阅读说明：本技术 一种氮掺杂碳-氧化锌复合材料及其制备方法和应用 (Nitrogen-doped carbon-zinc oxide composite material and preparation method and application thereof ) 是由 王红娟 郭巧芬 曹永海 余皓 于 2021-07-19 设计创作，主要内容包括：本发明公开了一种氮掺杂碳-氧化锌复合材料及其制备方法和应用。本发明的氮掺杂碳-氧化锌复合材料的组成包括掺氮碳纳米片和负载在掺氮碳纳米片上的氧化锌纳米颗粒,其制备方法包括以下步骤：1)将碳源、含氮有机物和碱金属碳酸盐混合后置于保护气氛中进行煅烧,再进行酸洗,得到掺氮碳纳米片；2)将可溶性锌盐、掺氮碳纳米片和碱分散在溶剂中,进行反应,即得氮掺杂碳-氧化锌复合材料。本发明的氮掺杂碳-氧化锌复合材料的结构稳定、粒径小、催化活性位点多,用于电催化CO-(2)还原产CO反应具有高催化活性和高选择性。(The invention discloses a nitrogen-doped carbon-zinc oxide composite material and a preparation method and application thereof. The nitrogen-doped carbon-zinc oxide composite material comprises nitrogen-doped carbon nano sheets and zinc oxide nano particles loaded on the nitrogen-doped carbon nano sheets, and the preparation method comprises the following steps: 1) mixing a carbon source, a nitrogenous organic matter and an alkali carbonate, then calcining in a protective atmosphere, and then carrying out acid washing to obtain a nitrogen-doped carbon nanosheet; 2) dispersing soluble zinc salt, nitrogen-doped carbon nanosheets and alkali in a solvent, and reacting to obtain the nitrogen-doped carbon-zinc oxide composite material. The nitrogen-doped carbon-zinc oxide composite material has stable structure, small particle size and more catalytic active sites, and is used for electrocatalysis of CO 2 The reaction for producing CO by reduction has high catalytic activity and high selectivity.)

1. The nitrogen-doped carbon-zinc oxide composite material is characterized by comprising nitrogen-doped carbon nano sheets and zinc oxide nano particles loaded on the nitrogen-doped carbon nano sheets.

2. The nitrogen-doped carbon-zinc oxide composite material of claim 1, wherein: the thickness of the nitrogen-doped carbon nanosheet is 80 nm-120 nm; the particle size of the zinc oxide nano-particles is 10 nm-20 nm.

3. The method of preparing a nitrogen-doped carbon-zinc oxide composite material according to claim 1 or 2, comprising the steps of:

1) mixing a carbon source, a nitrogenous organic matter and an alkali carbonate, then calcining in a protective atmosphere, then acid-washing,

obtaining nitrogen-doped carbon nanosheets;

2) dispersing soluble zinc salt, nitrogen-doped carbon nanosheets and alkali in a solvent, and reacting to obtain the nitrogen-doped carbon-zinc oxide composite material.

4. The method of claim 3, wherein the nitrogen-doped carbon-zinc oxide composite material is prepared by: the mass ratio of the carbon source, the nitrogen-containing organic matter and the alkali carbonate in the step 1) is 1: 0.1-1: 2-4.

5. The method for producing a nitrogen-doped carbon-zinc oxide composite material according to claim 3 or 4, wherein: the carbon source in the step 1) is at least one of glucose, cellulose and sucrose; step 1) the nitrogen-containing organic matter is at least one of melamine and urea; the alkali metal carbonate in the step 1) is at least one of lithium carbonate, sodium carbonate and potassium carbonate.

6. The method for producing a nitrogen-doped carbon-zinc oxide composite material according to claim 3 or 4, wherein: the calcination in the step 1) comprises the following specific operations: heating to 700-900 ℃ at the heating rate of 3-7 ℃/min, and keeping the temperature for 1-2 h.

7. The method of claim 3, wherein the nitrogen-doped carbon-zinc oxide composite material is prepared by: step 2), the mass ratio of the soluble zinc salt to the nitrogen-doped carbon nanosheet is 1: 0.11-1: 0.62; the molar ratio of the soluble zinc salt to the alkali in the step 2) is 1: 1-1: 2.5.

