A nickel-based bimetallic catalyst, its preparation method and use

Abstract

The present application relates to a kind of nickel-based bimetallic catalyst and its preparation method and use, the preparation method includes the following steps: mixing nickel source solution, aluminium source solution and lye, reaction, obtain nickel aluminium precursor;Mix nickel aluminium precursor with functional adjuvant solution, by first calcination, second calcination and reducing calcination, obtain the nickel-based bimetallic catalyst;The functional adjuvant solution includes any one or the combination of at least two in ruthenium source solution, palladium source solution or platinum source solution.The nickel-based bimetallic catalyst provided by the present application can catalyze each step of hydrogen production and oligomer hydrogenolysis reaction in aqueous phase reforming with nickel as main active component;Any combination of ruthenium, platinum, palladium and the like as functional adjuvant can greatly improve catalytic activity;Aluminum oxide is carrier, a small amount of aluminum oxide migrates to nickel site during synthesis to reduce site basicity, inhibit carbon deposition and thus enhance stability.After several cycles, the catalyst still has efficient aqueous phase reforming-hydrogenolysis cascade reaction activity.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and in particular to a nickel-based bimetallic catalyst, its preparation method, and its uses. Background Technology

[0002] Currently, a large amount of biomass waste, such as agricultural and forestry waste and papermaking lignin residues, is generated annually, which easily causes environmental pollution and harms human health. Resource-based transformation of biomass waste can not only control pollution, but its products can also replace some fossil resources, helping to mitigate carbon dioxide emissions.

[0003] Pyrolysis is an important method for the utilization of biomass resources. It breaks down solid biomass macromolecules into liquid pyrolysis oil molecules under high-temperature anaerobic conditions, providing a raw material for subsequent catalytic conversion into high-value-added chemicals. Pyrolysis oil has a complex composition, ranging from short-chain alcohols and aldehydes to incompletely depolymerized oligomers. The oligomers with higher content require further depolymerization into smaller monomers to maximize the yield of high-value products.

[0004] Conventional hydrolysis depolymerization processes rely on high-pressure hydrogen, leading to high system operation and maintenance costs. Furthermore, high-pressure conditions easily trigger deep hydrogenation of unsaturated structures such as benzene rings, increasing hydrogen consumption and raw material costs while reducing the added value of the products. A promising alternative strategy is to utilize pre-existing polyols, aldehydes, and other small molecules in pyrolysis oil for aqueous reforming, releasing hydrogen in situ and continuously within the reaction system to provide a hydrogen source for the hydrolysis of oligomers, thereby achieving complete depolymerization. This strategy not only avoids dependence on high-pressure hydrogen but also effectively inhibits deep hydrogenation of unsaturated functional groups. Such cascade reactions require a multifunctional catalytic system to simultaneously catalyze multiple steps in aqueous reforming for hydrogen production and oligomer hydrolysis, such as dehydrogenation, decarbonylation, water-vapor shift reaction, and carbon-oxygen bond activation.

[0005] Nickel possesses the multifunctional catalytic properties required for this series of catalysts; however, nickel-based catalysts still suffer from two main problems: weak hydrogenolysis activity and easy carbon deposition at catalytic sites. These issues severely weaken the overall catalytic activity and stability. This has become one of the key bottlenecks hindering the application of nickel-based catalysts in aqueous reforming-hydrogenolysis cascade reactions.

[0006] Therefore, how to provide an aqueous reforming-hydrogenolysis catalyst with high catalytic activity, strong stability, low carbon deposition, simple preparation method, and low cost, as well as its preparation method, has become an urgent problem to be solved. Summary of the Invention

[0007] To address the aforementioned technical problems, the present invention aims to provide a nickel-based bimetallic catalyst, its preparation method, and its applications. The nickel-based bimetallic catalyst of the present invention has high activity and high stability, and can inhibit carbon deposition.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing a nickel-based bimetallic catalyst, the method comprising the following steps:

[0010] A nickel source solution, an aluminum source solution, and an alkaline solution are mixed and reacted to obtain a nickel-aluminum precursor; the nickel-aluminum precursor is mixed with a functional additive solution and subjected to a first calcination, a second calcination, and a reducing calcination to obtain the nickel-based bimetallic catalyst; the functional additive solution includes any one or a combination of at least two of ruthenium source solution, palladium source solution, or platinum source solution.

