A double-site catalyst for deoxygenation of fatty acids to hydrocarbons and preparation and use thereof

Abstract

The application relates to the technical field of chemical catalysts, and particularly discloses a double-site catalyst for deoxygenation of fatty acids to produce hydrocarbons as well as preparation and application of the catalyst. The catalyst uses waste rice husks as a natural carbon source and a structure template. After carbonization, activation and washing, a biomass-derived activated carbon (bio-AC) with an ultrahigh specific surface area and rich surface oxygen-containing groups is obtained. Then, stacking modification of the bio-AC carrier is carried out through pi-pi interaction of aromatic amines, so that a novel carrier (A-bio-AC) with both oxygen-containing and nitrogen-containing anchoring groups is obtained. Trace amounts of metal Ni are loaded on the A-bio-AC through an adsorption reduction method. Due to the difference in anchoring ability of the two groups, Ni exists in the form of single atoms and nanoclusters on the carrier, that is, Ni 1+n / A-bio-AC catalyst. The preparation process of the catalyst realizes resource utilization of the waste rice husks, has extremely low preparation cost, and exhibits excellent conversion rate and long-chain linear alkane selectivity in the catalytic deoxygenation of fatty acids, and shows excellent industrial application potential.

Description

Technical Field

[0001] This invention relates to the field of chemical catalyst technology, specifically to a two-site catalyst for fatty acid deoxygenation to hydrocarbon production, its preparation, and its application. Background Technology

[0002] With the rapid growth of the world's population and economy, the massive consumption of fossil fuels has led to increasingly serious climate problems, while the demand for energy supply continues to rise. Therefore, the development of new green and renewable energy sources is urgently needed. Biomass energy is the only non-fossil resource that can provide a stable carbon source and has abundant reserves, demonstrating excellent development and application potential.

[0003] Oils and fats, with their high energy density and scalable utilization, are an important option for biomass utilization. The catalytic deoxygenation of long-chain fatty acids derived from oil hydrolysis to obtain long-chain linear hydrocarbons represents a novel and sustainable route to alleviate energy and chemical supply demands. The catalytic deoxygenation pathways for fatty acids mainly include decarboxylation, decarbonylation, and hydrodeoxygenation, yielding products such as long-chain linear alkanes or long-chain linear olefins. Current research on catalytic deoxygenation primarily focuses on the hydrodeoxygenation pathway in hydrogen-rich systems, and some high-performance hydrodeoxygenation catalysts have been developed (e.g., Ni / ZrO2 and NiRe / SBA-15). However, the use of high-pressure hydrogen or hydrogen-donating solvents leads to significant safety risks and high process costs, hindering its further application and development.

[0004] Catalytic deoxygenation of fatty acids in hydrogen-free or low-oxygen atmospheres can effectively avoid the aforementioned problems. However, current research on catalysts for hydrogen-free catalytic deoxygenation of fatty acids is limited, and they still face challenges such as low deoxygenation efficiency, poor selectivity for single products, easy carbon deposition and deactivation of catalysts, and high preparation costs. The rational design and preparation of high-performance, low-cost hydrogen-free deoxygenation catalysts for fatty acids is an important approach to solving these problems. Summary of the Invention

[0005] In view of this, in order to solve the safety problems caused by the use of high-pressure hydrogen and hydrogen-supplying solvents in the existing technology, as well as the problems of low deoxygenation efficiency and poor selectivity of long-chain linear alkanes, the purpose of this invention is to provide a method for preparing Ni single-atom and Ni nanocluster catalysts based on rice husk-derived activated carbon stacked with aromatic amines. This catalyst is used for fatty acid deoxygenation to produce straight-chain alkanes. The catalyst prepared by this method has an ultra-high specific surface area, and the abundant oxygen- and nitrogen-containing groups on the support serve as anchoring sites for Ni, anchoring Ni and Ni nanoclusters as dual active sites. These dual active sites have a good synergistic catalytic effect, effectively promoting the adsorption and conversion of fatty acids and improving the selectivity of long-chain linear alkanes, especially the selectivity of straight-chain alkanes.

[0006] In a first aspect, this invention proposes the preparation of a two-site catalyst for fatty acid deoxygenation to hydrocarbon production, comprising the following steps:

[0007] S1: The crushed and sieved rice husk powder is placed in an inert atmosphere and carbonized at high temperature. Then, the carbonized powder is mixed with a solid alkali and ground evenly. It is then activated in an inert atmosphere. After activation, it is washed and dried to obtain a rice husk-derived bio-AC carrier.

