversion of organic matter from Caragana korshinskii.

[0019] The advantages of this invention are that the preparation process is innovative, safe and feasible.

[0020] First, using ferric nitrate as the iron source and niobium oxalate hydrate as the niobium source, and ammonia as the pH adjuster to make the solution alkaline, a one-pot hydrothermal method was employed. After washing and tube furnace calcination, a magnetic FeNb₂O₆ nanocatalyst was obtained. Then, using nickel nitrate as the nickel source and the magnetic FeNb₂O₆ nanocatalyst as the support, a modified deposition precipitation method was used. After washing and tube furnace calcination, a magnetic Ni was obtained. x％ @FeNb2O6 composite catalyst.

[0021] Compared with existing technologies, this magnetic Ni x％ The FeNb2O6 composite catalyst has the following advantages:

[0022] (1) Magnetic Ni prepared by this method x％ In the FeNb2O6 composite catalyst, the iron, niobium and nickel species are highly dispersed and show no obvious agglomeration.

[0023] (2) Magnetic Ni x％ The preparation process of the FeNb2O6 composite catalyst is novel and highly safe, and the resulting magnetic Ni x％ The FeNb2O6 composite catalyst exhibits good stability.

[0024] (3) Magnetic Ni x％ The FeNb2O6 composite catalyst uses magnetic FeNb2O6 nanocatalysts as a support. Fe is the most abundant transition metal on Earth, and it exists mostly in the form of iron oxide, which is widely used in catalysts. Nb... 5+The ions are compatible with the iron oxide structure, and Nb2O5 is considered a promising additive for modifying the iron oxide structure due to its excellent chemical and thermal stability.

[0025] (4) Magnetic Ni x％ @FeNb2O6 composite catalyst is a supported bimetallic oxide catalyst. Ni is considered an ideal catalytic hydrogenation catalyst due to its excellent hydrogenation activity and low price. Ni also has strong activity in the activation of inert CO, CH and CC.

[0026] (5) Magnetic Ni x％ The FeNb2O6 composite catalyst has inherent magnetic characteristics, so it can be recycled and reused through an external magnetic field, which has the potential for large-scale application.

[0027] (6) One of the Ni components in the catalyst 20％ The FeNb2O6 composite catalyst exhibited excellent catalytic activity in the catalytic hydrogenation conversion of organic matter from Caragana korshinskii and in the catalytic hydrogenation conversion of related model compounds from Caragana korshinskii. It can effectively crack CO- bridging bonds and promote the depolymerization of organic matter from Caragana korshinskii, thereby obtaining bio-oil rich in high-value COH functional groups. Attached Figure Description

[0028] Figure 1 The magnetic Ni samples prepared in Examples 1, 2, 3, and 4 of this invention are respectively. 5％ @FeNb2O6、Ni 10％ @FeNb2O6, Ni 15％ @FeNb2O6 and Ni 20％ X-ray diffraction pattern of the FeNb2O6 composite catalyst;

[0029] Figure 2 The magnetic Ni obtained in Example 1 of this invention 5％ Scanning electron microscope image of FeNb2O6 composite catalyst;

[0030] Figure 3 The magnetic Ni obtained in Example 2 of this invention 10％ Scanning electron microscope image of FeNb2O6 composite catalyst;

[0031] Figure 4 The magnetic Ni obtained in Example 3 of this invention 15％ Scanning electron microscope image of FeNb2O6 composite catalyst;

[0032] Figure 5 The magnetic Ni obtained in Example 4 of this invention 20％ Scanning electron microscope image of FeNb2O6 composite catalyst;

[0033] Figure 6 The magnetic Ni obtained in Example 4 of this invention 20％ X-ray photoelectron spectroscopy of FeNb2O6 composite catalyst;

[0034] Figure 7 The infrared spectrum of the Caragana korshinskii-derived solubles obtained in Example 2 of this invention;

[0035] Figure 8 This is a distribution diagram of the family components of the soluble derivative of *Caragana korshinskii* obtained in Application Example 2 of the present invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0037] This invention addresses the problems of sintering, S / N sensitivity, easy loss of active components, and difficulty in recovery of bimetallic oxide catalysts, and discloses a magnetic Ni x％ The preparation method of FeNb2O6 composite catalyst greatly simplifies the catalyst preparation process, modifies the morphology, structure and size of the catalyst, and overcomes the defects of traditional bimetallic oxide catalysts such as easy sintering, S / N sensitivity, easy loss of active components and difficulty in recovery.