8. The method for producing a nitrogen-doped carbon-zinc oxide composite material according to any one of claims 3, 4 and 7, characterized in that: and 2) the soluble zinc salt is at least one of zinc nitrate, zinc chloride and zinc acetate.

9. The method for producing a nitrogen-doped carbon-zinc oxide composite material according to any one of claims 3, 4 and 7, characterized in that: the reaction in the step 2) is carried out at the temperature of 40-70 ℃, and the reaction time is 1-3 h.

10. Use of the nitrogen-doped carbon-zinc oxide composite material of claim 1 or 2 as electrocatalytic CO₂Application of reduction reaction catalyst.

Technical Field

The invention relates to the technical field of nano materials, in particular to a nitrogen-doped carbon-zinc oxide composite material and a preparation method and application thereof.

Background

The greenhouse effect, also known as the greenhouse effect, is commonly known as the atmospheric heat preservation effect. In recent years, with the development of industry and the advancement of science and technology, the combustion of a large amount of fossil fuels has led to a drastic increase in carbon dioxide emission into the atmosphere, which has been expected to bring about a serious problem to the entire ecological environment by the expectation that the concentration of carbon dioxide in the atmosphere will be doubled in the late 21 st century compared to the present (about 400 ppm). Therefore, how to reduce the carbon dioxide content in the atmosphere is a great problem that people have to face and wait to solve urgently.

The carbon dioxide is electrically reduced by adopting an external electric field and water as an energy source and an ion source respectively, and the conversion of the carbon dioxide can be realized at normal temperature and normal pressure, so that the method is considered to be a carbon dioxide treatment method with a great application prospect. However, the carbon dioxide electroreduction is a complex multi-electron reaction, which needs to be performed under a relatively high overpotential, and thermodynamic potentials involved in the carbon dioxide electroreduction process are relatively similar, so that the selectivity is poor, and side reactions (hydrogen evolution reaction is a main competitive reaction) are easy to occur. It is seen that the actual application of carbon dioxide by electrical reduction is difficult.

Therefore, the development of an electrocatalyst capable of effectively promoting the reaction of the target product is the key point for promoting the practical application of the electroreduction of carbon dioxide.

Disclosure of Invention

The invention aims to provide a nitrogen-doped carbon-zinc oxide composite material, and a preparation method and application thereof

The technical scheme adopted by the invention is as follows:

a nitrogen-doped carbon-zinc oxide composite material comprises nitrogen-doped carbon nano sheets and zinc oxide nano particles loaded on the nitrogen-doped carbon nano sheets.

Preferably, the thickness of the nitrogen-doped carbon nanosheet is 80nm to 120 nm.

Preferably, the particle size of the zinc oxide nano-particles is 10 nm-20 nm.

The preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing a carbon source, a nitrogenous organic matter and an alkali carbonate, then calcining in a protective atmosphere, and then carrying out acid washing to obtain a nitrogen-doped carbon nanosheet;

2) dispersing soluble zinc salt, nitrogen-doped carbon nanosheets and alkali in a solvent, and reacting to obtain the nitrogen-doped carbon-zinc oxide composite material.

Preferably, the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing a carbon source, a nitrogenous organic matter and an alkali carbonate, grinding, transferring to a tubular furnace, filling protective atmosphere, calcining, and then carrying out acid washing, water washing, suction filtration and drying to obtain nitrogen-doped carbon nanosheets;

2) dispersing soluble zinc salt and nitrogen-doped carbon nanosheets by using a solvent, dispersing alkali by using the solvent, mixing, reacting, filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Preferably, the mass ratio of the carbon source, the nitrogen-containing organic substance and the alkali metal carbonate in the step 1) is 1: 0.1-1: 2-4.

Preferably, the carbon source in step 1) is at least one of glucose, cellulose and sucrose.

Preferably, the nitrogen-containing organic substance in step 1) is at least one of melamine and urea.

Preferably, the alkali metal carbonate in step 1) is at least one of lithium carbonate, sodium carbonate and potassium carbonate.

Preferably, the protective atmosphere in step 1) is a nitrogen atmosphere or an argon atmosphere.

