A modified ruthenium-based composite catalytic material, a preparation method and application thereof

Abstract

The application provides a modified ruthenium-based composite catalytic material and a preparation method and application thereof, and the modified ruthenium-based composite catalytic material is composed of a cesium salt and a barium salt co-modified ruthenium-based catalyst and a structured cordierite carrier, and the molecular formula of the modified ruthenium-based composite catalytic material is: [(Cs a -Ba b )‑Ru c / C] d ‑[MgAlSi]; wherein, [(Cs a -Ba b )‑Ru c / C] represents a cesium salt and a barium salt co-modified ruthenium-based catalyst supported by activated carbon; and [MgAlSi] represents a structured cordierite carrier; in the modified ruthenium-based composite catalytic material, the ruthenium carbon is modified by means of an electron aid alkali metal cesium and a structure aid alkaline earth metal barium, so that the ruthenium carbon can efficiently catalyze and promote hydrogen production by ammonia decomposition under low-temperature conditions; and the structured cordierite is used as a carrier material, has the advantages of high thermal conductivity and good stability, can effectively avoid the defects that the activity is reduced due to the low surface temperature of the catalyst, and can effectively avoid the problem of catalyst pulverization under high space velocity. The catalyst has an ammonia decomposition conversion rate of no less than 90% under the conditions of a temperature of 400-500 DEG C and a pressure of 0.1-2 MPa.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, and in particular to a modified ruthenium-based composite catalytic material, its preparation method, and its application. Background Technology

[0002] Hydrogen energy, as a secondary energy source that is abundant, green, low-carbon, and widely used, can help the large-scale consumption of renewable energy, realize large-scale peak shaving of the power grid and cross-seasonal and cross-regional energy storage, and accelerate the decarbonization of industries, buildings, transportation and other fields. It is an important energy source for achieving the low-carbon energy transition. However, the stringent storage and transportation requirements limit the widespread application of hydrogen energy.

[0003] Ammonia (NH3) is a common chemical hydrogen storage material with a hydrogen storage capacity as high as 17.7 wt.%, and it can be easily stored in liquid form at room temperature and low pressure. Ammonia decomposition for hydrogen production is a highly valuable, clean, and efficient in-situ hydrogen release technology that can effectively solve the problems of traditional high-pressure hydrogen storage. However, in reality, ammonia decomposition for hydrogen production faces three major bottlenecks:

[0004] First, hydrogen production from ammonia decomposition typically requires temperatures of 600-800℃, which leads to significant energy consumption. Second, ammonia decomposition is a strongly endothermic reaction, while the thermal conductivity of typical catalyst supports is low; for example, activated carbon has a thermal conductivity of 0.17-0.28 W / mK. This results in locally low temperatures on the catalyst surface during the reaction, leading to a decrease in reaction activity. Third, existing commercially available particulate catalysts also suffer from problems such as pulverization under long-term use, leading to increased drag, low stability of ammonia decomposition under high space velocity conditions, and high mass transfer costs and energy consumption.

[0005] Ruthenium-based catalysts are currently considered the most active ammonia decomposition catalysts at low temperatures. However, the high ruthenium content in existing catalysts leads to high costs, hindering commercial application. Furthermore, their ammonia decomposition activity temperature range remains relatively high (>450℃). Doping with alkali metal promoters also helps improve the activity of ammonia decomposition; however, the interaction and activity of ruthenium active sites modified by different alkali metals are far from optimal. Improving the low-temperature ammonia decomposition activity, thermal stability, and high-space-velocity mechanical stability of catalysts is a new approach to constructing novel ammonia decomposition catalysts. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a modified ruthenium-based composite catalytic material, its preparation method, and its applications, aiming to improve the low-temperature ammonia decomposition activity, thermal stability, and high-space-velocity mechanical stability of the catalyst. The specific details of the invention are as follows:

[0007] In a first aspect, the present invention provides a modified ruthenium-based composite catalytic material, wherein the modified ruthenium-based composite catalytic material is composed of a ruthenium-based catalyst co-modified with cesium salt and barium salt, and a structured cordierite support thereof, and the molecular formula of the modified ruthenium-based composite catalytic material is: [(Cs a -Ba b )-Ru c / C] d -[MgAlSi]; where...

[0008] [(Cs a -Ba b )-Ru c [ / C] represents a ruthenium-based catalyst supported on activated carbon and co-modified with cesium and barium salts;

[0009] [MgAlSi] represents a structured cordierite carrier;

[0010] 'a' represents the molar percentage of cesium salt and metallic ruthenium, and 'a' ranges from 1 to 15.

[0011] b represents the molar percentage of barium salt and metallic ruthenium, and b is between 0.5 and 5.

[0012] c represents the mass percentage of ruthenium metal and activated carbon, and c is between 0.5 and 10.

[0013] d represents the mass percentage of the ruthenium-based catalyst supported on activated carbon and co-modified with cesium and barium salts to the structured cordierite support, and d ranges from 1 to 35.

[0014] Optionally, a is 5-10;

[0015] b is 1-2;

[0016] The value of c is 1-5;

[0017] The value of d is 20-30.