[0011] This invention first prepares a slurry-like nickel-aluminum precursor of hydroxide by deposition precipitation, and then mixes the functional additive directly with the nickel-aluminum precursor and calcines it to obtain the catalyst, instead of directly calcining the nickel-aluminum precursor to obtain a nickel-aluminum support and then impregnating it with the active component. Compared with the prior art, this invention uses a two-step calcination method, which can make the additive more uniformly dispersed. If the two-stage calcination is not performed, the dispersion of the additive will be reduced, resulting in a decrease in catalyst activity.

[0012] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0013] In some embodiments, the molar ratio of metal ions in the nickel source solution and the aluminum source solution is 1:(1.5-10), for example, it can be 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, 1:8.5, 1:9, 1:9.5 or 1:10, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0014] In some embodiments, the molar ratio of metal ions in the nickel source solution to solute in the alkaline solution is 1:(1-5), for example, it can be 1:1, 1:2, 1:3, 1:4 or 1:5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] In some embodiments, the concentration of the alkaline solution is 0.1 mol / L to 2 mol / L, for example, it can be 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.8 mol / L, 1 mol / L, 1.5 mol / L, 1.8 mol / L or 2 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] In some embodiments, the alkaline solution comprises any one or a combination of at least two of ammonia, ammonium bicarbonate solution, sodium bicarbonate solution, or sodium hydroxide solution. Typical but non-limiting combinations include combinations of ammonia and ammonium bicarbonate solution, combinations of ammonium bicarbonate solution and sodium bicarbonate solution, combinations of sodium bicarbonate solution and sodium hydroxide solution, combinations of ammonia, ammonium bicarbonate solution, and sodium bicarbonate solution, combinations of ammonium bicarbonate solution, sodium bicarbonate solution, and sodium hydroxide solution, and combinations of ammonia and sodium bicarbonate solution.

[0017] In some embodiments, the nickel source solution includes any one or a combination of at least two of nickel nitrate solution, nickel sulfate solution, or nickel chloride solution. Typical but non-limiting combinations include combinations of nickel nitrate solution and nickel sulfate solution, combinations of nickel sulfate solution and nickel chloride solution, combinations of nickel nitrate solution and nickel chloride solution, and combinations of nickel nitrate solution, nickel sulfate solution, and nickel chloride solution.

[0018] In some embodiments, the aluminum source solution includes any one or a combination of at least two of aluminum nitrate solution, aluminum sulfate solution, or aluminum chloride solution. Typical but non-limiting combinations include combinations of aluminum nitrate solution and aluminum sulfate solution, combinations of aluminum sulfate solution and aluminum chloride solution, combinations of aluminum nitrate solution and aluminum chloride solution, and combinations of aluminum nitrate solution, aluminum sulfate solution, and aluminum chloride solution.

[0019] In some embodiments, the ruthenium source solution includes any one or a combination of at least two of ruthenium nitrate solution, ruthenium sulfate solution, or ruthenium chloride solution. Typical but non-limiting combinations include combinations of ruthenium nitrate solution and ruthenium sulfate solution, combinations of ruthenium sulfate solution and ruthenium chloride solution, combinations of ruthenium nitrate solution and ruthenium chloride solution, and combinations of ruthenium nitrate solution, ruthenium sulfate solution, and ruthenium chloride solution.

