CN113559854A

CN113559854A - High-specific-surface-area ruthenium-loaded catalyst and preparation method and application thereof

Info

Publication number: CN113559854A
Application number: CN202110837635.7A
Authority: CN
Inventors: 杨明; 李裴杰; 董媛
Original assignee: China University of Geosciences
Current assignee: China University of Geosciences
Priority date: 2021-07-23
Filing date: 2021-07-23
Publication date: 2021-10-29
Anticipated expiration: 2041-07-23
Also published as: CN113559854B

Abstract

The invention discloses a ruthenium catalyst with high specific surface area, a preparation method and application thereof, belonging to the field of energy. The catalyst uses tungsten-aluminum composite oxide as a carrier, and then Ru is loaded on the oxide carrier by an impregnation method and a gas phase reduction method in RuCl₃Sodium acetate is added to the impregnation solution to reduce Ru³⁺The zeta potential of the catalyst is used for preventing Ru agglomeration in the dipping and sintering process, the grain diameter of Ru metal grains is 5-20nm, and the specific surface area of the catalyst is 200-600m²Per g, pore volume of 0.4-1.0cm³The pore diameter is 4-25 nm. The invention has simple process and lower equipment requirement, and the prepared catalyst has higher catalytic activity and stability for hydrogenation of the organic liquid hydrogen storage material.

Description

High-specific-surface-area ruthenium-loaded catalyst and preparation method and application thereof

Technical Field

The invention belongs to the field of energy and chemical engineering, and particularly relates to a ruthenium-loaded catalyst with a high specific surface area, and a preparation method and application thereof.

Background

The safe, convenient and large-storage hydrogen storage mode is a key factor for promoting the development of hydrogen energy, and compared with the traditional hydrogen storage technology, the organic liquid hydrogen storage technology has numerous advantages: the organic liquid hydrogen storage material uses organic macromolecules containing unsaturated bonds, absorbs hydrogen through chemical reaction, and then releases the hydrogen from organic liquid through heating catalysis, the organic molecules subjected to hydrogenation reaction can stably exist at normal temperature and normal pressure, the requirement on storage environment is not high, the organic liquid hydrogen storage material is suitable for large-scale pipeline transportation, the purity of the released hydrogen is high, and the hydrogen storage molecules can be recycled for multiple times, so that the organic liquid hydrogen storage material is one of the most promising hydrogen storage modes at present.

The catalyst generally consists of metal active components and a carrier, the activity of the metal is dominant, the effect of the carrier is usually ignored, and a plurality of transition metal oxides are selected as the carrier to provide abundant acid sites, so that the catalyst is very favorable for the dispersion of the metal active components and the adsorption reaction of reactants.

The solvothermal method is a common method for synthesizing a catalyst, but ethanol is less commonly used as a solvent, for example, Chinese patent CN104209118A reports that a high-performance Bi (OH) is synthesized by a simple one-pot solvent method by using ethanol and water as a mixed solvent₃/Bi₂WO₆A composite photocatalyst;

NiFe (CN) of Chinese patent CN108842165A₅Ultrasonically dispersing NO nano particles in ethanol, adding a sulfur source, and reacting at 120-200 ℃ for 8-16 h to obtain NiFe (CN) doped with sulfur₅NO electrolysis water oxygen evolution catalyst.

The Lokusan of Suzhou university reports the use of ethanol solvothermal synthesis of inorganic materials in Ph paper, with FeCl₃As solute, ethanol is used as solvent, mesoporous iron oxide material with core-shell structure is obtained through high-temperature alcoholysis, and Fe is synthesized by adding elementary iodine as ethanol carbonization catalyst₂O₃a/C composite material.

Currently, Ru/Al is generally used for hydrogenation of organic liquid hydrogen storage materials₂O₃The catalyst has high ruthenium loading capacity and high price, and improves the popularization cost of the organic liquid hydrogen storage technology. It is therefore of great importance to find a catalyst preparation process that can reduce the ruthenium loading while maintaining high efficiency.

Disclosure of Invention

Based on the catalyst, the invention provides the ruthenium-loaded catalyst with high specific surface area, the preparation process is simple and convenient, the equipment requirement is lower, and the prepared catalyst has higher activity and stability for the hydrogenation of organic liquid hydrogen storage materials, especially the hydrogenation reaction of carbazole hydrogen storage materials.

