A bimetallic catalyst, its preparation method and use

Abstract

The application provides a bimetallic catalyst and a preparation method and application thereof. The bimetallic catalyst comprises a carrier loaded with metal A and platinum, wherein the metal A is selected from any one or a combination of at least two of molybdenum, vanadium, rhenium, lanthanum or cerium. The preparation method comprises the following steps: (1) first impregnating a metal A-containing precursor solution on a carrier to obtain a first catalyst precursor through first calcination, wherein the metal A is selected from any one or a combination of at least two of molybdenum, vanadium, rhenium, lanthanum or cerium; (2) second impregnating a platinum-containing precursor solution on the first catalyst precursor in step (1) to obtain a second catalyst precursor through second calcination; and (3) performing reduction treatment on the second catalyst precursor in step (2) to obtain the bimetallic catalyst. The bimetallic catalyst prepared by the application can significantly improve the dehydrogenation degree of organic liquid in a continuous fixed bed reactor.

Description

Technical Field

[0001] This invention belongs to the field of catalyst materials, and relates to a bimetallic catalyst, its preparation method, and its 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 include 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, non-volatility, non-toxicity, and low melting point.

[0003] Currently, perhydrodibenzyltoluene typically uses a single-metal platinum-based catalyst, which suffers from problems such as low dehydrogenation efficiency and high cost.

[0004] The International Journal of Hydrogen Energy, 2021, 46(7), 5520, disclosed that using a continuous fixed-bed reactor, a CeO2-supported Pt catalyst can achieve a maximum conversion rate of 95% for dibenzyltoluene at 300°C. However, the amount of Pt used reached 5 wt%, which increased the cost of the catalyst.

[0005] Energy Conversion and Management, 2021, 239(1), 114124 discloses that the degree of dehydrogenation of dibenzyltoluene on an Al2O3-supported Pt-based catalyst is below 80% at a temperature of 300 °C.

[0006] In the existing disclosed technologies, the degree of dehydrogenation of dibenzyltoluene on catalysts containing 1 wt% Pt is less than 80% at temperatures below 300°C, which limits the use of dibenzyltoluene in hydrogen storage and release technologies.

[0007] Therefore, how to prepare a bimetallic catalyst that can significantly improve the dehydrogenation degree of organic liquid in a continuous fixed-bed reactor is an important research direction in this field. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a bimetallic catalyst that can significantly improve the dehydrogenation degree of organic liquid in a continuous fixed-bed reactor, as well as its preparation method and application.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] One objective of this invention is to provide a bimetallic catalyst comprising a support loaded with metal A and platinum, wherein metal A is selected from any one or a combination of at least two of molybdenum, vanadium, rhenium, lanthanum or cerium.

[0011] This invention provides a bimetallic catalyst, which is a support loaded with metal A and platinum. Bimetallic A promotes the dispersion of platinum, while the introduction of a second metal, such as molybdenum, vanadium, rhenium, lanthanum, or cerium, forms a "platinum-metal A" interface around the platinum nanoparticles. The dehydrogenation activity of perhydrodibenzyltoluene is higher at this interface. Therefore, the addition of metal A can enhance the dehydrogenation performance of perhydrodibenzyltoluene in a continuous fixed-bed reactor using the bimetallic catalyst. In a continuous fixed-bed reactor at a reaction temperature of 290°C, compared with a single-metal platinum-based dehydrogenation catalyst, the bimetallic catalyst of this invention can increase the degree of dehydrogenation by 5-20%, and the degree of dehydrogenation of dibenzyltoluene can reach over 80%. Using the bimetallic catalyst described in this invention can significantly improve the dehydrogenation efficiency of dibenzyltoluene.

[0012] As a preferred embodiment of the present invention, the compound containing metal A in the bimetallic catalyst includes any one of molybdenum oxide, vanadium oxide, rhenium oxide, lanthanum oxide, cerium oxide, or chromium oxide.

[0013] Preferably, in the bimetallic catalyst, the platinum-containing compound includes platinum oxide.

[0014] Preferably, the carrier comprises any one or a combination of at least two of alumina, silicon dioxide, activated carbon, zirconium oxide, titanium dioxide, or molecular sieve.