[0008] S2: Take the bio-AC support from step S1 into an alcoholic solution of aromatic amine, stir at room temperature, collect the solid, wash with alcohol, and obtain A-bio-AC powder;

[0009] S3: Disperse the A-bio-AC powder from step S2 in Ni 2+ The solution was stirred at room temperature, the solid was collected, washed with alcohol, dried, and then reduced by a reducing gas under heating to give Ni. 1+n / A-bio-AC catalyst.

[0010] In some specific embodiments, the carbonization temperature in step S1 is 300–800°C, and in some preferred embodiments of this specific embodiment, the carbonization temperature in step S1 is 400–700°C.

[0011] In some specific embodiments, the carbonization time in step S1 is 1 to 2 hours, and in some preferred embodiments of this specific embodiment, the carbonization time in step S1 is 1.5 hours.

[0012] In some specific embodiments, the inert atmosphere in step S1 is selected from nitrogen, helium, or argon.

[0013] In some specific embodiments, the activation temperature of step S1 is 700-800°C, and in some preferred embodiments of this specific embodiment, the activation temperature of step S1 is 600-750°C.

[0014] In some specific embodiments, the activation time of step S1 is 1 to 2 hours, and in some preferred embodiments of this specific embodiment, the activation time of step S1 is 1.5 hours.

[0015] In some specific embodiments, the alcohol in step S2 is selected from methanol, ethanol, and propanol.

[0016] In some specific embodiments, the stirring temperature in step S2 is room temperature.

[0017] In some specific embodiments, the stirring time of step S2 is 23-25 ​​hours, and in some preferred embodiments of this specific embodiment, the stirring time of step S2 is 24 hours.

[0018] In some specific embodiments, the washing liquid in step S2 is an alcohol, which is selected from methanol, ethanol or propanol.

[0019] In some specific embodiments, Ni in step S3 2+ The aqueous solution is selected from any one of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate.

[0020] In some specific embodiments, the concentration of aromatic amine in step S2 is 0.8 mol to 2.84 mol per liter of alcohol. In some preferred embodiments of this specific embodiment, the concentration of aromatic amine in step S2 is 0.8 to 1.65 mol per liter of alcohol. In some more preferred embodiments of this specific embodiment, the concentration of aromatic amine in step S2 is 1.65 mol per liter of alcohol.

[0021] In some specific embodiments, the stirring temperature in step S3 is room temperature.

[0022] In some specific embodiments, the stirring time in step S3 is 23-25 ​​hours, and in some preferred embodiments of this specific embodiment, the stirring time in step S3 is 24 hours.

[0023] In some specific embodiments, the washing liquid in step S3 is an alcohol, which is selected from methanol, ethanol and propanol.

[0024] In some specific embodiments, the reduction temperature in step S3 is 350–500°C, and in some preferred embodiments of this specific embodiment, the reduction temperature in step S3 is 400°C.

[0025] In some specific embodiments, the reducing gas in step S3 is a mixture of hydrogen and argon, with a volume ratio of hydrogen to argon of 1:30 to 1:10. In some preferred embodiments of this specific embodiment, the volume ratio of hydrogen to argon is 1:20.

[0026] In some specific embodiments, the restoration time of step S3 is 1 to 3 hours, and in some preferred embodiments of this specific embodiment, the restoration time of step S3 is 2 hours.

[0027] In some specific embodiments, in step S1, the solid alkali is one or more of NaOH, Na2CO3, KOH, and Ca(OH)2.

[0028] In some specific embodiments, in step S1, the mass ratio of carbonized powder to solid alkali is 1:2 to 1:5, preferably 1:3 to 1:5.

[0029] In some specific embodiments, in step S1, the bio-AC carrier is modified by a stack of aromatic amines, wherein the aromatic amines are one or more of aniline, m-phenylenediamine, p-phenylenediamine and o-phenylenediamine.

[0030] In some specific embodiments, in step S3, the Ni 2+ The solution is one or a mixture of nickel nitrate solution, nickel sulfate solution, nickel acetate solution, and nickel chloride solution.

[0031] In some specific embodiments, the Ni 2+ The nickel ion concentration in the solution is 0.12–0.48 mM. In some preferred embodiments of this specific example, the Ni... 2+ The nickel ion concentration in the solution is 0.12–0.4 mM. In some further preferred embodiments of this specific example, the Ni... 2+ The nickel ion concentration in the solution is 0.12–0.24 mM.

