A ruthenium-based catalyst Ru@RuO2 supported on zirconium phosphate, its preparation method and application

Abstract

This invention relates to the field of biomass degradation technology, specifically to a ruthenium-based catalyst Ru@RuO2 supported by zirconium phosphate, its preparation method, and its application in catalyzing the hydrogenolysis of lignin. This invention is based on the in-situ reduction of elemental ruthenium to needle-like ruthenium oxide supported by amorphous zirconium phosphate, constructing a RuO2 / zirconium phosphate composite nanomaterial. This material can efficiently catalyze the hydrogenolysis of alkali-degraded lignin and model compounds such as α-O-4 and 4-O-5. Furthermore, the ruthenium nanoparticles generated from the in-situ reduction on ruthenium oxide exhibit high stability and can be reused multiple times.

Description

Technical Field

[0001] This invention relates to the field of biomass degradation technology, specifically to a ruthenium-based catalyst Ru@RuO2 supported on zirconium phosphate, its preparation method, and its application in catalyzing the hydrogenolysis of lignin. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] To address the growing shortage of non-renewable fossil fuels, scientists are actively seeking alternative new energy sources. In recent years, clean and renewable resources such as hydropower, wind power, biomass, and nuclear energy have attracted widespread attention. Among numerous biomass resources, lignocellulose, as one of the most abundant renewable aromatic resources on Earth, offers a feasible alternative to petroleum derivatives; therefore, the efficient resource utilization of lignin has drawn the attention of scientists.

[0004] However, as a natural macromolecule, lignin has a complex chemical structure. How to break it down into smaller molecular fragments using biological or chemical means—that is, how to depolymerize it into directly usable small-molecule biochemicals—is a prerequisite for its efficient resource utilization. Existing technologies for lignin degradation mainly focus on the following methods: hydrogenolysis (including hydrogen transfer hydrogenation using hydrogen or a hydrogen-donating solvent), oxidative degradation (using oxygen and other oxidants), and acid-base depolymerization. However, these methods all have certain limitations. For example, although noble metal catalysts exhibit high conversion efficiency during hydrogenolysis, the tendency for their active sites to aggregate reduces catalyst stability; oxidative degradation methods typically have low catalytic activity and conversion efficiency; and acid-base depolymerization methods face difficulties in catalyst recovery and low separation efficiency from the reaction liquid. Therefore, there is an urgent need to develop a catalyst with high stability, high reaction efficiency, and high yield to achieve efficient lignin degradation. Summary of the Invention

[0005] To overcome the above problems, this invention provides a ruthenium-based catalyst Ru@RuO2 supported by zirconium phosphate, its preparation method, and its application in catalyzing the hydrogenolysis of lignin. This invention is based on the in-situ reduction of elemental ruthenium to needle-like ruthenium oxide supported by amorphous zirconium phosphate, constructing a Ru@RuO2 / zirconium phosphate composite nanomaterial. This material can efficiently catalyze the hydrogenolysis of dealkalized lignin and model compounds such as α-O-4 and 4-O-5. Furthermore, the ruthenium nanoparticles generated from the in-situ reduction on ruthenium oxide exhibit high stability and can be reused multiple times.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a ruthenium-based catalyst Ru@RuO2 supported on zirconium phosphate, comprising the following steps:

[0008] (1) Slowly add phosphoric acid solution to zirconium oxychloride aqueous solution, mix thoroughly and carry out hydrothermal reaction, and obtain amorphous zirconium phosphate after separation and drying.

[0009] (2) Add polyvinylpyrrolidone (PVP) to RuCl3 aqueous solution, then add sodium borohydride. After the reaction is complete, add the amorphous zirconium phosphate synthesized in step (1), mix thoroughly, and obtain the precursor RuO2 / zirconium phosphate after separation, washing, drying and calcination.

[0010] (3) Under the atmosphere of nitrogen and hydrogen mixed gas, the precursor is added to the isopropanol solution, and the reaction temperature is controlled at 190-210℃ and the pressure of nitrogen and hydrogen mixed gas is 1.5-2.5 MPa. The reaction is carried out for 3-5 hours to generate Ru@RuO2 / zirconium phosphate composite nanomaterial, namely ruthenium phosphate supported ruthenium-based catalyst Ru@RuO2.

[0011] In a second aspect, the present invention provides a ruthenium-based catalyst Ru@RuO2 supported on zirconium phosphate prepared by the above-described preparation method.