[0038] Highly active magnetic Ni prepared by this method x％ The FeNb2O6 composite catalyst significantly improved the conversion of related model compounds from Caragana korshinskii and the catalytic hydrogenation conversion of Caragana korshinskii organic matter.

[0039] Example 1

[0040] A magnetic Ni 5％ The preparation method of the FeNb2O6 composite catalyst is as follows:

[0041] (1) Disperse 0.5g ferric nitrate and 1.5g niobium oxalate hydrate in 40mL of deionized water and stir evenly at room temperature for later use.

[0042] (2) Transfer the obtained mixed solution to a polytetrafluoroethylene-lined hydrothermal reactor, slowly inject 5 mL of ammonia water, adjust the pH to 8, and then heat the reactor to 160°C and keep it warm for 12 hours.

[0043] (3) Cool the obtained solution to room temperature, centrifuge the sample at a speed of 5000 rpm for 5 min, and then wash it several times with deionized water and ethanol until it is neutral.

[0044] (4) The obtained solid sample was vacuum dried at 70°C for 6 hours.

[0045] (5) Place it in a tube furnace and calcine at 600℃, with a heating rate of 5℃ / min, and keep it at that temperature for 2 hours to obtain the magnetic FeNb2O6 nanocatalyst.

[0046] (6) Place 0.05g of nickel nitrate and 1g of magnetic FeNb2O6 nanocatalyst into 100mL of deionized water and add 5mL of ammonia.

[0047] (7) Place the beaker containing the mixed solution into a water bath and stir at 60°C for 1 hour.

[0048] (8) Cool the obtained solution to room temperature, centrifuge the sample at a speed of 5000 rpm for 5 min, and then wash it several times with deionized water and ethanol until it is neutral.

[0049] (9) The obtained mixture was vacuum dried at 80°C for 8 hours.

[0050] (10) The heating rate of the tube furnace was 3℃ / min, the holding temperature was 460℃, the holding time was 2h, and then the temperature was lowered to room temperature to obtain magnetic Ni. 5％ @FeNb2O6 composite catalyst.

[0051] Example 2

[0052] This invention discloses a magnetic Ni 10％ The preparation method of the FeNb2O6 composite catalyst includes the following steps:

[0053] (1) Disperse 0.7g ferric nitrate and 1.7g niobium oxalate hydrate in 40mL of deionized water and stir evenly at room temperature for later use.

[0054] (2) Transfer the obtained mixed solution to a polytetrafluoroethylene-lined hydrothermal reactor, slowly inject 10 mL of ammonia water, adjust the pH to 8, and then heat the reactor to 160°C and keep it warm for 14 hours.

[0055] (3) Cool the obtained solution to room temperature, centrifuge the sample at a speed of 5000 rpm for 5 min, and then wash it several times with deionized water and ethanol until it is neutral.

[0056] (4) The obtained solid sample was vacuum dried at 70°C for 6 hours.

[0057] (5) Place it in a tube furnace and calcine at 600℃, with a heating rate of 5℃ / min, and hold for 3 hours to obtain magnetic FeNb2O6 nanocatalyst.

[0058] (6) Place 0.1g of nickel nitrate and 1g of magnetic FeNb2O6 nanocatalyst into 100mL of deionized water and add 10mL of ammonia.

[0059] (7) Place the beaker containing the mixed solution into a water bath and stir at 60°C for 1 hour.

[0060] (8) Cool the obtained solution to room temperature, centrifuge the sample at a speed of 5000 rpm for 5 min, and then wash it several times with deionized water and ethanol until it is neutral.

[0061] (9) The obtained mixture was vacuum dried at 80°C for 10 hours.

[0062] (10) The heating rate of the tube furnace was 3℃ / min, the holding temperature was 460℃, the holding time was 2h, and then the temperature was lowered to room temperature to obtain magnetic Ni. 10％ @FeNb2O6 composite catalyst.

