A supported catalyst with low noble metal content, its preparation method and application
By controlling the impregnation depth and distribution uniformity of the catalyst, a supported catalyst with low precious metal content was prepared, solving the problem of high precious metal usage and achieving high catalytic efficiency and low-cost hydrogen production performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- INSTITUTE OF PROCESS ENGINEERING CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2025-01-06
- Publication Date
- 2026-05-26
AI Technical Summary
In existing technologies, the loading of the precious metal platinum is relatively high, resulting in low hydrogen production efficiency per unit mass of platinum. This leads to high catalyst costs and limits the application of dibenzyltoluene in hydrogen storage and release technologies.
By controlling the impregnation depth and distribution uniformity of the catalyst, using a supported catalyst with low precious metal content, including 0.2–0.4 wt% of active components, and combining rotary evaporation and reduction treatment, the catalyst preparation method is optimized to improve the utilization rate of active components.
It achieves efficient catalysis under low precious metal content conditions, reduces catalyst cost, and improves hydrogen production efficiency per unit mass of precious metal, reaching a dehydrogenation degree similar to that with high precious metal content.
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Figure CN119793447B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic catalysis technology, and in particular to a supported catalyst with low noble metal content, its preparation and application. Background Technology
[0002] Hydrogen energy is a clean energy source with zero carbon emissions. The development of hydrogen storage and transportation technology plays a crucial role in realizing the application of hydrogen energy. Hydrogen storage and transportation mainly includes solid-state hydrogen storage, high-pressure gaseous hydrogen storage, and organic liquid hydrogen storage. Organic liquid hydrogen storage technology is an emerging hydrogen energy storage and transportation method, possessing advantages such as convenient transportation, high hydrogen storage density, and high safety, and holds promise for solving the current challenges of long-distance hydrogen transportation. Organic liquid hydrogen storage technology utilizes a reversible chemical reaction between a liquid-phase organic hydrogen carrier and hydrogen under the action of a catalyst to generate alkane compounds, thereby achieving hydrogen storage and release. Liquid-phase organic hydrogen carriers currently under research include cycloalkanes, carbazoles, and N-heterocyclic compounds. Among them, dibenzyltoluene has become a highly promising liquid-phase organic hydrogen carrier due to its advantages such as high hydrogen storage density, low cost (commonly used in industrial heat transfer oils), non-flammability, non-explosiveness, low volatility, and low melting point.
[0003] Currently, perhydrodibenzyltoluene typically undergoes dehydrogenation using platinum-based catalysts, which suffers from low dehydrogenation efficiency and high cost. A continuous fixed-bed reactor is employed at 300°C with a liquid hourly space velocity (LHSV) of 1 h⁻¹. -1 Under certain conditions, the CeO2-supported platinum catalyst can achieve a maximum perhydrodibenzyltoluene conversion of 95% (International Journal of Hydrogen Energy, 2021, 46(7), 5520). However, the amount of platinum used reaches 5 wt%, increasing the cost of the catalyst. At 280 °C, the liquid space velocity is 1 h⁻¹. -1 Under the given reaction conditions, the degree of dehydrogenation of dibenzyltoluene using a standard 0.5% Pt / Al2O3 catalyst (purchased from Sigma-Aldrich) was only 38.0%, and a degree of dehydrogenation of 60% could only be achieved when the reaction temperature was increased to 340℃ (Energy Conversion and Management, 2021, 239(1), 114124). In summary, platinum-based catalysts suffer from problems such as low dehydrogenation activity or high platinum content, which limit the use of dibenzyltoluene in hydrogen storage and release technologies.
[0004] In summary, existing technologies suffer from high platinum loading and low hydrogen production efficiency per unit mass of platinum, which hinders industrial applications. Therefore, the hydrogen production efficiency per unit mass of platinum on the catalyst still needs improvement, and achieving high-efficiency hydrogen production with low platinum loading has become an urgent problem to be solved. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention develops a highly efficient and low-cost catalyst for dehydrogenation of liquid-phase organic hydrogen supports, solving the problems of high precious metal content and high cost in current precious metal-based dehydrogenation catalysts.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] In a first aspect, the present invention provides a supported catalyst with low noble metal content, the supported catalyst comprising a catalyst support and an active component, wherein the content of the active component is 0.2 to 0.4 wt%, for example, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, or 0.4 wt%, etc., and the relative impregnation depth of the active component is 0.05 to 0.16, for example, 0.05, 0.1, 0.12, 0.14, or 0.16, etc., wherein the relative impregnation depth is the ratio of the impregnation depth to the particle radius of the catalyst support.