The Ru loading capacity of the high specific surface area ruthenium-loaded catalyst is 0.1-1 wt%, and the grain diameter of Ru metal grains is 5-20 nm;

the specific surface area of the catalyst is 200-600m²Per g, pore volume of 0.2-1.0cm³The pore diameter is 4-25 nm.

Preferably, the support of the catalyst is a metal oxide support.

Preferably, the metal oxide support is WO₃0-70% of Al₂O₃The mass fraction is 30-100%.

Another object of the present invention is to provide a method for preparing a ruthenium catalyst with a high specific surface area, which comprises the following steps:

(1) weighing a certain amount of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, dissolving the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer in absolute ethyl alcohol, uniformly stirring to form a solution, weighing one or two of ammonium metatungstate and aluminum isopropoxide, adding the ammonium metatungstate and aluminum isopropoxide into the solution, and stirring for 6 hours;

(2) slowly dropwise adding nitric acid into the solution obtained in the step (1), stirring for 3-5h to obtain a mixed solution, and transferring the mixed solution into a hydrothermal reaction kettle.

(3) Placing the hydrothermal reaction kettle in the step (2) in an oven at the temperature of 100 ℃ and 180 ℃ for reaction for 6 hours to obtain white or yellow gel;

(4) carrying out vacuum filtration and washing on the gel obtained in the step (3) for 5-10 times by using absolute ethyl alcohol, then drying the washed gel, and grinding to obtain a precursor of the carrier;

(5) placing the precursor of the carrier in the step (4) at 550 ℃ for air calcination for 4-6h to obtain a metal oxide carrier;

(6) dissolving a certain amount of ruthenium chloride and sodium acetate in deionized water, performing ultrasonic dispersion for 20 minutes, adding a proper amount of metal oxide carrier obtained in the step (5), fully and uniformly mixing, and drying at 70 ℃ for 6 hours;

(7) drying the mixture obtained in the step (6)After being fully ground, the solid is placed at 300 ℃ for air calcination for 4-6H, and inert gas and H are introduced after cooling₂Calcining the mixed gas at the temperature of 200-350 ℃ for 6h, and then standing and cooling to room temperature to obtain the ruthenium catalyst with high specific surface area.

Preferably, the amount of the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer used in step (1) is 3g per 120ml of ethanol, and the amount of ammonium metatungstate and aluminum isopropoxide used is 5g of WO in the preparation of the carrier₃The specific dosage is calculated according to the content of the compound.

Preferably, the concentration of the nitric acid in the step (2) is 67 wt%, and the dosage is 9-10 ml.

Preferably, the drying method in the step (4) is to dry the washed gel in an oven at 50-80 ℃ for 4-6h, or to add the washed gel into 100ml of analytical pure ethanol, to perform supercritical drying at 250 ℃ in a nitrogen atmosphere, with an exhaust speed of 0.1MPa/min, and to cool.

Preferably, the volume of the deionized water in the step (6) is the same as the total pore volume of the carrier, and the molar ratio of the sodium acetate to the ruthenium chloride is 3: 1.

Preferably, the inert gas in the step (7) is Ar, the volume fraction of the hydrogen in the mixed gas is 10%, and the flow rate of the mixed gas is 70-150 ml/min.

The invention synthesizes WO by ethanol solvothermal method and air calcination₃-Al₂O₃Loading Ru on WO by using the method of impregnation loading, air calcination curing and gas phase reduction₃-Al₂O₃And finally obtaining the ruthenium catalyst with high specific surface area on the carrier. The catalyst maintains high specific surface area by introducing a certain proportion of tungsten oxide on carrier alumina, improves the acidity of the catalyst carrier, improves the activity of the catalyst, and has good stability and stability in RuCl₃Sodium acetate is added to the impregnation solution to reduce Ru³⁺The zeta potential prevents Ru agglomeration in the dipping and sintering process, increases the dispersion degree of ruthenium, controls the size of ruthenium in a nanometer level, has simple and convenient process and lower equipment requirement, and the prepared catalyst has higher activity and stability for the hydrogenation of organic liquid hydrogen storage materials, in particular to the hydrogenation reaction of carbazole hydrogen storage materials.