[0015] Preferably, the loading of metal A in the bimetallic catalyst is 0.01 to 30 wt%, wherein the loading can be 0.01 wt%, 0.5 wt%, 1 wt%, 2 wt%, 4 wt%, 6 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 16 wt%, 18 wt%, 20 wt%, 22 wt%, 24 wt%, 26 wt%, 28 wt%, or 30 wt%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0.05 to 20 wt%.

[0016] In this invention, if the loading of metal A in the bimetallic catalyst is too high, the particle size of metal A will be too large, and it will be unable to form an effective "platinum-metal A" interface with platinum; if the loading is too low, there will be too few "platinum-metal A" interfaces, and there will be no significant promoting effect.

[0017] Preferably, the platinum loading in the bimetallic catalyst is 0.1 to 5.0 wt%, wherein the loading can be 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0.2 to 3 wt%.

[0018] In this invention, excessively high platinum loading in the bimetallic catalyst not only leads to excessively high catalyst costs, but also causes excessively large platinum nanoparticle sizes, resulting in reduced dehydrogenation reaction activity; conversely, excessively low platinum loading in the bimetallic catalyst leads to excessively low dehydrogenation activity per unit mass of catalyst, rendering it impractical.

[0019] A second objective of this invention is to provide a method for preparing a bimetallic catalyst as described in one objective, the method comprising the following steps:

[0020] (1) The precursor solution containing metal A is first impregnated onto the support and then calcined to obtain the first catalyst precursor. The metal A is selected from any one or at least a combination of two of molybdenum, vanadium, rhenium, lanthanum or cerium.

[0021] (2) The platinum-containing precursor solution is second-impregnated onto the first catalyst precursor in step (1), and then calcined to obtain the second catalyst precursor;

[0022] (3) The second catalyst precursor in step (2) is reduced to obtain the bimetallic catalyst.

[0023] The impregnation method in this invention has advantages such as controllable operation and ease of scale-up. This invention first impregnates the precursor solution containing metal A, and then impregnates the precursor solution containing platinum, which is beneficial for forming an effective "platinum-metal A" interface and promoting the dehydrogenation reaction of perhydrodibenzyltoluene.

[0024] As a preferred technical solution of the present invention, the precursor solution containing metal A in step (1) includes any one or a combination of at least two of ammonium molybdate, ammonium vanadate, ammonium perrhenate, lanthanum nitrate or cerium nitrate. Typical but non-limiting examples of such combinations include: a combination of ammonium molybdate and ammonium vanadate, a combination of ammonium vanadate and ammonium perrhenate, a combination of ammonium perrhenate and lanthanum nitrate, or a combination of ammonium vanadate and cerium nitrate.

[0025] As a preferred technical solution of the present invention, the first immersion time in step (1) is 1 to 18 hours, wherein the time can be 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours or 18 hours, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 10 to 15 hours.

[0026] Preferably, after the first impregnation in step (1), the first drying and the first calcination are carried out in sequence.

[0027] Preferably, the temperature of the first drying is 100 to 140°C, wherein the temperature can be 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C or 140°C, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0028] Preferably, the first drying time is ≥10h, wherein the time can be 10h, 11h, 12h, 15h, 16h or 20h, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0029] Preferably, the temperature of the first calcination in step (1) is 300 to 900°C, wherein the temperature can be 300°C, 400°C, 500°C, 600°C, 700°C, 800°C or 900°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 400 to 700°C.

[0030] Preferably, the calcination time in step (1) is 1 to 10 hours, wherein the time can be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 3 to 6 hours.

[0031] As a preferred technical solution of the present invention, the platinum-containing precursor solution in step (2) includes chloroplatinic acid.

[0032] As a preferred technical solution of the present invention, the second immersion time in step (2) is 1 to 18 hours, wherein the time can be 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours or 18 hours, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 10 to 15 hours.

[0033] Preferably, after the second impregnation in step (2), the second drying and second calcination are carried out in sequence.