[0012] A third aspect of the present invention provides the application of the above-described zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 to the catalytic hydrogenolysis of lignin and / or lignin model compounds.

[0013] A fourth aspect of the present invention provides a method for hydrogenolysis of lignin and / or lignin model compounds, comprising:

[0014] In a nitrogen and hydrogen mixed gas atmosphere, the above-mentioned zirconium phosphate supported ruthenium-based catalyst Ru@RuO2 and lignin and / or lignin model compounds were added to the hydrogen-donating solvent, and the reaction was carried out at a temperature of 190-260℃ and a pressure of 1.5-2.5 MPa for 2-12 hours.

[0015] The beneficial effects of this invention are as follows:

[0016] (1) The present invention uses the sol-gel method to generate the precursor RuO2 / zirconium phosphate. During the reaction, RuCl3 reacts with alkaline sodium borohydride to generate ruthenium hydroxide. After calcination of ruthenium hydroxide and zirconium phosphate, the precursor RuO2 / zirconium phosphate is generated. The precursor RuO2 / zirconium phosphate is used to reduce RuO2 in situ to generate elemental Ru with extremely small size and uniform distribution on the surface of RuO2, thus constructing Ru@RuO2 / zirconium phosphate composite nanomaterial, namely the ruthenium-based catalyst Ru@RuO2 supported by zirconium phosphate. When Ru@RuO2 / zirconium phosphate composite nanomaterials are used for the catalytic cracking of dealkalized lignin and model compounds such as α-O-4 and 4-O-5, the formation of extremely small and uniformly distributed elemental Ru on the surface of RuO2 can significantly improve the efficiency of hydrogen dissociation to generate hydrogen protons. During the in-situ reduction process, RuO2 exhibits lattice oxygen deficiency, generating oxygen vacancies that promote the adsorption of O in the substrate, thus enhancing the adsorption of reactants such as dealkalized lignin and model compounds such as α-O-4 and 4-O-5. Furthermore, the introduction of a phosphorus source into the Zr-based support to form Zr-P enriches the acidic and basic sites of the catalytic system, promoting the adsorption and hydrogenation activation of CO bonds in the substrate. These three factors synergistically improve the hydrogenolysis of dealkalized lignin and model compounds such as α-O-4 and 4-O-5.

[0017] (2) The Ru@RuO2 / zirconium phosphate composite nanomaterial provided by the present invention, namely the ruthenium-based catalyst Ru@RuO2 supported by zirconium phosphate, achieves a CO bond breaking efficiency of 98.4%. At the same time, the extremely small and uniformly distributed elemental Ru generated in situ on the surface of RuO2 can effectively avoid the aggregation of elemental Ru, so that it has good stability during the reaction process and can be reused multiple times. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 The images are scanning electron microscope (SEM) images of zirconium phosphate prepared in Example 1 at different scales: (a) is an SEM image at a 5 μm scale, and (b) is an SEM image at a 2 μm scale.

[0020] Figure 2 The images are scanning electron microscope (SEM) images of the precursor RuO2 / zirconium phosphate prepared in Example 1 at different scales: (a) is an SEM image at a 2 μm scale, and (b) is an SEM image at a 1 μm scale.

[0021] Figure 3The images are scanning electron microscope (SEM) images of the precursor RuO2 / zirconium phosphate prepared in Example 1 at different scales: (a) is an SEM image at a scale of 100 nm, and (b) is an SEM image at a scale of 10 nm.

[0022] Figure 4 The images show the XRD patterns of the precursor RuO2 / zirconium phosphate and the Ru@RuO2 / zirconium phosphate composite nanomaterials in Example 1.

[0023] Figure 5 XPS O1s spectra in Example 1: a is the precursor RuO2 / zirconium phosphate, b is the Ru@RuO2 / zirconium phosphate composite nanomaterial;

[0024] Figure 6 XPS Ru3p spectra in Example 1: a represents the precursor RuO2 / zirconium phosphate, and b represents the Ru@RuO2 / zirconium phosphate composite nanomaterial.

[0025] Figure 7 XRD images of Ru / Zr-P prepared in Comparative Example 2;

[0026] Figure 8 The image shows the scanning electron microscope (SEM) images of Ru / Zr-P prepared in Comparative Example 2; (a) SEM image of Ru / Zr-P at a 2 μm scale, (a1) EDS mapping of Zr element, (a2) EDS mapping of P element, (a3) ​​EDS mapping of O element, (a4) EDS mapping of Ru element.