Tungsten oxide is a classical hydrogen overflow material, and can form abundant Bronsted acid sites through hydrogen overflow when used as a catalyst, so that more reactive active sites are provided for hydrogenation of organic matters.

The invention also provides application of the ruthenium catalyst with high specific surface area in hydrogenation reaction of the organic liquid hydrogen storage material. The reaction is carried out in a high-temperature high-pressure reaction kettle, and the experimental process is as follows: introducing pure hydrogen to evacuate air in the reaction kettle (avoid explosion in the reaction process), heating the reaction kettle to 160 ℃ for adding the organic solvent, introducing the hydrogen, starting the reaction, sampling and testing the reaction rate at intervals, wherein the reaction temperature is 160 ℃ for adding the organic solvent, the hydrogen pressure is 5-8MPa, and the reaction speed is 600r/min for adding the organic solvent at 400 ℃.

Preferably, the organic liquid hydrogen storage material is azopropylcarbazole or dibenzyltoluene.

Compared with the prior art, the invention has the following beneficial effects:

(1) the ruthenium catalyst with high specific surface area prepared by the invention can be applied to hydrogenation reaction of organic liquid hydrogen storage materials, has high catalytic activity and good stability, and can be repeatedly used.

(2) The invention reduces the usage amount of the noble metal Ru and greatly reduces the catalyst cost under the condition of ensuring the same catalytic effect.

(3) The Ru has good dispersibility on the carrier, and the particle size is kept at a nanometer level.

(4) The invention adopts an ethanol solvothermal method to prepare WO₃And Al₂O₃The acidity of the carrier is improved, the dispersion degree of Ru metal is improved, and the activity of the catalyst is improved.

(5) The invention has simple synthesis process and lower equipment requirement, and can be produced and applied in large scale.

Drawings

FIG. 1 shows Ru/WO in example 1₃-Al₂O₃A catalyst physical adsorption and desorption curve diagram;

FIG. 2 shows Ru/WO in example 1₃-Al₂O₃The pore size distribution diagram of the catalyst;

FIG. 3 shows the catalyst amplification of 5.8 x 10 in example 1⁴A microscopic topography map of the fold;

FIG. 4 is the catalyst amplification of 1.05 x 10 in example 1¹²A microscopic topography map of the fold;

FIG. 5 is a polycrystalline diffraction analysis plot of the region of FIG. 4 of the catalyst of example 1;

FIG. 6 is a high angle dark field TEM image of the region of FIG. 3 for the catalyst of example 1;

FIG. 7 is a graph of elemental scanning analysis of Al in the FIG. 3 region of the catalyst in example 1;

FIG. 8 is an elemental scan analysis plot of O in the FIG. 3 region of the catalyst in example 1;

FIG. 9 is an elemental scan analysis plot of W in the FIG. 3 region of the catalyst in example 1;

FIG. 10 is a graph of elemental scan analysis of Ru in the FIG. 3 region of the catalyst of example 1.

FIG. 11 shows Ru/WO in example 2₃-Al₂O₃A catalyst azopropylcarbazole hydrogenation reaction rate diagram;

FIG. 12 is a graph of five hydrogenation cycles hydrogen sorption for the catalyst in example 3;

FIG. 13 is a graph showing the desorption/adsorption curves of the catalyst in example 5;

FIG. 14 is a graph of the pore size distribution of the catalyst in example 5;

FIG. 15 is a graph of the hydrogenation profile of azopropylcarbazole catalyzed by the catalyst of example 6;

FIG. 16 is the graph of the hydrogenation curve of azopropylcarbazole catalyzed by the catalyst in example 7;

FIG. 17 is a graph of the hydrogenation profile of azopropylcarbazole catalyzed by the catalyst of example 8;

FIG. 18 is the graph of the hydrogenation of azopropylcarbazole catalyzed by the catalyst of example 9;

FIG. 19 is the graph of the hydrogenation curve of azopropylcarbazole catalyzed by the catalyst in example 10;

FIG. 20 is a commercial 0.5 wt% Ru/Al of comparative example 1₂O₃A hydrogenation curve diagram of nitrogen propyl carbazole catalyzed by the supported catalyst.