[0063] Example 3

[0064] This invention discloses a magnetic Ni 15％ The preparation method of the FeNb2O6 composite catalyst includes the following steps:

[0065] (1) Disperse 0.9g ferric nitrate and 1.9g niobium oxalate hydrate in 40mL of deionized water and stir evenly at room temperature for later use.

[0066] (2) Transfer the obtained mixed solution to a polytetrafluoroethylene-lined hydrothermal reactor, slowly inject 15 mL of ammonia water, adjust the pH to 8, and then heat the reactor to 160°C and keep it warm for 16 hours.

[0067] (3) Cool the obtained solution to room temperature, centrifuge the sample at a speed of 5000 rpm for 3 min, and then wash it several times with deionized water and ethanol until it is neutral.

[0068] (4) The obtained solid sample was vacuum dried at 70°C for 6 hours.

[0069] (5) Place it in a tube furnace and calcine at 600℃, with a heating rate of 5℃ / min, and keep it at that temperature for 2 hours to obtain the magnetic FeNb2O6 nanocatalyst.

[0070] (6) Place 0.15g of nickel nitrate and 1g of magnetic FeNb2O6 nanocatalyst into 100mL of deionized water and add 15mL of ammonia.

[0071] (7) Place the beaker containing the mixed solution into a water bath and stir at 60°C for 1 hour.

[0072] (8) Cool the obtained solution to room temperature, centrifuge the sample at a speed of 5000 rpm for 10 min, and then wash it several times with deionized water and ethanol until it is neutral.

[0073] (9) The obtained mixture was vacuum dried at 80°C for 12 hours.

[0074] (10) The heating rate of the tube furnace was 3℃ / min, the holding temperature was 460℃, the holding time was 2h, and then the temperature was lowered to room temperature to obtain magnetic Ni. 15％ @FeNb2O6 composite catalyst.

[0075] Example 4

[0076] This invention discloses a magnetic Ni 20％ The preparation method of the FeNb2O6 composite catalyst includes the following steps:

[0077] (1) Disperse 1.1g of ferric nitrate and 2.1g of niobium oxalate hydrate in 40mL of deionized water and stir evenly at room temperature for later use.

[0078] (2) Transfer the obtained mixed solution to a polytetrafluoroethylene-lined hydrothermal reactor, slowly inject 20 mL of ammonia water, then adjust the pH to 8, and then heat the reactor to 160°C and keep it at that temperature for 18 h.

[0079] (3) Cool the obtained solution to room temperature, centrifuge the sample at a speed of 5000 rpm for 3 min, and then wash it several times with deionized water and ethanol until it is neutral.

[0080] (4) The obtained solid sample was vacuum dried at 70°C for 6 hours.

[0081] (5) Place it in a tube furnace and calcine at 600℃, with a heating rate of 5℃ / min, and keep it at that temperature for 2 hours to obtain the magnetic FeNb2O6 nanocatalyst.

[0082] (6) Place 0.15g of nickel nitrate and 1g of magnetic FeNb2O6 nanocatalyst into 100mL of deionized water and add 20mL of ammonia.

[0083] (7) Place the beaker containing the mixed solution into a water bath and stir at 60°C for 1 hour.

[0084] (8) Cool the obtained solution to room temperature, centrifuge the sample at a speed of 5000 rpm for 5 min, and then wash it several times with deionized water and ethanol until it is neutral.

[0085] (9) The obtained mixture was vacuum dried at 80°C for 12 hours.

[0086] (10) The heating rate of the tube furnace was 3℃ / min, the holding temperature was 460℃, the holding time was 2h, and then the temperature was lowered to room temperature to obtain magnetic Ni. 20％ @FeNb2O6 composite catalyst.

[0087] The magnetic Ni obtained above x％ X-ray diffraction pattern of the FeNb2O6 composite catalyst, as shown Figure 1 As can be seen from the figure, Ni with different Ni loadings x％ @FeNb2O6 exhibits a good crystal structure. Characteristic derived peaks belonging to FeNb2O6 appear near 24.2°, 30.1°, 53.2°, and 64.2°. Furthermore, peaks belonging to Ni are observed near 44°. 0 The characteristic peaks of Ni0 gradually increase in intensity as the Ni loading X increases. Clearly, Ni species were successfully loaded onto the FeNb2O6 support via a deposition-precipitation method, forming Ni0. x％ @FeNb2O6 composite catalyst.