[0018] In a second aspect, the present invention provides a method for preparing the modified ruthenium-based composite catalytic material described in the first aspect above, the preparation method comprising the following steps:

[0019] S1, according to the molecular formula of the ruthenium-based catalyst co-modified with cesium and barium salts supported on activated carbon [(Cs a -Ba b )-Ru c The mixture consists of / C] weighed ruthenium trichloride and barium nitrate of a predetermined mass, dissolved in deionized water to form a mixed solution, and then activated carbon of a predetermined mass was added. The mixture was magnetically stirred at room temperature for 5-15 hours to form the first suspension.

[0020] S2. After vacuum drying the first suspension at 25-90℃ for 2-12 hours, the resulting black solid powder is transferred to a tube furnace and reduced at 500-600℃ for 2-5 hours in a reducing atmosphere to obtain the reduced product.

[0021] S3. Dissolve a predetermined amount of cesium nitrate in deionized water to obtain a cesium nitrate solution, then place the reduction product in the cesium nitrate solution and magnetically stir and soak at room temperature for 6-12 hours to form a second suspension.

[0022] S4. The second suspension is vacuum dried at 25-90℃ for 2-12 hours to obtain a ruthenium-based catalyst co-modified with cesium and barium salts supported on activated carbon [(Cs a -Ba b )-Ru c / C];

[0023] S5, according to the molecular formula of the modified ruthenium-based composite catalyst [(Cs a -Ba b )-Ru c / C] d -[MgAlSi] composition, wherein the [(Cs a -Ba b )-Ru c [C] is added to deionized water in a preset ratio with magnesium oxide and binder, and magnetically stirred at room temperature for 2-12 hours to form a colloidal solution. Then, structured cordierite is impregnated in the colloidal solution under vacuum at room temperature for 2-10 hours. The impregnated structured cordierite is then transferred to a tube furnace and calcined at 500-600℃ for 2-5 hours under an inert atmosphere. After cooling, it is removed to obtain the modified ruthenium-based composite catalyst [(Cs] a -Ba b )-Ru c / C] d -[MgAlSi].

[0024] Optionally, in the mixed solution, the concentration of ruthenium ions is 5-10 mg / mL, and the concentration of barium ions is 5-50 mg / mL;

[0025] The cesium ion concentration in the cesium nitrate solution is 5-50 mg / mL.

[0026] Optionally, the adhesive is polyethylene glycol, hydroxymethyl cellulose, or hydroxyethyl cellulose.

[0027] Optionally, the magnesium oxide accounts for 10-20% of the mass of the colloidal solution;

[0028] The binder accounts for 1-2% of the mass of the colloidal solution;

[0029] The [(Cs) a -Ba b )-Ru c / C] accounts for 5-10% of the mass of the colloidal solution.

[0030] Optionally, the structured cordierite has a pore size between 0.5-2 mm, a radial diameter between 10-200 mm, and a height between 20-300 mm.

[0031] Thirdly, the present invention provides an application of the modified ruthenium-based composite catalytic material described in the first aspect above, wherein the modified ruthenium-based composite catalytic material is used for hydrogen production from ammonia decomposition.

[0032] Optionally, the use of the modified ruthenium-based composite catalyst for ammonia decomposition to produce hydrogen includes: after loading the modified ruthenium-based composite catalyst into a fixed-bed reactor, ammonia gas is introduced to carry out the ammonia decomposition to produce hydrogen reaction;

[0033] The reaction space velocity of the ammonia gas is 1000-20000 h⁻¹. -1 The reaction temperature is 300-500℃ and the reaction pressure is 0.1-5MPa.

[0034] Optionally, the concentration of ammonia participating in the ammonia decomposition to produce hydrogen is 10-100 vol.%.

[0035] Compared with existing technologies, the modified ruthenium-based composite catalytic material, its preparation method, and its applications provided by this invention have the following advantages:

[0036] This invention provides a modified ruthenium-based composite catalytic material, which comprises a ruthenium-based catalyst co-modified with cesium and barium salts, and a structured cordierite support. The molecular formula of the modified ruthenium-based composite catalytic material is: [(Cs a -Ba b )-Ru c / C] d -[MgAlSi]; where, [(Cs a -Ba b )-Ru c [C] represents a ruthenium-based catalyst supported on activated carbon and co-modified with cesium and barium salts; [MgAlSi] represents a structured cordierite support.

[0037] The modified ruthenium-based composite catalyst provided by this invention modifies ruthenium carbon using alkali metal cesium as an electronic aid and alkaline earth metal barium as a structural aid, enabling it to efficiently catalyze the decomposition of ammonia to produce hydrogen at low temperatures. Structured cordierite is used as the support material, offering advantages such as high thermal conductivity and good stability, effectively avoiding the defects of reduced activity due to low catalyst surface temperature and catalyst pulverization at high space velocities. This catalyst exhibits highly efficient catalytic activity, achieving an ammonia decomposition conversion rate of no less than 90% under reaction conditions of 400-500℃ and 0.6 MPa. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A flowchart illustrating the preparation method of the modified ruthenium-based composite catalytic material provided in this embodiment of the invention is shown.

[0040] Figure 2 The image shows a physical diagram of the modified ruthenium-based composite catalytic material provided in an embodiment of the present invention;

[0041] Figure 3 The transmission electron microscope (TEM) image of [(Cs5-Ba2)-Ru5 / C] provided in the embodiment of the present invention is shown.