[0034] Preferably, the temperature of the second drying is 100-140°C, wherein the temperature can be 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C or 140°C, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0035] Preferably, the second drying time is ≥10h, wherein the time can be 10h, 11h, 12h, 15h, 16h or 20h, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0036] Preferably, the second calcination temperature in step (2) is 300 to 900°C, wherein the temperature can be 300°C, 400°C, 500°C, 600°C, 700°C, 800°C or 900°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 400 to 700°C.

[0037] Preferably, the second calcination time in step (2) is 1 to 10 hours, wherein the time can be 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 3 to 6 hours.

[0038] As a preferred technical solution of the present invention, the reducing gas in the reduction process of step (3) includes H2 and N2.

[0039] In the reduction process of this invention, a mixture of hydrogen and nitrogen is used as the reducing gas. Compared with using hydrogen alone, the reduction rate is more moderate. This will affect the particle size distribution of metal A and platinum after reduction, because a faster reduction rate will result in larger metal particle size.

[0040] Preferably, with the total volume of the reducing gas being 100%, the volume fraction of H2 is 1 to 100%, wherein the volume fraction can be 1%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 10 to 100%.

[0041] Preferably, the volume hourly space velocity (VHSV) of the reduction treatment is 500–5000 h⁻¹. -1 The volumetric space velocity mentioned therein can be 500 h⁻¹ -1 1000h -1 1500h -1 2000h -1 2500h -1 3000h-1 3500h -1 4000h -1 4500h -1 or 5000h -1 However, it is not limited to the listed values; other unlisted values ​​within this range are also suitable, preferably 500–2000 h. -1 .

[0042] Preferably, the pressure of the reduction treatment is 0.1 to 5.0 MPa, wherein the pressure can be 0.1 MPa, 1.0 MPa, 2.0 MPa, 3.0 MPa, 4.0 MPa or 5.0 MPa, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0.1 to 1.0 MPa.

[0043] Preferably, the temperature of the reduction treatment is 100 to 800°C, wherein the temperature can be 100°C, 200°C, 300°C, 400°C, 500°C, 600°C, 700°C or 800°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 200 to 600°C.

[0044] Preferably, the heating rate of the reduction treatment is 0.1 to 20 °C / min, wherein the heating rate can be 0.1 °C / min, 2 °C / min, 4 °C / min, 6 °C / min, 8 °C / min, 10 °C / min, 12 °C / min, 14 °C / min, 16 °C / min, 18 °C / min or 20 °C / min, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 1 to 10 °C / min.

[0045] Preferably, the reduction process takes 0.1 to 20 hours, and the time can be 0.1 hours, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours or 20 hours, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0.5 to 5 hours.

[0046] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0047] (1) The precursor solution containing metal A is first impregnated onto the support, and then first dried and first calcined to obtain the first catalyst precursor. The metal A is selected from any one or at least two of molybdenum, vanadium, rhenium, lanthanum or cerium. The first impregnation time is 1 to 18 h, the first drying temperature is 100 to 140 °C and the first drying time is ≥ 10 h, the first calcination temperature is 300 to 900 °C and the first calcination time is 1 to 10 h.

[0048] (2) The platinum-containing precursor solution is second-impregnated onto the first catalyst precursor in step (1), and then subjected to second drying and second calcination to obtain a second catalyst precursor. The second impregnation time is 1-18h, the second drying temperature is 100-140℃, the second drying time is ≥10h, the second calcination temperature is 300-900℃, and the second calcination time is 1-10h.

[0049] (3) The second catalyst precursor from step (2) is subjected to reduction treatment to obtain the bimetallic catalyst, wherein the volume hourly space velocity of the reduction treatment is 500-5000 h⁻¹. -1 The pressure is 0.1–5.0 MPa, the temperature is 100–800℃, the heating rate is 0.1–20℃ / min, and the time is 0.1–20 h.

[0050] A third objective of this invention is to provide an application of the bimetallic catalyst as described in one objective, wherein the bimetallic catalyst is applied in the field of catalyst materials.

