阅读说明：本技术 一种生物质基镍-氮-碳复合催化材料的制备方法及其应用 (Preparation method and application of biomass-based nickel-nitrogen-carbon composite catalytic material ) 是由 邱介山 张亚方 于畅 谭新义 崔崧 李文斌 于 2021-09-29 设计创作，主要内容包括：本发明属于碳基材料制备技术领域,一种生物质基镍-氮-碳复合催化材料的制备方法及其应用,其中制备方法包括以下步骤：(1)将生物质材料洗净、干燥、粉碎后作为碳源,再将碳源、氮源、金属盐混合球磨,得到粉末；(2)将粉末置于管式炉中,在氩气保护下经过两步恒温焙烧,制得生物质基镍-氮-碳复合催化材料预产物；(3)将生物质基镍-氮-碳复合催化材料预产物通过酸处理、水洗烘干,得到生物质基镍-氮-碳复合催化材料。本发明具有以下优点：一是,本发明方法工艺过程简单、操作难度小、原料来源广、生产成本低。二是,利用该方法制备的生物质基镍-氮-碳复合催化材料具有催化活性高、活性物质稳定、选择性高等优点。(The invention belongs to the technical field of preparation of carbon-based materials, and relates to a preparation method and application of a biomass-based nickel-nitrogen-carbon composite catalytic material, wherein the preparation method comprises the following steps: (1) cleaning, drying and crushing the biomass material to be used as a carbon source, and mixing and ball-milling the carbon source, the nitrogen source and the metal salt to obtain powder; (2) placing the powder in a tubular furnace, and roasting the powder under the protection of argon gas at constant temperature in two steps to obtain a biomass-based nickel-nitrogen-carbon composite catalytic material pre-product; (3) and (3) treating the biomass-based nickel-nitrogen-carbon composite catalytic material pre-product with acid, washing with water and drying to obtain the biomass-based nickel-nitrogen-carbon composite catalytic material. The invention has the following advantages: firstly, the method has the advantages of simple process, small operation difficulty, wide raw material source and low production cost. Secondly, the biomass-based nickel-nitrogen-carbon composite catalytic material prepared by the method has the advantages of high catalytic activity, stable active substances, high selectivity and the like.)

1. A preparation method of a biomass-based nickel-nitrogen-carbon composite catalytic material is characterized by comprising the following steps:

step 1, washing a biomass material with deionized water, placing the biomass material in an oven, drying the biomass material for 8-16h at 70-90 ℃, taking the dried and crushed biomass material as a carbon source, weighing 0.5-1g of the carbon source, 1.25-10g of a nitrogen source and 0.25-1g of metal salt, mixing the carbon source, the nitrogen source and the metal salt, placing the mixture in a ball milling tank made of a zirconia material, and carrying out ball milling for 30-60min to obtain ball-milled powder; the biomass material is selected from one of corn stalks, sweet potato leaves or ginkgo leaves; the nitrogen source is selected from one of urea, cyanamide, dicyandiamide or melamine, and the metal salt is selected from one of nickel chloride, nickel nitrate, nickel sulfate or nickel acetate;

step 2, placing the ball-milled powder obtained in the step 1 into a tube furnace, heating the powder from room temperature to 450 ℃ at a heating rate of 1-10 ℃/min under the protection of argon, roasting the powder for 1-4h at a constant temperature, heating the powder to 700 ℃ at a heating rate of 1-10 ℃/min, and roasting the powder for 1-4h at a constant temperature to obtain a biomass-based nickel-nitrogen-carbon composite catalytic material pre-product;

step 3, adding the biomass-based nickel-nitrogen-carbon composite catalytic material pre-product obtained in the step 2 into 2-4mol L with the volume of 80-100mL^-1Refluxing, stirring and heating the mixture for 8 to 16 hours at a temperature of between 60 and 100 ℃ in hydrochloric acid, washing the mixture with deionized water to be neutral, placing the mixture in an oven, drying the mixture for 10 to 14 hours at a temperature of between 70 and 90 ℃, adding 40 percent by mass of hydrofluoric acid with a volume of between 40 and 60mL into a biomass-based nickel-nitrogen-carbon composite catalytic material pre-product treated by the hydrochloric acid, stirring and soaking the mixture for 10 to 14 hours, washing the mixture with deionized water to be neutral, placing the mixture in the oven, and drying the mixture for 10 to 14 hours at a temperature of between 70 and 90 ℃ to obtain the biomass-based nickel-nitrogen-carbon composite catalytic material.