[0008] This invention improves the uniformity of active component distribution on the catalyst by controlling the impregnation depth of the catalyst, promotes the effective utilization of active components on the catalyst support, solves the technical problem of high cost due to high precious metal content in existing catalysts, and achieves high-efficiency catalysis with low precious metal content.
[0009] Preferably, the active component includes platinum.
[0010] Preferably, the catalyst support includes alumina, silicon dioxide, activated carbon, zirconium oxide, titanium dioxide, or molecular sieve.
[0011] Preferably, the particle size of the catalyst support is 2 to 4 mm, for example, it can be 2 mm, 2.5 mm, 3 mm, 3.5 mm or 4 mm.
[0012] Preferably, the impregnation depth of the active component is 0.1 to 0.32 mm, for example, it can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm or 0.32 mm.
[0013] By optimizing the particle size of the catalyst support, the fixed bed filled with the catalyst of the present invention has a suitable pressure drop and catalyst specific surface area. By optimizing the impregnation depth of the active component, the active material on the surface of the catalyst of the present invention has a good distribution state, thereby improving the utilization rate of the surface active material.
[0014] Secondly, the present invention provides a method for preparing the supported low-noble-metal content catalyst described in the first aspect, the method comprising the following steps:
[0015] (1) Spray the precursor solution of the active component evenly onto the surface of the catalyst support and impregnate it at room temperature;
[0016] (2) The impregnated catalyst support is rotary evaporated to remove the solvent and obtain the precursor support;
[0017] (3) The precursor support is dried and calcined in sequence to obtain the supported catalyst with low precious metal content.
[0018] Preferably, the precursor solution is a mixed solution of a noble metal precursor dissolved in an organic solvent and pure water.
[0019] Preferably, the noble metal precursor includes chloroplatinic acid.
[0020] Preferably, the volume content of the organic solvent in the mixed solution is 5% to 80%, for example, it can be 5%, 10%, 20%, 60% or 80%.
[0021] Preferably, the organic solvent includes ethanol.
[0022] Preferably, the soaking time is 0.2 to 10 hours, for example, 0.2 hours, 1 hour, 4 hours, 8 hours or 10 hours.
[0023] The method for preparing supported catalysts with low noble metal content provided by the present invention preferably uses a stirring and impregnation time of 0.2 to 10 hours. This allows the catalyst prepared by the present invention to have an appropriate impregnation depth, avoiding situations where the impregnation time is too short, resulting in insufficient impregnation and uneven loading of the precursor, or where the impregnation time is too long, resulting in excessive impregnation depth and difficulty in efficiently utilizing the internal active materials during the catalytic process.
[0024] Preferably, the pressure of the rotary evaporation is -0.10 to -0.05 MPa, for example, it can be -0.10 MPa, -0.09 MPa, -0.08 MPa, -0.07 MPa, -0.06 MPa or -0.05 MPa, etc.
[0025] Preferably, the temperature of the rotary evaporation is 30 to 80°C, for example, it can be 30°C, 40°C, 50°C, 60°C, 70°C or 80°C.
[0026] Preferably, the rotary evaporation time is 10 to 30 minutes, for example, 10 minutes, 15 minutes, 20 minutes, 25 minutes, or 30 minutes.
[0027] This invention employs a rotary evaporator to rapidly remove solvent at a low temperature under negative pressure. This avoids the aggregation of precursor molecules located at different adsorption sites due to the solvent during drying or calcination, which would otherwise cause a large agglomeration of noble metal atoms on the surface of the calcined catalyst, resulting in low dispersion and low utilization of active atoms in the catalyst. At the same time, the rapid removal of solvent by rotary evaporation allows for more precise control of the impregnation depth by adjusting the impregnation time, avoiding excessively deep impregnation caused by excessively long solvent removal time.
[0028] Preferably, the drying temperature is 100-120°C, for example, 100°C, 105°C, 110°C, 115°C or 120°C.
[0029] Preferably, the drying time is 10 to 20 hours, for example, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, or 20 hours.