[0032] A second aspect of this invention provides a two-site catalyst prepared by the method of the first aspect, wherein the two-site catalyst has the general formula Ni. 1+n / A-bio-AC.

[0033] In some specific embodiments of the second aspect, the dual-site catalyst includes a support and active sites supported on the support, wherein the support is rice husk-derived activated carbon stacked with aromatic amines, and the active sites include Ni single atoms and Ni nanoclusters / particles.

[0034] A third aspect of this invention provides an application of fatty acid deoxygenation to produce straight-chain alkanes, wherein the catalyst described in the second aspect participates in this application, and the application of the third aspect includes the following steps:

[0035] S1: In a reactor free of external hydrogen and solvent, stearic acid is added and heated to dissolve.

[0036] S2: Input Ni 1+n / A-bio-AC catalyst, stir evenly, heat up, and continue the reaction.

[0037] In some specific embodiments of the third aspect, the temperature in step S2 is raised to 340–370°C, and in some preferred embodiments of the third aspect, the temperature in step S2 is raised to 360°C.

[0038] In some specific embodiments of the third aspect, the reaction time of step S2 is 25 to 35 minutes, and in some preferred embodiments of the third aspect, the reaction time of step S2 is 30 minutes.

[0039] In this embodiment of the invention, "mM" means millimoles per liter, "M" means moles per liter, and "room temperature" means 25°C to 30°C.

[0040] TOF Ni " represents the catalyst's turnover frequency."

[0041] The advantages of this invention are:

[0042] 1. The present invention provides a method for preparing a Ni dual-site catalyst for the deoxygenation of fatty acids to long-chain linear alkanes, which has the following beneficial effects: The present invention utilizes waste rice husks as a natural carbon source and structural template agent, which can obtain an inexpensive carrier with ultra-high specific surface area and rich in surface oxygen-containing groups, effectively promoting the adsorption and conversion of fatty acids.

[0043] 2. In the catalyst preparation process of the present invention, aromatic amines are used to provide nitrogen-containing groups with stronger anchoring ability to the bio-AC support stack, thereby forming two kinds of metal sites: Ni single atoms and Ni nanoclusters. The synergistic catalytic effect between the two effectively improves the selectivity and yield of straight-chain alkanes. This catalyst can carry out fatty acid deoxygenation to alkanes under a hydrogen-free atmosphere, avoiding the safety risks caused by high-pressure hydrogenation and the use of hydrogen-donating solvents. At the same time, the catalyst of the present invention can achieve high selectivity, selectively catalyzing the hydrocarbon formation of straight-chain fatty acids in a mixed system of straight-chain fatty acids and branched-chain fatty acids. Attached Figure Description

[0044] Figure 1 Ni assembled from aniline-stacked rice husk-derived activated carbon prepared in Example 1 of this invention. 1+n Powder X-ray diffraction pattern of the / A-bio-AC dual-site catalyst.

[0045] Figure 2 Ni assembled from aniline-stacked rice husk-derived activated carbon prepared in Example 2 of this invention. 1+n Scanning electron microscope image of the / A-bio-AC dual-site catalyst. Detailed Implementation

[0046] To further explain the technical solution of the present invention, the present invention will be described in detail below through specific embodiments.

[0047] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0048] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0049] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0050] Example 1

[0051] S1: The crushed and sieved rice husk powder was placed in an inert atmosphere and carbonized at 400℃ for 2 hours. Subsequently, the carbonized powder was ground with NaOH at a mass ratio of 1:3 until uniform, and then placed in an inert atmosphere again and activated at 600℃ for 2 hours. After washing with deionized water and drying, the rice husk-derived bio-AC carrier was obtained.

[0052] S2: Disperse 0.3 g of bio-AC powder in an ethanol solution of 0.8 mol / L p-phenylenediamine and stir at room temperature for 24 h. Then, collect the product by centrifugation and wash it several times with ethanol to obtain the aromatic amine stacked bio-AC (A-bio-AC).

[0053] S3: The obtained 0.16 g A-bio-AC powder was dispersed in a 0.45 mmol / L nickel acetate aqueous solution, stirred at room temperature for 24 h, the product was collected by vacuum filtration and washed with ethanol to remove unanchored Ni. 2+ The dried sample was reduced at 400℃ with 5% H2 / Ar for 2 hours to obtain Ni containing Ni single atoms and nanoclusters. 1+n / A-bio-AC catalyst.