2. The application of the biomass-based nickel-nitrogen-carbon composite catalytic material prepared by the method of claim 1 in the electrochemical reduction catalytic reaction of carbon dioxide.

Technical Field

The invention relates to a preparation method and application of a biomass-based nickel-nitrogen-carbon composite catalytic material, belonging to the technical field of preparation of carbon-based materials.

Background

The electrochemical carbon dioxide reduction reaction (ECR) becomes a carbon dioxide conversion technology with wide development prospect by virtue of the characteristics of mild operation conditions, controllable reaction process and the like. In ECR processes, a highly efficient electrocatalyst is one that achieves CO₂Refining the key to conversion, it is therefore critical to develop high performance ECR electrocatalysts. The carbon-based catalyst has the advantages of stable performance, easily obtained raw materials, low cost and the like, and thus becomes one of ideal ECR catalysts. The carbon-based catalyst commonly used at present mainly comprises a non-metal heteroatom-doped carbon material, a metal-nitrogen-carbon material and a structure-adjustable defect carbon material. Wherein the carbon-based composite material based on the nickel-nitrogen-carbon skeleton can realize CO₂The reduction product of the catalyst can be used as a main raw material in important chemical processes such as Fischer-Tropsch synthesis and the like, so that the catalyst is widely concerned.

The carbon source of the existing nickel-nitrogen-carbon composite catalytic material mainly adopts commercial activated carbon, graphene oxide and the like. However, these carbon materials require preliminary synthesis, and some carbon sources have problems such as long time consumption and high cost in the production process. Compared with the prior art, the biomass serving as the carbon source has the advantages of wide source, large storage capacity, low price and the like, and is one of ideal carbon sources. Therefore, it is necessary to explore an environment-friendly and widely-available biomass carbon source for preparing the nickel-nitrogen-carbon composite catalytic material.

The waste biomass material is taken as a carbon source and is formed by adopting methods such as direct carbonization, hydrothermal carbonization, physical and chemical activation carbonization and the likeCarbon-based materials having a rich pore structure and a large number of defects. By researching the raw material proportion, the pyrolysis temperature and the post-treatment method, the preparation process of the biomass-based nickel-nitrogen-carbon composite catalytic material is further optimized to improve the application of the biomass-based nickel-nitrogen-carbon composite catalytic material in the electrocatalytic reduction of CO₂Actual performance in the process. Finally, a route for synthesizing the biomass-based nickel-nitrogen-carbon composite catalytic material with low cost and high efficiency is explored, and a foundation is laid for subsequent large-scale production and industrial application of the biomass-based nickel-nitrogen-carbon composite catalytic material.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention aims to provide a preparation method and application of a biomass-based nickel-nitrogen-carbon composite catalytic material. The method uses waste biomass as a low-cost carbon source, has simple process and small operation difficulty, and can prepare the nickel-nitrogen-carbon composite catalytic material with excellent performance. The biomass-based nickel-nitrogen-carbon composite catalytic material prepared by the method has the advantages of high catalytic activity, stable active substances, high selectivity and the like, and has great application potential in the field of catalysis. On the basis, the catalytic activity of the composite material in the carbon dioxide reduction reaction is researched.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows: a preparation method of a biomass-based nickel-nitrogen-carbon composite catalytic material comprises the following steps:

step 1, washing a biomass material with deionized water, placing the biomass material in an oven, drying the biomass material for 8-16h at 70-90 ℃, taking the dried and crushed biomass material as a carbon source, weighing 0.5-1g of the carbon source, 1.25-10g of a nitrogen source and 0.25-1g of metal salt, mixing the carbon source, the nitrogen source and the metal salt, placing the mixture in a ball milling tank made of a zirconia material, and carrying out ball milling for 30-60min to obtain ball-milled powder; the biomass material is selected from one of corn stalks, sweet potato leaves or ginkgo leaves; the nitrogen source is selected from one of urea, cyanamide, dicyandiamide or melamine, and the metal salt is selected from one of nickel chloride, nickel nitrate, nickel sulfate or nickel acetate;