[0030] Preferably, the calcination temperature is 400-700℃, for example, it can be 400℃, 450℃, 500℃, 550℃, 600℃ or 700℃.
[0031] Preferably, the calcination time is 3 to 6 hours, for example, 3 hours, 3.5 hours, 4 hours, 5 hours or 6 hours.
[0032] Preferably, the supported catalyst with low precious metal content is subjected to reduction treatment before use.
[0033] Preferably, the reduction process uses hydrogen or a mixture of hydrogen and nitrogen as the reducing gas.
[0034] Preferably, the hydrogen content of the reducing gas is 10% to 100%, for example, it can be 10%, 40%, 60%, 80% or 100%.
[0035] Preferably, the volume hourly space velocity (VHSV) of the reducing gas is 500–2000 h⁻¹. -1 For example, it could be 500h -1 800h -1 1000h -1 1500h -1 or 2000h -1 wait.
[0036] Preferably, the pressure of the reduction treatment is 0.1 to 1.0 MPa, for example, it can be 0.1 MPa, 0.2 MPa, 0.4 MPa, 0.8 MPa or 1.0 MPa.
[0037] Preferably, the temperature of the reduction treatment is 200 to 600°C, for example, 200°C, 300°C, 400°C, 500°C or 600°C.
[0038] Preferably, the heating rate of the reduction treatment is 1 to 10 °C / min, for example, it can be 1 °C / min, 2 °C / min, 5 °C / min, 8 °C / min or 10 °C / min.
[0039] Preferably, the reduction time is 0.5 to 5 hours, for example, it can be 0.5 hours, 1 hour, 2 hours, 4 hours or 5 hours.
[0040] Thirdly, the present invention provides an application of the supported low-noble-metal-content catalyst described in the first aspect, the application including dehydrogenation of a liquid organic hydrogen storage carrier.
[0041] Preferably, the liquid organic hydrogen storage carrier includes any one of perhydrodibenzyltoluene, perhydromonobenzyltoluene, methylcyclohexane, decahydronaphthalene, or bicyclohexane, with perhydrodibenzyltoluene being the most preferred.
[0042] Preferably, the method for dehydrogenating the liquid organic hydrogen storage carrier includes:
[0043] Liquid organic hydrogen storage carriers are subjected to catalytic dehydrogenation in a fixed-bed reactor packed with a supported catalyst of low precious metal content to obtain dehydrogenation products.
[0044] Preferably, the reaction temperature of the catalytic dehydrogenation reaction is 250-350°C, for example, it can be 250°C, 280°C, 300°C, 320°C or 350°C.
[0045] Preferably, the amount of the supported catalyst with low precious metal content is 5 to 100g, for example, 5g, 10g, 20g, 40g, 60g, 80g or 100g.
[0046] Preferably, the mass hourly space velocity (MSV) of the liquid organic hydrogen storage carrier is 0.1–20 h⁻¹. -1 For example, it could be 0.1h -1 1h -1 2h -1 10h -1 or 20h -1 wait.
[0047] Compared with the prior art, the present invention has at least the following beneficial effects:
[0048] This invention provides a supported catalyst with low precious metal content for use in the dehydrogenation reaction of liquid hydrogen carriers. Compared with high precious metal content dehydrogenation catalysts, the low precious metal content catalyst of this invention can achieve a similar degree of dehydrogenation under the same catalyst loading and reaction conditions. Overall, the efficiency of hydrogen production per unit mass of precious metal is significantly improved, and the cost of dehydrogenation catalysts is reduced. Attached Figure Description
[0049] Figure 1 This is a distribution diagram of platinum in the supported catalyst with low noble metal content prepared in Example 1. Detailed Implementation
[0050] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.
[0051] Example 1
[0052] This embodiment provides a supported catalyst with low noble metal content. The catalyst support is alumina, the active component is platinum with a platinum loading of 0.25 wt%, the alumina particle size is 3 mm, and the platinum impregnation depth is 0.2 mm. The catalyst is prepared by an impregnation method, and the specific preparation steps include:
[0053] 0.66 g of chloroplatinic acid was dissolved in a 100 mL mixture of ethanol and water (ethanol volume ratio 50%). This solution was then sprayed onto a 100 g alumina support. After impregnation at room temperature for 4 h, the solution was transferred to a rotary evaporator and dried under vacuum conditions at 55 °C for 20 min in a water bath. The solvent was then removed, followed by drying in a 120 °C oven for 12 h, and finally calcined in a muffle furnace at 500 °C for 4 h. The platinum elemental distribution of the prepared supported catalyst is shown below. Figure 1 As shown, the alumina spheres have a particle size of 3 mm, and platinum is distributed within a depth of 0.2 mm on the outer layer of the alumina spheres.
