High-activity and high-stability nickel-cobalt alloy catalyst as well as synthesis method and application thereof
By encapsulating nickel-cobalt alloy nanoparticles in a hollow S-1 zeolite shell and coating them with mesoporous carbon, the problems of simple structure of carbon-silicon composite materials and easy sintering of nickel-based catalysts are solved, achieving high activity and stability of the catalyst under high loading, which is suitable for biomass HDO reaction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2026-01-07
- Publication Date
- 2026-04-17
AI Technical Summary
Existing carbon-silicon composite materials have a simple structural design and low functional integration in Pickering emulsion catalysis systems. Nickel-based non-precious metal catalysts are prone to sintering and carbon deposition in biomass HDO reactions, and it is difficult to balance activity and stability under high loading.
By employing a dissolution-recrystallization process and an alloying strategy, nickel-cobalt alloy nanoparticles were encapsulated in a hollow S-1 zeolite shell. Mesoporous carbon was then coated with regioselective carbon to construct a high-load nickel-cobalt alloy catalyst, which inhibited metal sintering and migration and optimized interfacial wettability to promote reaction mass transfer.
It achieves synergistic enhancement of high catalyst activity and stability, exhibits excellent catalytic performance, with a yield of over 94% for the hydrogenation and deoxygenation of vanillin, and good cycle stability, making it suitable for the efficient conversion of biomass-derived aromatic compounds.
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Figure CN121869424A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of biomass energy catalysis and conversion technology, and particularly relates to a highly active and stable nickel-cobalt alloy catalyst, its synthesis method, and its application. Background Technology
[0002] The catalytic conversion of biomass and its derivatives into high-value-added fuels and chemicals is an important sustainable way to reduce dependence on fossil fuels and mitigate environmental pollution. Among them, oxygenated aromatic compounds in bio-oils can effectively improve their energy density and combustion performance through hydrodeoxygenation (HDO) reaction, which plays a key role in promoting the high-value utilization of biomass resources.
[0003] Pickering emulsion catalysis systems, with their stable oil-water interface and unique mass transfer advantages, provide an ideal platform for biphasic catalytic reactions. In this system, the interfacial wettability of the solid catalyst has a decisive impact on reaction efficiency. Therefore, developing solid catalysts with precisely tunable wettability that can be uniformly distributed at the oil-water interface and form stable emulsions has become crucial for achieving efficient upgrading of HDO, a biomass-derived platform compound. Carbon-silicon composites, such as carbon-coated silica, silicon carbide, and carbon-silicon aerogels, show great promise in this field due to their good stability, tunable surface properties, and excellent wettability. However, existing carbon-silicon composites still face challenges such as limited structural design and low functional integration. Therefore, developing carbon-silicon composites with novel structures and functions remains a key research focus and challenge.
[0004] Although pure silicon MFI zeolite (S-1) has regular micropores and excellent performance, its direct use in two-phase interface catalysis is still limited. By constructing mesoporous carbon on the surface of S-1 through a regional mesoporous carbon coating strategy, a composite structure with hierarchical channels and heterogeneous interfaces can be formed. This not only enhances the hydrophobicity of the material, extends its service life, and inhibits metal leaching, but also helps to overcome the bottleneck of its applicability in Pickering systems.
[0005] In the field of HDO reaction catalysts, although noble metals (such as Pd and Rh) exhibit excellent activity, their high cost and scarcity of resources limit their large-scale application. Nickel-based non-noble metal catalysts show better potential for industrial application due to their good catalytic performance and low cost. However, nickel-based catalysts still have problems such as easy sintering, easy carbon deposition, and difficulty in balancing activity and stability under high loading. Summary of the Invention
[0006] The purpose of this invention is to provide a method for synthesizing a highly active and stable nickel-cobalt alloy catalyst, thereby addressing the problems mentioned in the background section.
[0007] The present invention is implemented as follows: a method for synthesizing a highly active and stable nickel-cobalt alloy catalyst includes the following steps:
[0008] Step 1: Mix tetrapropylammonium hydroxide with deionized water evenly, then slowly add tetraethyl orthosilicate and stir continuously at room temperature. After stirring, transfer the clear solution to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and statically heat it in an oven at 170 °C for 72 h to promote crystal growth. After the reaction is complete, allow the autoclave to cool naturally to room temperature, centrifuge to collect the solid product, wash and dry it, and calcine it in static air at 550 °C for 6 h to remove the organic template to obtain S-1 zeolite.