step 2, placing the ball-milled powder obtained in the step 1 into a tube furnace, and placing the tube furnace at the temperature of 1-10 ℃ for min under the protection of argon^-1The temperature rising rate is increased from room temperature to 450-500 ℃, the mixture is roasted for 1 to 4 hours at constant temperature and thenAt 1-10 deg.C for min^-1The heating rate is increased to 700-;

step 3, adding the biomass-based nickel-nitrogen-carbon composite catalytic material pre-product obtained in the step 2 into 2-4mol L with the volume of 80-100mL^-1Refluxing, stirring and heating the mixture for 8 to 16 hours at a temperature of between 60 and 100 ℃ in hydrochloric acid, washing the mixture with deionized water to be neutral, placing the mixture in an oven, drying the mixture for 10 to 14 hours at a temperature of between 70 and 90 ℃, adding 40 percent by mass of hydrofluoric acid with a volume of between 40 and 60mL into a biomass-based nickel-nitrogen-carbon composite catalytic material pre-product treated by the hydrochloric acid, stirring and soaking the mixture for 10 to 14 hours, washing the mixture with deionized water to be neutral, placing the mixture in the oven, and drying the mixture for 10 to 14 hours at a temperature of between 70 and 90 ℃ to obtain the biomass-based nickel-nitrogen-carbon composite catalytic material.

The biomass-based nickel-nitrogen-carbon composite catalytic material prepared by the method is applied to the electrochemical reduction catalytic reaction of carbon dioxide.

The invention has the beneficial effects that: a preparation method and application of biomass-based nickel-nitrogen-carbon composite catalytic material are disclosed, wherein the preparation method comprises the following steps: (1) the biomass material is washed by deionized water, and the dried and crushed biomass material is used as a carbon source. Mixing a carbon source, a nitrogen source and metal salt, and placing the mixture in a ball mill for ball milling to obtain powder; (2) placing the ball-milled powder obtained in the step 1 into a tubular furnace, and roasting the powder at constant temperature in two steps under the protection of argon gas to obtain a biomass-based nickel-nitrogen-carbon composite catalytic material pre-product; (3) and (3) adding the biomass-based nickel-nitrogen-carbon composite catalytic material pre-product obtained in the step (2) into hydrochloric acid, refluxing, stirring and heating, washing with deionized water to be neutral, placing in an oven for drying, adding hydrofluoric acid with the mass fraction of 40% into the biomass-based nickel-nitrogen-carbon composite catalytic material pre-product treated by the hydrochloric acid, stirring and dipping, washing with deionized water to be neutral, and placing in the oven for drying to obtain the biomass-based nickel-nitrogen-carbon composite catalytic material. The invention has the following advantages: firstly, the method has the advantages of simple process, low operation difficulty, wide raw material source and low production cost, can prepare the nickel-nitrogen-carbon composite catalytic material with excellent performance, and the XRD pattern shows that the material is successfully preparedAnd (4) preparing. Secondly, the biomass-based nickel-nitrogen-carbon composite catalytic material prepared by the method has the advantages of high catalytic activity, stable active substances, high selectivity and the like, and has great application potential in the field of catalysis. On the basis, the catalytic activity of the composite material in the reduction reaction of carbon dioxide is researched, the Faraday efficiency of carbon monoxide is up to 96.2% and the current density can reach 15.5mA cm under the operation voltage of-1.6V (vs. Ag/AgCl)^-2。

Drawings

FIG. 1 is a photograph of a cold field scanning electron microscope of a sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material prepared in example 4.

FIG. 2 is a Raman test chart of a sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material prepared in example 7.

FIG. 3 is the XRD pattern of the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material prepared in example 8.

Fig. 4 is a graph showing the performance of electrochemical reduction of carbon dioxide in example 10.

Detailed Description

The present invention will be further described with reference to the following examples.