[0042] Figure 4 The variation of ammonia decomposition efficiency of the modified ruthenium-based composite catalytic material provided in Example 1 of the present invention at different temperatures is shown.

[0043] Figure 5 The variation of ammonia decomposition efficiency of the modified ruthenium-based composite catalytic material provided in Example 1 of the present invention under different pressures is shown.

[0044] Figure 6 The ammonia conversion rates of the modified ruthenium-based composite catalysts provided in Examples 1-5 of this invention are shown.

[0045] Figure 7 The ammonia conversion rate of the ammonia decomposition hydrogen production catalytic material provided by the present invention is shown in the comparative example. Detailed Implementation

[0046] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0047] Specific experimental steps or conditions are not specified in the examples; however, they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products.

[0048] Currently, ruthenium-based catalysts are considered to be the most active ammonia decomposition catalysts at low temperatures. However, the high ruthenium content of these catalysts leads to high preparation costs, and their active temperature range for ammonia decomposition remains relatively high (>450℃), resulting in energy consumption and short catalyst lifespan. Therefore, this invention modifies ruthenium-based catalysts using alkali metals and alkaline earth metals and combines them with a structured cordierite support to obtain novel ammonia decomposition hydrogen production catalyst materials. This invention further investigates the performance of the modified ruthenium-based ammonia decomposition catalyst material, thereby verifying that the catalyst possesses good low-temperature ammonia decomposition activity, thermal stability, and high space velocity mechanical stability. Specific implementation methods are as follows:

[0049] In a first aspect, the present invention provides a modified ruthenium-based composite catalytic material, wherein the modified ruthenium-based composite catalytic material is composed of a ruthenium-based catalyst co-modified with cesium salt and barium salt, and a structured cordierite support thereof, and the molecular formula of the modified ruthenium-based composite catalytic material is: [(Cs a -Ba b )-Ru c / C] d -[MgAlSi]; where...

[0050] [(Cs a -Ba b )-Ru c [ / C] represents a ruthenium-based catalyst supported on activated carbon and co-modified with cesium and barium salts;

[0051] [MgAlSi] represents a structured cordierite carrier;

[0052] 'a' represents the molar percentage of cesium salt and metallic ruthenium, and 'a' ranges from 1 to 15.

[0053] b represents the molar percentage of barium salt and metallic ruthenium, and b is between 0.5 and 5.

[0054] c represents the mass percentage of ruthenium metal and activated carbon, and c is between 0.5 and 10.

[0055] d represents the mass percentage of the ruthenium-based catalyst supported on activated carbon and co-modified with cesium and barium salts to the structured cordierite support, and d ranges from 1 to 35.

[0056] In specific implementation, the modified ruthenium-based composite catalytic material provided by this invention modifies the ruthenium-carbon catalyst using alkali metal cesium as an electronic aid and alkaline earth metal barium as a structural aid. Cesium effectively provides electrons to ruthenium particles, facilitating the breaking of nitrogen-hydrogen bonds in ammonia. Barium, on the other hand, helps form more B5 active sites on ruthenium particles, promoting ammonia adsorption on ruthenium. This achieves highly efficient catalytic promotion of ammonia decomposition to hydrogen production at low temperatures. This invention uses structured cordierite as a support material to carry the modified ruthenium-based catalyst, which has the advantages of high thermal conductivity and good stability, effectively avoiding the defects of reduced activity due to low catalyst surface temperature and catalyst pulverization at high space velocities. This catalyst exhibits highly efficient catalytic activity; under reaction conditions of 450℃ and 0.6 MPa, the ammonia decomposition conversion rate can reach 99.1%.

[0057] In some implementations, 'a' can be taken from 5 to 10; 'b' can be taken from 1 to 2; 'c' can be taken from 1 to 5; and 'd' can be taken from 20 to 30.

[0058] Secondly, the present invention provides a method for preparing the modified ruthenium-based composite catalytic material described in the first aspect above. Figure 1 A flowchart illustrating the preparation method of the modified ruthenium-based composite catalytic material provided in this embodiment of the invention is shown, as follows: Figure 1 As shown, the preparation method includes the following steps:

[0059] S1, according to the molecular formula of the ruthenium-based catalyst co-modified with cesium and barium salts supported on activated carbon [(Cs a -Ba b )-Ru c The mixture consists of / C] weighed ruthenium trichloride and barium nitrate of a predetermined mass, dissolved in deionized water to form a mixed solution, and then activated carbon of a predetermined mass was added. The mixture was magnetically stirred at room temperature for 5-15 hours to form the first suspension.

[0060] S2. After vacuum drying the first suspension at 25-90℃ for 2-12 hours, the resulting black solid powder is transferred to a tube furnace and reduced at 500-600℃ for 2-5 hours in a reducing atmosphere to obtain the reduced product.

[0061] S3. Dissolve a predetermined amount of cesium nitrate in deionized water to obtain a cesium nitrate solution, then place the reduction product in the cesium nitrate solution and magnetically stir and soak at room temperature for 6-12 hours to form a second suspension.