[0009] Step 2: S-1 zeolite was mixed with aqueous solutions of Ni(NO3)2·6H2O and Co(NO3)2·6H2O at a liquid-to-solid ratio of 2 mL / g for impregnation. The theoretical total metal loading was 15 wt%. The impregnated material was placed in tetrapropylammonium hydroxide solution at a liquid-to-solid ratio of 40 mL / g and hydrothermally treated at 170 ℃ for 72 h. After cooling, the material was collected by centrifugation and dried. It was then calcined in static air at 540 ℃ for 4 h to obtain Ni. x Co y O@S-1 nanocrystals;
[0010] Step 3: Ni x Co y O@S-1 nanocrystals were mixed with polymers P123 and F127, dopamine hydrochloride, and 1,3,5-trimethylbenzene, and ultrasonically dispersed in a mixed solvent of water and ethanol. Ammonia was added to react the mixture, and the Ni was collected by centrifugation. x Co y O@S-1@mPDA and dry it; Ni x Co y O@S-1@mPDA was heated to 350 °C at 2 °C / min and held for 2 h in a nitrogen atmosphere, then carbonized at 700 °C at 5 °C / min for 2 h, and finally reduced at 750 °C in hydrogen for 1 h to obtain Ni. x Co y @S-1@mC catalyst.
[0011] Another objective of this invention is to provide a highly active and stable nickel-cobalt alloy catalyst, which is synthesized using the above-described synthesis method.
[0012] Another objective of this invention is to provide an application of a highly active and stable nickel-cobalt alloy catalyst in the catalytic hydrogenation and deoxygenation reaction of vanillin.
[0013] This invention combines a "dissolution-recrystallization" process, alloying construction, and a regioselective carbon coating strategy to successfully encapsulate high-loading nickel-cobalt alloy nanoparticles in a hollow S-1 zeolite shell and selectively coat its outer surface with mesoporous carbon, thus synthesizing a regioselective mesoporous carbon-coated S-1 zeolite catalyst with high-loading nickel-cobalt alloy. This not only effectively inhibits the sintering and migration of metal nanoparticles and improves the hydrothermal stability of S-1, but also promotes reaction mass transfer by optimizing interfacial wettability, achieving a synergistic enhancement of catalytic activity and stability, providing a new solution for the application of non-precious metal catalysts in biomass conversion.
[0014] This catalyst exhibits excellent catalytic performance in the hydrogenation and deoxygenation of vanillin. Under mild conditions, it can efficiently convert vanillin to MMP with a yield exceeding 94%, and demonstrates excellent cycling stability, maintaining high activity and selectivity even after five consecutive uses. Through a hollow zeolite confinement encapsulation strategy, a high degree of dispersion of NiCo alloy nanoparticles under high metal loading was successfully achieved, effectively suppressing sintering and aggregation. The regioselective coating of mesoporous carbon not only acts as a physical barrier to reduce metal leaching, but also constructs a stable Pickering emulsion reaction interface by regulating surface wettability, significantly improving the water-oil two-phase mass transfer efficiency and the catalyst's hydrothermal stability.
[0015] This catalyst employs a non-precious metal system, combining the advantages of low cost and high performance, and provides a catalytic material with industrial application potential for the efficient conversion of biomass-derived aromatic compounds. Attached Figure Description
[0016] Figure 1 This is a SEM image of the NiCo@S-1@mC catalyst prepared in Example 1 of this invention;
[0017] Figure 2 This is a TEM image of the NiCo@S-1@mC catalyst prepared in Example 1 of this invention;
[0018] Figure 3 The XRD pattern of the NiCo@S-1@mC catalyst prepared in Example 1 of this invention;
[0019] Figure 4 The results of the cycling experiment are for the NiCo@S-1@mC catalyst prepared in Example 1 of this invention;
[0020] Figure 5 The results show the catalytic performance of the NiCo@S-1@mC catalyst prepared in Example 1 of this invention at different reaction temperatures;
[0021] Figure 6The results show the catalytic performance of the NiCo@S-1@mC catalyst prepared in Example 1 of this invention at different rotation speeds.
[0022] Figure 7 The results show the catalytic performance of the NiCo@S-1@mC catalyst prepared in Example 1 of this invention under different hydrogen pressures.
[0023] Figure 8 The results show the catalytic performance of the NiCo@S-1@mC catalyst prepared in Example 1 of this invention under different solvent ratios. Detailed Implementation
[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0025] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.