[0020] In some embodiments, the palladium source solution includes any one or a combination of at least two of palladium nitrate solution, palladium sulfate solution, or palladium chloride solution. Typical but non-limiting combinations include combinations of palladium nitrate solution and palladium sulfate solution, combinations of palladium sulfate solution and palladium chloride solution, combinations of palladium nitrate solution and palladium chloride solution, and combinations of palladium nitrate solution, palladium sulfate solution, and palladium chloride solution.

[0021] In some embodiments, the platinum source solution includes any one or a combination of at least two of platinum nitrate solution, platinum sulfate solution, or platinum chloride solution. Typical but non-limiting combinations include combinations of platinum nitrate solution and platinum sulfate solution, combinations of platinum sulfate solution and platinum chloride solution, combinations of platinum nitrate solution and platinum chloride solution, and combinations of platinum nitrate solution, platinum sulfate solution, and platinum chloride solution.

[0022] In some embodiments, the reaction is accompanied by stirring, and the reaction time is 1-3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] In some embodiments, the molar ratio of the nickel-aluminum precursor to the functional additive in the functional additive solution is 100:(0.01-0.5), for example, it can be 100:0.01, 100:0.02, 100:0.05, 100:0.1, 100:0.2, 100:0.3, 100:0.4 or 100:0.5, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] This invention further controls the molar ratio of the nickel-aluminum precursor to the functional additive in the functional additive solution to 100:(0.01-0.5). An appropriate amount of functional additive can significantly improve catalytic activity; if the content of functional additive is too high, it will over-modify the nickel sites and reduce the catalyst activity; if the content of functional additive is too low, the modification of the nickel sites will be limited and the degree of activity improvement will be low.

[0025] In some embodiments, the atmosphere for the first calcination is an inert atmosphere.

[0026] In some embodiments, the inert atmosphere includes nitrogen and / or argon.

[0027] In some embodiments, the temperature of the first calcination is 600℃-900℃, for example, it can be 600℃, 650℃, 700℃, 750℃, 800℃, 850℃ or 900℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0028] In some embodiments, the first calcination time is 0.5h-10h, for example, it can be 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] In some embodiments, the atmosphere for the second calcination is an oxygen-containing atmosphere, wherein the oxygen content in the oxygen-containing atmosphere is 5%-50%.

[0030] In some embodiments, the second calcination temperature is 600℃-900℃, for example, it can be 600℃, 650℃, 700℃, 750℃, 800℃, 850℃ or 900℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0031] This invention further controls the temperature of the second calcination to 600℃-900℃, and the second calcination is carried out in an air atmosphere. The second calcination process enhances the dispersion of the additives. The temperature of the second calcination affects the dispersion effect of the additives and the number of nickel sites. If the second calcination temperature is too high, it will cause nickel sintering and reduce the number of nickel sites. If the second calcination temperature is too low, the additive dispersion effect cannot be achieved.

[0032] In some embodiments, the second calcination time is 0.5h-10h, for example, it can be 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] In some embodiments, the reducing calcination atmosphere is a hydrogen-containing atmosphere, wherein the volume fraction of H2 in the hydrogen-containing atmosphere is 5 vol.%-10 vol.%, for example, it can be 5 vol.%, 6 vol.%, 7 vol.%, 8 vol.%, 9 vol.% or 10 vol.%, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0034] In some embodiments, the gas flow rate of the hydrogen-containing atmosphere is 10 mL / min to 1000 mL / min, for example, it can be 10 mL / min, 50 mL / min, 100 mL / min, 200 mL / min, 300 mL / min, 400 mL / min, 500 mL / min, 600 mL / min, 700 mL / min, 800 mL / min, 900 mL / min or 1000 mL / min, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0035] In some embodiments, the reducing calcination temperature is 500℃-700℃, for example, it can be 500℃, 550℃, 600℃, 650℃ or 700℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0036] In some embodiments, the reducing calcination time is 0.5h-4h, for example, it can be 0.5h, 1h, 2h, 2.5h, 3h, 3.5h or 4h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] As a preferred embodiment of the preparation method of the present invention, the preparation method includes the following steps:

[0038] (1) Mix nickel source solution, aluminum source solution and alkaline solution with a concentration of 0.1mol / L-2mol / L, stir the reaction for 1h-3h, wash the product until the washing solution is neutral, and obtain nickel-aluminum precursor;

[0039] The molar ratio of metal ions in the nickel source solution and the aluminum source solution is 1:(1.5-10), and the molar ratio of metal ions in the nickel source solution to solutes in the alkaline solution is 1:(1-5).