[0054] Prior to the reaction, the catalyst was reduced and activated in situ using hydrogen in a fixed-bed reactor. The specific conditions were: 7g of catalyst was packed, a mixture of nitrogen and hydrogen was used as the feed gas (hydrogen volume content 50%), and the gas hourly space velocity (GHSV) of the mixture was 2000 h⁻¹. -1 The reduction reaction pressure was 0.1 MPa, the reduction temperature was 300℃, the reduction temperature was programmed and the heating rate was controlled at 2℃ / min, and the reduction time was 1 h.
[0055] Example 2
[0056] This embodiment provides a supported catalyst with low noble metal content. The catalyst support is alumina, the active component is platinum, the platinum loading is 0.2 wt%, the alumina particle size is 2 mm, and the platinum impregnation depth is 0.1 mm. The catalyst is prepared by an impregnation method, and the specific preparation steps include:
[0057] 0.53 g of chloroplatinic acid was dissolved in a 100 mL mixture of ethanol and water, with ethanol accounting for 5% by volume. The solution was then sprayed onto a 100 g alumina support and impregnated at room temperature for 0.5 h. The solution was then transferred to a rotary evaporator and vacuumed with a water pump. The solvent was removed by heating in a water bath at 50 °C for 30 min. The solution was then dried in an oven at 100 °C for 20 h and calcined in a muffle furnace at 400 °C for 6 h.
[0058] Prior to the reaction, the catalyst was reduced and activated in situ using hydrogen in a fixed-bed reactor. The specific conditions were: 5g of catalyst was loaded, a mixture of nitrogen and hydrogen was used as the feed gas (hydrogen volume content 10%), and the gas hourly space velocity (GHSV) of the mixture was 500 h⁻¹. -1 The reduction reaction pressure was 0.5 MPa, the reduction temperature was 200℃, the reduction temperature was programmed and the heating rate was controlled at 1℃ / min, and the reduction time was 5h.
[0059] Example 3
[0060] This embodiment provides a supported catalyst with low noble metal content. The catalyst support is alumina, the active component is platinum, the platinum loading is 0.4 wt%, the alumina particle size is 4 mm, and the platinum impregnation depth is 0.32 mm. The catalyst is prepared by an impregnation method, and the specific preparation steps include:
[0061] 1.06 g of chloroplatinic acid was dissolved in a 100 mL mixture of ethanol and water, with ethanol accounting for 5% by volume. The solution was then sprayed onto an alumina support and impregnated at room temperature for 10 h. The solution was then transferred to a rotary evaporator and vacuumed with a water pump. The solvent was removed by heating in a water bath at 80 °C for 10 min. The solution was then dried in an oven at 110 °C for 3 h and finally calcined in a muffle furnace at 700 °C for 3 h.
[0062] Prior to the reaction, the catalyst was reduced and activated in situ using hydrogen in a fixed-bed reactor. The specific conditions were: 100g of catalyst was packed, hydrogen was used as the feedstock, and the volume hourly space velocity (VHSV) was 1000h⁻¹. -1 The reduction reaction pressure was 1 MPa, the reduction temperature was 600℃, the reduction temperature was programmed and the heating rate was controlled at 10℃ / min, and the reduction time was 0.5h.
[0063] Example 4
[0064] This embodiment is the same as Example 1, except that rotary evaporation is not performed after impregnation of the catalyst support.
[0065] Example 5
[0066] Except for the rotary evaporation temperature of 25°C, this embodiment is the same as that in Example 1.
[0067] Example 6
[0068] Except for the rotary evaporation temperature of 90°C, this embodiment is the same as Example 1.
[0069] Comparative Example 1
[0070] This comparative example is identical to Example 1 except that the platinum loading is 1.0 wt%.
[0071] Comparative Example 2
[0072] Except for the immersion time of 0.1 hours and the immersion depth of 0.05 mm, this comparative example is the same as Example 1.