[0062] S4. The second suspension is vacuum dried at 25-90℃ for 2-12 hours to obtain a ruthenium-based catalyst co-modified with cesium and barium salts supported on activated carbon [(Cs a -Ba b )-Ru c / C];

[0063] S5, according to the molecular formula of the modified ruthenium-based composite catalyst [(Cs a -Ba b )-Ru c / C] d -[MgAlSi] composition, wherein the [(Cs a -Ba b )-Ru c [C] is added to deionized water in a preset ratio with magnesium oxide and binder, and magnetically stirred at room temperature for 2-12 hours to form a colloidal solution. Then, structured cordierite is impregnated in the colloidal solution under vacuum at room temperature for 2-10 hours. The impregnated structured cordierite is then transferred to a tube furnace and calcined at 500-600℃ for 2-5 hours under an inert atmosphere. After cooling, it is removed to obtain the modified ruthenium-based composite catalyst [(Cs] a -Ba b )-Ru c / C] d -[MgAlSi].

[0064] In practical implementation, the preset quality refers to the quality based on the molecular formula of the modified ruthenium-based composite catalyst [(Cs a -Ba b )-Ru c / C] d -In [MgAlSi], the range of values ​​for a, b, c, and d, and the specific amounts of each raw material determined; as an example, in step S1, a predetermined mass of ruthenium trichloride and barium nitrate is weighed and dissolved in a mixed solution formed by deionized water, with a ruthenium ion concentration of 5-10 mg / mL and a barium ion concentration of 5-50 mg / mL; in step S3, a predetermined mass of cesium nitrate is dissolved in a cesium nitrate solution obtained by deionized water, with a cesium ion concentration of 5-50 mg / mL.

[0065] Thirdly, the present invention provides an application of the modified ruthenium-based composite catalyst material described in the first aspect above, wherein the modified ruthenium-based composite catalyst material is used for ammonia decomposition to produce hydrogen. Specifically, this includes: loading the modified ruthenium-based composite catalyst material into a fixed-bed reactor, and then introducing ammonia gas to carry out the ammonia decomposition to produce hydrogen reaction; the reaction space velocity of the ammonia gas is 1000-20000 h⁻¹. -1 The reaction temperature is 300-500℃ and the reaction pressure is 0.1-5MPa.

[0066] To enable those skilled in the art to better understand this application, the following embodiments are provided to illustrate in detail a modified ruthenium-based composite catalytic material, its preparation method, and its application.

[0067] The structured cordierite carriers used in the following examples and comparative examples were all purchased from Suzhou Guohongtai Environmental Protection Technology Co., Ltd.

[0068] Example 1

[0069] 0.102 g of ruthenium trichloride and 0.258 g of barium nitrate were weighed and dissolved in 10 mL of deionized water to form a mixed solution with a ruthenium ion concentration of 5 mg / mL and a barium ion concentration of 13.5 mg / mL. 1.0 g of activated carbon was added to the solution, and the mixture was magnetically stirred at room temperature for 12 hours. The resulting first suspension was vacuum dried at 80 °C for 12 hours, and the resulting black solid powder was placed in a porcelain boat. Reduction was performed at 600 °C for 5 hours in a tube furnace under a hydrogen-argon mixture atmosphere (10% hydrogen content) at a heating rate of 5 °C / min. 0.482 g of cesium nitrate was weighed and dissolved in 30 mL of deionized water, with a cesium ion concentration of 10.9 mg / mL. The reduced solid was placed in the solution and magnetically stirred at room temperature for 12 hours. The resulting second suspension was vacuum dried at 80 °C for 12 hours, yielding the [(Cs5-Ba2)-Ru5 / C] catalyst.

[0070] Weigh 1.0 g of [(Cs5-Ba2)-Ru5 / C], 1.0 g of magnesium oxide, and 0.1 g of polyethylene glycol PEG-300, add 5 mL of deionized water, and magnetically stir at room temperature for 12 hours to form a colloidal solution. Take a structured cordierite support with a diameter of 10 mm, a height of 50 mm, and a pore size of 1 mm, weighing 3.70 g. Weigh 0.74 g of the colloidal solution, place the cordierite support in the colloidal solution, and vacuum impregnate at room temperature for 2 hours. Then, turn the cordierite over and continue vacuum impregnation for another 2 hours. After impregnation, calcine the cordierite at 600 °C for 2 hours in a tube furnace under argon atmosphere at a heating rate of 5 °C / min. After cooling, remove the [(Cs5-Ba2)-Ru5 / C] solution. 20 -[MgAlSi].

[0071] Figure 2 The image shown is a physical diagram of the modified ruthenium-based composite catalytic material provided in the embodiments of the present invention. Figure 3 A transmission electron microscope (TEM) image of [(Cs5-Ba2)-Ru5 / C] provided in an embodiment of the present invention is shown.

[0072] [(Cs5-Ba2)-Ru5 / C] is loaded into a fixed-bed tubular reactor. 20The ammonia decomposition to hydrogen reaction was carried out using a [MgAlSi] catalyst. Nitrogen gas was introduced at a rate of 50 mL / min at room temperature, and the temperature was increased to 500 °C at a rate of 5 °C / min. After stabilization at 500 °C for 1 hour, the ammonia decomposition performance was tested by introducing a reaction gas. Ammonia in the product gas was absorbed with dilute sulfuric acid and then detected by ion chromatography. The reaction space velocity was 1500 h⁻¹. -1 The reaction temperature range is 350-500℃, the reaction pressure range is 0.1-2MPa, and the ammonia concentration range is 10-100 vol.%.

