阅读说明：本技术 一种纳米多孔Ni-Fe合金催化剂的制备方法 (Preparation method of nano-porous Ni-Fe alloy catalyst ) 是由 胡勋 亓敬波 于 2019-10-08 设计创作，主要内容包括：本发明提供了一种纳米多孔Ni-Fe合金催化剂的制备方法,通过高温氢气还原脱氧化锌模板。首先,通过水热合成法制得含有Zn、Ni和Fe元素的复合金属氧化物前驱物,然后,对所得前驱体进行过滤、洗涤和干燥处理,最后,将所得复合金属氧化物在高温条件下经氢气还原脱除氧化锌并得到纳米多孔金属催化剂。本申请所制得的纳米多孔Ni-Fe合金催化剂,具有孔隙丰富,比表面积大,催化活性好的有益效果,用于木质素基酚类加氢脱氧反应时,具有反应条件较为温和,原料转化率高,且产物中苯类选择性较高的优势,无需使用强酸或强碱脱除模板,制备工艺环保。(The invention provides a preparation method of a nano-porous Ni-Fe alloy catalyst, which deoxidizes a zinc oxide template through high-temperature hydrogen reduction. Firstly, preparing a composite metal oxide precursor containing Zn, Ni and Fe elements by a hydrothermal synthesis method, then filtering, washing and drying the obtained precursor, and finally, reducing the obtained composite metal oxide by hydrogen at a high temperature to remove zinc oxide and obtain the nano porous metal catalyst. The nano-porous Ni-Fe alloy catalyst prepared by the method has the beneficial effects of rich pores, large specific surface area and good catalytic activity, has the advantages of mild reaction conditions, high raw material conversion rate and high benzene selectivity in the product when being used for the hydrodeoxygenation reaction of lignin-based phenols, does not need to use strong acid or strong base to remove a template, and is environment-friendly in preparation process.)

1. A preparation method of a nano-porous Ni-Fe alloy catalyst is characterized by comprising the following steps:

(1) sequentially adding a precursor of metal zinc, a precursor of metal nickel, a precursor of metal iron and alkali into deionized water to prepare a solution with a certain concentration, and magnetically stirring until the solution is fully dissolved;

(2) transferring the solution obtained in the step (1) into a hydrothermal kettle for hydrothermal reaction, and filtering, washing and drying the product after the reaction is finished;

(3) and (3) placing the dried sample in the step (2) into a tubular furnace, and introducing hydrogen to reduce at high temperature.

2. The method for preparing a nanoporous Ni-Fe alloy catalyst according to claim 1, wherein in step (1), the precursor of metallic zinc is one of zinc nitrate hexahydrate, zinc acetate dihydrate, zinc sulfate heptahydrate, and anhydrous zinc chloride.

3. The method for preparing a nanoporous Ni-Fe alloy catalyst according to claim 1, wherein in step (1), the precursor of metallic nickel is one of nickel nitrate hexahydrate, nickel acetate tetrahydrate, nickel sulfate hexahydrate, and nickel dichloride hexahydrate.

4. The preparation method of the nanoporous Ni-Fe alloy catalyst according to claim 1, wherein in the step (1), the precursor of metallic iron is one of ferric nitrate nonahydrate, ferric sulfate hydrate and ferric trichloride hexahydrate.

5. The method for preparing a nanoporous Ni-Fe alloy catalyst according to claim 1, wherein the Zn in the solution obtained in step (1)²⁺The concentration of (A) is 0.1 to 0.5mol/L, preferably 0.2; ni²⁺The concentration of (A) is 0.1-0.5 mol/L, preferably 0.2; ni²⁺With Fe³⁺The molar ratio of (0.5-10): 1, preferably 5: 1.

6. the method for preparing a nanoporous Ni-Fe alloy catalyst according to any one of claims 2-5, wherein in step (1), the base is one of urea, ammonia, sodium carbonate, sodium hydroxide, potassium carbonate and potassium hydroxide.

7. The method for preparing a nano-porous Ni-Fe alloy catalyst according to claim 6, wherein in the step (2), the hydrothermal reaction conditions are as follows: the temperature is 100-180 ℃, preferably 120 ℃; the time is 2-24 h, preferably 18 h.

8. The method for preparing a nanoporous Ni-Fe alloy catalyst according to claim 7, wherein in the step (3), the reduction conditions are: the temperature is 400-800 ℃, preferably 700 ℃; the time is 1-6 h, preferably 2 h.

9. The method of claim 1, wherein the catalyst is used for hydrodeoxygenation of lignin-based phenols.

10. The method for preparing the nanoporous Ni-Fe alloy catalyst according to claim 9, wherein the lignin is dissolved in 40mL of dodecane to prepare the reaction solution, and the reaction solution is prepared by: weighing the catalyst according to the mass ratio of the catalyst being 5:1, putting the reaction solution and the catalyst into a reaction kettle, sealing, introducing hydrogen for replacement for 5 times, then introducing 2MPa hydrogen at room temperature, stirring at the speed of 700r/min, heating while stirring to the reaction temperature of 220 ℃, and reacting for 2 hours.

Technical Field

The invention relates to the technical field of preparation of nano catalysts, and mainly relates to a preparation method of a nano porous Ni-Fe alloy catalyst.

Background

Lignin has gained increasing attention as a cheap and abundant biomass resource for its development and utilization. The utilization of lignin as a raw material for the production of liquid fuels or chemicals is an effective way for the high-value utilization thereof. Catalytic hydrodeoxygenation of lignin-based bio-oils to varying degrees can yield various chemicals or fully hydrodeoxygenated hydrocarbon fuels. Because the lignin structure is rich in benzene rings, the benzene ring structure is remained in the hydrodeoxygenation process to obtain the benzene platform compound, and the benzene platform compound has higher economic benefit.

