Co / Ti3C2Tx catalyst as well as preparation method and application thereof
By preparing Co/Ti3C2Tx catalyst, the selectivity problem of existing catalysts was solved, and the selectivity and cost of cyclohexanol were improved. Through the etching preparation method, the technical problems existing in the existing technology were solved, the efficient production of cyclohexanol was achieved, and the problems of insufficient selectivity of cyclohexanol and high cost of precious metals were solved.
Patent Information
- Application Number
- CN202511125044.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-12
- Publication Date
- 2025-09-23
AI Technical Summary
Existing Co/T catalysts have poor selectivity in the hydrodeoxygenation reaction of phenolic compounds, with the selectivity for cyclohexanol less than 90%. In addition, the cost of precious metal catalysts is high, the activity of non-precious metal catalysts is insufficient, the support performance limits the electron transfer efficiency, and the reaction pathway is out of control.
Ti3C2Tx was used as a carrier, and a Co/Ti3C2Tx catalyst was prepared by etching to load cobalt metal. The high conductivity and surface functional groups of Ti3C2Tx were used to anchor Co particles, optimize electronic interactions, and control the reaction path. The preparation method included etching, calcination, and high-temperature reduction steps.
The efficient and directional conversion of guaiacol to cyclohexanol was achieved, with a catalyst selectivity of over 90% and a cost reduction of 50%. Metal sintering was suppressed during the reaction, which improved the reaction efficiency of the catalyst and made it suitable for hydrodeoxygenation reactions.
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Figure CN120679536A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of hydrodeoxygenation of phenolic compounds, and particularly to a Co / Ti3C2T x Catalyst, preparation method and application thereof. Background Art
[0002] With the increasing depletion of fossil energy and the intensification of global climate change, the development of renewable energy and high-value-added chemical production technologies has become a core strategic direction in the energy and chemical industry. As the only renewable resource containing carbon, the catalytic conversion of biomass to produce liquid fuels and fine chemicals is considered a key pathway to achieving the "carbon cycle." Bio-oil produced by pyrolysis or liquefaction of lignin is rich in phenolic compounds (such as guaiacol and 4-methylguaiacol). However, the presence of these oxygenated compounds results in low energy density and poor stability in bio-oil, necessitating the removal of oxygen atoms through hydrodeoxygenation (HDO) to improve its fuel quality.
[0003] The HDO reaction of phenolic compounds faces the following core challenges: Conflict between catalyst cost and activity: Although traditional precious metal catalysts (such as Pt and Pd) have high HDO activity, their resource scarcity leads to high costs and makes it difficult to meet industrial needs; non-precious metal catalysts (such as Ni and Co) are insufficiently active and easily deactivated due to carbon deposition or metal sintering.
[0004] Support performance limitations: Conventional oxide supports (such as A 、Si ) have weak interactions with active metals, which makes metal particles easily agglomerated; their low conductivity limits the efficiency of electron transfer, and the surface acidic sites are prone to cause coking.
[0005] Difficulty in selectivity regulation: The HDO reaction requires a balance between deoxygenation depth and product selectivity. Existing catalysts are prone to excessive deoxygenation to produce alkanes, or retain too many oxygen-containing groups due to incomplete deoxygenation, making it difficult to obtain high-value-added intermediates (such as cyclohexanol) in a targeted manner.
[0006] In recent years, two-dimensional transition metal carbon / nitride (MXene) has attracted attention due to its unique physical and chemical properties. ( As a typical MXene material, it has the following advantages: High conductivity and specific surface area: The graphene-like layered structure gives it ultra-high electron mobility and large specific surface area, which is conducive to the exposure of active sites and the diffusion of reactants; Adjustable surface chemistry: Abundant surface functional groups such as -OH and -O can anchor metal particles and regulate their electronic state, thereby enhancing metal-support interactions. Thermal stability: Maintains structural stability during high-temperature reactions and inhibits metal sintering.
[0007] Loading transition metals (such as Co) on T Surface-constructed composite catalysts are believed to be able to simultaneously solve the cost and activity issues. However, the existing Co / T The catalyst still has the following defects in the HDO reaction of phenols: Insufficient selectivity: The selectivity for the target product cyclohexanol is usually less than 90%, and the proportion of by-products (such as alkanes and phenolic intermediates) generated is relatively high; Low utilization of active sites: some Co particles are occupied by T Excessive coverage of surface functional groups leads to a reduction in the effective catalytic area; Uncontrolled reaction pathway: Excessive hydrogenation or cracking reactions are prone to occur, making it difficult to achieve precise control of deoxygenation depth and product selectivity.