[0073] Figure 4 The variation of ammonia decomposition efficiency of the modified ruthenium-based composite catalyst provided in Example 1 of the present invention at different temperatures is shown (reaction conditions: reaction temperatures of 375, 400, 425, 450, 475, and 500 °C, reaction pressure of 0.6 MPa, ammonia concentration of 10 vol.%, and reaction space velocity of 1500 h⁻¹). -1 ),like Figure 4 As shown, the ammonia conversion rates at ammonia decomposition reaction temperatures of 375, 400, 425, 450, 475, and 500℃ are 77.6%, 93.0%, 97.9%, 99.1%, 99.7%, and 99.8%, respectively; the corresponding hydrogen production rates are 19.4, 23.3, 24.5, 24.9, 25.0, and 25.1 mmol / h, respectively. It is evident that the modified ruthenium-based composite catalyst provided in Example 1 achieves an ammonia decomposition conversion rate of no less than 90% under reaction conditions of 400-500℃ and 0.6 MPa. Furthermore, the modified ruthenium-based composite catalyst provided in Example 1 achieves an ammonia decomposition conversion rate of 99.1% under reaction conditions of 450℃ and 0.6 MPa.

[0074] Figure 5 The variation of ammonia decomposition efficiency of the modified ruthenium-based composite catalyst provided in Example 1 of this invention under different pressures is shown (reaction conditions: reaction temperature 450℃, reaction pressure 0.1, 0.5, 1.0, 1.5, 2.0 MPa, ammonia concentration 10 vol.%, reaction space velocity 1500 h⁻¹). -1 ),like Figure 5 As shown, when the ammonia decomposition reaction pressure is 0.1, 0.5, 1.0, 1.5, and 2.0 MPa, the corresponding ammonia conversion rates are 99.5%, 99.3%, 97.9%, 96.9%, and 96.3%, respectively; and the corresponding hydrogen production rates are 25.0, 24.9, 24.5, 24.2, and 24.0 mmol / h, respectively.

[0075] Example 2

[0076] 0.102 g of ruthenium trichloride and 0.129 g of barium nitrate were weighed and dissolved in 10 mL of deionized water to form a mixed solution with a ruthenium ion concentration of 5 mg / mL and a barium ion concentration of 6.8 mg / mL. 1.0 g of activated carbon was added to the solution, and the mixture was magnetically stirred at room temperature for 12 hours. The resulting first suspension was vacuum dried at 80 °C for 12 hours, and the resulting black solid powder was placed in a porcelain boat. Reduction was performed at 600 °C for 5 hours in a tube furnace under a hydrogen-argon mixture atmosphere (10% hydrogen content) at a heating rate of 5 °C / min. 0.482 g of cesium nitrate was weighed and dissolved in 30 mL of deionized water, with a cesium ion concentration of 10.9 mg / mL. The reduced solid was placed in the solution and magnetically stirred at room temperature for 12 hours. The resulting second suspension was vacuum dried at 80 °C for 12 hours, yielding the [(Cs5-Ba1)-Ru5 / C] catalyst.

[0077] Weigh 1.0 g of [(Cs5-Ba1)-Ru5 / C], 1.0 g of magnesium oxide, and 0.1 g of polyethylene glycol PEG-300, add 5 mL of deionized water, and magnetically stir at room temperature for 12 hours to form a colloidal solution. Take a structured cordierite support with a diameter of 10 mm, a height of 50 mm, and a pore size of 1 mm, weighing 3.70 g. Weigh 0.74 g of the colloidal solution, place the cordierite support in the colloidal solution, and vacuum impregnate at room temperature for 2 hours. Then, turn the cordierite over and continue vacuum impregnation for another 2 hours. After impregnation, calcine the cordierite at 600 °C for 2 hours in a tube furnace under argon atmosphere at a heating rate of 5 °C / min. After cooling, remove the [(Cs5-Ba1)-Ru5 / C] solution. 20 -[MgAlSi].

[0078] [(Cs5-Ba1)-Ru5 / C] is loaded into a fixed-bed tubular reactor. 20 The ammonia decomposition to hydrogen production reaction was carried out using a [MgAlSi] catalyst at a reaction space velocity of 1500 h⁻¹. -1 The reaction temperature was 450℃, the reaction pressure was 0.6MPa, and the ammonia concentration was 10 vol.%.

[0079] Example 3

[0080] Weigh 0.102 g of ruthenium trichloride and 0.258 g of barium nitrate, respectively, and dissolve them in 10 mL of deionized water to form a mixed solution with a ruthenium ion concentration of 5 mg / mL and a barium ion concentration of 13.5 mg / mL. Add 1.0 g of activated carbon to the solution and impregnate with magnetic stirring at room temperature for 12 hours. Vacuum dry the resulting first suspension at 80 °C for 12 hours, and place the resulting black solid powder in a porcelain boat. Reduce the powder in a tube furnace at 600 °C for 5 hours under a hydrogen-argon mixture atmosphere (10% hydrogen content) at a heating rate of 5 °C / min. Weigh 0.964 g of cesium nitrate and dissolve it in 50 mL of deionized water, with a cesium ion concentration of 13.1 mg / mL. Place the reduced solid in the solution and impregnate with magnetic stirring at room temperature for 12 hours. Vacuum dry the resulting second suspension at 80 °C for 12 hours, and then remove the powder to obtain [(Cs 10 [Ba2)-Ru5 / C] catalyst.