[0027] Figure 9 The image shows the XRD pattern of the Ru / NFPC prepared in Comparative Example 3.

[0028] Figure 10 The image shows a scanning electron microscope (SEM) image of the Ru / NFPC prepared in Comparative Example 3.

[0029] Figure 11 The image shows the XRD pattern of the Ru@RuO2 / ZrO2 composite nanomaterial prepared in Comparative Example 4.

[0030] Figure 12 The image shows a scanning electron microscope (SEM) image of the Ru@RuO2 / ZrO2 composite nanomaterial prepared in Comparative Example 4; (a) SEM image of the Ru@RuO2 / ZrO2 composite nanomaterial at a 2 μm scale, (a1) EDS mapping of Zr element, (a2) EDS mapping of O element, (a3) ​​EDS mapping of Ru element. Detailed Implementation

[0031] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0032] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0033] A first typical embodiment of the present invention provides a method for preparing a ruthenium-based catalyst Ru@RuO2 supported on zirconium phosphate, comprising the following steps:

[0034] (1) Slowly add phosphoric acid solution to zirconium oxychloride aqueous solution, mix thoroughly and carry out hydrothermal reaction, and obtain amorphous zirconium phosphate after separation and drying.

[0035] (2) Add polyvinylpyrrolidone to RuCl3 aqueous solution, then add sodium borohydride. After the reaction is complete, add the amorphous zirconium phosphate synthesized in step (1), mix thoroughly, and obtain the precursor RuO2 / zirconium phosphate after separation, washing, drying and calcination.

[0036] (3) Under the atmosphere of nitrogen and hydrogen mixed gas, the precursor is added to the isopropanol solution, and the reaction temperature is controlled at 190-210℃ and the pressure of nitrogen and hydrogen mixed gas is 1.5-2.5 MPa. The reaction is carried out for 3-5 hours to generate Ru@RuO2 / zirconium phosphate composite nanomaterial, namely ruthenium phosphate supported ruthenium-based catalyst Ru@RuO2.

[0037] In one or more embodiments, in step (1), the concentration of zirconium oxychloride in the zirconium oxychloride aqueous solution is 0.15 to 0.18 mol / L, preferably 0.167 mol / L.

[0038] In one or more embodiments, in step (1), the concentration of the phosphoric acid solution is 0.45 to 0.55 mol / L, preferably 0.5 mol / L.

[0039] In one or more embodiments, in step (1), the molar ratio of zirconium oxychloride to phosphoric acid is (6.75-8.1):(13.5-16.5), preferably 1:2.

[0040] In one or more embodiments, in step (1), the temperature of the hydrothermal reaction is 190-210°C, preferably 200°C; and the reaction time is 20-30 h, preferably 24 h.

[0041] In one or more embodiments, in step (2), the concentration of RuCl3 in the RuCl3 aqueous solution is 0.0045 to 0.0055 mol / L, preferably 0.005 mol / L.

[0042] In one or more embodiments, in step (2), the molar ratio of RuCl3, polyvinylpyrrolidone and sodium borohydride is 0.9-1.1:1.1-1.3:4.5-5.5, preferably 1:1.2:5.

[0043] In one or more embodiments, in step (2), the mass ratio of RuCl3 to the amorphous zirconium phosphate synthesized in step (1) is 9 to 11:100, preferably 1:10.

[0044] In one or more embodiments, in step (2), the calcination temperature is 380-420°C, preferably 400°C, and the calcination time is 2.5-3.5h, preferably 3h.

[0045] In one or more embodiments, in step (2), the volume ratio of the nitrogen and hydrogen mixture is 1-3:9-7.

[0046] In one or more embodiments, in step (3), the mass ratio of the precursor to the volume of isopropanol is 0.0067 to 0.02 g / L, preferably 0.02 g / L.

[0047] In one or more embodiments, in step (3), the volume ratio of the nitrogen and hydrogen mixture is 1-3:9-7.

[0048] A second typical embodiment of the present invention provides a ruthenium-based catalyst Ru@RuO2 supported on zirconium phosphate prepared by the above preparation method.

[0049] A third typical embodiment of the present invention provides the above-mentioned zirconium phosphate supported ruthenium-based catalyst Ru@RuO2 for the catalytic hydrogenolysis of lignin and / or lignin model compounds.

[0050] In one or more embodiments, the lignin is alkali-degraded lignin.

[0051] In one or more embodiments, the lignin model compound is an α-O-4 or 4-O-5 model compound.