[0051] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0052] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0053] (1) In a continuous fixed-bed reactor, at a reaction temperature of 290°C, compared with a single-metal platinum-based dehydrogenation catalyst, the bimetallic catalyst of the present invention can increase the degree of dehydrogenation by 5 to 20%, and the degree of dehydrogenation of dibenzyltoluene can reach more than 80%. Using the bimetallic catalyst of the present invention can significantly improve the dehydrogenation efficiency of dibenzyltoluene.

[0054] (2) The preparation method of the bimetallic catalyst of the present invention is simple and can be applied to large-scale industrial production. Detailed Implementation

[0055] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0056] Example 1

[0057] This embodiment provides a bimetallic catalyst, which is alumina loaded with molybdenum and platinum. Molybdenum exists in the bimetallic catalyst in the form of molybdenum oxide, and the loading amount of molybdenum in the bimetallic catalyst is 4 wt%. Platinum exists in the bimetallic catalyst in the form of platinum oxide, and the loading amount of platinum in the bimetallic catalyst is 1 wt%.

[0058] This embodiment also provides a method for preparing the above-mentioned bimetallic catalyst, the method comprising:

[0059] (1) The ammonium molybdate solution was first impregnated onto alumina, and the first catalyst precursor was obtained by first drying and first calcination. The first impregnation time was 12h, the first drying temperature was 120℃ and the time was 10h, the first calcination temperature was 500℃ and the first calcination time was 4.5h.

[0060] (2) The chloroplatinic acid solution is second-impregnated onto the first catalyst precursor in step (1) for 12 hours. The second catalyst precursor is obtained by second drying and second calcination. The second drying temperature is 120°C and the second drying time is 10 hours. The second calcination temperature is 500°C and the second calcination time is 4.5 hours.

[0061] (3) The second catalyst precursor from step (2) is subjected to reduction treatment to obtain the bimetallic catalyst, wherein the reduction atmosphere is 50% H2 and 50% N2 by volume, and the volume space velocity of the reduction treatment is 1250 h⁻¹. -1 The pressure was 0.5 MPa, the temperature was 300℃, the heating rate was 5℃ / min, and the time was 2.5 h.

[0062] Example 2

[0063] This embodiment provides a bimetallic catalyst, which is alumina supported on vanadium and platinum. Vanadium exists in the bimetallic catalyst in the form of vanadium oxide, and the loading of vanadium in the bimetallic catalyst is 6.5 wt%. Platinum exists in the bimetallic catalyst in the form of platinum oxide, and the loading of platinum in the bimetallic catalyst is 1 wt%.

[0064] This embodiment also provides a method for preparing the above-mentioned bimetallic catalyst, the method comprising:

[0065] (1) The ammonium vanadate solution is first impregnated onto alumina, and the first catalyst precursor is obtained by first drying and first calcination. The first impregnation time is 10h, the first drying temperature is 100℃ and the time is 10h, the first calcination temperature is 400℃ and the first calcination time is 3h.

[0066] (2) The chloroplatinic acid solution is second-impregnated onto the first catalyst precursor in step (1) for 10 hours. The second catalyst precursor is obtained by second drying and second calcination. The second drying temperature is 100°C and the second drying time is 10 hours. The second calcination temperature is 400°C and the second calcination time is 3 hours.

[0067] (3) The second catalyst precursor from step (2) is subjected to reduction treatment to obtain the bimetallic catalyst, wherein the reduction atmosphere is 50% H2 and 50% N2 by volume, and the volume space velocity of the reduction treatment is 500 h⁻¹. -1 The pressure was 0.1 MPa, the temperature was 400℃, the heating rate was 1℃ / min, and the time was 0.5 h.

[0068] Example 3

[0069] This embodiment provides a bimetallic catalyst, which is alumina supported on rhenium and platinum. Rhenium exists in the bimetallic catalyst in the form of rhenium oxide, and the loading amount of rhenium in the bimetallic catalyst is 0.2 wt%. Platinum exists in the bimetallic catalyst in the form of platinum oxide, and the loading amount of platinum in the bimetallic catalyst is 1 wt%.

