阅读说明：本技术 一种氮掺杂生物碳负载金属镍催化剂及其应用 (Nitrogen-doped biochar-loaded metal nickel catalyst and application thereof ) 是由 胡勋 亓敬波 于 2019-10-08 设计创作，主要内容包括：本发明提供了一种氮掺杂生物碳负载金属镍催化剂及应用,属于催化剂制备技术领域。该催化剂采用单宁酸作为碳源,与镍源共同溶解配成溶液,在碱性环境下进行水热合成得到镍-多元酚配位聚合物,然后经高温碳化还原得到催化剂。该催化剂应用于糠醛转化制备糠醇的反应。本发明具有工艺简单、成本低廉,所得催化剂活性组分分散度高、催化性能优异的有益效果,催化剂用于糠醛转化制备糠醇的反应时,具有实现糠醛完全转化,且糠醇选择性达到97.2％,催化剂的稳定性高,重复使用五次后糠醛转化率仍保持在95％以上的有益效果。(The invention provides a nitrogen-doped biochar-loaded metal nickel catalyst and application thereof, and belongs to the technical field of catalyst preparation. The catalyst adopts tannic acid as a carbon source, is dissolved together with a nickel source to prepare a solution, is subjected to hydrothermal synthesis in an alkaline environment to obtain a nickel-polyphenol coordination polymer, and is subjected to high-temperature carbonization reduction to obtain the catalyst. The catalyst is applied to the reaction for preparing furfuryl alcohol by furfural conversion. The invention has the advantages of simple process, low cost, high dispersion degree of the active components of the obtained catalyst and excellent catalytic performance, when the catalyst is used for the reaction of preparing furfuryl alcohol by furfural conversion, the catalyst can realize the complete conversion of furfural, the selectivity of the furfuryl alcohol reaches 97.2 percent, the stability of the catalyst is high, and the conversion rate of the furfural is still kept above 95 percent after the catalyst is repeatedly used for five times.)

1. The nitrogen-doped biochar loaded metal nickel catalyst is characterized by being prepared by the following preparation steps:

(1) dissolving tannic acid in deionized water, then sequentially dropwise adding a nickel salt water solution and adding an alkaline nitrogen source, and violently stirring;

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

(3) and (3) placing the sample dried in the step (2) in a tubular furnace, introducing nitrogen gas, and treating at high temperature to obtain the nitrogen-doped biological carbon supported nickel catalyst.

2. The nitrogen-doped biochar-supported metallic nickel catalyst as claimed in claim 1, wherein in the step (1), the nickel salt is one of nickel nitrate hexahydrate, nickel acetate tetrahydrate, nickel sulfate hexahydrate and nickel dichloride hexahydrate, and the nickel nitrate hexahydrate is preferred.

3. The nitrogen-doped biochar-supported metallic nickel catalyst as claimed in claim 2, wherein in the step (1), the basic nitrogen source is one of hexamethylenetetramine, tetrapropylammonium hydroxide, ammonia water and urea, and preferably hexamethylenetetramine.

4. The nitrogen-doped biochar-supported metallic nickel catalyst as claimed in claim 3, wherein in step (1), Ni in the obtained solution ²⁺The concentration of (b) is 0.01-0.1 mol/L, preferably 0.05 mol/L; the concentration of the tannic acid is 50-200 g/L, preferably 100 g/L; the concentration of the basic nitrogen source is 10-50 g/L, preferably 25 g/L.

5. The nitrogen-doped biochar-supported metallic nickel catalyst according to any one of claims 1 to 4, characterized in that in the step (2), the hydrothermal reaction temperature is 100 ℃ to 180 ℃, preferably 120 ℃, the hydrothermal reaction time is 2 to 24 hours, preferably 12 hours, the reaction product is naturally cooled to room temperature, the product is repeatedly washed to neutrality with deionized water and absolute ethyl alcohol, and the product is dried at 120 ℃ for 12 hours under vacuum condition.

6. The nitrogen-doped biochar-supported metallic nickel catalyst as claimed in claim 5, wherein in the step (3), the nitrogen flow rate is 100mL/min, the temperature rise rate is 2 ℃/min, the treatment temperature is 500-800 ℃, preferably 700 ℃, and the treatment time is 1-5 h, preferably 3 h.

7. The application of the nitrogen-doped biochar-supported metallic nickel catalyst as claimed in claim 6, which is applied to furfural catalytic hydrogenation reaction under the following conditions: n-dodecane is used as a solvent, the concentration of furfural in the n-dodecane is 0.3mol/L, the mass ratio of furfural to catalyst is 5:1, the initial hydrogen pressure is 2MPa, the stirring speed is 700r/min, the reaction temperature is 160 ℃, and the reaction time is 2 h.