[0052] A fourth typical embodiment of the present invention provides a method for hydrogenolysis of lignin and / or lignin model compounds, comprising:

[0053] In a nitrogen and hydrogen mixed gas atmosphere, the above-mentioned zirconium phosphate supported ruthenium-based catalyst Ru@RuO2 and lignin and / or lignin model compounds were added to the hydrogen-donating solvent, and the reaction was carried out at a temperature of 190-260℃ and a pressure of 1.5-2.5 MPa for 2-12 hours.

[0054] In one or more embodiments, the volume ratio of the nitrogen and hydrogen mixture is 1-3:9-7.

[0055] In one or more embodiments, the hydrogen-donating solvent includes methanol, ethanol, n-propanol, n-butanol, 2-butanol, and isopropanol, preferably isopropanol.

[0056] In one or more embodiments, the mass ratio of the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 to the volume ratio of the hydrogen-donating solvent is 0.0067 to 0.02 g / L, preferably 0.02 g / L.

[0057] In one or more embodiments, the mass ratio of the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 to lignin and / or lignin model compounds is 1:3 to 6.

[0058] In one or more embodiments, the lignin is alkali-degraded lignin.

[0059] In one or more embodiments, the lignin model compound is an α-O-4 or 4-O-5 model compound.

[0060] In one or more embodiments, the overall reaction is carried out under stirring conditions at a stirring speed of 600–900 rpm.

[0061] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0062] Example 1

[0063] Synthesis of ruthenium-based catalyst Ru@RuO2 supported by zirconium phosphate

[0064] (1) Weigh 2.42 g (7.5 mmol) of zirconium oxychloride octahydrate (ZrOCl2·8H2O) and dissolve it in 45 mL of deionized water to form an aqueous solution of zirconium oxychloride. Dissolve 1.025 mL (15.0 mmol) of 85% phosphoric acid (H3PO4) in 30 mL of water to form a phosphoric acid solution. Slowly add the phosphoric acid solution to the zirconium oxychloride aqueous solution, stir continuously for 1 h, and sonicate for 20 min to ensure thorough mixing. Heat the mixture at 200 °C in a hydrothermal environment for 24 h, and then centrifuge to obtain a colloidal substance. Dry the colloid under vacuum at 80 °C for 12 h to obtain amorphous zirconium phosphate (Zr-P). Figure 1 These are electron microscopy scan images of Zr-P at different magnifications.

[0065] (2) Dissolve 20 mg RuCl3 in 200 mL of deionized water, add 4 mL of 0.3 wt% PVP aqueous solution, stir at room temperature for 1 h, then add 5 mL of 0.1 mol / L NaBH4 aqueous solution, continue stirring at room temperature for 1 h to obtain a colloidal solution, then add 0.2 g of Zr-P solid synthesized in step (1) to the colloidal system to obtain a colloidal suspension. Stir the suspension at room temperature overnight (24 h), then centrifuge (8000 r / min, 5 min), wash the solid part three times with deionized water and ethanol respectively, and then dry it overnight in a vacuum oven at 60 °C. Calcine the dried solid at 400 °C in air atmosphere for 3 h to obtain the precursor RuO2 / zirconium phosphate (RuO2 / Zr-P). Figure 2 These are electron microscope (EM) images of RuO2 / Zr-P at different magnifications. Figure 3 Transmission electron microscopy (TEM) images of RuO2 / Zr-P at different magnifications, from Figure 2 and Figure 3 It can be seen that needle-shaped RuO2 is loaded on amorphous zirconium phosphate.

[0066] (3) RuO2 / Zr-P (20 mg) and isopropanol (10 mL) were mixed and loaded into the reactor. The air in the reactor was purged with 10% H2 / N2 (H2 to N2 volume ratio of 1:9). Finally, the autoclave was pressurized with 2 MPa and 30% H2 / N2 (H2 to N2 volume ratio of 3:7). Then, the reactor was heated from room temperature to 200 °C at a rate of 5 °C / min, and the reaction was started at 800 r / min and maintained for 4 h to generate Ru@RuO2 / zirconium phosphate composite nanomaterials, namely, ruthenium-based catalyst Ru@RuO2 supported by zirconium phosphate.