[0040] (2) The nickel-aluminum precursor obtained in step (1) is mixed with the ruthenium source solution, dried, and then calcined at 600℃-900℃ for 0.5h-10h in an inert atmosphere. After cooling to room temperature, it is calcined at 600℃-900℃ for 0.5h-10h in an air atmosphere, and then calcined in a reducing manner at 500℃-700℃ for 0.5h-4h in a 5vol.%-10vol.% H2 / N2 atmosphere to obtain the nickel-based bimetallic catalyst.

[0041] The molar ratio of the nickel-aluminum precursor to the metal ions in the ruthenium source solution is 100:(0.01-0.5).

[0042] In a second aspect, the present invention provides a nickel-based bimetallic catalyst, which is prepared according to the preparation method described in the first aspect.

[0043] In some embodiments, the nickel-based bimetallic catalyst comprises an alumina support, nickel nanoparticles, and a single-atom functional additive; the functional additive comprises any one or a combination of at least two of ruthenium, palladium, or platinum, the nickel nanoparticles are supported on the alumina support, and the single-atom functional additive forms a single-atom alloy with the nickel nanoparticles.

[0044] In this invention, a single-atom functional additive is loaded onto nickel nanoparticles to form a Ru-Ni coordination environment, thereby forming a single-atom alloy.

[0045] In some embodiments, based on a total mass of 100 wt% of the nickel-based bimetallic catalyst, the mass fraction of the single-atom functional auxiliary is 0.01 wt% to 0.5 wt%, for example, it can be 0.01 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, or 0.5 wt%, but is not limited to the listed values; other unlisted values ​​within the range are also applicable.

[0046] The nickel-based bimetallic catalyst provided by this invention uses nickel as the main active component, catalyzing all steps of the aqueous reforming hydrogen production and oligomer hydrogenolysis reaction. Ruthenium, platinum, palladium, and other components are used in any combination as functional additives, significantly enhancing catalytic activity. Alumina serves as the support; during synthesis, a small amount of alumina migrates to nickel sites, reducing site basicity and inhibiting carbon deposition, thereby enhancing stability. All three types of components play crucial roles in achieving a highly efficient aqueous reforming-hydrogenolysis cascade reaction.

[0047] Thirdly, the present invention provides the use of the nickel-based bimetallic catalyst as described in the second aspect, said nickel-based bimetallic catalyst for an aqueous reforming-hydrogenolysis reaction.

[0048] 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.

[0049] Compared with the prior art, the present invention has at least the following beneficial effects:

[0050] (1) The present invention first prepares a nickel-aluminum precursor of hydroxide slurry by deposition precipitation method, and then mixes the functional additive directly with the nickel-aluminum precursor and calcines it to obtain a catalyst, instead of directly calcining the nickel-aluminum precursor to obtain a nickel-aluminum carrier and then loading the active component by impregnation. Compared with the prior art, the method of the present invention can make the additive more uniformly dispersed and the process is more simplified, which is conducive to large-scale production.