[0088] The magnetic Ni obtained above x％ Scanning electron microscope image of the FeNb2O6 composite catalyst, as shown. Figure 2 , Figure 3 , Figure 4 and Figure 5 Four different Ni loading values ​​X are listed, each corresponding to Ni 5％ @FeNb2O6, Ni 10％ @FeNb2O6, Ni 15％ @FeNb2O6 and Ni 20％ SEM images of the FeNb2O6 composite catalysts. The images show that all four catalysts exhibit uniform nanospheres, with some smaller particles spontaneously aggregating.

[0089] Magnetic Ni prepared in Example 4 20％ X-ray photoelectron spectroscopy (XPS) of FeNb2O6 composite catalyst, such as Figure 6 XPS was used to study the surface elemental composition and chemical state of the sample. The figures show that Ni... 20％ @FeNb2O6 contains three metallic elements: Ni, Fe, and Nb. The Ni 2p peaks are located near 856.0 eV and 874.0 eV, representing its core binding energy. Two vibrational satellite peaks are observed near 861.3 eV and 879.7 eV, while the peak at 852.6 eV, representing the vibrational binding energy, is attributed to Ni. 0 The graph then shows that the Fe 2p peaks are located around 710.4 eV and 723.7 eV, mainly composed of Fe. 2+ The Nb3d peaks are located at 206.9 eV and 209.6 eV, indicating that the chemical valence state of Nb in the sample is Nb3d. 5+ This ion is compatible with the iron oxide structure and can better modify the iron oxide structure.

[0090] The following is about magnetic Ni 20％ Two applications of the FeNb2O6 composite catalyst are illustrated with examples.

[0091] Application Example 1

[0092] The above magnetic Ni x％ The FeNb2O6 composite catalyst was applied to the catalytic hydrogenation cracking reaction of a model compound of Caragana korshinskii (this experiment used a representative model compound of Caragana korshinskii, namely benzylphenyl ether, as the experimental material).

[0093] The specific application process is as follows:

[0094] 1. Ni with four different Ni loadings 5％ @FeNb2O6, Ni 10％ @FeNb2O6, Ni 15％ @FeNb2O6 and Ni 20％ Screening of FeNb2O6 composite catalysts under the same conditions:

[0095] (1) Prepare Ni 5％ @FeNb2O6, Ni 10％ @FeNb2O6, Ni 15％ @FeNb2O6 and Ni 20％ Each of the FeNb2O6 composite catalysts (5g each) was placed in four 1000mL high-pressure reactors along with 20g of benzylphenyl ether and 200mL of deionized water.

[0096] (2) After replacing the air in the reactor with N2, 4 MPa of H2 was introduced and the reaction was carried out at 260℃ for 4 h.

[0097] (3) After the reaction was completed, the four high-pressure reactors were cooled to room temperature and the reaction mixture was removed. The filtered filtrate was analyzed by gas chromatography-mass spectrometry to detect the magnetic Nix with different Ni loadings. ％ The performance analysis results of the @FeNb2O6 composite catalyst for the catalytic hydrogenation conversion of benzylphenyl ether, a model compound related to Caragana korshinskii, are shown in Table 1 below.

[0098] Table 1

[0099]

[0100] 2. From Table 1 above, we can obtain Ni 20％ The FeNb2O6 composite catalyst showed the best relative performance, followed by Ni. 20％ Further experiments were conducted using the FeNb2O6 composite catalyst.

[0101] (1) 5g magnetic Ni 20％ @FeNb2O6 composite catalyst and 20g benzylphenyl ether were placed in a 1000mL high-pressure reactor and 200mL deionized water was added.

[0102] (2) Replace the air in the reactor with N2 and then charge it with 1-4 MPa H2. React at 200℃-280℃ for 0.5-4 h.

