Method for preparing Ru / ZrPO4 catalyst by microfluidic continuous synthesis process, catalyst and application thereof

Abstract

The invention provides a method for preparing a Ru / ZrPO4 catalyst by a microfluidic continuous synthesis process, the catalyst and application of the catalyst. The method comprises the following steps: S1, adding an ammonium dihydrogen phosphate solution into a zirconium salt solution for reaction, and drying to obtain a ZrPO4 precursor; s2, placing the ZrPO4 precursor prepared in the step S1 in a solvent to form a suspension, and respectively loading the suspension and a ruthenium source solution in a microfluidic injector; s3, injecting the two solutions into a heating microtube at the same time, and carrying out a microfluidic load reduction continuous synthesis reaction; and S4, after the reaction is finished, cooling the reaction liquid through a cooling micropipe, collecting the reaction liquid, centrifuging, washing and drying to obtain the Ru / ZrPO4 catalyst. The micro-fluidic confinement reaction environment effectively inhibits metal particle aggregation, and the metal dispersity and the catalytic utilization efficiency are remarkably improved; the efficient mass and heat transfer characteristic of the microtube system enables the reaction temperature and concentration distribution to be more uniform, and the reaction controllability and repeatability are improved.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, and in particular to a method for preparing Ru / ZrPO4 catalysts using a microfluidic continuous synthesis process, the catalysts themselves, and their applications. Background Technology

[0002] Fossil fuels, including coal, oil, and natural gas, have long been widely used as primary energy sources. However, their overexploitation and use have severely impacted the ecological environment, particularly in terms of greenhouse gas emissions and global climate change. This high dependence on these non-renewable resources not only exacerbates energy security issues but also leads to ecosystem destruction and environmental pollution. Therefore, developing renewable and sustainable alternative energy sources is urgently needed.

[0003] Lignin, an important component of biomass, is widely available and inexpensive. Its structure is rich in various phenolic monomers, giving it high functionalization potential. Pyrolysis can convert lignin into bio-oil, which is rich in various phenolic compounds. Further hydrogenation and deoxygenation of these phenolic components to convert them into high-calorific-value, low-oxygen-content hydrocarbon liquid fuels not only improves the stability and fuel performance of bio-oil but also provides an important pathway for the development of renewable aviation fuels.

[0004] The synergistic effect of the metal and acidic sites on a catalyst is a key factor determining the performance of hydrodeoxygenation. Metal sites primarily function in the adsorption, activation, and dissociation of hydrogen, effectively generating active hydrogen species and promoting the hydrogenation of aromatic rings. Currently, commonly used metal sites mainly include noble metals and some transition metals. Although noble metals are expensive, they possess excellent catalytic activity, resistance to sintering, and strong oxidation resistance, thus exhibiting superior reaction efficiency and stability in HDO reactions. However, common noble metals such as Ru typically require high-temperature reduction in a hydrogen atmosphere during catalyst preparation, which is not only sensitive to the atmosphere but also poses a safety hazard due to the flammability and explosiveness of hydrogen itself. Traditional catalysts require a support to provide sites for the loaded metal, but common methods for preparing catalysts using ZrPO4 as a support generally involve multiple steps such as metal impregnation, drying, and reduction, which are cumbersome and have low preparation efficiency.

[0005] Besides the raw materials, existing catalyst preparation methods also have many shortcomings. Traditional catalyst preparation methods mainly include impregnation-calcination-reduction and ethylene glycol reduction. The impregnation method carries the risk of uneven stirring and uneven distribution of metal precursors. During high-temperature reduction, metal particle agglomeration easily occurs, resulting in large catalyst metal particle size and poor dispersibility, thus affecting catalytic activity and utilization efficiency. Although the ethylene glycol reduction method improves the above problems to some extent by utilizing the reducing properties of ethylene glycol, the reaction time is long and the efficiency of the metal loading process is low, making it difficult to meet the requirements for rapid and efficient catalyst preparation.