[0026] Example 1: A highly active and stable nickel-cobalt alloy catalyst, the preparation method of which includes the following steps:
[0027] Step 1: First, 3 mL of tetrapropylammonium hydroxide (25 wt%) was mixed evenly with 25 mL of deionized water. Then, 3 mL of tetraethyl orthosilicate was slowly added to the solution. The mixture was stirred continuously at room temperature for 6 h. After stirring, the clear solution was transferred to a 50 mL stainless steel hydrothermal reactor lined with polytetrafluoroethylene. The reactor was statically heated at 170 ℃ in an oven for 72 h to promote crystal growth. After the reaction was completed, the autoclave was allowed to cool naturally to room temperature. The solid product was collected by centrifugation and washed several times with deionized water and ethanol. The product was dried at 80 ℃ for 12 h. Finally, the product was calcined in static air at 550 ℃ for 6 h to remove the organic template, yielding S-1 zeolite.
[0028] Step 2: S-1 was impregnated with an equal volume of Ni(NO3)2·6H2O and Co(NO3)2·6H2O aqueous solution, with a solution-to-S-1 ratio of 2 mL / g and a theoretical total metal loading of 15 wt%. The impregnated S-1 sample was placed in a tetrapropylammonium hydroxide (0.3 M) solution at a liquid-to-solid ratio of 40 mL / g and hydrothermally treated at 170 ℃ for 72 h. After hydrothermal treatment, the solid product was separated by centrifugation and dried at 100 ℃ for 12 h. Finally, the dried sample was calcined in static air at 540 ℃ for 4 h to remove the organic template, yielding NiCoO@S-1 nanocrystals.
[0029] Step 3: In the standard synthesis process, 0.015 g of NiCoO@S-1 nanocrystals, 0.005 g of P123, 0.095 g of F127, 0.15 g of dopamine hydrochloride, and 0.4 mL of 1,3,5-trimethylbenzene were prepared. These materials were uniformly dispersed by ultrasonic treatment for 1 min in a mixed solvent of 5 mL deionized water and 5 mL ethanol. Subsequently, 0.4 mL of ammonia solution was added under stirring. After 2 h of reaction, the mesoporous polydopamine regionally coated NiCoO@S-1 sample (NiCoO@S-1@mPDA) was collected by centrifugation and dried at 100 °C for 12 h. The obtained NiCoO@S-1@mPDA was heated from room temperature to 350 °C at a heating rate of 2 °C / min under a nitrogen atmosphere and held at this temperature for 2 h. Then, the temperature was increased to 700 °C at a heating rate of 5 °C / min and held at this temperature for 2 h. The carbonization process was completed in h, and the sample was finally reduced in a hydrogen atmosphere at 750 °C for 1 h to obtain the NiCo@S-1@mC catalyst, in which the percentage of Ni was 7.0 wt% and the percentage of Co was 6.2 wt%.
[0030] The structure of the NiCo@S-1@mC catalyst prepared in Example 1 was characterized. Figure 1 SEM images of the catalyst in Example 1 are shown, revealing that mesoporous carbon regions selectively coat the surface of NiCo@S-1 nanocrystals; Figure 2 The TEM image shows that nickel-cobalt alloy nanoparticles are uniformly embedded in the hollow S-1 zeolite shell, with an average particle size of 6.8 nm. Figure 3 The X-ray diffraction (XRD) spectrum shows the characteristic diffraction peaks of the (111), (200) and (220) crystal planes of the nickel-cobalt alloy, indicating that the method successfully synthesized a nickel-cobalt alloy with high purity, good crystallinity and complete crystal form.
[0031] The NiCo@S-1@mC catalyst prepared in Example 1 was applied to the catalytic reaction of vanillin HDO. The specific steps are as follows:
[0032] 1.0 mmol vanillin, 30 mg NiCo@S-1@mC catalyst, 10 mL water, and 30 mL decahydronaphthalene were added to a 100 mL magnetically driven high-pressure reactor. The reaction was carried out at 120 °C, with an initial hydrogen pressure of 1.2 MPa and a rotation speed of 600 rpm for 4 h. The conversion rate of vanillin HDO was found to be 83.3%, and the selectivity of the target product 2-methoxy-4-methylphenol was 82.9%.
[0033] Figure 4The results of the cycle stability test of the NiCo@S-1@mC catalyst prepared in Example 1 are shown. As can be seen from the figure, the catalyst can still maintain excellent catalytic performance after five consecutive cycles of reuse. The yield of the target product 2-methoxy-4-methylphenol did not decrease significantly, demonstrating excellent structural stability and recyclability. This result fully demonstrates that the catalyst has excellent industrial application potential and long-term operational reliability.