Example 1

Washing corn stalks with deionized water, placing the corn stalks in an oven, drying the corn stalks for 12 hours at 70 ℃, and taking the dried and crushed corn stalks as a carbon source. Weighing 1g of corn straw, 0.25g of nickel nitrate and 2.5g of urea, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 50min to obtain ball-milled powder; then placing the ball-milled powder in a tube furnace, and performing argon protection at 5 ℃ for min^-1The temperature rising rate is increased from room temperature to 450 ℃, the mixture is roasted for 2 hours at constant temperature and then is roasted for 5min^-1The temperature rise rate is increased to 900 ℃, and the mixture is roasted for 2 hours at constant temperature to prepare a corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product; adding 2mol L of corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product with volume of 80mL^-1Refluxing and stirring in hydrochloric acid at 60 ℃ for 10h, washing with deionized water to neutrality, drying in a drying oven at 70 ℃ for 10h, adding 40 mass percent of 40 volume mL of hydrofluoric acid into the corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product treated with hydrochloric acid, stirring and soaking for 10h,and washing the composite material to be neutral by using deionized water, placing the composite material in an oven, and drying the composite material for 10 hours at 70 ℃ to obtain the corn straw-based nickel-nitrogen-carbon composite catalytic material.

Example 2

Cleaning sweet potato leaves with deionized water, placing in a drying oven, drying at 80 deg.C for 12h, and taking dried and pulverized sweet potato leaves as carbon source. Weighing 1g of sweet potato leaves, 0.5g of nickel nitrate and 5g of cyanamide, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 60min to obtain ball-milled powder; then placing the ball-milled powder in a tube furnace, and under the protection of argon, keeping the temperature at 10 ℃ for min^-1The temperature rising rate is increased from room temperature to 500 ℃, the mixture is roasted for 4 hours at constant temperature and then is roasted for 10 min^-1The temperature rise rate is increased to 700 ℃, and the mixture is roasted for 4 hours at constant temperature to prepare a sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product; adding 4mol L of sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product with volume of 100mL^-1Refluxing and stirring the mixture in hydrochloric acid at 100 ℃ for 16h, washing the mixture with deionized water to be neutral, drying the mixture in an oven at 90 ℃ for 14h, adding hydrofluoric acid with the mass fraction of 40% and the volume of 60mL into the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product treated by the hydrochloric acid, stirring and soaking the mixture for 14h, washing the mixture with deionized water to be neutral, and drying the mixture in the oven at 90 ℃ for 14h to obtain the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material.

Example 3

Cleaning folium Ginkgo with deionized water, drying at 80 deg.C for 8 hr in oven, and taking dried and pulverized folium Ginkgo as carbon source. Weighing 1g of ginkgo leaves, 1g of nickel chloride and 10g of dicyandiamide, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 40min to obtain ball-milled powder; then placing the ball-milled powder in a tube furnace, and performing argon protection at 5 ℃ for min^-1The temperature rising rate is increased from room temperature to 500 ℃, the mixture is roasted for 4 hours at constant temperature and then is roasted at 5 ℃ for min^-1The temperature rise rate is increased to 700 ℃, and the mixture is roasted for 4 hours at constant temperature to prepare a ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material pre-product; adding 3mol L of ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material pre-product with volume of 90mL^-1Refluxing and stirring in hydrochloric acid at 80 deg.C for 12 hr, washing with deionized water to neutrality, drying at 80 deg.C for 12 hr, adding saltAdding hydrofluoric acid with the mass fraction of 40% and the volume of 60mL into the ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material pre-product subjected to acid treatment, stirring and soaking for 12h, washing the ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material to be neutral by using deionized water, placing the ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material in an oven, and drying the ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material for 12h at the temperature of 80 ℃ to obtain the ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material.

Example 4

Cleaning sweet potato leaves with deionized water, placing in a drying oven, drying at 80 deg.C for 14h, and taking dried and pulverized sweet potato leaves as carbon source. Weighing 1g of sweet potato leaves, 0.5g of nickel acetate and 5g of melamine, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 30min to obtain ball-milled powder; then placing the ball-milled powder in a tube furnace, and performing argon protection at 10 ℃ for min^-1The temperature rising rate is increased from room temperature to 450 ℃, the mixture is roasted for 3 hours at constant temperature and then is roasted at 10 ℃ for min^-1The temperature rise rate is increased to 800 ℃, and the mixture is roasted for 3 hours at constant temperature to prepare a sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product; adding 2mol L of sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product with volume of 100mL^-1Refluxing and stirring in hydrochloric acid at 90 ℃ for 10h, washing with deionized water to neutrality, placing in a drying oven, and drying at 90 ℃ for 12 h. And adding 40 mass percent of hydrofluoric acid with the volume of 40mL into the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product treated by hydrochloric acid, stirring and soaking for 12h, washing the product to be neutral by using deionized water, placing the product in an oven, and drying the product for 12h at 90 ℃ to obtain the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material. The cold field scanning electron micrograph of the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material is shown in figure 1, wherein the material is in a blocky structure and the surface of the material is rich in concave-convex folds.