[0006] For example, Chinese patent CN 115894177A describes a Ru / α-MoC catalyst prepared using an impregnation-carbonization method. At 250℃, the guaiacol conversion was 98.25%, but the hydrocarbon yield was only 2.99%, exhibiting poor hydrodeoxygenation activity. Chinese patent CN113181955A first prepared the support S-HZSM-5 via hydrothermal synthesis, then loaded ruthenium metal via impregnation to obtain the Ru / S-HZSM-5 catalyst, with an average Ru particle size of 3.57 nm. The Ru / HZSM-5 catalyst prepared by Luo et al. was used for the selective hydrogenolysis of lignin-derived substituted phenols to produce aromatics, with an average Ru particle size of approximately 4.1 nm (Green Chem., 2016, 18, 5845-5858). Chen et al. prepared a Ru / CNT catalyst via wet impregnation, with an average Ru particle size of 4.6 nm (GreenChem., 2015, 17, 1710-1717). The particle size was generally large, indicating that agglomeration occurred during the preparation process.

[0007] In summary, existing literature and patents mostly use impregnation or ethylene glycol reduction methods to prepare catalysts, which generally suffer from problems such as large metal particles, poor dispersibility, and long reaction time. Summary of the Invention

[0008] This invention provides a method for preparing Ru / ZrPO4 catalysts using a microfluidic continuous synthesis process, the catalysts themselves, and their applications. The purpose is to solve the problems of large metal particles, poor dispersibility, and long reaction times in existing catalyst preparation technologies.

[0009] To achieve the above objectives, this invention provides a method for preparing Ru / ZrPO4 catalysts using a microfluidic continuous synthesis process, comprising the following steps:

[0010] S1. Add ammonium dihydrogen phosphate solution to zirconium salt solution to react, and dry to obtain ZrPO4 precursor;

[0011] S2. The ZrPO4 precursor prepared in S1 is placed in a solvent to form a suspension, and then loaded into a microfluidic syringe along with the ruthenium source solution.

[0012] S3. Simultaneously inject the two solutions into the heating microtube to carry out a microfluidic loading reduction continuous synthesis reaction;

[0013] S4. After the reaction is complete, the reaction solution is cooled through a cooling microtube, collected, centrifuged, washed and dried to obtain the Ru / ZrPO4 catalyst.

[0014] Microfluidic continuous synthesis processes, with their advantages in mass and heat transfer, enable precise control of reaction parameters within microtubes. In microfluidic systems, the reaction liquid flows in the form of microdroplets, resulting in rapid heat transfer, uniform mixing, and the confined space helps suppress excessive growth of metal particles, significantly improving metal dispersibility and catalyst structural uniformity. Furthermore, microfluidic processes offer advantages such as short reaction times, continuous production capability, and high controllability, providing a novel pathway for the large-scale preparation of highly efficient catalysts.

[0015] Compared with traditional impregnation and ethylene glycol reduction methods, this application employs a microfluidic continuous synthesis process. This process offers significant advantages in controlling particle size distribution, improving metal dispersibility, and enhancing catalytic performance. When applied to the preparation of Ru / ZrPO4 catalysts, it effectively inhibits metal particle agglomeration. Ru, due to its excellent hydrogen activation capacity, is widely used in hydrodeoxygenation reactions, achieving highly efficient hydrogenation under relatively low temperatures and hydrogen pressures. ZrPO4, with its abundant acidic sites facilitating carbon-oxygen bond breaking and its high thermal stability, is an excellent catalyst support. After the hydrogenation reaction of phenolic compounds, metallic Ru lowers the activation energy of the carbon-oxygen bond. The ZrPO4 support, with the synergistic effect of the Ru metal sites, significantly enhances the breaking of C–O bonds in phenolic compounds, thereby effectively improving the conversion and selectivity of the HDO reaction.

[0016] Preferably, the concentration of the ammonium dihydrogen phosphate solution is 1.0 mol / L and the volume is 100 mL; the zirconium salt is zirconium oxychloride, and the concentration of the zirconium salt solution measured by zirconium ions is 1.0 mol / L and the volume is 50 mL; the reaction temperature is 110-130℃ and the reaction time is 22-26 h; the drying temperature is 70-90℃ and the drying time is 16-20 h.