Technical Field

The invention relates to a nitrogen-doped biochar loaded metal nickel catalyst and application thereof, which can be used for furfural hydrogenation and belong to the technical field of catalyst preparation.

Background

With the continuous development and consumption of petrochemical resources, the development and utilization of renewable biomass resources are more and more emphasized. The biomass can be converted to obtain various high value-added chemicals, and the catalytic hydrogenation technology is an important means in the conversion process of the biomass and is widely applied.

The most commonly used hydrogenation catalysts are metal catalysts. In order to reduce the cost and improve the dispersion of the active component, metal catalysts are generally used by being supported on various carriers such as metal oxides and carbon materials. Among them, the carbon material has been widely paid attention as a carrier for hydrogenation catalysts because of its good thermal stability, strong acid-base corrosion resistance and large specific surface area. Compared with carbon materials such as carbon nanotubes and graphene, the biomass-derived carbon material has the advantages of rich source and low price. In addition, nitrogen atoms are doped in the carbon material, so that the structural property of the carbon material can be changed, the interaction between the carbon carrier and the metal active component is enhanced, and the activity and the stability of the catalyst are improved. However, most studies at present are to carbonize biomass to prepare a carbon material, and then to prepare a supported metal hydrogenation catalyst by using the carbon material as a carrier through an impregnation method. The metal active component of the obtained catalyst is easy to sinter and agglomerate on the carrier in the preparation process, the dispersity is low, and the stability is poor.

Disclosure of Invention

The invention provides a nitrogen-doped biochar-loaded metal nickel catalyst and application thereof, and solves the problems that metal active components of the catalyst are easy to sinter and agglomerate on a carrier in the preparation process, the dispersity is low, and the stability is poor.

The invention is realized by adopting the following preparation steps:

(1) dissolving tannic acid in deionized water, then sequentially dropwise adding a nickel salt water solution and adding an alkaline nitrogen source, and violently stirring;

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

(3) and (3) placing the sample dried in the step (2) in a tubular furnace, introducing nitrogen gas, and treating at high temperature to obtain the nitrogen-doped biological carbon supported nickel catalyst.

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

In a preferred embodiment, in step (1), the basic nitrogen source is one of hexamethylenetetramine, tetrapropylammonium hydroxide, ammonia water and urea, preferably hexamethylenetetramine.

As a preferred embodiment, in step (1), Ni is contained in the solution obtained ²⁺The concentration of (b) is 0.01-0.1 mol/L, preferably 0.05 mol/L; the concentration of the tannic acid is 50-200 g/L, preferably 100 g/L; the concentration of the basic nitrogen source is 10-50 g/L, preferably 25 g/L.

As a preferred embodiment, in the step (2), the hydrothermal reaction temperature is 100 ℃ to 180 ℃, preferably 120 ℃, the hydrothermal reaction time is 2 to 24 hours, preferably 12 hours, the reaction product is naturally cooled to room temperature after the reaction, the product is repeatedly washed to be neutral by deionized water and absolute ethyl alcohol, and the product is dried for 12 hours at 120 ℃ under a vacuum condition.

In a preferred embodiment, in the step (3), the nitrogen flow rate is 100mL/min, the temperature rise rate is 2 ℃/min, the treatment temperature is 500-800 ℃, preferably 700 ℃, and the treatment time is 1-5 h, preferably 3 h.

The application of the nitrogen-doped biochar-supported metallic nickel catalyst is characterized in that the catalyst is applied to furfural catalytic hydrogenation reaction under the following conditions: n-dodecane is used as a solvent, the concentration of furfural in the n-dodecane is 0.3mol/L, the mass ratio of furfural to catalyst is 5:1, the initial hydrogen pressure is 2MPa, the stirring speed is 700r/min, the reaction temperature is 160 ℃, and the reaction time is 2 h.

The invention has the beneficial effects that: the active metal and the carrier of the catalyst synthesized by the method are relatively cheap and easily available, and the cost advantage is obvious; the adopted carbon source tannic acid can be added with nickel salt for hydrothermal synthesis in an alkaline environment due to the special structure of the tannic acid to obtain a nickel-polyphenol coordination polymer, and the dispersion degree of nickel active centers is high after carbonization, so that the tannic acid has higher catalytic activity; the nitrogen doping can enhance the interaction between the carbon carrier and the metal active component, and improve the activity and stability of the catalyst; the method has simple process, and the nickel load and the nitrogen doping can be realized in situ by a one-pot method, thereby having better practical prospect; the synthesized catalyst can realize 100 percent conversion rate of furfural, and the selectivity of furfuryl alcohol is as high as 97.2 percent; the catalyst has good stability, and the conversion rate of the furfural is still kept above 95% after the catalyst is repeatedly used for five times.

Drawings

FIG. 1 is a graph showing the conversion of furfural with the number of catalyst cycles in application example 7 of the present invention.

Detailed Description

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