Example 5

Washing corn stalks with deionized water, placing the corn stalks in a drying oven, drying the corn stalks for 15 hours at 85 ℃, and taking the dried and crushed corn stalks as a carbon source. Weighing 1g of corn straw, 0.25g of nickel nitrate and 10g of melamine, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 60min to obtain ball-milled powder; then placing the ball-milled powder in a tube furnace, and performing argon protection at 10 ℃ for min^-1The temperature rising rate is increased from room temperature to 500 ℃, the mixture is roasted for 3 hours at constant temperature and then is roasted at 10 ℃ for min^-1The temperature rise rate is increased to 800 ℃, and the mixture is roasted for 3 hours at constant temperature to prepare a corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product; adding a corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product into 4mol L of 80mL^-1Refluxing and stirring in hydrochloric acid at 95 ℃ for 15h, washing with deionized water to neutrality, placing in a drying oven, and drying at 85 ℃ for 13 h. And adding 40 mass percent of hydrofluoric acid with the volume of 50mL into the corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product treated by hydrochloric acid, stirring and soaking for 13h, washing the product to be neutral by using deionized water, placing the product in an oven, and drying the product for 13h at 85 ℃ to obtain the corn straw-based nickel-nitrogen-carbon composite catalytic material.

Example 6

Cleaning folium Ginkgo with deionized water, drying at 75 deg.C for 9 hr in oven, and taking dried and pulverized folium Ginkgo as carbon source. Weighing 1g of ginkgo leaves, 1g of nickel chloride and 6g of cyanamide, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 30min to obtain ball-milled powder; then placing the ball-milled powder in a tube furnace, and performing argon protection at 5 ℃ for min^-1The temperature rising rate is increased from room temperature to 480 ℃, the mixture is roasted for 2 hours at constant temperature and then is roasted at 5 ℃ for min^-1The temperature rising rate is increased to 850 ℃, and the mixture is roasted for 2 hours at constant temperature to prepare a ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material pre-product; adding 3mol L of ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material pre-product with volume of 90mL^-1Refluxing and stirring in hydrochloric acid at 95 ℃ for heating for 13h, washing with deionized water to be neutral, placing in a drying oven, drying at 85 ℃ for 13h, adding hydrofluoric acid with the mass fraction of 40% and the volume of 60mL into the corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product treated by the hydrochloric acid, stirring and soaking for 13h, washing with deionized water to be neutral, placing in the drying oven, and drying at 85 ℃ for 13h to obtain the ginkgo leaf-based nickel-nitrogen-carbon composite catalytic material.

Example 7

Cleaning sweet potato leaves with deionized water, placing in a drying oven, drying at 80 deg.C for 14h, and taking dried and pulverized sweet potato leaves as carbon source. Weighing 1g of sweet potato leaves, 0.25g of nickel acetate and 5g of urea, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 55min to obtain ball-milled powder; ball milling is carried outPlacing the powder in a tube furnace under the protection of argon gas at 10 deg.C for min^-1The temperature rising rate is increased from room temperature to 480 ℃, the mixture is roasted for 3 hours at constant temperature and then is roasted at 10 ℃ for min^-1The temperature rise rate is increased to 800 ℃, and the mixture is roasted for 3 hours at constant temperature to prepare a sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product; adding 2mol L of sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product with volume of 80mL^-1Refluxing and stirring the mixture in hydrochloric acid at 80 ℃ for 10 hours, washing the mixture with deionized water to be neutral, placing the mixture in a drying oven, drying the mixture for 12 hours at 80 ℃, adding 40 mass percent of hydrofluoric acid with the volume of 40mL into the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product treated by the hydrochloric acid, stirring and soaking the mixture for 12 hours, washing the mixture with deionized water to be neutral, placing the mixture in the drying oven, and drying the mixture for 12 hours at 80 ℃ to obtain the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material. The Raman test chart of the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material is shown in figure 2, and I thereof is_D/I_GThe value was 1.053.