[0017] More preferably, the reaction temperature is 120°C and the reaction time is 24 h; the drying temperature is 80°C and the drying time is 18 h.

[0018] Preferably, the solvent for forming the suspension from the ZrPO4 precursor and the solvent for the ruthenium source solution are reducing solvents, wherein the reducing solvent includes at least one of ethylene glycol, glycerol, glucose or ascorbic acid, and the concentration of ruthenium metal in the ruthenium source solution is 0.006-0.010 g / mL;

[0019] More preferably, in step S2, the solvent is ethylene glycol, and the concentration of ruthenium metal in the solution is 0.008 g / mL.

[0020] Preferably, in step S3, the injection flow rate of the simultaneously injected heating microtube is 1-2 mL / min.

[0021] Preferably, in step S3, the temperature of the heating microtube is 180-220℃, and the diameter of the heating microtube is 2-6mm.

[0022] Preferably, in step S4, the temperature of the cooling microtube is room temperature, the drying temperature is 60-80℃, and the drying time is 16-20h.

[0023] Under the same technical concept, the present invention provides a Ru / ZrPO4 catalyst prepared by the above preparation method.

[0024] Preferably, the Ru in the catalyst is supported on the ZrPO4 surface, the Ru particle size is 2.8-3.2 nm, the theoretical loading is 4-8 wt%, and the catalyst specific surface area is 70-90 m². 2 / g, the mass ratio of Ru to ZrPO4 in the catalyst is 1:18-22.

[0025] More preferably, the Ru in the catalyst is supported on the ZrPO4 surface, the Ru particle size is 3.03 nm, the loading is 5 wt%, and the catalyst specific surface area is 76.11 m². 2 / g, the mass ratio of Ru to ZrPO4 in the catalyst is 1:20.

[0026] Under the same technical concept, the present invention provides a Ru / ZrPO4 catalyst prepared by the above preparation method or the application of the above Ru / ZrPO4 catalyst in the hydrodeoxygenation reaction of light phenolic components.

[0027] Preferably, the application conditions in the hydrodeoxygenation reaction are as follows: the amount of catalyst is 0.4-0.6 g, the amount of light phenolic substrate is 0.05-0.20 g, and the amount of solvent is 10-30 mL; the light phenolic substrate includes one or more of phenol, guaiacol, or eugenol, and the solvent includes n-octane; the reaction temperature is 200-260℃, the reaction pressure is 0.6-0.8 MPa, and the reaction time is 2-4 h.

[0028] The above-described solution of the present invention has the following beneficial effects:

[0029] (1) This invention provides a method for preparing Ru / ZrPO4 catalyst by microfluidic continuous synthesis process. The microfluidic confined reaction environment effectively inhibits the agglomeration of metal particles and significantly improves the metal dispersion and catalytic utilization efficiency. The efficient mass and heat transfer characteristics of the microtube system make the reaction temperature and concentration distribution more uniform, improving the controllability and repeatability of the reaction. The microfluidic system is suitable for continuous and scalable catalyst preparation process, overcoming the difference problem in traditional batch synthesis.

[0030] (2) The Ru / ZrPO4 catalyst prepared in this invention has a synergistic effect between metallic Ru and ZrPO4 support, which can significantly enhance the activation and cleavage of C–O bonds in phenolic compounds. It exhibits a conversion rate of nearly 100% and excellent selectivity in the hydrodeoxygenation reaction of light phenols, and has broad prospects for industrial application.

[0031] (3) The Ru / ZrPO4 catalyst prepared by this invention has small particle size, high loading, and large specific surface area, which reflects the characteristics of less agglomeration and high catalytic utilization efficiency during its preparation process. It also reflects the significant influence of the choice of preparation process on the catalyst product.

[0032] Other beneficial effects of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0033] Figure 1 The XRD patterns of the Ru / ZrPO4-EG-micro catalyst prepared in the embodiments of the present invention and the comparative Ru / ZrPO4-EG-imp and Ru / ZrPO4-EG catalysts are used to compare their crystal structures and metal dispersion.