[0070] This embodiment also provides a method for preparing the above-mentioned bimetallic catalyst, the method comprising:

[0071] (1) The ammonium perrhenate solution is first impregnated onto alumina, and the first catalyst precursor is obtained by first drying and first calcination, wherein the first impregnation time is 15h, the first drying temperature is 140℃ and the time is 10h, the first calcination temperature is 550℃ and the first calcination time is 6h;

[0072] (2) The chloroplatinic acid solution is second-impregnated onto the first catalyst precursor in step (1) for 15 hours. The second catalyst precursor is obtained by second drying and second calcination. The second drying temperature is 140°C and the second drying time is 10 hours. The second calcination temperature is 550°C and the second calcination time is 6 hours.

[0073] (3) The second catalyst precursor from step (2) is subjected to reduction treatment to obtain the bimetallic catalyst, wherein the reduction atmosphere is 50% H2 and 50% N2 by volume, and the volume space velocity of the reduction treatment is 2000 h⁻¹. -1 The pressure was 1.0 MPa, the temperature was 500℃, the heating rate was 10℃ / min, and the time was 5h.

[0074] Example 4

[0075] This embodiment provides a bimetallic catalyst, which is alumina loaded with molybdenum and platinum. Molybdenum exists in the bimetallic catalyst in the form of molybdenum oxide, and the loading amount of molybdenum in the bimetallic catalyst is 0.01 wt%. Platinum exists in the bimetallic catalyst in the form of platinum oxide, and the loading amount of platinum in the bimetallic catalyst is 1 wt%.

[0076] This embodiment also provides a method for preparing the above-mentioned bimetallic catalyst, the method comprising:

[0077] (1) The ammonium molybdate solution is first impregnated onto alumina, and then dried and calcined to obtain the first catalyst precursor. The first impregnation time is 1 h, the first drying temperature is 100 °C, the first calcination time is 10 h, and the first calcination temperature is 300 °C for 10 h.

[0078] (2) The chloroplatinic acid solution is second-impregnated onto the first catalyst precursor in step (1) for 1 hour. The second catalyst precursor is obtained by second drying and second calcination. The second drying temperature is 100°C and the second drying time is 10 hours. The second calcination temperature is 300°C and the second calcination time is 10 hours.

[0079] (3) The second catalyst precursor from step (2) is subjected to reduction treatment to obtain the bimetallic catalyst, wherein the reduction atmosphere is 50% H2 and 50% N2 by volume, and the volume space velocity of the reduction treatment is 500 h⁻¹. -1 The pressure was 0.1 MPa, the temperature was 100℃, the heating rate was 0.1℃ / min, and the time was 20 h.

[0080] Example 5

[0081] This embodiment provides a bimetallic catalyst, which is alumina loaded with molybdenum and platinum. Molybdenum exists in the bimetallic catalyst in the form of molybdenum oxide, and the loading of molybdenum in the bimetallic catalyst is 30 wt%. Platinum exists in the bimetallic catalyst in the form of platinum oxide, and the loading of platinum in the bimetallic catalyst is 1 wt%.

[0082] This embodiment also provides a method for preparing the above-mentioned bimetallic catalyst, the method comprising:

[0083] (1) The ammonium molybdate solution is first impregnated onto alumina, and then dried and calcined to obtain the first catalyst precursor. The first impregnation time is 18h, the first drying temperature is 140℃ and the time is 10h, the first calcination temperature is 900℃ and the first calcination time is 1h.

[0084] (2) The chloroplatinic acid solution is second-impregnated onto the first catalyst precursor in step (1) for 18 hours. The second catalyst precursor is obtained by second drying and second calcination. The second drying temperature is 140°C and the second drying time is 10 hours. The second calcination temperature is 900°C and the second calcination time is 1 hour.

[0085] (3) The second catalyst precursor from step (2) is subjected to reduction treatment to obtain the bimetallic catalyst, wherein the reduction atmosphere is 50% H2 and 50% N2 by volume, and the volume space velocity of the reduction treatment is 5000 h⁻¹. -1 The pressure was 5.0 MPa, the temperature was 800℃, the heating rate was 20℃ / min, and the time was 0.1 h.