[0008] Therefore, a Co / T The highly selective HDO catalyst can achieve the efficient and directional conversion of guaiacol into cyclohexanol, which is of great significance for the quality improvement and high-value utilization of biomass fuels. Summary of the Invention
[0009] The problem in the prior art is that conventional Co / T The selectivity of guaiacol hydrodeoxygenation to cyclohexanol catalyzed by the catalyst is poor, and the selectivity of cyclohexanol is difficult to reach above 90%. x The catalyst, the preparation method of which comprises the following steps: (1) Ti3AlC2 was added to a hydrofluoric acid aqueous solution, and the Al layer in the Ti3AlC2 layered structure was completely removed by the etching action of hydrofluoric acid to obtain a product containing an accordion-like layered structure, Ti3C2T x Etching solution; (2) Add soluble cobalt salt to the etching solution in step (1), and conduct ultrasonic reaction at 35°C. After the reaction is completed, separate the solid and liquid, collect the solid product, wash the solid product with water until it is neutral, dry it, and calcine it at 400°C under the protection of N2 or inert gas. After the calcination is completed, Co / Ti3C2T x Precursor; (3) Co / Ti3C2T obtained in step (3) x The precursor is reduced at high temperature in a reducing atmosphere to obtain Co / Ti3C2T x , the Co / Ti3C2T x The carrier Ti3C2T x It has a hexagonal close-packed structure.
[0010] Preferably, the soluble cobalt salt is hydrated cobalt chloride.
[0011] Preferably, Co / Ti3C2T x The loading amount of Co in the Ti3C2T is 5-15%. More preferably, Co / Ti3C2T x The Co loading is 10-15%.
[0012] Preferably, the reducing atmosphere in step (3) is H2.
[0013] Preferably, the high-temperature reduction temperature in step (3) is 250°C.
[0014] Preferably, the high-temperature reduction time in step (3) is at least 180 minutes.
[0015] Preferably, the pressure of the high-temperature reduction in step (3) is 2 MPa.
[0016] The present invention has the following beneficial effects: The Co / T The catalyst and its application in the hydrodeoxygenation reaction of phenolic compounds have the following significant beneficial effects compared with the existing technology: (1) Breakthrough in conversion rate and selectivity: In the reaction of guaiacol hydrodeoxygenation to cyclohexanol, the catalyst makes the conversion rate of guaiacol reach over 90%, and the selectivity of the target product cyclohexanol reach over 90%, which is significantly better than traditional catalysts (usually with selectivity less than 90%). The strong electronic interaction between the support and Co inhibits excessive deoxygenation or cracking reactions, achieving efficient and directional conversion of phenolic compounds to cyclohexanol. (2) Using cobalt (Co) as the active metal to replace traditional precious metals (Pt, Pd), the catalyst cost is reduced by more than 50%, and it has the potential for large-scale application; (3) T Surface functional groups (-OH, -O) anchor Co particles to prevent agglomeration, achieving high activity at 5%-15% loading, reducing metal usage; (4) Hexagonal close packed (hcp) carrier: The present invention has proved through experiments that T The crystalline morphology of surface-loaded Co is related to the high-temperature reduction temperature, and the hexagonal close-packed crystalline morphology of Co (Co-hcp) is three times more active for benzene ring hydrogenation than the face-centered cubic crystalline morphology of Co (Co-fcc). BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 : 250-10% Co / Ti3C2T obtained in Example 1 x XRD pattern of . DETAILED DESCRIPTION
[0018] The present invention will be described in detail below with reference to the following examples. However, it should be understood that the following examples are merely illustrative of the embodiments of the present invention and are not intended to limit the scope of the present invention.
[0019] The Al2O3 powder used in the present invention is prepared by the following method: An aluminum chloride solution was added dropwise to an ammonium carbonate solution at a constant rate, with a molar ratio of ammonium carbonate to aluminum chloride of 3:1. The reaction was stirred for 30 minutes. The resulting precipitate was allowed to stand, centrifuged, filtered, washed three times with deionized water, and then frozen in a refrigerator. The frozen sample was freeze-dried in a freeze dryer (-50°C, 30 Pa) and ground to obtain a white powder. The resulting powder was heated to 850°C at a rate of 5°C / min and calcined at 850°C for 2 hours to obtain Al2O3 powder.
[0020] The TiO2 powder used in the present invention is prepared by the following method: 0.075 g of CaTiO₃ and 0.34 g of ethylenediaminetetraacetic acid (EDTA) were dissolved in a mixture of 10 mL of ethylene glycol and 30 mL of deionized water. The mixture was then transferred to a reactor and hydrothermally reacted at 180°C for 12 hours. After the reaction, the solid product was collected, washed, and dried overnight. The resulting powder was heated to 400°C at a rate of 5°C / min and calcined at 400°C for 2 hours to obtain TiO₂ powder.