[0081] Weigh 1.0g [(Cs 10 [Ba2)-Ru5 / C], 1.0 g magnesium oxide and 0.1 g polyethylene glycol PEG-300 were added to 5 mL of deionized water and magnetically stirred at room temperature for 12 hours to form a colloidal solution. A cordierite support with a diameter of 10 mm, a height of 50 mm, and a pore size of 1 mm (3.70 g) was taken, and 0.74 g of the colloidal solution was weighed. The cordierite support was placed in the colloidal solution and vacuum impregnated at room temperature for 2 hours. The cordierite was then turned over and vacuum impregnated for another 2 hours. After impregnation, the cordierite was calcined in a tube furnace at 600 °C for 2 hours under an argon atmosphere at a heating rate of 5 °C / min. After cooling, [(Cs)-Ru5 / C] was obtained. 10 -Ba2)-Ru5 / C] 20 -[MgAlSi].

[0082] [(Cs)] were loaded into a fixed-bed tubular reactor. 10 -Ba2)-Ru5 / C] 20 The ammonia decomposition to hydrogen production reaction was carried out using a [MgAlSi] catalyst at a reaction space velocity of 1500 h⁻¹. -1 The reaction temperature was 450℃, the reaction pressure was 0.6MPa, and the ammonia concentration was 10 vol.%.

[0083] Example 4

[0084] 0.041 g of ruthenium trichloride and 0.258 g of barium nitrate were weighed and dissolved in 4 mL of deionized water to form a mixed solution with a ruthenium ion concentration of 5 mg / mL and a barium ion concentration of 33.8 mg / mL. 1.0 g of activated carbon was added to the solution, and the mixture was magnetically stirred at room temperature for 12 hours. The resulting first suspension was vacuum dried at 80 °C for 12 hours, and the resulting black solid powder was placed in a porcelain boat. Reduction was performed at 600 °C for 5 hours in a tube furnace under a hydrogen-argon mixture atmosphere (10% hydrogen content) at a heating rate of 5 °C / min. 0.482 g of cesium nitrate was weighed and dissolved in 30 mL of deionized water, with a cesium ion concentration of 10.9 mg / mL. The reduced solid was placed in the solution and magnetically stirred at room temperature for 12 hours. The resulting second suspension was vacuum dried at 80 °C for 12 hours, yielding the [(Cs5-Ba2)-Ru2 / C] catalyst.

[0085] Weigh 1.0 g of [(Cs5-Ba2)-Ru2 / C], 1.0 g of magnesium oxide, and 0.1 g of polyethylene glycol PEG-300, add 5 mL of deionized water, and magnetically stir at room temperature for 12 hours to form a colloidal solution. Take a structured cordierite support with a diameter of 10 mm, a height of 50 mm, and a pore size of 1 mm, weighing 3.70 g. Weigh 0.74 g of the colloidal solution, place the cordierite support in the colloidal solution, and vacuum impregnate at room temperature for 2 hours. Then, turn the cordierite over and continue vacuum impregnation for another 2 hours. After impregnation, calcine the cordierite at 600 °C for 2 hours in a tube furnace under argon atmosphere at a heating rate of 5 °C / min. After cooling, remove the [(Cs5-Ba2)-Ru2 / C] solution. 20 -[MgAlSi].

[0086] [(Cs5-Ba2)-Ru2 / C] is loaded into a fixed-bed tubular reactor. 20 The ammonia decomposition to hydrogen production reaction was carried out using a [MgAlSi] catalyst at a reaction space velocity of 1500 h⁻¹. -1 The reaction temperature was 450℃, the reaction pressure was 0.6MPa, and the ammonia concentration was 10 vol.%.

[0087] Example 5

[0088] 0.102 g of ruthenium trichloride and 0.258 g of barium nitrate were weighed and dissolved in 10 mL of deionized water to form a mixed solution with a ruthenium ion concentration of 5 mg / mL and a barium ion concentration of 13.5 mg / mL. 1.0 g of activated carbon was added to the solution, and the mixture was magnetically stirred at room temperature for 12 hours. The resulting first suspension was vacuum dried at 80 °C for 12 hours, and the resulting black solid powder was placed in a porcelain boat. Reduction was performed at 600 °C for 5 hours in a tube furnace under a hydrogen-argon mixture atmosphere (10% hydrogen content) at a heating rate of 5 °C / min. 0.482 g of cesium nitrate was weighed and dissolved in 30 mL of deionized water, with a cesium ion concentration of 10.9 mg / mL. The reduced solid was placed in the solution and magnetically stirred at room temperature for 12 hours. The resulting second suspension was vacuum dried at 80 °C for 12 hours, yielding the [(Cs5-Ba2)-Ru5 / C] catalyst.