[0086] Example 6

[0087] Except for replacing the rhenium supported in the bimetallic catalyst with lanthanum and replacing the ammonium molybdate solution in step (1) of the preparation method with lanthanum nitrate, all other conditions in this embodiment are the same as in Example 3.

[0088] Example 7

[0089] Except for replacing the rhenium supported in the bimetallic catalyst with cerium, and replacing the ammonium molybdate solution in step (1) of the preparation method with cerium nitrate, all other conditions in this embodiment are the same as in Example 3.

[0090] Example 8

[0091] In this embodiment, the loading of molybdenum in the bimetallic catalyst is replaced with 35 wt%, while all other conditions are the same as in Example 1.

[0092] Example 9

[0093] In this embodiment, all conditions are the same as in Example 1, except that the loading of platinum in the bimetallic catalyst is replaced with 6 wt%.

[0094] Comparative Example 1

[0095] In this comparative example, except that the ammonium molybdate solution was not used for impregnation, the chloroplatinic acid solution was directly impregnated onto alumina to obtain a single metal platinum catalyst, all other conditions were the same as in Example 1.

[0096] Comparative Example 2

[0097] In this comparative example, the first catalyst precursor is obtained by impregnating alumina with chloroplatinic acid solution, and the second catalyst precursor is obtained by impregnating the first catalyst precursor with ammonium molybdate solution. The impregnation parameters of chloroplatinic acid solution and ammonium molybdate solution remain unchanged, and all other conditions are the same as in Example 1.

[0098] The catalysts prepared in Examples 1-9 and Comparative Examples 1-2 were evaluated for their catalytic reaction performance using the following methods:

[0099] The reactivity of the catalyst was determined using a continuous fixed-bed reactor.

[0100] The dehydrogenation reaction was carried out in a continuous fixed-bed reactor. The reactant was perhydrodibenzyltoluene (active ingredient ≥98%). The reaction pressure was atmospheric pressure, the reaction temperature was 290℃, the catalyst dosage was 10 mL, and the liquid hourly space velocity was 1 h⁻¹. -1 The real-time rate of hydrogen gas is monitored online using a flow meter.

[0101] The extent of the dehydrogenation reaction is measured by the degree of dehydrogenation: Degree of dehydrogenation = Real-time hydrogen production rate / Theoretical maximum hydrogen production rate, Theoretical maximum hydrogen production rate (mL / min) = Feed mass flow rate / Molar mass of feed × 9 × 22.4 × 1000.

[0102] The test results of the degree of dehydrogenation in Examples 1-9 and Comparative Examples 1-2 of this invention are shown in Table 1.

[0103] Table 1

[0104] Example 1 82 Example 2 72 Example 3 73 Example 4 52 Example 5 34 Example 6 70 Example 7 81 Example 8 25 Example 9 54 Comparative Example 1 65 Comparative Example 2 42

[0105] This invention focuses on developing a bimetallic catalyst for the dehydrogenation of liquid-phase organic hydrogen supports (mainly perhydrodibenzyltoluene), addressing the problems of low dehydrogenation efficiency and high cost of current monometallic platinum-based dehydrogenation catalysts. Currently, at temperatures below 300°C, the dehydrogenation degree of perhydrodibenzyltoluene on catalysts containing 1 wt% Pt is difficult to exceed 80%, which limits the application of dibenzyltoluene in hydrogen storage and release.

[0106] In a continuous fixed-bed reactor, at reaction temperatures up to 290°C, the bimetallic catalyst of this invention can increase the degree of dehydrogenation by 5–20% compared to a monometallic platinum-based dehydrogenation catalyst, with the degree of dehydrogenation of dibenzyltoluene reaching over 80%. Using the bimetallic catalyst described in this invention can significantly improve the efficiency of the dibenzyltoluene dehydrogenation reaction.

[0107] As can be seen from the table above, comparing Examples 1-3, Examples 6-7, and Comparative Example 1, it is evident that the bimetallic catalyst prepared by adding molybdenum, vanadium, rhenium, lanthanum, or cerium can significantly improve the dehydrogenation degree of the organic liquid compared to the single-metal catalyst in Comparative Example 1. Examples 4-5 show that excessively large or small calcination and reduction parameters will decrease the dehydrogenation degree of the organic liquid. Examples 8-9 show that excessive loading of metal A or platinum will decrease the dehydrogenation degree of the organic liquid. In Comparative Example 2, the different loading order of metal A and platinum affects the dehydrogenation degree of the organic liquid.