[0073] Comparative Example 3
[0074] Except for the immersion time of 24 hours and the immersion depth of 0.6 mm, this comparative example is the same as Example 1.
[0075] Application Example 1
[0076] This application example provides a method for applying the supported low-noble-metal-content catalyst to dehydrogenation of a liquid organic hydrogen storage carrier. The method includes: directly carrying out the dehydrogenation reaction in a fixed-bed reactor after reduction, using perhydrodibenzyltoluene (active component ≥98%) as the reactant, at atmospheric pressure, at a reaction temperature of 290°C, and at a liquid hourly space velocity of 3.0 h⁻¹. -1 The supported catalyst with low noble metal content is the catalyst prepared in Example 1.
[0077] Application Example 2
[0078] This application example provides a method for applying the supported low-noble-metal-content catalyst to dehydrogenation of a liquid organic hydrogen storage carrier. The method includes: carrying out the dehydrogenation reaction directly in a fixed-bed reactor after reduction, using perhydrodibenzyltoluene (active ingredient ≥98%) as the reactant, at atmospheric pressure, at a reaction temperature of 270°C, and at a liquid hourly space velocity (LHSV) of 1 h⁻¹. -1 The supported catalyst with low noble metal content is the catalyst prepared in Example 1.
[0079] Application Example 3
[0080] This application example provides a method for applying the supported low-noble-metal-content catalyst to dehydrogenation of a liquid organic hydrogen storage carrier. The method includes: carrying out the dehydrogenation reaction directly in a fixed-bed reactor after reduction, using perhydrodibenzyltoluene (active ingredient ≥98%) as the reactant, at atmospheric pressure, at a reaction temperature of 350°C, and at a liquid hourly space velocity of 20 h⁻¹. -1 The supported catalyst with low noble metal content is the catalyst prepared in Example 1.
[0081] Application Example 4
[0082] Except for the supported low-noble-metal-content catalyst used, which is the catalyst prepared in Example 2, all other aspects of this application example are the same as those in Application Example 1.
[0083] Application Example 5
[0084] Except for the supported low-noble-metal-content catalyst used, which is the catalyst prepared in Example 3, all other aspects of this application example are the same as those in Application Example 1.
[0085] Application Example 6
[0086] Except for the supported low-noble-metal-content catalyst used, which is the catalyst prepared in Example 4, all other aspects of this application example are the same as those in Application Example 1.
[0087] Application Example 7
[0088] Except for the supported low-noble-metal-content catalyst used, which is the catalyst prepared in Example 5, all other aspects of this application example are the same as those in Application Example 1.
[0089] Application Example 8
[0090] Except for the supported low-noble-metal-content catalyst used, which is the catalyst prepared in Example 6, all other aspects of this application example are the same as those in Application Example 1.
[0091] Application Comparative Example 1
[0092] Except for the fact that the supported low-noble-metal-content catalyst used in this application example is the catalyst prepared in Comparative Example 1, everything else is the same as in Application Example 1.
[0093] Application Comparative Example 2
[0094] Except for the fact that the supported low-noble-metal-content catalyst used in this application example is the catalyst prepared in Comparative Example 2, everything else is the same as in Application Example 1.
[0095] Application Comparative Example 3
[0096] Except for the fact that the supported low-noble-metal-content catalyst used in this application example is the catalyst prepared in Comparative Example 3, everything else is the same as in Application Example 1.
[0097] Test methods
[0098] The real-time rate of hydrogen gas is monitored online using a flow meter.
[0099] Test Standards
[0100] Dehydrogenation degree = Real-time hydrogen production rate / Theoretical maximum hydrogen production rate
[0101] Theoretical maximum hydrogen production rate (mL / min) = (feed mass flow rate / feed molar mass) * 9 * 22.4 * 1000
[0102] hydrogen space-time yield (g) H2 / g 铂 / h) = Hydrogen production rate / Mass of platinum in catalyst = Liquid hourly space velocity * Degree of dehydrogenation * 9 * 2 / Molecular weight of perhydrodibenzyltoluene / Platinum loading
[0103] The test results are shown in Table 1:
[0104] Table 1
[0105]
[0106]
[0107] The test results show that:
[0108] (1) As can be seen from Application Examples 1 and 4-5, by controlling the impregnation depth and distribution uniformity of the active component on the catalyst support, the present invention can achieve high-efficiency utilization of the active component. Under the condition of low noble metal active component content, it can achieve a catalytic effect similar to that of high noble metal content, and a noble metal utilization rate per unit mass that is much higher than that of high noble metal content. At a reaction temperature of 290°C, its hydrogen space-time yield can reach 20 h⁻¹. -1 above.