[0054] Example 2

[0055] S1: The crushed and sieved rice husk powder was placed in an inert atmosphere and carbonized at 500℃ for 1 hour. Subsequently, the carbonized powder was ground with KOH at a mass ratio of 1:3 until uniform, and then placed in an inert atmosphere again and activated at 750℃ for 1 hour. After washing with deionized water and drying, the rice husk-derived bio-AC carrier was obtained.

[0056] S2: Disperse 0.3 g of bio-AC powder in an ethanol solution of 1.65 mmol / L aniline and stir at room temperature for 4 h. Then, collect the product by centrifugation and wash it several times with ethanol to obtain the aromatic amine stacked bio-AC (A-bio-AC).

[0057] S3: Disperse the obtained 0.16 g A-bio-AC powder in a 0.24 mmol / L nickel nitrate aqueous solution, stir at room temperature for 24 h, collect the product by vacuum filtration and wash with ethanol to remove unanchored Ni. 2+ The dried sample was reduced at 350℃ with 5% H2 / Ar for 2 hours to obtain Ni containing Ni single atoms and nanoclusters. 1+n / A-bio-AC catalyst.

[0058] Example 3

[0059] S1: The crushed and sieved rice husk powder was placed in an inert atmosphere and carbonized at 600℃ for 1 hour. Subsequently, the carbonized powder was ground with Na2CO3 at a mass ratio of 1:5 until uniform, and then placed in an inert atmosphere again and activated at 750℃ for 1 hour. After washing with deionized water and drying, the rice husk-derived bio-AC carrier was obtained.

[0060] S2: Disperse 0.6 g of bio-AC powder in an ethanol solution of 2.84 mmol / L p-phenylenediamine and stir at room temperature for 4 h. Then, collect the product by centrifugation and wash it several times with ethanol to obtain the aromatic amine stacked bio-AC (A-bio-AC).

[0061] S3 dispersed 0.16 g of the obtained A-bio-AC powder in a 0.24 mmol / L nickel nitrate aqueous solution, stirred at room temperature for 24 h, collected the product by vacuum filtration, and washed with ethanol to remove unanchored Ni. 2+ The dried sample was reduced at 500℃ with 5% H2 / Ar for 2 hours to obtain Ni containing Ni single atoms and nanoclusters. 1+n / A-bio-AC catalyst.

[0062] Example 4

[0063] S1: The crushed and sieved rice husk powder was placed in an inert atmosphere and carbonized at 500℃ for 1 hour. Subsequently, the carbonized powder was ground with KOH at a mass ratio of 1:4 until uniform, and then placed in an inert atmosphere again and activated at 700℃ for 1 hour. After washing with deionized water and drying, the rice husk-derived bio-AC carrier was obtained.

[0064] S2: Disperse 0.3 g of bio-AC powder in an ethanol solution of 1.65 mmol / L o-phenylenediamine and stir at room temperature for 24 h. Then, collect the product by centrifugation and wash it several times with ethanol to obtain the aromatic amine stacked bio-AC (A-bio-AC).

[0065] S3: The obtained 0.16 g A-bio-AC powder was dispersed in a 0.48 mmol / L nickel chloride aqueous solution, stirred at room temperature for 24 h, and the product was collected by vacuum filtration and washed with ethanol to remove unanchored Ni. 2+ The dried sample was reduced at 500℃ with 5% H2 / Ar for 2 hours to obtain Ni containing Ni single atoms and nanoclusters. 1+n / A-bio-AC catalyst.

[0066] Example 5

[0067] S1: The crushed and sieved rice husk powder was placed in an inert atmosphere and carbonized at 500℃ for 1 hour. Subsequently, the carbonized powder was ground with NaOH at a mass ratio of 1:3 until uniform, and then placed in an inert atmosphere again and activated at 750℃ for 1 hour. After washing with deionized water and drying, the rice husk-derived bio-AC carrier was obtained.

[0068] S2: Disperse 0.6 g of bio-AC powder in an ethanol solution of 1.65 mmol / L m-phenylenediamine and stir at room temperature for 24 h. Then, collect the product by centrifugation and wash it several times with ethanol to obtain the aromatic amine stacked bio-AC (A-bio-AC).