Detailed Description

The present invention is further illustrated by the following examples.

Example 1

A high specific surface area tungsten-aluminum composite oxide ruthenium-supported catalyst is prepared by the following steps:

(1) 3g of a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer were dispersed with stirring in 120ml of absolute ethanol, stirred to homogeneity to form a solution, and 12.015g of aluminum isopropoxide [ Al (OPri) ] was added₃]And 2.125g of ammonium metatungstate [ (NH)₄)₁₀W₁₂O₄₁·xH₂O]Stirring for 6 hours;

(2) 9.6mL of HNO at 67 wt% concentration was slowly added₃Stirring the mixed solution in the solution obtained in the step (1) for 4 hours to obtain a mixed solution, and transferring the mixed solution into a 250ml hydrothermal reaction kettle;

(3) placing the hydrothermal reaction kettle in the step (2) in an oven at 140 ℃ for reaction for 6 hours to obtain yellow gel;

(4) carrying out air suction filtration washing on the precipitate obtained in the step (3) for 5 times by using absolute ethyl alcohol, then drying the washed precipitate in a 70 ℃ drying oven for 6 hours, and grinding to obtain a precursor of the carrier;

(5) placing the precursor of the carrier in the step (4) at 550 ℃ for air calcination for 4h to obtain a metal oxide carrier;

(6) 0.0272g of RuCl ruthenium chloride₃(Ru content: 37 wt%) and 0.03g of sodium acetate CH₃COONa was dissolved in 0.6752ml of deionized water, and dispersed by sonication for 20 minutes to prepare WO in step (5)₃-Al₂O₃Putting the composite carrier into the solution after ultrasonic treatment, fully and uniformly mixing, and drying at 70 ℃ for 6 hours;

(7) fully grinding the dried solid in the step (6), calcining the solid in air at 300 ℃ for 6h, cooling, and introducing Ar andH₂mixed gas (H) of (2)₂10%), calcined at 300 ℃ for 6h and then placed and cooled to room temperature to obtain the Ru with the loading of 0.49 wt%, WO₃Ru/WO with a theoretical loading of 40 wt%₃-Al₂O₃A catalyst.

The physical adsorption and desorption curve of the catalyst is shown in figure 1;

the pore size distribution is shown in FIG. 2. it can be seen from FIG. 2 that there is a clear hysteresis curve illustrating Ru/WO₃-Al₂O₃The specific surface area of the catalyst is large, and the aperture is 5-9 nm;

the catalyst had an amplification of 5.8 x 10⁴The microscopic topography is shown in FIG. 3; amplification 1.05 x 10¹²The microscopic topography is shown in FIG. 4; FIG. 5 is a polycrystalline diffraction analysis plot of the region of FIG. 4; the high angle dark field TEM image of the region of fig. 3 is shown in fig. 6; FIG. 3 is an elemental scan analysis of region Al as shown in FIG. 7; FIG. 3 is an elemental scan analysis chart of region O as shown in FIG. 8; FIG. 3 is an elemental scan analysis of region W as shown in FIG. 9; FIG. 3 is an elemental scan analysis of region Ru as shown in FIG. 10. The Ru/WO can be seen from FIGS. 4 and 5₃-Al₂O₃The crystallinity of Ru metal particles on the catalyst is better, the particle diameter is 10-20nm, and the dispersion degree of Ru and W elements is also very good as can be seen from figures 9 and 10.

Example 2

Using the high specific surface area Ru/WO of example 1₃-Al₂O₃The catalyst is subjected to an organic liquid hydrogen storage material (azopropylcarbazole) hydrogenation experiment.

Wherein, 0.2g of catalyst and 1.0g of azopropylcarbazole are added with 40ml of normal hexane as a solvent, the reaction pressure is 7MPa, the reaction temperature is 150 ℃, the rotation speed is 10rev/s, the reaction time is 120min, the total hydrogenation of azopropylcarbazole can be realized, no other by-products are generated, and the hydrogenation reaction rate of the catalyst to azopropylcarbazole is shown in figure 11.

Example 3

Using the high specific surface area Ru/WO of example 1₃-Al₂O₃The catalyst is subjected to a cyclic hydrogenation experiment of an organic liquid hydrogen storage material (azopropylcarbazole).