[0034] Example 2, compared with Example 1, differs only in that the equal volume of Ni(NO3)2·6H2O and Co(NO3)2·6H2O aqueous solution in step 2 is replaced with a single Co(NO3)2·6H2O aqueous solution; finally, a single metal Co@S-1@mC catalyst is obtained, and the percentage content of Co in the catalyst is 12.5 wt%.
[0035] The catalyst was tested for catalytic performance under the same reaction conditions as in Example 1. The conversion rate of vanillin was 46.9%, and the selectivity of the target product 2-methoxy-4-methylphenol was 66.6%.
[0036] Example 3: Compared with Example 1, the only difference is that the equal volumes of Ni(NO3)2·6H2O and Co(NO3)2·6H2O aqueous solutions in step 2 are replaced with a single Ni(NO3)2·6H2O aqueous solution;
[0037] The final single-metal Ni@S-1@mC catalyst was prepared, with a Ni percentage of 13.4 wt%.
[0038] The catalyst was tested under the same reaction conditions as in Example 1, and the conversion rate of vanillin was found to be 82.6%, and the selectivity of the target product 2-methoxy-4-methylphenol was 80.5%.
[0039] Example 4: Compared with Example 1, the only difference is that the equal volumes of Ni(NO3)2·6H2O and Co(NO3)2·6H2O aqueous solution in step 2 are replaced with a Ni(NO3)2·6H2O and Co(NO3)2·6H2O aqueous solution with a volume ratio of 1:2.
[0040] The bimetallic NiCo2@S-1@mC catalyst was finally prepared, with Ni content of 4.6 wt% and Co content of 8.1 wt%.
[0041] The catalyst was tested under the same reaction conditions as in Example 1, and the conversion rate of vanillin was found to be 76.5%, and the selectivity of the target product 2-methoxy-4-methylphenol was 61.5%.
[0042] Example 5: Compared with Example 1, the only difference is that the equal volumes of Ni(NO3)2·6H2O and Co(NO3)2·6H2O aqueous solution in step 2 are replaced with a Ni(NO3)2·6H2O and Co(NO3)2·6H2O aqueous solution with a volume ratio of 2:1.
[0043] The bimetallic Ni2Co@S-1@mC catalyst was finally prepared, with Ni content of 10.1 wt% and Co content of 3.8 wt%.
[0044] The catalyst was tested for catalytic performance under the same reaction conditions as in Example 1. The conversion rate of vanillin was 80.8%, and the selectivity of the target product 2-methoxy-4-methylphenol was 58.7%.
[0045] Example 6: Compared with Example 1, the only difference is that step 3 is omitted, and the NiCoO@S-1 nanocrystals obtained in step 2 are reduced at 750 °C for 1 h in a hydrogen atmosphere to obtain NiCo@S-1 catalyst without regional coating of mesoporous carbon. The catalyst has a Ni percentage content of 7.5 wt% and a Co percentage content of 6.9 wt%.
[0046] The catalyst was tested for catalytic performance under the same reaction conditions as in Example 1. The conversion rate of vanillin was found to be 80.3%, and the selectivity of the target product 2-methoxy-4-methylphenol was 71.3%.
[0047] Table 1 summarizes the catalytic activity of the catalysts prepared in Examples 1-6 for vanillin HDO:
[0048] Table 1
[0049]
[0050] It can be seen that the NiCo@S-1@mC catalyst prepared in Example 1 has the best activity.
[0051] Effect of different conditions on catalytic performance: In a 100 mL magnetically driven high-pressure reactor, 40 mg of the NiCo@S-1@mC catalyst prepared in Example 1 and 0.5 mmol of vanillin were added. The reaction temperature was set at 100-140 °C, the stirring speed at 400-1000 rpm, the hydrogen pressure at 0.8-1.5 MPa, and the volume ratio of water to decahydronaphthalene was adjusted (0:40, 10:30, 20:20, 30:10, and 40:0). The reaction was carried out for 4 h. The effect of reaction conditions on the catalytic performance of the NiCo@S-1@mC catalyst in the vanillin HDO reaction was investigated.
[0052] Figure 5-8The figures show a comparison of the catalytic performance of the NiCo@S-1@mC catalyst prepared in Example 1 under different reaction temperatures, stirring speeds, hydrogen pressures, and solvent ratios. It can be seen that the optimal catalytic reaction conditions are: reaction temperature 120 °C, stirring speed 600 rpm, hydrogen pressure 1.2 MPa, water to decahydronaphthalene volume ratio 10:30, catalyst dosage 40 mg, vanillin dosage 0.5 mmol, and reaction time 4 h. Under these conditions, the yield of the target product 2-methoxy-4-methylphenol can reach 94%. The results indicate that the catalyst prepared in this embodiment exhibits high catalytic activity and excellent stability for the vanillin HDO reaction under mild conditions.