[0103] (3) After the reaction was completed, the high-pressure reactor was cooled to room temperature and the reaction mixture was removed. The filtrate after filtration was analyzed by gas chromatography-mass spectrometry. Magnetic Ni 20％ The performance analysis results of the @FeNb2O6 composite catalyst for the catalytic hydrogenation conversion of benzylphenyl ether, a model compound related to Caragana korshinskii, are shown in Table 2 below.

[0104] Table 2

[0105]

[0106] As can be seen from Tables 1 and 2, the main products of the catalytic hydrogenation conversion of benzylphenyl ether are aromatic hydrocarbons, especially toluene, phenol, and benzyl alcohol. These products are then analyzed by magnetic Ni... x％ The active hydrogen species formed by H2 activation on the FeNb2O6 composite catalyst play a crucial role in the acquisition of derived aromatics.

[0107] First, H2 can be found in Ni x％ @FeNb2O6 is effectively activated to diatomic active hydrogen (H…H). Due to the low bond dissociation energy of H…H, it is effective in Ni. x％On @FeNb2O6, H…H tends to uniformly split into hydrogen radicals (H·), and the co-transfer of H· and H…H further promotes the conversion of benzylphenyl ethers and their intermediates into aromatics. Therefore, Ni synthesized using this invention… x％ The FeNb2O6 composite catalyst features high catalytic activity, high selectivity for aromatics, and easy recovery.

[0108] Application Example 2

[0109] magnetic Ni 20％ The FeNb2O6 composite catalyst was applied to the catalytic hydrogenation cracking reaction of Caragana korshinskii powder, with the addition of a certain amount of magnetic Ni prepared in Example 4. 20％ @FeNb2O6 composite catalyst.

[0110] The specific application process is as follows:

[0111] (1) 5g magnetic Ni 20％ @FeNb2O6 composite catalyst and 20g of Caragana korshinskii powder were placed in a 1000mL high-pressure reactor and 200mL of deionized water was added.

[0112] (2) After replacing the air in the reactor with N2, 4MPa H2 was introduced and the reaction was carried out at 260℃ for 4h. After the reaction was completed, the reactor was cooled to room temperature.

[0113] (3) The reaction mixture was completely extracted with n-hexane to obtain the Caragana spp. solubles were obtained, and the catalyst was recovered by adding an external magnet. The remainder was Caragana spp. residue.

[0114] With reference to the attached diagram, magnetic Ni x％ The preparation method, performance indicators and catalytic effect of the FeNb2O6 composite catalyst are described in detail. This example is only used to explain the present invention and does not constitute a limitation on the scope of protection of the present invention.

[0115] Figure 7 The functional group distribution of the soluble derivative of *Caragana korshinskii* from the reaction product of Example 2 is shown. The values ​​at 622, 808, 1112, 1259, 1600, 2364, 2813, 3035, and 3446 cm⁻¹ are also shown. -1 Typical characteristic absorption peaks were observed nearby; at 3446 cm⁻¹ -1 Characteristic absorption bands attributable to -OH vibrations were observed nearby, indicating that this bio-oil contains abundant -OH-containing species; at 2813 cm⁻¹ -1 The presence of a strong CH bond stretching vibration peak nearby indicates the presence of alkane, alkene, or aliphatic side chains; 2364 cm⁻¹ -1 The nearby absorption bands primarily involve stretching vibrations of C≡C and C≡N triple bonds. Additionally, at 1600 and 808 cm⁻¹... -1Characteristic peaks of aromatic ring vibrations appeared nearby, at 1259 and 1112 cm⁻¹. -1 Stretching vibrations of the >CO- bonds were observed nearby. These results clearly indicate that the derived bio-oil contains abundant oxygen-containing organic species.

[0116] like Figure 8 As shown, the GC / MS analysis of the soluble derivatives of *Caragana korshinskii* revealed three main categories of products: oxygen-containing compounds, hydrocarbon compounds, and nitrogen-containing compounds. Oxygen-containing compounds were the dominant category, accounting for 85.57%. Hydrocarbons and nitrogen-containing compounds were the next most abundant, accounting for 13.84% and 0.59%, respectively. The distribution of oxygen-containing compounds is shown in Table 3 below.