Wherein 0.2g of catalyst and 1.0g of N-propylcarbazole are added with 40ml of n-hexane as a solvent, the reaction pressure is 7MPa, the reaction temperature is 150 ℃, the rotation speed is 10rev/s, and the result of hydrogenation data is shown in figure 12. As can be seen from fig. 12, the hydrogenation performance was gradually reduced in five cycles of hydrogenation experiments, but complete hydrogenation could be achieved within 180min, which indicates that the catalyst could be recycled for multiple times and the hydrogenation performance was not greatly reduced.

Example 4

Using the high specific surface area Ru/WO of example 1₃-Al₂O₃The catalyst is subjected to hydrogenation experiments of organic liquid hydrogen storage materials (dibenzyltoluene, DBT).

Wherein 0.2g of catalyst and 1.0g of N-propylcarbazole are added with 40ml of normal hexane as a solvent, the reaction pressure is 7MPa, the reaction temperature is 150 ℃, and the rotation speed is 10 rev/s. The reaction can realize basically complete hydrogenation within 180min without other byproducts.

Example 5

The preparation method of the aluminum oxide supported ruthenium catalyst with high specific surface area comprises the following steps:

(1) 3g of P123 were dispersed with stirring in 120ml of absolute ethanol, stirred well to form a solution, and 20.0245g of aluminum isopropoxide [ Al (OPri) ]were added₃]Stirring for 6 hours;

(2) 9.6mL of HNO at 67 wt% concentration was slowly added₃Stirring the mixed solution in the solution obtained in the step (1) for 4 hours to obtain a mixed solution, and transferring the mixed solution into a 250ml hydrothermal reaction kettle; wherein, the beakers are sealed by polyethylene films in the stirring process to prevent the solution from volatilizing;

(4) carrying out vacuum filtration and washing on the precipitate obtained in the step (3) for 5 times by using absolute ethyl alcohol, then drying the washed precipitate in a 70 ℃ drying oven for 6 hours, and grinding to obtain a precursor of the carrier;

(5) placing the precursor of the carrier in the step (4) at 550 ℃ for air calcination for 4h to obtain white powder Al₂O₃A carrier;

(6) 0.0272g of RuCl ruthenium chloride₃(Ru content is more than or equal to 37 wt%) And 0.03g of sodium acetate CH₃COONa is dissolved in deionized water, ultrasonic dispersion is carried out for 20 minutes, and Al in the step (5) is added₂O₃Putting the carrier into the solution after ultrasonic treatment, fully and uniformly mixing, and drying at 70 ℃ for 6 hours;

(7) fully grinding the dried solid in the step (6), calcining the ground solid in air at 300 ℃ for 6 hours to ensure that Ru is completely oxidized and fixed on a carrier, cooling, and then introducing H₂The mixed gas of/Ar (the volume fraction of hydrogen is 10 percent) is calcined at 300 ℃ for 6 hours and then is placed and cooled to room temperature to obtain Ru/Al with the Ru loading of 0.49 weight percent₂O₃The physical adsorption and desorption curves of the catalyst are shown in fig. 13, and the pore diameter distribution diagram is shown in fig. 14. It can be seen from FIG. 13 that there is a clear hysteresis curve illustrating Ru/Al₂O₃The specific surface area of the catalyst is large, and it can be seen from FIG. 14 that the pore diameter of the catalyst is mainly distributed in the range of 0 to 8nm and is intensively distributed in the vicinity of 4nm and 7 nm.

Examples 6 to 9

A high specific surface area ruthenium catalyst on tungsten-aluminum composite oxide was prepared according to the preparation method of example 1, except that Al (OPri)₃And (NH)₄)₁₀W₁₂O₄₁·xH₂Amount of O, preparation of WO₃WO with different theoretical loadings₃-Al₂O₃The carrier and the catalyst on which Ru was supported are specifically shown in table 1.