[0053] In summary, the embodiments of the present invention have innovatively developed a multifunctional catalyst suitable for Pickering emulsion systems through a synergistic strategy combining "metal alloy embedded in a hollow zeolite framework" and "selective coating of mesoporous carbon regions." This effectively solves key technical problems such as low activity and poor stability of non-precious metal catalysts in bio-oil HDO reactions and the limitation of mass transfer in water-oil two-phase reaction systems, demonstrating good prospects for industrial application.
[0054] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for synthesizing a highly active and stable nickel-cobalt alloy catalyst, characterized in that, Includes the following steps: Step 1: Mix tetrapropylammonium hydroxide with deionized water evenly, then slowly add tetraethyl orthosilicate and stir continuously at room temperature. After stirring, transfer the clear solution to a stainless steel hydrothermal reactor lined with polytetrafluoroethylene and statically heat it in an oven at 170 °C for 72 h to promote crystal growth. After the reaction is complete, allow the autoclave to cool naturally to room temperature, centrifuge to collect the solid product, wash and dry it, and calcine it in static air at 550 °C for 6 h to remove the organic template to obtain S-1 zeolite. Step 2: S-1 zeolite was mixed with aqueous solutions of Ni(NO3)2·6H2O and Co(NO3)2·6H2O at a liquid-to-solid ratio of 2 mL / g for impregnation. The theoretical total metal loading was 15 wt%. The impregnated material was placed in tetrapropylammonium hydroxide solution at a liquid-to-solid ratio of 40 mL / g and hydrothermally treated at 170 ℃ for 72 h. After cooling, the material was collected by centrifugation and dried. It was then calcined in static air at 540 ℃ for 4 h to obtain Ni. x Co y O@S-1 nanocrystals; Step 3: Ni x Co y O@S-1 nanocrystals were mixed with polymers P123 and F127, dopamine hydrochloride, and 1,3,5-trimethylbenzene, and ultrasonically dispersed in a mixed solvent of water and ethanol. Ammonia was added to react the mixture, and the Ni was collected by centrifugation. x Co y O@S-1@mPDA and dry it; Ni x Co y O@S-1@mPDA was heated to 350 °C at 2 °C / min and held for 2 h in a nitrogen atmosphere, then carbonized at 700 °C at 5 °C / min for 2 h, and finally reduced at 750 °C in hydrogen for 1 h to obtain Ni. x Co y @S-1@mC catalyst.
2. The method for synthesizing the highly active and stable nickel-cobalt alloy catalyst according to claim 1, characterized in that, In step 2, the volume ratio of Ni(NO3)2·6H2O and Co(NO3)2·6H2O in the aqueous solution is one of 0:1, 1:2, 1:1, 2:1, or 1:
0.
3. The method for synthesizing the highly active and stable nickel-cobalt alloy catalyst according to claim 1, characterized in that, In step 2, the concentration of the tetrapropylammonium hydroxide solution is 0.3M.
4. The method for synthesizing the highly active and stable nickel-cobalt alloy catalyst according to claim 1, characterized in that, In step 3, the Ni x Co y The mass ratio of O@S-1 nanocrystals to polymers P123, F127, and dopamine hydrochloride is 0.015:0.005:0.095:0.
15.
5. The method for synthesizing the highly active and stable nickel-cobalt alloy catalyst according to claim 1, characterized in that, In step 3, the volume ratio of 1,3,5-trimethylbenzene, water, ethanol, and ammonia is 0.4:5:5:0.
4.
6. A highly active and highly stable nickel-cobalt alloy catalyst, characterized in that, It is synthesized using the synthesis method described in any one of claims 1-5.
7. The application of a highly active and stable nickel-cobalt alloy catalyst as described in claim 6 in the catalytic hydrogenation deoxygenation reaction of vanillin.
8. The application according to claim 7, characterized in that, Includes the following steps: Vanillin, a highly active and stable nickel-cobalt alloy catalyst, and a solvent were sealed in a high-pressure reactor and reacted for 4 h at a temperature of 100-140 °C, a hydrogen pressure of 0.8-1.5 MPa, and a rotation speed of 400-1000 rpm.
9. The application according to claim 8, characterized in that, The solvent is a mixture of water and decahydronaphthalene, with a volume ratio of water to decahydronaphthalene of 1:3.