[0034] Figure 2 TEM images of the Ru / ZrPO4-EG-micro catalyst prepared in the embodiments of the present invention and the comparative Ru / ZrPO4-EG-imp and Ru / ZrPO4-EG catalysts are used to observe their particle size distribution and morphological characteristics.

[0035] Figure 3 The H2-TPD spectra of the Ru / ZrPO4-EG-micro catalyst and the comparative Ru / ZrPO4-EG-imp and Ru / ZrPO4-EG catalysts prepared in the embodiments of the present invention are used to analyze their metal surface activity and hydrogen adsorption capacity. Detailed Implementation

[0036] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] like Figure 1 As shown, an embodiment of the present invention provides a

[0041] Example 1: Preparation of Ru / ZrPO4-EG-micro (prepared using a microfluidic continuous synthesis process)

[0042] (1) Prepare 100 mL of 1.0 mol / L ammonium dihydrogen phosphate (NH4H2PO4) solution, add it to 50 mL of 1.0 mol / L zirconium oxychloride (ZrOCl2) solution, mix well, transfer to a high-pressure reactor, and react at 120℃ for 24 hours. After the reaction, the resulting white product is washed alternately with deionized water and ethanol, centrifuged, and dried at 80℃ for 18 hours to obtain ZrPO4 support;

[0043] (2) Weigh 0.1 g of ZrPO4 solid obtained in step (1) and dissolve it in 50 mL of ethylene glycol solution to form a suspension. Separately, seal the suspension with 50 mL of RuCl3 ethylene glycol solution with a concentration of 0.008 g / mL in two syringes for later use.

[0044] (3) Set the injection rate to 1.5 mL / min, and inject the two solutions into the microfluidic capillary reaction system after mixing them through the T-type interface;

[0045] (4) The mixed solution was first subjected to a confined reaction by heating the microtube segment at 180°C. The diameter of the heating microtube was 2-6 mm. After cooling the microtube to room temperature, it was collected in a centrifuge tube. After washing, it was dried in a vacuum drying oven at 70°C for 18 hours to finally obtain the Ru / ZrPO4-EG-micro catalyst.

[0046] In the prepared Ru / ZrPO4-EG-micro catalyst, Ru was supported on the ZrPO4 surface, with a Ru particle size of 3.03 nm and a loading of 5 wt%. The catalyst had a specific surface area of ​​76.11 m². 2 / g, the mass ratio of Ru to ZrPO4 in the catalyst is 1:20.

[0047] Comparative Example 1: Preparation of Ru / ZrPO4-EG-imp (impregnation method)

[0048] 1 g of ZrPO4 was weighed and placed in a crucible, and a RuCl3 solution containing 0.4 g of Ru was added, followed by 10 mL of deionized water. The mixture was stirred at 300 r / min for 6 hours. After stirring, the mixture was dried at 60 °C, and then dried in a vacuum drying oven at 70 °C for 18 hours. Finally, the sample was placed in a tube furnace and reduced at 400 °C and a hydrogen flow rate of 60 mL / min for 3 hours to obtain the impregnated supported catalyst Ru / ZrPO4-EG-imp.

[0049] Comparative Example 2: Ru / ZrPO4-EG (prepared by ethylene glycol reduction method)

[0050] 1 g of ZrPO4 was weighed and added to a hydrothermal reactor, followed by a RuCl3 solution containing 0.4 g of Ru and 20 mL of ethylene glycol solvent. The mixture was heated to 200 °C with stirring at 300 r / min and maintained for 2 hours. After the reaction was completed, the mixture was cooled to room temperature, the solid product was separated by centrifugation, and dried in a vacuum drying oven at 70 °C for 18 hours to obtain the Ru / ZrPO4-EG catalyst prepared by the ethylene glycol reduction method.