TABLE 1

	Al(OPri)₃	(NH₄)₁₀W₁₂O₄₁·xH₂O	WO₃Theoretical loading
				Example 6	10.008g	2.656g	50wt％
Example 7	14.011g	1.608g	30wt％
				Example 8	17.974g	0.53g	10wt％
Example 9	16.34g	1.084g	20wt％

Ru/WO prepared using examples 6-9₃-Al₂O₃The catalyst, which was subjected to the hydrogenation test of azopropylcarbazole according to the method of example 2, showed the results shown in FIGS. 15 to 18, respectively.

Example 10

(1) 3g of P123 were dispersed with stirring in 120ml of absolute ethanol, stirred well to form a solution, and 14.011g of aluminum isopropoxide [ Al (OPri) ]were added₃]And 1.608g of ammonium tungstate [ (NH)₄)₁₀W₁₂O₄₁·xH₂O]Stirring for 6 hours;

(2) 9.6mL of HNO at 67 wt% concentration was slowly added₃To step (1)Stirring the solution for 4 hours to obtain a mixed solution, and transferring the mixed solution into a 250ml hydrothermal reaction kettle; wherein, the beakers are sealed by polyethylene films in the stirring process to prevent the solution from volatilizing;

(4) carrying out vacuum filtration and washing on the precipitate obtained in the step (3) for 5 times by using absolute ethyl alcohol, then adding 100ml of analytically pure ethyl alcohol into the washed precipitate, carrying out supercritical drying at the temperature of 250 ℃ in a nitrogen atmosphere, and cooling at the exhaust speed of 0.1MPa/min to obtain a precursor;

(5) placing the precursor of the carrier in the step (4) at 550 ℃ for air calcination for 4h to obtain WO₃-Al₂O₃A composite oxide support;

(6) 0.0272g of RuCl ruthenium chloride₃(Ru content: 37 wt%) and 0.03g of sodium acetate CH₃COONa is dissolved in deionized water, ultrasonic dispersion is carried out for 20 minutes, and WO in the step (5) is added₃-Al₂O₃Putting the composite carrier into the solution after ultrasonic treatment, fully and uniformly mixing, and drying at 70 ℃ for 6 hours;

(7) fully grinding the dried solid in the step (6), calcining the ground solid in air at 300 ℃ for 6 hours to ensure that Ru is completely oxidized and fixed on a carrier, cooling, and then introducing H₂Mixed gas of/Ar (the volume fraction of hydrogen is 10 percent), calcined at 300 ℃ for 6 hours, placed and cooled to room temperature to obtain the material with the Ru loading of 0.49 weight percent, WO₃Ru/WO with a theoretical loading of 30 wt%₃-Al₂O₃The supercritical dried catalyst was subjected to the nitrogen propylcarbazole hydrogenation test in the same manner as in example 2, and the results are shown in FIG. 19.

Example 11

The catalysts prepared in examples 1, 5, 6, 7, 8 and 9 were subjected to nitrogen physical adsorption and desorption tests under the test conditions of degassing at 150 ℃ for 6 hours and 0.1g of sample, the single-layer adsorption capacity was calculated by the BET multilayer molecular adsorption theory, the specific surface area of the catalyst was calculated from the size of nitrogen molecules, the pore volume was calculated by the BJH method, and the analysis results are shown in table 2.

TABLE 2

	Example 1	Example 5	Example 6	Example 7	Example 8	Example 9
							WO₃Theoretical loading (wt%)	40	0	50	30	10	20
Specific surface area (m)²/g)	365.6377	394.8267	255.4160	376.5089	353.3950	393.1347
							Pore volume (cm)³/g)	0.5106	0.6205	0.4961	0.6150	0.9086	0.5519

The results are shown in WO₃The theoretical loading is in the range of 10 wt% to 50 wt%, with WO₃The theoretical loading is increased, the specific surface area of the catalyst is increased and then reduced, and a certain amount of WO is shown₃Incorporation of porous structures which can participate in the formation of composite oxide supports, but WO₃The increase in the content destroys the porous structure of the carrier, even if the specific surface area of the catalyst is still greater than 250m²The fact that the catalyst synthesis method has certain advantages is shown in the specification.

Example 12

Preparation Steps 1 to 5 according to example 1, adjusting only Al (OPri)₃And (NH)₄)₁₀W₁₂O₄₁·xH₂O is used in the amount to prepare different WO₃Theoretical amount of WO₃-Al₂O₃Vectors, specific amounts of both and corresponding WO₃The theoretical loading and the pore volume data calculated by the BJH method after the nitrogen physical adsorption and desorption test are shown in Table 3.