[0051] (2) The nickel-based bimetallic catalyst provided by this invention uses nickel as the main active component, which can catalyze each step of the aqueous reforming hydrogen production and oligomer hydrogenolysis reaction. Ruthenium, platinum, palladium and other components can be combined as functional additives to significantly improve catalytic activity. Alumina serves as a support, and during the synthesis process, a small amount of alumina migrates to nickel sites to reduce site basicity and inhibit carbon deposition, thereby enhancing stability. The above three types of components all play an important role in realizing the efficient aqueous reforming-hydrogenolysis cascade reaction. Attached Figure Description

[0052] Figure 1 These are aberration-corrected high-angle annular dark-field electron microscope images and intensity analysis of the nickel-based bimetallic catalyst of Example 1 of this invention. Detailed Implementation

[0053] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0054] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0055] Unless otherwise specified, all reagents and consumables used in the following examples and comparative examples were purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and techniques used were conventional methods and techniques in the art.

[0056] Example 1

[0057] This embodiment provides a nickel-based bimetallic catalyst, which comprises an Al2O3 support, Ni nanoparticles, and 0.3 wt% single-atom Ru;

[0058] The preparation method of the nickel-based bimetallic catalyst provided in this embodiment includes the following steps:

[0059] (1) Mix nickel nitrate solution, aluminum nitrate solution and ammonia water with a concentration of 1 mol / L, stir and react for 1 h, wash the product until the washing liquid is neutral, and obtain nickel-aluminum precursor;

[0060] The molar ratio of metal ions in the nickel nitrate solution and the aluminum nitrate solution is 1:2, and the molar ratio of metal ions in the nickel nitrate solution to ammonia is 1:4.

[0061] (2) The nickel-aluminum precursor obtained in step (1) is mixed with ruthenium nitrate, dried at 80°C for 12 hours, then calcined at 800°C for 8 hours under a nitrogen atmosphere, cooled to room temperature, and then calcined at 800°C for 8 hours in an air atmosphere in a muffle furnace, and then calcined at 600°C for 3 hours under a 5 vol.% H2 / N2 atmosphere to obtain the nickel-based bimetallic catalyst;

[0062] The molar ratio of the nickel-aluminum precursor to the metal ions in ruthenium nitrate is 100:0.3.

[0063] Aberration-corrected high-angle annular dark-field electron microscopy image of the prepared nickel-based bimetallic catalyst is shown below. Figure 1 As shown, from Figure 1 As can be seen from this, the additive ruthenium exists in the form of single atoms on the nickel nanoparticles.

[0064] Example 2

[0065] This embodiment provides a nickel-based bimetallic catalyst, which comprises an Al2O3 support, Ni nanoparticles, and 0.05 wt% single-atom Pd;

[0066] The preparation method of the nickel-based bimetallic catalyst provided in this embodiment includes the following steps:

[0067] (1) Mix nickel nitrate solution, aluminum nitrate solution and sodium hydroxide with a concentration of 0.5 mol / L, stir and react for 1.5 h, wash the product until the washing liquid is neutral, and obtain nickel-aluminum precursor;

[0068] The molar ratio of metal ions in the nickel nitrate solution and the aluminum nitrate solution is 1:0.8, and the molar ratio of metal ions to sodium hydroxide in the nickel nitrate solution is 1:3.

[0069] (2) The nickel-aluminum precursor obtained in step (1) is mixed with palladium nitrate, dried at 80°C for 12 hours, then calcined at 700°C for 8 hours in an argon atmosphere, cooled to room temperature, calcined at 700°C for 10 hours in an air atmosphere, and then calcined in a reducing manner at 500°C for 4 hours in an 8 vol.% H2 / N2 atmosphere to obtain the nickel-based bimetallic catalyst.

[0070] The molar ratio of the nickel-aluminum precursor to the metal ions in palladium nitrate is 100:0.05.

[0071] Example 3

[0072] This embodiment provides a nickel-based bimetallic catalyst, which comprises an Al2O3 support, single-atom Ni nanoparticles, and 0.4 wt% single-atom Pt.

[0073] The preparation method of the nickel-based bimetallic catalyst provided in this embodiment includes the following steps:

[0074] (1) Mix nickel sulfate solution, aluminum sulfate solution and ammonium bicarbonate solution with a concentration of 2 mol / L, stir for 3 h, wash the product until the washing solution is neutral, and obtain nickel aluminum precursor;

[0075] The molar ratio of metal ions in the nickel sulfate solution and aluminum sulfate solution is 1:2.5, and the molar ratio of metal ions to ammonium bicarbonate in the nickel sulfate solution is 1:5.