[0069] S3: The obtained 0.16 g A-bio-AC powder was dispersed in a 0.12 mmol / L nickel nitrate aqueous solution, stirred at room temperature for 24 h, and the product was collected by vacuum filtration and washed with ethanol to remove unanchored Ni. 2+ The dried sample was reduced at 400℃ with 5% H2 / Ar for 2 hours to obtain Ni containing Ni single atoms and nanoclusters. 1+n / A-bio-AC catalyst.

[0070] Comparative Example 1

[0071] S1: The crushed and sieved wheat bran hull powder was placed in an inert atmosphere and carbonized at 400℃ for 2 hours. Subsequently, the obtained carbonized powder was ground with NaOH at a mass ratio of 1:3 until uniform, and then placed in a nitrogen atmosphere again and activated at 600℃ for 1 hour. The resulting black powder 1 was washed with deionized water and dried.

[0072] S2: Disperse 0.6 g of the black powder 1 from step S1 in an ethanol solution of 1.65 mmol / L aniline and stir at room temperature for 24 h. Then, collect the product by centrifugation and wash it several times with ethanol, and let it air dry.

[0073] S3: Disperse 0.16 g of the naturally dried powder from step S2 in a 0.45 mmol / L nickel nitrate aqueous solution. After stirring at room temperature for 24 h, collect the product by vacuum filtration and wash with ethanol to remove unanchored Ni. 2+ The dried sample was reduced at 400℃ with 5% H2 / Ar for 2 hours to obtain control catalyst 1.

[0074] Comparative Example 2

[0075] S1: The crushed and sieved rice husk powder was placed in an inert atmosphere and carbonized at 500℃ for 1 hour. Subsequently, the obtained carbonized powder was ground with NaOH at a mass ratio of 1:3 until uniform, and then placed in a nitrogen atmosphere again and activated at 750℃ for 1 hour. After washing and drying with deionized water, black powder 2 was obtained.

[0076] S2: Take 0.6 g of black powder 2 prepared in step S1, disperse it in an ethanol solution of 1.65 mmol / L n-heptylamine, and stir at room temperature for 24 h. Then, collect the product by centrifugation and wash it several times with ethanol, and let it air dry.

[0077] S3: Take 0.16 g of the naturally dried solid powder from step S2 and disperse it in a 0.24 mmol / L nickel nitrate aqueous solution. After stirring at room temperature for 24 h, collect the product by vacuum filtration and wash with ethanol to remove unanchored Ni. 2+ The dried sample was reduced at 350℃ with 5% H2 / Ar for 2 hours to obtain control catalyst 2.

[0078] Comparative Example 3

[0079] S1: The crushed and sieved rice husk powder was placed in an inert atmosphere and carbonized at 600℃ for 1 hour. Subsequently, the obtained carbonized powder was ground with NaOH at a mass ratio of 1:1 until homogeneous, and then placed again in a nitrogen atmosphere and activated at 600℃ for 1 hour.

[0080] Black powder 3 after washing and drying with deionized water;

[0081] S2: Disperse 0.6 g of the black powder 3 from step S1 in an ethanol solution of 1.65 mmol / L catechol and stir for 24 h at room temperature. Then, collect the product by centrifugation, wash it several times with ethanol, and air dry.

[0082] S3: Take 0.16 g of the naturally dried powder from step S2 and disperse it in a 0.24 mmol / L nickel nitrate aqueous solution. After stirring at room temperature for 24 h, collect the product by vacuum filtration and wash with ethanol to remove unanchored Ni. 2+ The dried sample was reduced at 500℃ with 5% H2 / Ar for 2 hours to obtain comparative catalyst 3.

[0083] Comparative Example 4

[0084] S1: The crushed and sieved rice husk powder was placed in an inert atmosphere and carbonized at 500℃ for 1 hour. Subsequently, the obtained carbonized powder was ground with NaOH at a mass ratio of 1:4 until a uniform powder was obtained. The powder was dispersed in a 0.24 mmol / L nickel nitrate aqueous solution and stirred at room temperature for 24 hours. The solid was obtained by suction filtration and placed in a nitrogen atmosphere again for activation at 650℃ for 1 hour. After washing and drying with deionized water, black powder 4 was obtained.

[0085] S2: Take 0.6 g of black powder 4 from step S1 and disperse it in an ethanol solution of 1.65 mmol / L o-phenylenediamine, and stir for 24 h at room temperature. Then, collect the product by centrifugation, wash it several times with ethanol, and dry it.