[0067] This embodiment also characterizes the generated Ru@RuO2 / zirconium phosphate composite nanomaterials. Figure 4 XRD images of the precursor RuO2 / Zr-P and Ru@RuO2 / zirconium phosphate composite nanomaterials. Figure 5XPS O1s spectra of the precursor RuO2 / Zr-P and Ru@RuO2 / zirconium phosphate composite nanomaterials; Figure 6 XPS Ru3p spectra of the precursor RuO2 / Zr-P and Ru@RuO2 / zirconium phosphate composite nanomaterials. Figure 4 As can be seen, diffraction peaks of elemental Ru appear in the XRD image of the Ru@RuO2 / zirconium phosphate composite nanomaterial. From... Figure 5 As can be seen, O1s shifts to higher binding energy regions during in-situ reduction, and lattice oxygen (O) L The decrease in oxygen content indicates the creation of more oxygen vacancies in the oxygen environment of the catalytic material, which is key evidence for the adsorption of O from the CO bonds in the substrate; from Figure 6 As can be seen, Ru3p shifts to a lower binding energy, which is a process of gaining electrons. This proves that the valence state of the Ru active site decreases during the in-situ reduction process, which is important evidence for the appearance of the Ru(0) site.

[0068] Comparative Example 1: Amorphous Zirconium Phosphate (Zr-P) Alone

[0069] Weigh 2.42 g (7.5 mmol) of zirconium oxychloride octahydrate (ZrOCl2·8H2O) and dissolve it in 45 mL of deionized water to form an aqueous solution of zirconium oxychloride. Dissolve 1.025 mL (15.0 mmol) of 85% phosphoric acid (H3PO4) in 30 mL of water to form a phosphoric acid solution. Slowly add the phosphoric acid solution dropwise to the zirconium oxychloride aqueous solution, stirring continuously for 1 h, and sonicate for 20 min to ensure thorough mixing. Heat the mixture at 200 °C in a hydrothermal environment for 24 h, and then centrifuge to obtain a colloidal substance. Dry the colloid under vacuum at 80 °C for 12 h to obtain amorphous zirconium phosphate (Zr-P).

[0070] Comparative Example 2Ru / Zr-P Composite Nanomaterials

[0071] (1) Weigh 2.42 g (7.5 mmol) of zirconium oxychloride octahydrate (ZrOCl2·8H2O) and dissolve it in 45 mL of deionized water to form an aqueous solution of zirconium oxychloride. Dissolve 1.025 mL (15.0 mmol) of 85% phosphoric acid (H3PO4) in 30 mL of water to form a phosphoric acid solution. Slowly add the phosphoric acid solution to the zirconium oxychloride aqueous solution, stir continuously for 1 h, and sonicate for 20 min to ensure thorough mixing. Heat the mixture at 200 °C in a hydrothermal environment for 24 h, and then centrifuge to obtain a colloidal substance. Dry the colloid under vacuum at 80 °C for 12 h to obtain amorphous zirconium phosphate (Zr-P).

[0072] (2) Dissolve 20 mg RuCl3 in 200 mL of deionized water, add 4 mL of 0.3 wt% PVP aqueous solution, stir at room temperature for 1 h, then add 5 mL of 0.1 mol / L NaBH4 aqueous solution, and continue stirring at room temperature for 1 h.

[0073] A colloidal solution was obtained, and 0.2 g of the Zr-P solid synthesized in step (1) was added to the colloidal system to obtain a colloidal suspension. The suspension was stirred overnight (24 h) at room temperature, then centrifuged (8000 r / min, 5 min). The solid part was washed three times each with deionized water and ethanol, and then dried overnight in a vacuum oven at 60 °C. The dried solid was calcined at 400 °C in air for 3 h to obtain the precursor RuO2 / zirconium phosphate (RuO2 / Zr-P). The precursor RuO2 / zirconium phosphate (RuO2 / Zr-P) was reduced at 400 °C in hydrogen atmosphere for 3 h to obtain Ru / Zr-P. The XRD pattern of Ru / Zr-P is shown below. Figure 7 As shown, a distinct characteristic peak is observed at 44.0°, confirming the presence of the Ru(0) species (JCPDS#06-0663). Furthermore, no characteristic peaks of any oxidation state are present, indicating that all Ru species are reduced to Ru(0) under high-temperature H2 atmosphere conditions. Scanning electron microscopy (SEM) images and EDS mappings of Ru / Zr-P at 2 μm are shown below. Figure 8 As shown, this indicates the presence of zirconium phosphate and Ru species.