[0051] Characterization and testing

[0052] (1) XRD characterization

[0053] The Ru / ZrPO4-EG-micro catalyst prepared in Example 1, as well as the Ru / ZrPO4-EG-imp and Ru / ZrPO4-EG catalysts prepared in Comparative Examples 1 and 2, were characterized by XRD, and the resulting spectra are shown in Figure 1. The characteristic diffraction peaks of Ru metal appeared at 2θ = 42.1° (002) and 44.0° (101), consistent with the standard card Ru (PDF#06-0663), indicating that metallic Ru was formed in the samples, rather than in oxide form. In Comparative Examples 1 and 2 (i.e., samples prepared by impregnation and ethylene glycol reduction methods), the Ru peaks were clear and sharp, indicating larger particle size and poor dispersibility. However, in the Ru / ZrPO4-EG-micro sample prepared by the microfluidic method of this invention, the Ru peaks were significantly broadened, reflecting smaller metal particle size and better dispersibility. This effect is attributed to the confined reaction environment in the microfluidic system: within the microdroplets, the limited contact area between ZrPO4 and the ruthenium precursor facilitates highly dispersed metal loading.

[0054] (2) TEM characterization

[0055] The Ru / ZrPO4-EG-micro catalyst prepared in Example 1, as well as the Ru / ZrPO4-EG-imp and Ru / ZrPO4-EG catalysts prepared in Comparative Examples 1 and 2, were characterized by TEM. The resulting spectra are shown in Figure 2, where (a) Ru / ZrPO4-imp, (b) Ru / ZrPO4-EG, and (c) Ru / ZrPO4-EG-micro. Fifty metal particles were randomly selected from each sample for size statistical analysis. The results showed that the Ru particle size in the Ru / ZrPO4-EG-imp (impregnation method) sample was approximately 9.97 nm, in the Ru / ZrPO4-EG (hydrothermal ethylene glycol reduction method) sample it was 3.32 nm, while in the Ru / ZrPO4-EG-micro sample of this invention it was only 3.03 nm, exhibiting the smallest particle size and optimal dispersibility. The microfluidic confinement space facilitates the formation of nanodroplets, within which the generated metal particles effectively limit aggregation. Simultaneously, ethylene glycol acts as both a reducing agent and a protective agent, preventing further particle growth or aggregation in the post-reaction stage. Furthermore, TEM images show that all Ru nanoparticles are uniformly loaded on the support surface, with no free metal particles observed, indicating that Ru is primarily deposited on the support surface via heterogeneous nucleation. Energy dispersive spectroscopy (EDS) further validates the uniform metal distribution, consistent with particle size statistics.

[0056] (3) H2-TPD characterization

[0057] The Ru / ZrPO4-EG-micro catalyst prepared in Example 1, as well as the Ru / ZrPO4-EG-imp and Ru / ZrPO4-EG catalysts prepared in Comparative Examples 1 and 2, were characterized by H2-TPD, and the resulting spectra are shown in Figure 3. The Ru / ZrPO4-EG-imp catalyst exhibited a mesothermal hydrogen adsorption peak at approximately 372.2 °C, but the peak intensity was weak, indicating that due to severe Ru particle aggregation, there were few effective active sites available for hydrogen molecules. In contrast, both Ru / ZrPO4-EG and the Ru / ZrPO4-EG-micro catalyst of this invention exhibited adsorption peaks at metal sites in the mesothermal region, and the temperature of the latter's adsorption peak shifted upward to 394.5 °C, indicating stronger interaction with the support, better metal dispersion, and stronger hydrogen adsorption capacity, which is beneficial for subsequent hydrogenation reactions.

[0058] (4) BET representation

[0059] The Ru / ZrPO4-EG-micro catalyst prepared in Example 1, as well as the Ru / ZrPO4-EG-imp and Ru / ZrPO4-EG catalysts prepared in Comparative Examples 1 and 2, were characterized by BET analysis. The results are shown in Table 1. The specific surface area of ​​Ru / ZrPO4-EG-imp is 62.93 m². 2 / g, with an average pore size of 6.14 nm; the specific surface area of ​​Ru / ZrPO4-EG is 70.83 m² / g. 2 / g, with an average pore size of 7.53 nm; the specific surface area of ​​Ru / ZrPO4-EG-micro in this invention reaches 76.11 m² / g. 2 The Ru / ZrPO4-EG-micro sample exhibits a higher specific surface area, with an average pore size of 6.57 nm. This demonstrates that the microfluidic process achieves high metal dispersion loading without significantly clogging the pores. In contrast, the impregnation method tends to lead to the aggregation of large metal particles, clogging the pores on the support surface; the ethylene glycol reduction method mitigates this problem, while microfluidics further enhances particle control and pore retention, facilitating effective contact between reactants and active sites, thereby improving catalytic activity.