[0076] (2) The nickel-aluminum precursor obtained in step (1) is mixed with platinum nitrate, dried at 80°C for 12 hours, then calcined at 900°C for 2 hours under a nitrogen atmosphere, cooled to room temperature, calcined at 900°C for 6 hours under an air atmosphere, and then calcined at 700°C for 2 hours under a 10 vol.% H2 / N2 atmosphere to obtain the nickel-based bimetallic catalyst.

[0077] The molar ratio of the nickel-aluminum precursor to the metal ions in platinum nitrate is 100:0.4.

[0078] Example 4

[0079] This embodiment provides a nickel-based bimetallic catalyst. The only difference from Example 1 is that, in preparing this nickel-based bimetallic catalyst, the molar ratio of the nickel-aluminum precursor to the metal ions in ruthenium nitrate in step (2) is 100:1, while the other steps remain unchanged.

[0080] Example 5

[0081] This embodiment provides a nickel-based bimetallic catalyst. The only difference from Example 1 is that, when preparing the nickel-based bimetallic catalyst, the molar ratio of metal ions in the nickel nitrate solution and the aluminum nitrate solution in step (1) is 1:1, and the other steps remain unchanged.

[0082] Example 6

[0083] This embodiment provides a nickel-based bimetallic catalyst. The only difference from Example 1 is that, when preparing the nickel-based bimetallic catalyst, the atmosphere for the first calcination in step (2) is air, while the other steps remain unchanged.

[0084] Example 7

[0085] This embodiment provides a nickel-based bimetallic catalyst. The only difference from Embodiment 1 is that, when preparing the nickel-based bimetallic catalyst, the atmosphere for the second calcination in step (2) is an argon atmosphere, while the other steps remain unchanged.

[0086] Comparative Example 1

[0087] This comparative example provides a nickel-based bimetallic catalyst, which is prepared by the following method:

[0088] Ruthenium nitrate and nickel nitrate were impregnated onto an alumina support, followed by calcination at 800°C for 10 h, and then reducing calcination at 600°C for 3 h in a 5 vol.% H2 / N2 atmosphere.

[0089] Comparative Example 2

[0090] This comparative example provides a nickel-based metal catalyst, which is prepared by the following method:

[0091] (I) Mix nickel nitrate solution, aluminum nitrate solution and ammonia water with a concentration of 1 mol / L, stir and react for 1 h, wash the product until the washing liquid is neutral, dry at 80 °C for 12 h, and then calcine at 800 °C for 8 h under an argon atmosphere. After cooling to room temperature, nickel-aluminum support is obtained.

[0092] The molar ratio of metal ions in the nickel nitrate solution and the aluminum nitrate solution is 1:2, and the molar ratio of metal ions in the nickel nitrate solution to ammonia is 1:4.

[0093] (II) The nickel-aluminum support obtained in step (I) and ruthenium nitrate are mixed and calcined for 8 hours at 800°C in an air atmosphere in a muffle furnace, and then calcined for 3 hours at 600°C in a 5 vol.% H2 / N2 atmosphere to obtain the nickel-based metal catalyst; the molar ratio of the nickel-aluminum precursor to the metal ions in ruthenium nitrate is 100:0.3.

[0094] Comparative Example 3

[0095] This comparative example provides a nickel-based metal catalyst, which differs from Example 1 only in that a ruthenium source was not added in step (2) when preparing the nickel-based metal catalyst.