[0089] Weigh 1.0 g of [(Cs5-Ba2)-Ru5 / C], 1.0 g of magnesium oxide, and 0.1 g of polyethylene glycol PEG-300, add 5 mL of deionized water, and magnetically stir at room temperature for 12 hours to form a colloidal solution. Take a structured cordierite support with a diameter of 25 mm, a height of 50 mm, and a pore size of 1 mm, weighing 22.30 g. Weigh 6.69 g of the colloidal solution, place the cordierite support in the colloidal solution, and vacuum impregnate at room temperature for 2 hours. Then, turn the cordierite over and continue vacuum impregnation for another 2 hours. After impregnation, calcine the cordierite at 600 °C for 2 hours in a tube furnace under argon atmosphere at a heating rate of 5 °C / min. After cooling, remove the [(Cs5-Ba2)-Ru2 / C] solution. 30 -[MgAlSi].

[0090] [(Cs5-Ba2)-Ru2 / C] is loaded into a fixed-bed tubular reactor. 30 The ammonia decomposition to hydrogen production reaction was carried out using a [MgAlSi] catalyst at a reaction space velocity of 1500 h⁻¹. -1 The reaction temperature was 450℃, the reaction pressure was 0.6MPa, and the ammonia concentration was 10 vol.%.

[0091] Figure 6 The ammonia conversion rates of the modified ruthenium-based composite catalysts provided in Examples 1-5 of this invention are shown, for example... Figure 6 As shown, at a reaction space velocity of 1500 h⁻¹ -1 Under the conditions of a reaction temperature of 450℃, a reaction pressure of 0.6MPa, and an ammonia concentration of 10 vol.%, the ammonia conversion rate of the modified ruthenium-based composite catalysts provided in Examples 1-5 is not less than 95%.

[0092] Comparative Example 1

[0093] Weigh 0.102 g of ruthenium trichloride and dissolve it in 10 mL of deionized water to form a mixed solution with a ruthenium ion concentration of 5 mg / mL. Add 1.0 g of activated carbon to the solution and impregnate with magnetic stirring at room temperature for 12 hours. Dry the resulting suspension under vacuum at 80 °C for 12 hours, and place the resulting black solid powder in a porcelain boat. Reduce the powder in a tube furnace at 600 °C for 5 hours under a hydrogen-argon mixture atmosphere (10% hydrogen content) at a heating rate of 5 °C / min. The resulting catalyst is [Ru₅ / C].

[0094] Weigh 1.0 g [Ru5 / C], 1.0 g magnesium oxide, and 0.1 g polyethylene glycol PEG-300, add 5 mL of deionized water, and magnetically stir at room temperature for 12 hours to form a colloidal solution. Take a structured cordierite support with a diameter of 10 mm, a height of 50 mm, and a pore size of 1 mm, weighing 3.70 g. Weigh 0.74 g of the colloidal solution, place the cordierite support in the colloidal solution, and vacuum impregnate at room temperature for 2 hours. Then, turn the cordierite over and continue vacuum impregnation for another 2 hours. After impregnation, calcine the cordierite at 600 °C for 2 hours in a tube furnace under argon atmosphere at a heating rate of 5 °C / min. After cooling, remove the [Ru5 / C] solution. 20 -[MgAlSi].

[0095] [Ru5 / C] is loaded into a fixed-bed tubular reactor. 20 -[MgAlSi] undergoes ammonia decomposition to produce hydrogen, with a reaction space velocity of 1500 h⁻¹. -1 The reaction temperature was 450℃, the reaction pressure was 0.6MPa, and the ammonia concentration ranged from 10 vol.%.

[0096] Comparative Example 2

[0097] Ammonia decomposition for hydrogen production was carried out in a fixed-bed tubular reactor loaded with the structured cordierite support [MgAlSi] used in Comparative Example 1, with a reaction space velocity of 1500 h⁻¹. -1 The reaction temperature was 450℃, the reaction pressure was 0.6MPa, and the ammonia concentration ranged from 10 vol.%.

[0098] Figure 7 The ammonia conversion rate of the ammonia decomposition hydrogen production catalytic material provided in the comparative example of the present invention is shown, such as... Figure 7As shown in the comparison between Example 1 and Comparative Example 1, it can be seen that the modification of ruthenium-based catalysts with alkali metal cesium and alkaline earth metal barium can effectively improve the ammonia decomposition activity. This is mainly because the electron auxiliary agent cesium can effectively provide electrons to ruthenium particles, thereby facilitating the breaking of nitrogen-hydrogen bonds in ammonia; while the structural auxiliary agent barium helps to form more B5 active sites on ruthenium particles, which is beneficial for the adsorption of ammonia on ruthenium. Therefore, the ruthenium-based composite catalytic material based on structured cordierite proposed in this invention has excellent catalytic activity and stability, and can perform ammonia decomposition to hydrogen production under milder conditions (temperature 400-500℃, pressure 0.1-2MPa), demonstrating broad practical application prospects.

[0099] In summary, the modified ruthenium-based composite catalytic material [(Cs] provided by this invention... a -Ba b )-Ru c / C] d -[MgAlSi] exhibits good ammonia decomposition activity, achieving an ammonia conversion rate of over 90% under conditions of 400-500℃ and 0.1-2MPa.

[0100] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0101] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the present invention is not limited to the described order of actions, as some steps can be performed in other orders or simultaneously according to the present invention. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and components involved are not necessarily essential to the present invention.