Example 8

Cleaning sweet potato leaves with deionized water, placing in a drying oven, drying at 80 deg.C for 14h, and taking dried and pulverized sweet potato leaves as carbon source. Weighing 1g of sweet potato leaves, 0.25g of nickel acetate and 5g of melamine, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 45min to obtain ball-milled powder; then placing the ball-milled powder in a tube furnace, and performing argon protection at 5 ℃ for min^-1The temperature rising rate is increased from room temperature to 490 ℃, the mixture is roasted for 3 hours at constant temperature and then is roasted at 5 ℃ for min^-1The temperature rise rate is increased to 700 ℃, and the mixture is roasted for 3 hours at constant temperature to prepare a sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product; adding 3mol L of sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product with volume of 100mL^-1Refluxing and stirring the mixture in hydrochloric acid at 80 ℃ for 14h, washing the mixture with deionized water to be neutral, drying the mixture in an oven at 80 ℃ for 14h, adding hydrofluoric acid with the mass fraction of 40% and the volume of 60mL into the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material pre-product treated by the hydrochloric acid, stirring and soaking the mixture for 12h, washing the mixture with deionized water to be neutral, and drying the mixture in the oven at 80 ℃ for 12h to obtain the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material. The XRD pattern of the sweet potato leaf-based nickel-nitrogen-carbon composite catalytic material is shown in figure 3.

Example 9

Washing corn stalks with deionized water, placing the corn stalks in a drying oven, drying the corn stalks for 15 hours at 85 ℃, and taking the dried and crushed corn stalks as a carbon source. Weighing 1g of corn straw, 7.5g of cyanamide and 0.25g of nickel sulfate, mixing, placing in a ball milling tank made of zirconia, and carrying out ball milling for 30min to obtain ball-milled powder; then placing the ball-milled powder in a tube furnace, and performing argon protection at 10 ℃ for min^-1The temperature rising rate is increased from room temperature to 500 ℃, the mixture is roasted for 2 hours at constant temperature and then is roasted for 10 min^-1The temperature rise rate is increased to 700 ℃, and the mixture is roasted for 2 hours at constant temperature to prepare a corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product; adding 3mol L of corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product with volume of 80mL^-1Refluxing and stirring in hydrochloric acid at 95 ℃ for 15h, washing with deionized water to neutrality, placing in a drying oven, and drying at 85 ℃ for 12 h. And adding 40 mass percent of hydrofluoric acid with the volume of 60mL into the corn straw-based nickel-nitrogen-carbon composite catalytic material pre-product treated by hydrochloric acid, stirring and soaking for 12h, washing the product to be neutral by using deionized water, placing the product in an oven, and drying the product for 12h at the temperature of 80 ℃ to obtain the corn straw-based nickel-nitrogen-carbon composite catalytic material.

Example 10

The prepared biomass-based nickel-nitrogen-carbon composite catalytic material is subjected to an electrochemical reduction carbon dioxide performance test, and an electrochemical workstation used is Shanghai Chenghua CHI 660E. An H-type electrolytic cell is taken as an electrolytic bath, Nafion117 is taken as a proton exchange membrane, and 0.1M NaHCO is used₃The solution is used as electrolyte, an Ag/AgCl electrode is used as a reference electrode, a Pt sheet is used as a counter electrode, and a conductive carbon paper or glassy carbon electrode coated with a catalyst is used as a working electrode to form a three-electrode system. Specifically, the catalyst prepared in the example is used for carrying out electrochemical reduction carbon dioxide performance test, 5mg of the prepared biomass-based nickel-nitrogen-carbon composite catalytic material is dissolved in 970 mu L of ethanol, 30 mu L of Nafion binder is added, 100 mu L of the Nafion binder is dropwise coated on 0.2cm of the catalyst after ultrasonic treatment is carried out for 30min²The carbon paper or glassy carbon electrode with the diameter of 12mm is dried at room temperature to be used as a working electrode. The biomass-based nickel-nitrogen-carbon composite catalytic material shows excellent performance,under the voltage of-1.6V (vs. Ag/AgCl), the Faraday efficiency of carbon monoxide is as high as 96.2%, and the current density can reach 15.5mA cm^-2The performance results are shown in figure 4.