[0060] Table 1

[0061]

[0062] Example 2

[0063] Application of the prepared Ru / ZrPO4 catalyst in the hydrodeoxygenation reaction of light phenolic components:

[0064] 0.5 g of the Ru / ZrPO4-EG-micro catalyst prepared in Example 1, 0.1 g of guaiacol, and 20 mL of n-octane were added to a high-pressure reactor. The reaction was carried out at 240 °C and a hydrogen pressure of 1 MPa for 4 hours. After the reaction was completed, the mixture was cooled to room temperature and samples were taken. The conversion rate of guaiacol and the selectivity of the hydrocarbon cyclohexane in the product were detected by gas chromatography-mass spectrometry (GC-MS), as detailed in Table 2.

[0065] Example 3

[0066] The reaction temperature was 220℃. The catalyst preparation method, dosage, and reaction conditions were the same as in Application Example 1. The conversion rate of guaiacol and the selectivity of hydrocarbon cyclohexane in the product were obtained, as detailed in Table 2.

[0067] Example 4

[0068] The reaction temperature was 200℃, and the catalyst preparation method, dosage, and reaction conditions were the same as in Application Example 1. The conversion rate of guaiacol and the selectivity of hydrocarbon cyclohexane in the product were obtained, as detailed in Table 2.

[0069] Table 2

[0070]

[0071] Example 5

[0072] The hydrogen pressure was 0.8 MPa. The catalyst preparation method, dosage, and reaction conditions were the same as in Application Example 1. The conversion rate of guaiacol and the selectivity of hydrocarbon cyclohexane in the product were obtained, as detailed in Table 3.

[0073] Example 6

[0074] The hydrogen pressure was 0.6 MPa. The catalyst preparation method, dosage, and reaction conditions were the same as in Application Example 1. The conversion rate of guaiacol and the selectivity of hydrocarbon cyclohexane in the product were obtained, as detailed in Table 3.

[0075] Table 3

[0076]

[0077] Example 7

[0078] The reaction time was 3 hours. The catalyst preparation method, dosage, and reaction conditions were the same as in Application Example 1. The conversion rate of guaiacol and the selectivity of hydrocarbon cyclohexane in the product were obtained, as detailed in Table 4.

[0079] Example 8

[0080] The reaction time was 2 hours. The catalyst preparation method, dosage, and reaction conditions were the same as in Application Example 1. The conversion rate of guaiacol and the selectivity of hydrocarbon cyclohexane in the product were obtained, as detailed in Table 4.

[0081] Table 4

[0082]

[0083] Comparative Example 3

[0084] Under the same experimental conditions as in Example 2, the catalyst was replaced with the Ru / ZrPO4-EG-imp (impregnation method) catalyst prepared in Comparative Example 1, and the conversion rate of guaiacol and the selectivity of hydrocarbon cyclohexane were tested, as detailed in Table 4.

[0085] Comparative Example 4

[0086] Under the same experimental conditions as in Example 2, the catalyst was replaced with the Ru / ZrPO4-EG (ethylene glycol reduction) catalyst prepared in Comparative Example 2, and the conversion rate of guaiacol and the selectivity of hydrocarbon cyclohexane were tested, as detailed in Table 5.

[0087] Table 5

[0088]

[0089] As shown in Table 5, the conversion rates of guaiacol by the three catalysts were all above 99%, achieving almost complete conversion. The reaction products mainly included cyclohexane, cyclohexanol, methoxycyclohexanol, and phenol. The Ru / ZrPO4-EG-imp catalyst prepared by the impregnation method exhibited low deoxygenation efficiency, with a cyclohexane yield of only 47.4%. In contrast, the Ru / ZrPO4-EG catalyst prepared by the ethylene glycol reduction method showed an improved cyclohexane selectivity of 79.7%. Furthermore, the Ru / ZrPO4-EG-micro catalyst, prepared by a microfluidic continuous synthesis process, showed a significantly improved cyclohexane selectivity of 97.9%, demonstrating the best hydrodeoxygenation performance.