[0096] Comparative Example 4

[0097] This comparative example provides a nickel-based metal catalyst, which differs from Example 1 only in that, in the preparation of this nickel-based metal catalyst, step (2) does not involve the first calcination, but only the second calcination. That is, step (2) becomes: mixing the nickel-aluminum precursor obtained in step (1) with ruthenium nitrate, drying at 80°C for 12 hours, then calcining at 800°C for 8 hours in an air atmosphere in a muffle furnace, and then reducing calcination at 600°C for 3 hours in a 5 vol.% H2 / N2 atmosphere to obtain the nickel-based metal catalyst.

[0098] test:

[0099] The nickel-based bimetallic catalysts prepared in the examples and comparative examples were tested under the following conditions: 10 mL diphenyl ether; 500 mL of 0.4 wt% ethylene glycol aqueous solution; 0.5 g catalyst; reaction temperature: 240°C; stirring speed: 600 rpm; reaction time: 3 h. After each reaction, the reactor was allowed to stand for 30 minutes, after which the mixed solution was removed, and the remaining slurry catalyst was used for the next reaction.

[0100] The gas and liquid phase products were analyzed using gas chromatography-mass spectrometry. The test results are shown in Table 1 below.

[0101] Table 1

[0102]

[0103] " / " indicates that no test was performed.

[0104] The test results show that:

[0105] (1) As can be seen from Examples 1-3, the nickel-based bimetallic catalyst provided by the present invention has nickel as the main active component, which can catalyze each step of the aqueous reforming hydrogen production and oligomer hydrogenolysis reaction; ruthenium, platinum, palladium and other arbitrary combinations are used as functional additives, which can greatly improve the catalytic activity; alumina is used as a support, and a small amount of alumina migrates to nickel sites during the synthesis process to reduce the site basicity and inhibit carbon deposition, thereby enhancing stability. After multiple cycles, the catalyst still has highly efficient aqueous reforming-hydrogenolysis cascade reaction activity.

[0106] (2) By comparing Example 1 and Example 4, it can be seen that the present invention further controls the molar ratio of the nickel-aluminum precursor to the functional additive in the functional additive solution to 100:(0.01-0.5). The molar ratio of the nickel-aluminum precursor to the functional additive affects the catalytic activity; if the content of the functional additive is too high or too low, the activity will be reduced.

[0107] (3) By comparing Example 1 and Example 5, it can be seen that the present invention can achieve better catalytic activity by further controlling the molar ratio of metal ions in nickel source solution and aluminum source solution to 1:(1.5-2.5).

[0108] (4) By comparing Example 1 with Examples 6-7, it can be seen that the present invention can improve the activity and achieve a better depolymerization effect by further controlling the gas atmosphere in the first and second roasting processes.

[0109] (5) As can be seen from Example 1 and Comparative Examples 1-2, the present invention can obtain the highest catalytic activity through deposition and direct loading. However, when deposition is not used, both activity and stability decrease significantly. When deposition and loading are used, the activity decreases.

[0110] (6) As can be seen from Example 1 and Comparative Example 3, when functional additives are not lacking, it is impossible to achieve high catalytic activity and stability.

[0111] (7) As can be seen from Example 1 and Comparative Example 4, the present invention adopts a two-step calcination method, which can make the additives more uniformly dispersed. When only one-step calcination is performed, it cannot achieve high catalytic activity and stability.

[0112] In summary, the nickel-based bimetallic catalyst provided by this invention uses nickel as the main active component and can catalyze all steps of the aqueous reforming hydrogen production and oligomer hydrogenolysis reaction. Ruthenium, platinum, palladium, and other elements are used in any combination as functional additives, which can significantly enhance the catalytic activity. Alumina serves as the support; during synthesis, a small amount of alumina migrates to nickel sites, reducing site basicity and inhibiting carbon deposition, thereby enhancing stability. After multiple cycles, the catalyst still exhibits highly efficient aqueous reforming-hydrogenolysis cascade reaction activity.