[0102] The above provides a detailed description of the modified ruthenium-based composite catalytic material, its preparation method, and its applications. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. An application of a modified ruthenium-based composite catalytic material, characterized in that, The modified ruthenium-based composite catalyst was used for hydrogen production from ammonia decomposition. The modified ruthenium-based composite catalytic material consists of a ruthenium-based catalyst co-modified with cesium and barium salts, and a structured cordierite support. The molecular formula of the modified ruthenium-based composite catalytic material is: [(Csa-Bab)-Ruc / C]d-[MgAlSi]; where... [(Csa-Bab)-Ruc / C] represents a ruthenium-based catalyst supported on activated carbon and co-modified with cesium and barium salts. The electronic aid cesium and the structural aid alkaline earth barium modify the ruthenium carbon. [MgAlSi] represents a structured cordierite carrier; 'a' represents the molar percentage of cesium salt and metallic ruthenium, and 'a' ranges from 1 to 15. b represents the molar percentage of barium salt and metallic ruthenium, and b is between 0.5 and 5. c represents the mass percentage of metallic ruthenium to activated carbon, and c is between 0.5 and 10. d represents the mass percentage of the ruthenium-based catalyst supported on activated carbon and co-modified with cesium and barium salts to the structured cordierite support, and d ranges from 1 to 35.

2. The application of the modified ruthenium-based composite catalytic material according to claim 1, characterized in that, The value of a is 5-10; b is 1-2; The value of c is 1-5; The value of d is 20-30.

3. The application of the modified ruthenium-based composite catalytic material according to claim 1, characterized in that, The preparation method of the modified ruthenium-based composite catalytic material includes the following steps: S1. According to the molecular formula [(Csa-Bab)-Ruc / C] of the ruthenium-based catalyst supported by activated carbon and co-modified by cesium and barium salts, weigh out a predetermined amount of ruthenium trichloride and barium nitrate, dissolve them in deionized water to form a mixed solution, add a predetermined amount of activated carbon, and impregnate with magnetic stirring at room temperature for 5-15 h to form the first suspension. S2. After vacuum drying the first suspension at 25-90 °C for 2-12 h, the resulting black solid powder is transferred to a tube furnace and reduced at 500-600 °C for 2-5 h in a reducing atmosphere to obtain the reduced product. S3. Dissolve a predetermined amount of cesium nitrate in deionized water to obtain a cesium nitrate solution, then place the reduction product in the cesium nitrate solution and magnetically stir and soak at room temperature for 6-12 hours to form a second suspension. S4. The second suspension is vacuum dried at 25-90 °C for 2-12 h to obtain a ruthenium-based catalyst [(Csa-Bab)-Ruc / C] supported on activated carbon and co-modified with cesium and barium salts. S5. According to the molecular formula [(Csa-Bab)-Ruc / C]d-[MgAlSi] of the modified ruthenium-based composite catalyst, the [(Csa-Bab)-Ruc / C] is added to deionized water in a preset ratio with magnesium oxide and binder and mixed. The mixture is magnetically stirred at room temperature for 2-12 h to form a colloidal solution. Then, the structured cordierite is impregnated in the colloidal solution and vacuum impregnated at room temperature for 2-10 h. The impregnated structured cordierite is transferred to a tube furnace and calcined at 500-600 ℃ for 2-5 h under an inert atmosphere. After cooling, the material is removed to obtain the modified ruthenium-based composite catalyst [(Csa-Bab)-Ruc / C]d-[MgAlSi].

4. The application of the modified ruthenium-based composite catalytic material according to claim 3, characterized in that, In the mixed solution, the concentration of ruthenium ions is 5-10 mg / mL, and the concentration of barium ions is 5-50 mg / mL; The cesium ion concentration in the cesium nitrate solution is 5-50 mg / mL.

5. In the application of the modified ruthenium-based composite catalytic material according to claim 3, the binder is polyethylene glycol, hydroxymethyl cellulose, or hydroxyethyl cellulose.

6. The application of the modified ruthenium-based composite catalytic material according to claim 3, characterized in that, The magnesium oxide accounts for 10-20% of the mass of the colloidal solution; The binder accounts for 1-2% of the mass of the colloidal solution; The [(Csa-Bab)-Ruc / C] constitutes 5-10% of the mass of the colloidal solution.

7. The application of the modified ruthenium-based composite catalytic material according to claim 3, characterized in that, The structured cordierite has a pore size between 0.5 and 2 mm, a radial diameter between 10 and 200 mm, and a height between 20 and 300 mm.

8. The application of the modified ruthenium-based composite catalytic material according to claim 1, characterized in that, The method of using the modified ruthenium-based composite catalyst for ammonia decomposition to produce hydrogen includes: after loading the modified ruthenium-based composite catalyst into a fixed-bed reactor, ammonia gas is introduced to carry out the ammonia decomposition to produce hydrogen reaction; The reaction space velocity of the ammonia gas is 1000-20000 h⁻¹. -1 The reaction temperature is 300-500 ℃ and the reaction pressure is 0.1-5 MPa.

9. The application of the modified ruthenium-based composite catalytic material according to claim 1 or 8, characterized in that, The concentration of ammonia gas participating in the ammonia decomposition to hydrogen production reaction is 10-100 vol.%.

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