[0021] The activated carbon powder used in the present invention is prepared by the following method: Dissolve 7.2 g of anhydrous glucose in 60 mL of deionized water and stir continuously for 30 minutes. The glucose solution is then transferred to a reactor and placed in an oven for a hydrothermal reaction at 180°C for 9 hours. The product is then filtered and washed with deionized water and anhydrous ethanol until the filtrate is clear. Finally, the solid product is dried at 80°C for 12 hours to obtain activated carbon powder.
[0022] Example 1
[0023] (1) Weigh 1g of LiF and soak it in 10mL of 9mol / L hydrochloric acid. Stir for 30min to obtain a hydrofluoric acid aqueous solution. (2) Weigh 1g Ti3AlC2 and add it to the hydrofluoric acid aqueous solution obtained in step (1) in small amounts and multiple times to prevent the reaction from overheating and boiling. After the addition is completed, stir and cool until the temperature of the reaction system drops to 35°C. Then add 0.4g cobalt chloride hexahydrate to the reaction system, react in a water bath at 35°C for 24h, and then ultrasonicate for 1h. After the reaction is completed, centrifuge and wash (8000rpm, 15min) to collect the solid product. The obtained solid product is washed with deionized water until neutral. Then, the solid precipitate is collected and dried at 60°C for 12h. Then, it is calcined at 400°C for 4h under N2 atmosphere to obtain Co / Ti3C2T x Precursor; (3) Take 0.4g Co / Ti3C2T x The precursor was placed in a tube furnace and reduced in a hydrogen atmosphere with a hydrogen flow rate of 80 mL / min and a hydrogen pressure of 2 MPa. The reduction reaction was carried out at a constant temperature of 250 ° C for 180 min and a heating rate of 5 ° C / min. After the reduction was completed, it was naturally cooled to room temperature to obtain 250-10%Co / Ti3C2T with a Co loading of 10%. x .
[0024] The hydrodeoxygenation reaction was carried out in a fixed bed reactor under the following conditions: a hydrogen flow rate of 80 mL / min was introduced into the reaction system by means of a high-pressure constant flow pump, guaiacol and n-decane were used as raw materials, the amount of guaiacol added was 9 g and the amount of n-decane added was 291 g, and the catalyst (250-10% Co / Ti3C2T x ) was used in an amount of 0.4 g. The reaction pressure was 2 MPa and the reaction temperature was 220°C. The test results of catalytic hydrodeoxygenation are shown in Table 1.
[0025] Instructions attached Figure 1 250-10%Co / Ti3C2T obtained in Example 1 x The XRD pattern shows distinct peaks at 2θ = 9.46° and 17.64°, indicating the successful synthesis of the MXene material. Strong peaks at 41.74°, 48.74°, 60.18°, and 73.84° in the XRD pattern confirm the presence of cobalt, indicating high crystallinity and metallic diffraction signals.
[0026] Example 2 is the same as Example 1, except that the amount of cobalt chloride hexahydrate used in step (2) of Example 2 is 0.2 g, and the Co loading in the catalyst obtained in Example 2 is 5%, which is recorded as 250-5%Co / Ti3C2T x .
[0027] Example 3 is the same as Example 1, except that the amount of cobalt chloride hexahydrate used in step (2) of Example 3 is 0.2 g, and the Co loading in the catalyst obtained in Example 3 is 15%, which is recorded as 250-15%Co / Ti3C2T x .
[0028] Comparative Example 1 is the same as Example 1, except that the reduction temperature in step (3) of Comparative Example 1 is changed to 350°C. The obtained catalyst is recorded as 350-10%Co / Ti3C2T x .
[0029] Comparative Example 2 is the same as Example 2, except that the reduction temperature in step (3) of Comparative Example 2 is changed to 350°C. The obtained catalyst is recorded as 350-5%Co / Ti3C2T x .
[0030] Comparative Example 3 is the same as Example 3, except that the reduction temperature in step (3) of Comparative Example 3 is changed to 350°C. The obtained catalyst is recorded as 350-15%Co / Ti3C2T x .
[0031] Comparative Example 4
[0032] Dissolve 2.7g of cobalt nitrate hexahydrate in 2mL of deionized water, then add 5g of Al2O3 powder and mix thoroughly. Soak overnight for approximately 12 hours, then dry in a 120°C forced air oven for 12 hours. Grind the collected solid product to a powder (as long as it is free of granules), transfer it to a ceramic ark, heat it in a muffle furnace to 550°C at a rate of 2°C / min, and calcine at this temperature for 4 hours. Reduction is carried out under a hydrogen atmosphere with a hydrogen flow rate of 80mL / min and a hydrogen pressure of 2MPa. Reduction is carried out at 250°C for 180 minutes, with a heating rate of 5°C / min, to obtain the Co / Al2O3 catalyst.