[0074] Comparative Example 3Ru(0) supported on a carbon-based support

[0075] RuCl3 (0.1168 g), H3BTC (0.0778 g), HAc (0.2 g), and H2O (36.0 g) were added to the lining of a 50 mL reactor. After mechanical stirring for 10 min and ultrasonic treatment for 10 min, the reactor was placed in a forced-air drying oven at 160 °C for 72 h. After natural cooling, the sample was collected by centrifugation and washed three times with deionized water (25 mL) and ethanol (25 mL), respectively. The sample was dried under vacuum at 110 °C for 24 h. Finally, the obtained solid was calcined at 300 °C for 2 h under a hydrogen atmosphere to obtain Ru / NFPC. The XRD image of Ru / NFPC is shown below. Figure 9 As shown, the scanning electron microscope image of Ru / NFPC is as follows. Figure 10 As shown.

[0076] Comparative Example 4Ru@RuO2 / ZrO2

[0077] 20 mg RuCl3 was dissolved in 200 mL of deionized water, and 4 mL of 0.3 wt% PVP aqueous solution was added. The mixture was stirred at room temperature for 1 h, and then 5 mL of 0.1 mol / L NaBH4 aqueous solution was added dropwise. The mixture was stirred at room temperature for another 1 h to obtain a colloidal solution. 0.2 g of ZrO2 solid was then added to the colloidal system to obtain a colloidal suspension. The suspension was stirred overnight (24 h) at room temperature, then centrifuged (8000 r / min, 5 min). The solid fraction was washed three times each with deionized water and ethanol, and then dried overnight in a vacuum oven at 60 °C. The dried solid was calcined at 400 °C in air for 3 h to obtain the precursor RuO2 / ZrO2 (RuO2 / ZrO2).

[0078] RuO2 / ZrO2 (20 mg) and isopropanol (10 mL) were mixed and loaded into a reactor. Air was purged from the reactor using a 10% H2 / N2 mixture (H2 to N2 volume ratio 1:9). Finally, the autoclave was pressurized to 2 MPa with a 30% H2 / N2 mixture (H2 to N2 volume ratio 3:7). The reactor was then heated from room temperature to 200 °C at a rate of 5 °C / min, and the reaction was initiated at 800 rpm and maintained for 4 h to generate Ru@RuO2 / ZrO2 composite nanomaterials. The XRD image of the Ru@RuO2 / ZrO2 composite nanomaterials is shown below. Figure 11 As shown, the scanning electron microscope image of the Ru@RuO2 / ZrO2 composite nanomaterial is as follows. Figure 12 As shown.

[0079] Experimental Example 1

[0080] The nanomaterials prepared in Example 1 and Comparative Examples 1-4 were used to catalyze the hydrogenolysis of benzylphenyl ether.

[0081] The specific process included: mixing benzylphenyl ether (0.1 g), the nanomaterials prepared in Example 1 and Comparative Examples 1-4 (20 mg), and isopropanol (10 mL) and loading them into a reactor; purging the reactor with 10% H2 / N2 (H2 to N2 volume ratio 1:9); and finally pressurizing the autoclave with 2 MPa and 30% H2 / N2 (H2 to N2 volume ratio 3:7). The reactor was then heated from room temperature to 200 °C at a rate of 5 °C / min, and the reaction was started at 800 rpm and maintained for 4 h. The product was obtained by diluting the reaction solution and analyzing the chromatogram-mass spectrometry data. The results are shown in Table 1.

[0082] Table 1. Effects of the nanomaterials prepared in Example 1 and Comparative Examples 1-4 on the catalytic hydrogenolysis of benzyl phenyl ether.

[0083]

[0084] Table 1 shows that the Ru@RuO2 / zirconium phosphate composite nanomaterial prepared in Example 1 exhibits the best catalytic effect in the hydrogenolysis of benzylphenyl ether. In Comparative Example 1, zirconium phosphate alone does not show any catalytic effect. In Comparative Examples 2 and 3, the presence of elemental ruthenium provides some catalytic effect, as elemental Ru significantly improves the efficiency of hydrogen dissociation to generate hydrogen protons. However, excessive elemental Ru in Comparative Examples 2 and 3 leads to agglomeration, thus reducing the catalytic effect. In Comparative Example 4, changing the support resulted in a decrease in catalytic hydrogenolysis performance.