TABLE 3

Comparative example 1

As commercial 0.5 wt% Ru/Al₂O₃The supported catalyst (purchased from shanxi kaida chemical company, analytical pure AR) was used as a comparative example, and the result of the hydrogenation test of the azopropylcarbazole was shown in fig. 20 according to the method of example 2. It can be seen from FIG. 20 that complete hydrogenation can be achieved by the time the reaction proceeds to 300 min. Obtained as in example 1Compared to the hydrogenation data of example 1, the hydrogenation performance of the commercial 0.5 wt% catalyst was lower than that of the catalyst of example 1. Can illustrate the novel Ru/WO₃-Al₂O₃The catalyst can improve the catalytic hydrogenation performance of the catalyst while realizing the same Ru loading capacity, and has great industrial application potential.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. The catalyst is characterized in that the Ru loading amount of the catalyst is 0.1-1 wt%, and the grain diameter of Ru metal grains is 5-20 nm;

the specific surface area of the catalyst is 200-600m²Per g, pore volume of 0.4-1.0cm³The pore diameter is 4-25 nm.

2. The ruthenium catalyst according to claim 1, wherein the support of the catalyst is a metal oxide support.

3. The ruthenium catalyst according to claim 2, wherein the metal oxide support comprises WO₃0-70% of Al₂O₃The mass fraction is 30-100%.

4. The method for preparing the ruthenium catalyst with high specific surface area according to any one of claims 1 to 3, comprising the steps of:

(1) dissolving a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer in absolute ethyl alcohol, uniformly stirring to form a solution, weighing one or two of ammonium metatungstate and aluminum isopropoxide, adding the solution into the solution, and stirring for 6 hours;

(2) slowly dropwise adding nitric acid into the solution obtained in the step (1), stirring for 3-5h to obtain a mixed solution, and transferring the mixed solution into a hydrothermal reaction kettle;

(3) placing the hydrothermal reaction kettle in the step (2) in an oven at 100-180 ℃ for reaction for 6 hours to obtain white or yellow gel;

(6) dissolving ruthenium chloride and sodium acetate in deionized water, performing ultrasonic dispersion for 20 minutes, adding a proper amount of metal oxide carrier in the step (5), fully and uniformly mixing, and drying at 70 ℃ for 6 hours;

(7) fully grinding the dried solid in the step (6), calcining the solid in air at 300 ℃ for 4 to 6 hours, cooling, and introducing Ar and H₂Calcining the mixed gas at the temperature of 200-350 ℃ for 6h, and then standing and cooling to room temperature to obtain the ruthenium catalyst with high specific surface area.

5. The method according to claim 4, wherein the amount of the triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide in step (1) is 3g per 120ml of ethanol, and the amount of the ammonium metatungstate and aluminum isopropoxide is adjusted to 5g of the WO in the preparation of the carrier₃The specific dosage is calculated according to the content of the compound.

6. The preparation method according to claim 4, wherein the nitric acid in the step (2) has a concentration of 67 wt% and is used in an amount of 9-10 ml.

7. The preparation method according to claim 4, wherein the drying in step (4) is carried out by drying the washed gel in an oven at 50-80 ℃ for 4-6 hours, or by adding the washed gel into 100ml of analytical grade ethanol, carrying out supercritical drying at 250 ℃ in a nitrogen atmosphere at an exhaust rate of 0.1MPa/min, and cooling.

8. The method according to claim 4, wherein the volume of the deionized water in the step (6) is equal to the total pore volume of the carrier, and the molar ratio of sodium acetate to ruthenium chloride is 3: 1.

9. The method according to claim 4, wherein the inert gas in the step (7) is Ar, the volume fraction of the hydrogen gas in the mixed gas is 10%, and the flow rate of the mixed gas is 70 to 150 ml/min.

10. The application of the high specific surface area ruthenium-loaded catalyst according to any one of claims 1 to 3, wherein the catalyst is used for hydrogenation reaction of an organic liquid hydrogen storage material, and the organic liquid hydrogen storage material is azopropylcarbazole or dibenzyltoluene.