[0108] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An application of a bimetallic catalyst, characterized in that, The bimetallic catalyst is used for the dehydrogenation reaction of perhydrodibenzyltoluene. In a continuous fixed-bed reactor, at a reaction temperature of 290°C, the bimetallic catalyst can achieve a dehydrogenation degree of more than 80% for dibenzyltoluene. The bimetallic catalyst comprises a support loaded with metal A and platinum, wherein metal A is selected from any one or a combination of at least two of molybdenum, vanadium, rhenium, lanthanum or cerium; The introduction of metal A can form a "platinum-metal A" interface around platinum nanoparticles, which can improve the dehydrogenation reactivity of perhydrodibenzyltoluene. The bimetallic catalyst is prepared by the following method, the method comprising: (1) The precursor solution containing metal A is first impregnated onto the support and then calcined to obtain the first catalyst precursor, wherein the metal A is selected from any one or at least a combination of two of molybdenum, vanadium, rhenium, lanthanum or cerium; (2) The platinum-containing precursor solution is second-impregnated onto the first catalyst precursor in step (1), and then calcined a second time to obtain the second catalyst precursor; (3) The second catalyst precursor in step (2) is reduced to obtain the bimetallic catalyst; The reducing gases in step (3) include H2 and N2.

2. The application of the bimetallic catalyst according to claim 1, characterized in that, In the bimetallic catalyst, the compound containing metal A includes any one of molybdenum oxide, vanadium oxide, rhenium oxide, lanthanum oxide, cerium oxide, or chromium oxide.

3. The application of the bimetallic catalyst according to claim 1, characterized in that, In the bimetallic catalyst, the platinum-containing compound includes platinum oxide.

4. The application of the bimetallic catalyst according to claim 1, characterized in that, The carrier includes any one or a combination of at least two of alumina, silicon dioxide, activated carbon, zirconium oxide, titanium dioxide, or molecular sieves.

5. The application of the bimetallic catalyst according to claim 1, characterized in that, The loading of metal A in the bimetallic catalyst is 0.01~30 wt%.

6. The application of the bimetallic catalyst according to claim 5, characterized in that, The loading of metal A in the bimetallic catalyst is 0.05~20 wt%.

7. The application of the bimetallic catalyst according to claim 1, characterized in that, The platinum loading in the bimetallic catalyst is 0.1~5.0 wt%.

8. The application of the bimetallic catalyst according to claim 7, characterized in that, The platinum loading in the bimetallic catalyst is 0.2~3 wt%.

9. The application of the bimetallic catalyst according to claim 1, characterized in that, The precursor solution containing metal A in step (1) includes any one or a combination of at least two of ammonium molybdate, ammonium vanadate, ammonium perrhenate, lanthanum nitrate, or cerium nitrate.

10. The application of the bimetallic catalyst according to claim 1, characterized in that, Step (1) The first immersion time is 1~18h.

11. The application of the bimetallic catalyst according to claim 10, characterized in that, Step (1) The first immersion time is 10~15h.

12. The application of the bimetallic catalyst according to claim 1, characterized in that, Step (1) After the first impregnation, the first drying and the first calcination are carried out in sequence.

13. The application of the bimetallic catalyst according to claim 12, characterized in that, The temperature for the first drying process is 100~140℃.

14. The application of the bimetallic catalyst according to claim 12, characterized in that, The first drying time is ≥10h.

15. The application of the bimetallic catalyst according to claim 1, characterized in that, Step (1) The temperature of the first calcination is 300~900℃.

16. The application of the bimetallic catalyst according to claim 15, characterized in that, Step (1) The temperature of the first calcination is 400~700℃.

17. The application of the bimetallic catalyst according to claim 1, characterized in that, Step (1) The first calcination time is 1~10h.

18. The application of the bimetallic catalyst according to claim 17, characterized in that, Step (1) The first calcination time is 3~6h.