[0085] Analysis of the reasons: The formation of extremely small and uniformly distributed elemental Ru on the surface of RuO2 can significantly improve the efficiency of hydrogen dissociation to generate hydrogen protons. During the in-situ reduction process of RuO2, the absence of lattice oxygen creates oxygen vacancies, which promotes the adsorption of O in the substrate. This can improve the adsorption of reactants such as dealkalized lignin and model compounds such as α-O-4 and 4-O-5. Furthermore, the introduction of a phosphorus source into the Zr-based support to form Zr-P enriches the acidic and basic sites of the catalytic system, promoting the adsorption and hydrogenation activation of CO bonds in the substrate. These three factors synergistically improve the hydrogenolysis of dealkalized lignin and model compounds such as α-O-4 and 4-O-5.

[0086] Experiment Example 2

[0087] The Ru@RuO2 / zirconium phosphate composite nanomaterials prepared in Example 1 were used to catalyze the hydrogenation of alkali-degrading lignin.

[0088] The specific process included: 0.1 g of dealkalized lignin, 20 mg of the nanomaterials prepared in Examples 1 and Comparative Examples 1-4, and 10 mL of isopropanol were mixed and loaded into a reactor. Air was purged from the reactor using a 10% H2 / N2 mixture (H2 to N2 volume ratio of 1:9). Finally, the autoclave was pressurized at 2 MPa with a 30% H2 / N2 mixture (H2 to N2 volume ratio of 3:7). The reactor was then heated from room temperature to 250 °C at a rate of 5 °C / min, and the reaction was initiated at 800 rpm and maintained for 12 h. The product was obtained by diluting the reaction solution and analyzing the chromatogram-mass spectrometry data. The results are shown in Table 2.

[0089] Table 2. Effects of Ru@RuO2 / zirconium phosphate composite nanomaterials on catalytic hydrogenolysis and lignin removal.

[0090]

[0091] Experimental Example 3

[0092] The Ru@RuO2 / zirconium phosphate composite nanomaterials prepared in Example 1 were used to catalyze the hydrogenolysis of diphenyl ether.

[0093] The specific process included: mixing diphenyl ether (0.1 g), the nanomaterials prepared in Examples 1 and Comparative Examples 1-4 (20 mg), and isopropanol (10 mL) and loading them into a reactor; purging the reactor with 10% H2 / N2 (H2 to N2 volume ratio 1:9); and finally pressurizing the autoclave at 2 MPa with 30% H2 / N2 (H2 to N2 volume ratio 3:7). The reactor was then heated from room temperature to 240 °C at a rate of 5 °C / min, and the reaction was initiated at 800 r / min and maintained for 6 h. The product was obtained by diluting the reaction solution and analyzing the chromatogram-mass spectrometry data. After the reaction was complete, the catalyst was centrifuged and directly used for the next round of catalysis. The results are shown in Table 3.

[0094] Table 3. Effect of Ru@RuO2 / zirconium phosphate composite nanomaterials on the catalytic hydrogenolysis of diphenyl ether

[0095]

[0096] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a ruthenium-based catalyst Ru@RuO2 supported on zirconium phosphate, characterized in that, Elemental ruthenium was generated in situ from needle-shaped ruthenium oxide supported by amorphous zirconium phosphate, thus constructing Ru@RuO2 / zirconium phosphate composite nanomaterials. Includes the following steps: (1) Phosphoric acid solution was slowly added dropwise to zirconium oxychloride aqueous solution, and after thorough mixing, a hydrothermal reaction was carried out. After separation and drying, amorphous zirconium phosphate was obtained. (2) Add polyvinylpyrrolidone to RuCl3 aqueous solution, then add sodium borohydride. After the reaction is complete, add the amorphous zirconium phosphate synthesized in step (1), mix thoroughly, and obtain the precursor RuO2 / zirconium phosphate after separation, washing, drying and calcination. (3) Under the atmosphere of nitrogen and hydrogen mixed gas, the precursor is added to the isopropanol solution, and the reaction temperature is controlled at 190~210 ℃ and the pressure of nitrogen and hydrogen mixed gas is 1.5~2.5 MPa. The reaction is carried out for 3~5 h to generate Ru@RuO2 / zirconium phosphate composite nanomaterial, namely zirconium phosphate supported ruthenium-based catalyst Ru@RuO2.

2. The method for preparing the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 as described in claim 1, characterized in that, In step (1), the concentration of zirconium oxychloride in the zirconium oxychloride aqueous solution is 0.15~0.18 mol / L; Alternatively, in step (1), the concentration of the phosphoric acid solution is 0.45~0.55 mol / L; Alternatively, in step (1), the molar ratio of zirconium oxychloride to phosphoric acid is (6.75~8.1):(13.5~16.5). Alternatively, in step (1), the temperature of the hydrothermal reaction is 190~210 ℃; the reaction time is 20~30 h.