[0033] Comparative Example 5
[0034] Dissolve 2.7g of cobalt nitrate hexahydrate in 3mL of deionized water, then add 5g of TiO2 powder and mix thoroughly. Soak overnight for approximately 12h, then dry in a 120°C forced air oven for 12h. Grind the collected solid product to a powder (as long as it is free of granules), transfer it to a ceramic ark, heat it in a muffle furnace to 550°C at a rate of 2°C / min, and calcine at this temperature for 4h. Reduction is carried out under a hydrogen atmosphere with a hydrogen flow rate of 80mL / min and a hydrogen pressure of 2MPa. Reduction is carried out at 250°C for 180min, with a heating rate of 5°C / min, to obtain the Co / TiO2 catalyst.
[0035] Comparative Example 6
[0036] Dissolve 2.7g of cobalt nitrate hexahydrate in 1.5mL of deionized water, then add 5g of activated carbon powder and mix thoroughly. Grind the impregnated solid to a powder (no granules are required) and dry it in a 120°C forced air oven for 12 hours. Then, transfer it to a ceramic ark and heat it in a muffle furnace to 550°C at a rate of 2°C / min. Calcinate at this temperature for 4 hours. Reduction is carried out under a hydrogen atmosphere with a hydrogen flow rate of 80mL / min and a hydrogen pressure of 2MPa. Reduction is carried out at 250°C for 180 minutes, with a heating rate of 5°C / min. The resulting catalyst, Co / C, is obtained.
[0037] Table 1
[0038] From the test results analysis in Table 1, we can see that Cobalt (Co) is loaded on Ti3C2T x The surface can optimize the dispersion, electronic state and catalytic activity of cobalt through the strong electronic interaction between the metal and the support, and is suitable for hydrodeoxygenation reaction. According to the above examples and comparative examples, it is not difficult to see that the catalyst prepared by the present invention has a good catalytic effect in the partial selective deoxygenation reaction of guaiacol hydrogenation. x The best effect. If the loading is too low, the active site density is insufficient, while if the loading is too high, more metal active sites are exposed on the catalyst surface, which improves the hydrogenation capacity of the catalyst and makes it easier for the deoxygenated intermediate to be further hydrogenated to cyclohexane.
[0039] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.
Claims
1. A Co / Ti3C2T x A catalyst characterized in that The preparation method comprises the following steps: (1) Ti3AlC2 was added to a hydrofluoric acid aqueous solution, and the Al layer in the Ti3AlC2 layered structure was completely removed by the etching action of hydrofluoric acid to obtain a product containing an accordion-like layered structure, Ti3C2T x Etching solution; (2) Adding a soluble cobalt salt to the etching solution obtained in step (1), ultrasonically reacting at 35°C, after the reaction is completed, collecting the solid product by solid-liquid separation, washing the obtained solid product with water until neutral, drying, and calcining it at 400°C under the protection of N2 or inert gas. After the calcination is completed, Co / Ti3C2T x Precursor; (3) Co / Ti3C2T obtained in step (3) x The precursor is reduced at high temperature in a reducing atmosphere to obtain Co / Ti3C2T x , the Co / Ti3C2T x The carrier Ti3C2T x It has a hexagonal close-packed structure.
2. A Co / Ti3C2T3 according to claim 1 x A catalyst characterized in that The soluble cobalt salt is hydrated cobalt chloride.
3. A Co / Ti3C2T according to claim 1 x A catalyst characterized in that Co / Ti3C2T x The Co loading is 5-15%.
4. A Co / Ti3C2T3 according to claim 3 x A catalyst characterized in that Co / Ti3C2T x The Co loading is 10-15%.
5. A Co / Ti3C2T according to claim 1 x A catalyst characterized in that The reducing atmosphere in step (3) is H2.
6. A Co / Ti3C2T3 according to claim 1 x A catalyst characterized in that The high temperature reduction temperature in step (3) is 250°C.
7. A Co / Ti3C2T3 according to claim 1 x A catalyst characterized in that The high-temperature reduction time in step (3) is at least 180 minutes.
8. A Co / Ti3C2T3 according to claim 1 x A catalyst characterized in that The pressure of high temperature reduction in step (3) is 2 MPa.
9. A method for hydrodeoxygenation of phenolic compounds, characterized in that: The Co / Ti3C2T3 according to any one of claims 1 to 8 is used. x As a catalyst for hydrodeoxygenation reactions.
10. The method for hydrodeoxygenation of phenolic compounds according to claim 9, characterized in that: The phenolic compound is guaiacol.