19. The application of the bimetallic catalyst according to claim 1, characterized in that, The platinum-containing precursor solution in step (2) includes chloroplatinic acid.

20. The application of the bimetallic catalyst according to claim 1, characterized in that, Step (2) The second immersion time is 1~18h.

21. The application of the bimetallic catalyst according to claim 20, characterized in that, Step (2) The second soaking time is 10~15h.

22. The application of the bimetallic catalyst according to claim 1, characterized in that, After the second impregnation in step (2), the second drying and second calcination are carried out in sequence.

23. The application of the bimetallic catalyst according to claim 22, characterized in that, The second drying temperature is 100~140℃.

24. The application of the bimetallic catalyst according to claim 22, characterized in that, The second drying time is ≥10 hours.

25. The application of the bimetallic catalyst according to claim 1, characterized in that, In step (2), the second calcination temperature is 300~900℃.

26. The application of the bimetallic catalyst according to claim 25, characterized in that, In step (2), the second calcination temperature is 400~700℃.

27. The application of the bimetallic catalyst according to claim 1, characterized in that, Step (2) The second calcination time is 1~10h.

28. The application of the bimetallic catalyst according to claim 27, characterized in that, Step (2) The second calcination time is 3~6h.

29. The application of the bimetallic catalyst according to claim 1, characterized in that, With the total volume of reducing gas being 100%, the volume fraction of H2 is 1-90%.

30. The application of the bimetallic catalyst according to claim 29, characterized in that, The volume fraction of H2 is 10-90%.

31. The application of the bimetallic catalyst according to claim 1, characterized in that, The volume hourly space velocity (VHSV) of the reduction treatment is 500-5000 h⁻¹. -1 .

32. The application of the bimetallic catalyst according to claim 31, characterized in that, The volume hourly space velocity (VHSV) of the reduction treatment is 500-2000 h⁻¹. -1 .

33. The application of the bimetallic catalyst according to claim 1, characterized in that, The pressure of the reduction process is 0.1~5.0 MPa.

34. The application of the bimetallic catalyst according to claim 33, characterized in that, The pressure of the reduction process is 0.1~1.0 MPa.

35. The application of the bimetallic catalyst according to claim 1, characterized in that, The reduction treatment temperature is 100~800℃.

36. The application of the bimetallic catalyst according to claim 35, characterized in that, The reduction treatment temperature is 200~600℃.

37. The application of the bimetallic catalyst according to claim 1, characterized in that, The heating rate of the reduction treatment is 0.1~20℃ / min.

38. The application of the bimetallic catalyst according to claim 37, characterized in that, The heating rate of the reduction treatment is 1~10℃ / min.

39. The application of the bimetallic catalyst according to claim 1, characterized in that, The reduction process takes 0.1 to 20 hours.

40. The application of the bimetallic catalyst according to claim 39, characterized in that, The reduction process takes 0.5 to 5 hours.

41. The application of the bimetallic catalyst according to claim 1, characterized in that, The method includes the following steps: (1) The precursor solution containing metal A is first impregnated onto the support, and then first dried and first calcined to obtain the first catalyst precursor. The metal A is selected from any one or at least two of molybdenum, vanadium, rhenium, lanthanum or cerium. The first impregnation time is 1~18h, the first drying temperature is 100~140℃ and the first drying time is ≥10h, the first calcination temperature is 300~900℃ and the first calcination time is 1~10h. (2) The platinum-containing precursor solution is second-impregnated onto the first catalyst precursor in step (1), and then subjected to second drying and second calcination to obtain the second catalyst precursor. The second impregnation time is 1~18h, the second drying temperature is 100~140℃, the second drying time is ≥10h, the second calcination temperature is 300~900℃, and the second calcination time is 1~10h. (3) The second catalyst precursor in step (2) is subjected to reduction treatment to obtain the bimetallic catalyst, wherein the volume hourly space velocity of the reduction treatment is 500~5000 h⁻¹. -1 The pressure is 0.1~5.0MPa, the temperature is 100~800℃, the heating rate is 0.1~20℃ / min, and the time is 0.1~20h.