3. The method for preparing the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 as described in claim 2, characterized in that, In step (1), the concentration of zirconium oxychloride in the zirconium oxychloride aqueous solution is 0.167 mol / L; In step (1), the concentration of the phosphoric acid solution is 0.5 mol / L; Alternatively, in step (1), the molar ratio of zirconium oxychloride to phosphoric acid is 1:2; In step (1), the temperature of the hydrothermal reaction is 200 °C; the reaction time is 24 h.

4. The method for preparing the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 as described in claim 1, characterized in that, In step (2), the concentration of RuCl3 in the RuCl3 aqueous solution is 0.0045~0.0055 mol / L; Alternatively, in step (2), the molar ratio of RuCl3, polyvinylpyrrolidone, and sodium borohydride is 0.9~1.1:1.1~1.3:4.5~5.5; Alternatively, in step (2), the mass ratio of RuCl3 to the amorphous zirconium phosphate synthesized in step (1) is 9~11:100; Alternatively, in step (2), the calcination temperature is 380~420 ℃ and the calcination time is 2.5~3.5 h; Alternatively, in step (3), the volume ratio of the nitrogen and hydrogen mixture is 1~3:9~7.

5. The method for preparing the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 as described in claim 4, characterized in that, In step (2), the concentration of RuCl3 in the RuCl3 aqueous solution is 0.005 mol / L; Alternatively, in step (2), the molar ratio of RuCl3, polyvinylpyrrolidone, and sodium borohydride is 1:1.2:5; Alternatively, in step (2), the mass ratio of RuCl3 to the amorphous zirconium phosphate synthesized in step (1) is 1:10; Alternatively, in step (2), the calcination temperature is 400 ℃ and the calcination time is 3 h.

6. The method for preparing the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 as described in claim 1, characterized in that, In step (3), the mass ratio of the precursor to the volume of isopropanol is 0.0067~0.02 g / L; Alternatively, in step (3), the volume ratio of the nitrogen and hydrogen mixture is 1~3:9~7.

7. The method for preparing the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 as described in claim 6, characterized in that, In step (3), the mass ratio of the precursor to the volume of isopropanol is 0.02 g / L.

8. The ruthenium-based catalyst Ru@RuO2 supported by zirconium phosphate prepared by the method of any one of claims 1 to 7.

9. The zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 according to claim 8 is used to catalyze the hydrogenolysis of lignin and / or lignin model compounds.

10. The application as described in claim 9, characterized in that, The lignin is alkali-degraded lignin; Alternatively, the lignin model compound may be an α-O-4 or 4-O-5 model compound.

11. A method for the hydrogenolysis of lignin and / or lignin model compounds, characterized in that, include: In an atmosphere of nitrogen and hydrogen mixed gas, the ruthenium-based catalyst Ru@RuO2 supported by zirconium phosphate as described in claim 8, as well as lignin and / or lignin model compounds, are added to a hydrogen-donating solvent, and the reaction is carried out at a temperature of 190~260 °C and a pressure of 1.5~2.5 MPa for 2~12 h.

12. The method for hydrogenolysis of lignin and / or lignin model compounds as described in claim 11, characterized in that, The volume ratio of the nitrogen and hydrogen mixture is 1~3:9~7; Alternatively, the hydrogen-donating solvent may include methanol, ethanol, n-propanol, n-butanol, 2-butanol, and isopropanol.

13. The method for hydrogenolysis of lignin and / or lignin model compounds as described in claim 12, characterized in that, The hydrogen-donating solvent is isopropanol.

14. The method for hydrogenolysis of lignin and / or lignin model compounds as described in claim 11, characterized in that, The mass-to-volume ratio of the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 to the hydrogen-donating solvent is 0.0067~0.02 g / L; Alternatively, the mass ratio of the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 to lignin and / or lignin model compounds is 1:3~6; Alternatively, the overall reaction can be carried out under stirring conditions at a speed of 600-900 rpm.

15. The method for hydrogenolysis of lignin and / or lignin model compounds as described in claim 14, characterized in that, The mass ratio of the zirconium phosphate-supported ruthenium-based catalyst Ru@RuO2 to the volume ratio of the hydrogen-donating solvent is 0.02 g / L.

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