The key to the preparation of benzene chemicals from lignin-based phenolic compounds is the study of suitable catalysts. The metal Ni is a high-efficiency phenol hydrodeoxygenation catalyst and is widely applied, but the Ni catalyst is high in activity and easy to perform saturated hydrogenation on benzene rings. The metal Fe catalyst can realize high selectivity of benzene compounds, but the catalytic activity of the metal Fe catalyst is low. The prepared Ni-Fe bimetallic alloy catalyst can make up the defects of the Ni-Fe bimetallic alloy catalyst and the Fe bimetallic alloy catalyst, and realizes the quantitative and efficient conversion of lignin-based phenols to benzene compounds through the synergistic effect. The Ni-Fe bimetallic catalyst for hydrodeoxygenation of lignin-based phenols researched at present is mostly a supported catalyst, and the upper limit of the activity of the supported catalyst is limited by the supported amount. Almost no report is made on the synthesis method of the bulk Ni-Fe alloy catalyst, particularly the bulk Ni-Fe alloy with a nano-porous structure.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a preparation method of a nano porous Ni-Fe alloy catalyst, the method has the advantages of simple and environment-friendly process, low cost, uniform size distribution of the obtained catalyst, large specific surface area and high activity, and the catalyst is used for hydrogenation and deoxidation of lignin-based phenols.

In order to achieve the above object, the present invention is realized by:

the method comprises the following steps:

(1) sequentially adding a precursor of metal zinc, a precursor of metal nickel, a precursor of metal iron and alkali into deionized water to prepare a solution with a certain concentration, and magnetically stirring until the solution is fully dissolved;

(2) transferring the solution obtained in the step (1) into a hydrothermal kettle for hydrothermal reaction, and filtering, washing and drying the product after the reaction is finished;

(3) and (3) placing the dried sample in the step (2) into a tubular furnace, and introducing hydrogen to reduce at high temperature.

As a preferred embodiment, in the step (1), the precursor of the metallic zinc is one of zinc nitrate hexahydrate, zinc acetate dihydrate, zinc sulfate heptahydrate and anhydrous zinc chloride.

As a preferred embodiment, in the step (1), the precursor of the metallic nickel is one of nickel nitrate hexahydrate, nickel acetate tetrahydrate, nickel sulfate hexahydrate and nickel dichloride hexahydrate.

In a preferred embodiment, in the step (1), the precursor of metallic iron is one of ferric nitrate nonahydrate, ferric sulfate hydrate and ferric trichloride hexahydrate.

As a preferred embodiment, Zn is contained in the solution obtained in the step (1)²⁺The concentration of (A) is 0.1-0.5 mol/L, preferably 0.2; ni²⁺The concentration of (A) is 0.1-0.5 mol/L, preferably 0.2; the concentration of the alkali is 0.1-1 mol/L, preferably 0.8; ni²⁺With Fe³⁺The molar ratio of (0.5-10): 1, preferably 5: 1.

as a preferred embodiment, in the step (1), the base is one of urea, ammonia water, sodium carbonate, sodium hydroxide, potassium carbonate and potassium hydroxide.

As a preferred embodiment, in the step (2), the hydrothermal reaction conditions are: the temperature is 100-180 ℃, preferably 120 ℃; the time is 2-24 h, preferably 18 h.

As a preferred embodiment, in step (3), the reduction conditions are: the temperature is 400-800 ℃, preferably 700 ℃; the time is 1-6 h, preferably 2 h.

As a preferred embodiment, the catalyst is used for hydrodeoxygenation of lignin-based phenols.

In a preferred embodiment, the lignin is dissolved in 40mL of dodecane to prepare a reaction solution, and the reaction solution is prepared by: weighing the catalyst according to the mass ratio of the catalyst being 5:1, putting the reaction solution and the catalyst into a reaction kettle, sealing, introducing hydrogen for replacement for 5 times, then introducing 2MPa hydrogen at room temperature, stirring at the speed of 700r/min, heating while stirring to the reaction temperature of 220 ℃, and reacting for 2 hours.

The invention also discloses application of the catalyst in catalytic hydrogenation and deoxidation reaction of guaiacol, which is characterized in that guaiacol is dissolved in 40mL of dodecane to prepare reaction liquid, and reactants in mass ratio: weighing the catalyst in a ratio of 5: 1; putting the reaction solution and a catalyst into a reaction kettle, sealing, introducing hydrogen for replacing for 5 times, then introducing 2MPa hydrogen at room temperature, stirring at the speed of 700r/min, heating while stirring to the reaction temperature of 220 ℃, and reacting for 2 hours. The product is qualitatively and quantitatively analyzed by gas chromatograph-mass spectrometer and gas chromatograph.

The invention has the beneficial effects that:

(1) the method has the advantages of simple process, cheap and easily-obtained raw materials, low cost, short production period, high yield and repeatability, and is suitable for large-scale industrial production.

(2) Compared with the prior art, the method can realize the complete removal of the template and avoid the corrosion and pollution of strong alkali.

(3) The obtained nano porous bimetallic catalyst has the advantages of uniform size, large specific surface area, high activity for the hydrodeoxygenation reaction of lignin-based phenols and high selectivity of the benzene in the product.

Detailed Description

For further disclosure, but not limitation, the present invention is described in further detail below with reference to examples.