[0113] 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 method for preparing a nickel-based bimetallic catalyst, characterized in that, The preparation method includes the following steps: A nickel source solution, an aluminum source solution, and an alkaline solution are mixed and reacted to obtain a nickel-aluminum precursor. The nickel-based bimetallic catalyst is obtained by mixing a nickel-aluminum precursor with a functional additive solution and then subjecting it to a first calcination, a second calcination, and a reducing calcination. The functional additive solution includes any one or a combination of at least two of the following: ruthenium source solution, palladium source solution, or platinum source solution.

2. The preparation method according to claim 1, characterized in that, The molar ratio of metal ions in the nickel source solution and the aluminum source solution is 1:(1.5-10); And / or, the molar ratio of metal ions in the nickel source solution to solute in the alkaline solution is 1:(1-5); And / or, the concentration of the alkaline solution is 0.1 mol / L to 2 mol / L; And / or, the reaction is accompanied by stirring, and the reaction time is 0.5h-3h.

3. The preparation method according to claim 1 or 2, characterized in that, The molar ratio of the nickel-aluminum precursor to the functional additive in the functional additive solution is 100:(0.01-0.5).

4. The preparation method according to any one of claims 1-3, characterized in that, The atmosphere for the first roasting is an inert atmosphere; And / or, the temperature of the first calcination is 600℃-900℃; And / or, the first calcination time is 0.5h-10h.

5. The preparation method according to any one of claims 1-4, characterized in that, The second roasting atmosphere is an oxygen-containing atmosphere with an oxygen content of 5%-50%; And / or, the temperature of the second calcination is 600℃-900℃; And / or, the second calcination time is 0.5h-10h.

6. The preparation method according to any one of claims 1-5, characterized in that, The reducing calcination atmosphere is a hydrogen-containing atmosphere, wherein the volume fraction of H2 in the hydrogen-containing atmosphere is 5 vol.%-10 vol.%. And / or, the reducing calcination temperature is 500℃-700℃; And / or, the reducing calcination time is 0.5h-4h.

7. The preparation method according to any one of claims 1-6, characterized in that, The preparation method includes the following steps: (1) Mix nickel source solution, aluminum source solution and alkaline solution with a concentration of 0.1mol / L-2mol / L, stir the reaction for 1h-3h, wash the product until the washing solution is neutral, and obtain nickel-aluminum precursor; The molar ratio of metal ions in the nickel source solution and the aluminum source solution is 1:(1.5-10), and the molar ratio of metal ions in the nickel source solution to solutes in the alkaline solution is 1:(1-5). (2) The nickel-aluminum precursor obtained in step (1) is mixed with the ruthenium source solution, dried, and then calcined at 600℃-900℃ for 0.5h-10h in an inert atmosphere. After cooling to room temperature, it is calcined at 600℃-900℃ for 0.5h-10h in an air atmosphere, and then calcined in a reducing manner at 500℃-700℃ for 0.5h-4h in a 5vol.%-10vol.% H2 / N2 atmosphere to obtain the nickel-based bimetallic catalyst. The molar ratio of the nickel-aluminum precursor to the metal ions in the ruthenium source solution is 100:(0.01-0.5).

8. A nickel-based bimetallic catalyst, characterized in that, The nickel-based bimetallic catalyst is prepared according to any one of claims 1-7.

9. The nickel-based bimetallic catalyst according to claim 8, characterized in that, The nickel-based bimetallic catalyst comprises an alumina support, nickel nanoparticles, and a single-atom functional additive. The single-atom functional additive includes any one or a combination of at least two of ruthenium, palladium, or platinum; the nickel nanoparticles are loaded on an alumina support, and the single-atom additive forms a single-atom alloy with the nickel nanoparticles; And / or, based on a total mass of 100 wt% of the nickel-based bimetallic catalyst, the mass fraction of the single-atom functional auxiliary is 0.01 wt% to 0.5 wt%.

10. Use of a nickel-based bimetallic catalyst as described in claim 8 or 9, characterized in that, The nickel-based bimetallic catalyst is used for aqueous reforming-hydrogenolysis reaction.

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