[0090] The above results demonstrate that the Ru / ZrPO4 catalyst prepared by the microfluidic continuous synthesis process described in this invention has the advantage of highly dispersed active components, significantly improving the catalyst's hydrodeoxygenation activity and selectivity. Under conditions of 1 MPa hydrogen pressure and 240 °C for 4 hours, the guaiacol conversion reached 99.9%, and the cyclohexane selectivity reached 97.9%, achieving highly efficient conversion of guaiacol to cyclohexane.

[0091] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing Ru / ZrPO4 catalyst using a microfluidic continuous synthesis process, characterized in that, Includes the following steps: S1. Add ammonium dihydrogen phosphate solution to zirconium salt solution to react, and dry to obtain ZrPO4 precursor; S2. The ZrPO4 precursor prepared in S1 is placed in a solvent to form a suspension, and then loaded into a microfluidic syringe along with the ruthenium source solution. S3. Simultaneously inject the two solutions into the heating microtube to carry out a microfluidic loading reduction continuous synthesis reaction; S4. After the reaction is complete, the reaction solution is cooled through a cooling microtube, collected, centrifuged, washed and dried to obtain the Ru / ZrPO4 catalyst.

2. The method as described in claim 1, characterized in that, In step S1, the concentration of the ammonium dihydrogen phosphate solution is 0.5-1.5 mol / L; the zirconium salt includes zirconium oxychloride, zirconium nitrate, and zirconium sulfate, and the concentration of the zirconium salt solution, measured by zirconium ions, is 0.5-1.5 mol / L; the volume ratio of the ammonium dihydrogen phosphate solution to the zirconium salt solution is 1-3:1; the reaction temperature is 110-130℃, and the reaction time is 22-26 h; the drying temperature is 70-90℃, and the drying time is 16-20 h.

3. The method as described in claim 1, characterized in that, In step S2, the solvents for forming the suspension of the ZrPO4 precursor and the solvents for the ruthenium source solution are reducing solvents, including at least one of ethylene glycol, glycerol, glucose, or ascorbic acid, and the ruthenium metal concentration in the ruthenium source solution is 0.006-0.010 g / mL.

4. The method as described in claim 1, characterized in that, In step S3, the injection flow rate of the simultaneously injected heating microtube is 1-2 mL / min.

5. The method as described in claim 1, characterized in that, In step S3, the temperature of the heating microtube is 180-220℃, and the diameter of the heating microtube is 2-6mm.

6. The method as described in claim 1, characterized in that, In step S4, the temperature of the cooling microtube is room temperature, the drying temperature is 60-80℃, and the drying time is 16-20h.

7. A Ru / ZrPO4 catalyst prepared by the preparation method according to any one of claims 1-6.

8. The method as described in claim 7, characterized in that, In the catalyst, Ru is supported on the ZrPO4 surface, with a Ru particle size of 2.8-3.2 nm and a theoretical loading of 4-8 wt%. The catalyst has a specific surface area of ​​70-90 m². 2 / g, the mass ratio of Ru to ZrPO4 in the catalyst is 1:18-22.

9. The application of a Ru / ZrPO4 catalyst prepared by any one of claims 1-6 or the Ru / ZrPO4 catalyst as described in any one of claims 7-8 in the hydrodeoxygenation reaction of light phenolic components.

10. The application as described in claim 9, characterized in that, The application conditions for the hydrodeoxygenation reaction are as follows: the amount of catalyst is 0.4-0.6 g, the amount of light phenolic substrate is 0.05-0.20 g, and the amount of solvent is 10-30 mL; the light phenolic substrate includes one or more of phenol, guaiacol, or eugenol, and the solvent includes n-octane; the reaction temperature is 200-260℃, the reaction pressure is 0.6-0.8 MPa, and the reaction time is 2-4 h.

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