[0086] S3: The sample dried in step S2 was reduced at 500℃ for 2 hours with 5% H2 / Ar to obtain the control catalyst 4.

[0087] Catalyst performance testing

[0088] In a batch reactor free of external hydrogen and solvents, 2.85 kg of C18 straight-chain stearic acid was added and heated to dissolve it. The catalyst powder from Examples 1-5 and Comparative Examples 1-4 was then added, with a mass of C... 18 The amount of linear stearin used is 3% of the feed weight.

[0089] After reacting at 360℃ for 30 min, samples were taken from the batch reactor to detect the content of straight-chain alkanes and branched-chain alkanes. The results are shown in Table 1.

[0090]

[0091] Table 1: Yield Where m x m represents the product mass of this compound. tatol C represents the total mass of the transformed product. 18 Total conversion rate of linear stearic acid Where m1 is the unconverted C 18 The mass of linear stearic acid, m2 is the C of the feed. 18 Quality of linear stearic acid.

[0092] Conclusion: In a batch reactor without external hydrogen and without solvent, C 18 Straight-chain stearic acid in Ni 1+n After reacting at 360℃ for 30 min on the / A-bio-AC catalyst, the conversion rate of straight-chain fatty acids can reach 90.24%–96.81%. Among heptadecane and heptadeene, the selectivity for heptadecane is as high as 90%, corresponding to a reaction turnover frequency (TOF). Ni Up to 230h -1 Furthermore, the catalyst showed no significant deactivation after 50 cycles of reaction.

[0093] A series of mechanistic characterizations revealed that Ni clusters promote the adsorption and activation of fatty acids, while Ni single atoms, acting as highly dispersed Lewis acid sites, promote the conversion of fatty alcohol intermediates in the in-situ hydrodeoxygenation process. The two work synergistically to achieve high conversion rates and selectivity. However, when the preparation order of the catalyst in this invention is changed, such as in Comparative Example 4, where Ni metal is first loaded onto a rice husk carbon powder support before adding aromatic amines, the Ni... 1+n The metal was loaded onto the rice husk carbon powder before the aromatic amine formed a stacked modification; therefore, Comparative Example 4 did not form a single Ni1 atom and Ni... n Nanoclusters supported in the form of A-bio-AC, consisting only of single metal sites (Ni), catalyze C 18 When the straight-chain stearin was converted to heptadecane, both the yield and selectivity were lower than in Example 4.

[0094] In Comparative Examples 2 and 3, the aromatic amines were replaced with n-heptane and catechol, respectively. Although the other conditions in Comparative Examples 2 and 3 were the same as those in Examples 2 and 3, the replacement of the aromatic amines meant that even when using bio-AC as a support, it was still impossible to achieve the same conversion rate and selectivity as in Examples 2 and 3 by stacking the aromatic amines on the bio-AC support through π-π interactions. In Comparative Example 1, wheat bran husks were used to prepare the support. Although aromatic amines were used for modification, due to the difference in the group structure on the surface of rice husks and wheat bran husks, the aromatic amines did not stack with the wheat bran husks. Therefore, Comparative Example 1 did not achieve the same conversion rate and selectivity as in Example 1.

[0095] Therefore, this invention prepares bio-AC from rice husk powder, and then modifies the bio-AC support with aromatic amine stacking through π-π interactions, thereby obtaining a novel support (A-bio-AC) with both oxygen-containing and nitrogen-containing anchoring groups. Trace amounts of metallic Ni are then loaded onto the A-bio-AC via adsorption-reduction. Benefiting from the difference in anchoring ability between the two groups, Ni is expressed in single-atom and nano-cluster forms. n The forms coexist on the carrier, namely Ni 1+nThe A-bio-AC catalyst and the catalyst interact electronically, which effectively promotes the desorption of the COO* intermediate and improves the activity of the decarboxylation pathway.

[0096] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for preparing a two-site catalyst for fatty acid deoxygenation to hydrocarbon production, characterized in that, Including the following steps: S1: Rice husk powder is carbonized at high temperature in an inert atmosphere. Then, the carbonized powder is mixed and ground evenly with solid alkali and activated in an inert atmosphere. After activation, it is washed and dried to obtain rice husk-derived bio-AC carrier. S2: Take the bio-AC support from step S1 into an alcoholic solution of aromatic amine, stir at room temperature, collect the solid, wash with alcohol, and obtain A-bio-AC powder; S3: Disperse the A-bio-AC powder from step S2 in Ni 2+ The solid was collected in an aqueous solution at room temperature by stirring, washed with alcohol, dried, and then reduced by a reducing gas under heating to obtain Ni. 1+n / A-bio-AC catalyst.