[0109] (2) As can be seen from Application Examples 1 and 2-3, the supported low-noble-metal content catalyst provided by the present invention retains the characteristic that the catalytic effect is affected by the reaction temperature, and it can maintain good catalytic effect in the range of 270℃ to 350℃. Its hydrogen space-time yield is maintained at 12.7h at 270℃. -1 At 350℃, it reaches as high as 165.0h. -1 .
[0110] (2) As can be seen from Application Examples 1 and 6-8, the present invention can achieve better precious metal distribution by rapidly removing the impregnation solvent under negative pressure and low temperature conditions using a rotary evaporator. Rapid solvent removal at low temperature avoids precious metal agglomeration caused by the solvent during evaporation. When rotary evaporation is not used to remove the solvent or the rotary evaporation temperature is too low, the solvent cannot be completely removed, and precious metal agglomeration occurs in the next drying process. The hydrogen space-time yield is reduced from 30.8 h in Application Example 1. -1 It decreased to 15.7h in application example 6. -1 And application example 7, 18.2h -1 When the rotary evaporation temperature is too high, the precious metals agglomerate during the process, and the hydrogen space-time yield decreases from 30.8 h⁻¹ in Application Example 1. -1It decreased to 11.8h in application example 8. -1 .
[0111] (3) As can be seen from Application Example 1 and Comparative Application Example 1, compared with the high-noble-metal dehydrogenation catalyst, the supported low-noble-metal content catalyst provided by the present invention can achieve a similar degree of dehydrogenation under the same catalyst loading and reaction conditions. The degree of dehydrogenation decreased by only 4.3% from 45.2% in the comparative application example to 40.9% in application example 1. The hydrogen space-time yield, which characterizes the dehydrogenation efficiency per unit mass of noble metal, was significantly improved from 8.5 h⁻¹. -1 Increased to 30.8h -1 This significantly reduces the cost of dehydrogenation catalysts.
[0112] (4) As can be seen from Application Example 1 and Comparative Examples 2-3, the present invention controls the impregnation depth of the active material on the catalyst support surface by optimizing the impregnation time, thereby improving the utilization rate of the active material while ensuring a suitable loading of the active material. When the impregnation time is too short, the precursor solution is not evenly distributed on the catalyst surface due to insufficient impregnation, resulting in severe aggregation of the active component Pt on the catalyst, and the hydrogen space-time yield decreases from 30.8 h in Application Example 1. -1 It decreased to 23.5h in Comparative Example 2. -1 When the impregnation time is too long, the impregnation depth is too deep, resulting in a low utilization rate of the active material Pt inside the carrier, and the hydrogen space-time yield decreases from 30.8 h in Application Example 1. -1 It decreased to 21.3h in Comparative Example 3. -1 .
[0113] In summary, this invention provides a supported catalyst with low noble metal content. By controlling the impregnation depth and distribution of its active components through the preparation method, the hydrogen production efficiency per unit mass of noble metal is improved. Compared with high-noble metal dehydrogenation catalysts, the low-load noble metal catalyst of this invention can achieve a similar degree of dehydrogenation under the same catalyst loading and reaction conditions. Overall, using the low-load catalyst described in this invention can significantly reduce the cost of dehydrogenation catalysts.
[0114] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.
Claims
1. A supported catalyst with low noble metal content, characterized in that, The supported low-precious-metal-content catalyst includes a catalyst support and an active component, wherein the content of the active component is 0.2~0.4wt%, and the relative impregnation depth of the active component is 0.1~0.16, wherein the relative impregnation depth is the ratio of the impregnation depth to the particle radius of the catalyst support. The supported catalyst with low noble metal content is prepared by a method comprising the following steps: (1) Spray the precursor solution of the active component evenly onto the surface of the catalyst support and impregnate it at room temperature for 0.5~10h; (2) The impregnated catalyst support is rotary evaporated, and the rotary evaporation temperature is controlled at 30~80℃, the pressure is -0.10~-0.05MPa, and the time is 10~30min. The solvent is removed to obtain the precursor support. (3) The precursor support is successively dried and calcined to obtain the supported catalyst with low precious metal content; The active component is platinum; The impregnation depth of the active component is 0.1~0.32 mm.