[0117] Table 3

[0118]

[0119] Notably, typical biomass derivatives, such as phenols and alcohols, were detected in the bio-oil after catalytic hydrolysis. These results further indicate that Ni... 20％ @FeNb2O6-induced catalytic hydrolysis can effectively destroy the lignin structure in the organic matter of Caragana korshinskii.

[0120] The lower content of derived aromatics means that this catalytic hydrolysis system exhibits higher selectivity for oxygen-containing monomers compared to conventional liquefaction methods. These characteristics of the derived bio-oil facilitate the further extraction of high-value oxygen-containing chemical purities.

[0121] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A magnetic Ni x% The preparation method of the FeNb2O6 composite catalyst is characterized by, The specific steps are as follows: a. Disperse a certain amount of niobium oxalate hydrate and ferric nitrate in deionized water, stir at room temperature, transfer the mixed solution to a polytetrafluoroethylene-lined hydrothermal reactor, slowly inject a certain amount of ammonia water, adjust the pH, and then place the reactor in a forced-air drying oven for heating and heat preservation. b. After the product obtained in step a is cooled to room temperature, it is centrifuged and then washed several times with deionized water and ethanol. The solid sample is then vacuum dried and then placed in a tube furnace for calcination to obtain the support, namely the magnetic FeNb2O6 nanocatalyst. c. A certain amount of nickel nitrate and magnetic FeNb2O6 nanocatalyst is added to deionized water, ammonia is added, and then water bath stirring is performed. The mixture is centrifuged and washed with deionized water and ethanol alternately, and then dried in a drying box. The obtained solid is placed in a tube furnace for calcination to obtain magnetic Ni x% @FeNb2O6 composite catalyst, and x is the mass ratio of nickel nitrate to magnetic FeNb2O6 nanocatalyst.

2. A magnetic Ni as described in claim 1 x% The preparation method of the FeNb2O6 composite catalyst is characterized by, In step a, the molar ratio of niobium oxalate hydrate to ferric nitrate is 2:1, the volume ratio of the mixed solution to the volume of the polytetrafluoroethylene-lined hydrothermal reactor is (60-75):100, and the pH is adjusted to 8.

3. A magnetic Ni as described in claim 2 x% The preparation method of the FeNb2O6 composite catalyst is characterized by, In steps a and b, the volume ratio of ammonia water to deionized water is (5-20):100; the hydrothermal insulation temperature is 160 ℃, and the insulation time is 12~18h.

4. A magnetic Ni as described in claim 3 x% The preparation method of the FeNb2O6 composite catalyst is characterized by, In step b, the centrifugation speed is 5000 rpm and the centrifugation time is 5~8 min; the vacuum drying temperature is 80 ℃ and the drying time is 8~12 h; the heating rate of the tube furnace is 3 ℃ / min, the holding temperature is 600 ℃ and the holding time is 2 h.

5. A magnetic Ni as described in claim 4 x% The preparation method of the FeNb2O6 composite catalyst is characterized by, In step c, the mass ratio of nickel nitrate to magnetic FeNb2O6nanocatalyst is x:100, x=5, 10, 15, 20, and the prepared catalysts are Ni 5% @FeNb2O6, Ni 10% @FeNb2O6, Ni 15% @FeNb2O6, and Ni 20% @FeNb2O6, and the volume ratio of added ammonia water to deionized water is (5-20):

100.

6. A magnetic Ni as described in claim 5 x% The preparation method of the FeNb2O6 composite catalyst is characterized by, In step c, the beaker containing the mixed solution is placed in a water bath and stirred at 60 ℃ for 1 h; the centrifugation speed is 5000 rpm and the centrifugation time is 5~15 min; the vacuum drying temperature is 80 ℃ and the drying time is 4~12 h.

7. A magnetic Ni as described in claim 6 x% The preparation method of the FeNb2O6 composite catalyst is characterized by, In step c, the heating rate of the tube furnace is 3℃ / min, the holding temperature is 460℃, and the holding time is 2 h.

8. Magnetic Ni prepared by any one of the preparation methods described in claims 1-7 x% Application of FeNb2O6 composite catalyst in the catalytic hydrogenation conversion of organic matter from Caragana korshinskii and benzylphenyl ether.

Images