2. The method for preparing the catalyst according to claim 1, characterized in that, In step S1, the carbonization temperature is 300~800℃, and / or the carbonization time is 1~2h, and / or the inert atmosphere in step S1 is selected from nitrogen, helium or argon, and / or the activation temperature is 600~800℃, and / or the activation time in step S1 is 1~2h, and / or the concentration of aromatic amine in each liter of alcohol in step S2 is 0.8mol to 2.84mol.

3. The method for preparing the catalyst according to claim 2, characterized in that, The carbonization temperature in step S1 is 400~700℃.

4. The method for preparing the catalyst according to claim 2, characterized in that, The activation temperature is 700~750℃.

5. The method for preparing the catalyst according to claim 2, characterized in that, The activation time for step S1 is 1.5 hours.

6. The method for preparing the catalyst according to claim 2, characterized in that, In step S2, the concentration of aromatic amines in each liter of alcohol is 0.8 to 1.65 mol.

7. The method for preparing the catalyst according to claim 1, characterized in that, The alcohol in step S2 is selected from methanol, ethanol, and propanol, and / or the stirring temperature in step S2 is room temperature, and / or the stirring time in step S2 is 23-25 ​​hours, and / or the washing liquid in step S2 is an alcohol selected from methanol, ethanol, or propanol.

8. The method for preparing the catalyst according to claim 1, characterized in that, Ni in step S3 2+ The aqueous solution is selected from any one of nickel sulfate, nickel chloride, nickel nitrate, and nickel acetate, and / or the stirring temperature in step S3 is room temperature, and / or the stirring time in step S3 is 23~25h, and / or the washing liquid in step S3 is an alcohol, selected from any one of methanol, ethanol, and propanol, and / or the reduction temperature in step S3 is 350~500℃, and / or the reducing gas in step S3 is a mixture of hydrogen and argon, with a hydrogen to argon volume ratio of 1:30~1:10, and / or the reduction time in step S3 is 1~3h.

9. The method for preparing the catalyst according to claim 8, characterized in that, The reduction temperature in step S3 is 400℃.

10. The method for preparing the catalyst according to claim 8, characterized in that, The reducing gas in step S3 is a mixture of hydrogen and argon, with a volume ratio of 1:

20.

11. The method for preparing the catalyst according to any one of claims 1 to 4, characterized in that, In step S1, the solid alkali is one or more of NaOH, Na2CO3, KOH and Ca(OH)2, and / or, in step S1, the mass ratio of carbonized powder to solid alkali is 1:2 to 1:

5.

12. The method for preparing the catalyst according to claim 11, characterized in that, In step S1, the mass ratio of carbonized powder to solid alkali is 1:3 to 1:

5.

13. The method for preparing the catalyst according to claim 1, characterized in that, In step S2, the bio-AC carrier is modified by stacking aromatic amines, wherein the aromatic amines are one or more of aniline, m-phenylenediamine, p-phenylenediamine and o-phenylenediamine.

14. The method for preparing the catalyst according to claim 1, characterized in that, In step S3, the Ni 2+ The aqueous solution is one or a mixture of nickel nitrate solution, nickel sulfate solution, nickel acetate solution, and nickel chloride solution, and / or, the Ni 2+ The nickel ion concentration in the solution is 0.12~0.48 mM.

15. The method for preparing the catalyst according to claim 1, characterized in that, The Ni 2+ The concentration of nickel ions in the solution is 0.12~0.4mM.

16. A general formula is Ni 1+n The dual-site catalyst of / A-bio-AC, characterized in that, The general formula is Ni 1+n The / A-bio-AC dual-site catalyst was prepared by the preparation method according to any one of claims 1 to 15.

17. The use of the catalyst of claim 16 in the deoxygenation of fatty acids to straight-chain alkanes, comprising, S1: Stearic acid is added to a reactor free of external hydrogen and solvent, and then heated to dissolve. S2: Input Ni 1+n / A-bio-AC catalyst, stirred until homogeneous, heated, and reacted continuously. The temperature in step S2 is increased to 340~370 ℃, and the reaction time is 25~35 min.

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