2. The supported catalyst with low noble metal content according to claim 1, characterized in that, The catalyst support includes alumina, silicon dioxide, activated carbon, zirconium oxide, titanium dioxide, or molecular sieve.
3. A method for preparing the supported low-noble-metal content catalyst according to claim 1 or 2, characterized in that, The method includes the following steps: (1) Spray the precursor solution of the active component evenly onto the surface of the catalyst support and impregnate it at room temperature for 0.5~10h; (2) The impregnated catalyst support is rotary evaporated, and the rotary evaporation temperature is controlled at 30~80℃, the pressure is -0.10~-0.05MPa, and the time is 10~30min. The solvent is removed to obtain the precursor support. (3) The precursor support is successively dried and calcined to obtain the supported catalyst with low precious metal content; The active component is platinum; The impregnation depth of the active component is 0.1~0.32 mm.
4. The method according to claim 3, characterized in that, The precursor solution is a mixed solution of a noble metal precursor dissolved in an organic solvent and pure water; The noble metal precursor is chloroplatinic acid.
5. The method according to claim 4, characterized in that, The organic solvent includes ethanol.
6. The method according to claim 4, characterized in that, The volume content of organic solvent in the mixed solution is 5-80%.
7. The method according to claim 3, characterized in that, The drying temperature is 100~120℃.
8. The method according to claim 3, characterized in that, The drying time is 10-20 hours.
9. The method according to claim 3, characterized in that, The calcination temperature is 400~700℃.
10. The method according to claim 3, characterized in that, The calcination time is 3-6 hours.
11. The method according to claim 3, characterized in that, The supported catalyst with low precious metal content is subjected to reduction treatment before use.
12. The method according to claim 11, characterized in that, The reduction process uses hydrogen or a mixture of hydrogen and nitrogen as the reducing gas.
13. The method according to claim 12, characterized in that, The hydrogen content of the reducing gas is 10-100%.
14. The method according to claim 12, characterized in that, The volume hourly space velocity of the reducing gas is 500~2000 h⁻¹. -1 .
15. The method according to claim 11, characterized in that, The pressure of the reduction process is 0.1~1.0 MPa.
16. The method according to claim 11, characterized in that, The reduction treatment temperature is 200~600℃.
17. The method according to claim 11, characterized in that, The heating rate of the reduction treatment is 1~10℃ / min.
18. The method according to claim 11, characterized in that, The reduction process takes 0.5 to 5 hours.
19. The application of a supported low-noble-metal content catalyst as described in claim 1 or 2, characterized in that, The application includes dehydrogenation of liquid organic hydrogen storage carriers.
20. The application of the supported low-noble-metal content catalyst according to claim 19, characterized in that, The liquid organic hydrogen storage carrier includes any one of perhydrodibenzyltoluene, perhydromonobenzyltoluene, methylcyclohexane, decahydronaphthalene, or bicyclohexane.
21. The application of the supported low-precious-metal-content catalyst according to claim 20, characterized in that, The liquid organic hydrogen storage carrier is perhydrodibenzyltoluene.
22. The application of the supported low-precious-metal content catalyst according to claim 19, characterized in that, The method for dehydrogenating the liquid organic hydrogen storage carrier includes: A liquid organic hydrogen storage carrier is passed into a fixed-bed reactor filled with a supported catalyst of low precious metal content as described in claim 1 or 2 to carry out a catalytic dehydrogenation reaction and obtain dehydrogenation products.
23. The application of the supported low-precious-metal content catalyst according to claim 22, characterized in that, The temperature of the catalytic dehydrogenation reaction is 250~350℃.
24. The application of the supported low-precious-metal content catalyst according to claim 22, characterized in that, The amount of the supported catalyst with low precious metal content is 5~100g.
25. The application of the supported low-precious-metal content catalyst according to claim 22, characterized in that, The mass hourly space velocity (MSV) of the liquid organic hydrogen storage carrier is 1–20 h⁻¹. -1 .