Preferably, the calcination in step 1) is specifically performed by: heating to 700-900 ℃ at the heating rate of 3-7 ℃/min, and keeping the temperature for 1-2 h.

Preferably, the mass ratio of the soluble zinc salt to the nitrogen-doped carbon nanosheet in the step 2) is 1: 0.11-1: 0.62.

Preferably, the molar ratio of the soluble zinc salt to the alkali in the step 2) is 1: 1-1: 2.5.

Preferably, the soluble zinc salt in step 2) is at least one of zinc nitrate, zinc chloride and zinc acetate.

Preferably, the alkali in step 2) is at least one of sodium hydroxide and potassium hydroxide.

Preferably, the solvent in step 2) is an alcohol solvent.

Preferably, the reaction in the step 2) is carried out at 40-70 ℃, and the reaction time is 1-3 h.

The invention has the beneficial effects that: the nitrogen-doped carbon-zinc oxide composite material has stable structure, small particle size and more catalytic active sites, and is used for electrocatalysis of CO₂The reaction for producing CO by reduction has high catalytic activity and high selectivity.

Specifically, the method comprises the following steps:

1) according to the invention, the nitrogen-doped carbon nanosheet with a thin lamella can be obtained by adding the alkali metal carbonate and utilizing the stripping effect of alkali metal ions;

2) according to the invention, by utilizing the coordination effect of zinc ions and an alcohol solvent, the rapid hydrolysis of zinc salt is avoided, the growth of zinc oxide particles is facilitated, and the obtained zinc oxide particles have the advantages of uniform particle dispersion, small particle size and the like;

3) according to the invention, the nitrogen-doped carbon nanosheet loads the zinc oxide particles, so that the defects of poor conductivity, unstable structure and the like of nano zinc oxide are overcome;

4) the nitrogen-doped carbon-zinc oxide composite material is used for electrocatalysis of CO₂The Faraday efficiency of the reduction CO production reaction is up to more than 90%;

5) the preparation method of the nitrogen-doped carbon-zinc oxide composite material is simple and easy to implement, has low requirements on equipment, wide sources of raw materials and low price, is controllable and environment-friendly in preparation process, and is easy to realize mass preparation.

Drawings

Fig. 1 is a TEM image of nitrogen-doped carbon nanosheets in step 1) of example 1.

Fig. 2 is a TEM image of the nitrogen doped carbon-zinc oxide composite of example 4.

Fig. 3 is an XRD pattern of the nitrogen-doped carbon-zinc oxide composite of comparative example 1.

FIG. 4 shows the N-doped carbon-zinc oxide composite of example 8 and the N-doped carbon nanosheets of comparative example 2 as catalysts for electrocatalytic CO₂Faradaic efficiency plot of the reduction CO reaction.

FIG. 5 shows an embodimentNitrogen-doped carbon-zinc oxide composite material of example 9 and nitrogen-doped carbon nanosheet of comparative example 2 as catalysts for electrocatalysis of CO₂Current density plot of the reduction CO reaction.

Detailed Description

The invention will be further explained and illustrated with reference to specific examples.

Example 1:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of glucose, 1.000g of melamine and 4.000g of potassium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12 hours, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.0804g (0.27mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.0303g (0.54mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 40 ℃, filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

A Transmission Electron Microscope (TEM) image of the nitrogen-doped carbon nanosheet in step 1) of this example is shown in fig. 1.

As can be seen from fig. 1: the nitrogen-doped carbon nanosheet is a nanosheet with a thin and folded lamella, and the thickness of the nanosheet is 80-120 nm.

Example 2:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of cellulose, 1.000g of melamine and 4.000g of sodium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 700 ℃ at a heating rate of 5 ℃/min, preserving heat for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12 hours, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.183g (0.6mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.0345g (0.6mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 60 ℃, and filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Example 3:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of sucrose, 1.000g of melamine and 2.000g of lithium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 900 ℃ at a heating rate of 5 ℃/min, keeping the temperature for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring for 12 hours at the room temperature, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.183g (0.6mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.084g (1.5mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 60 ℃, and filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Example 4:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of glucose, 1.000g of melamine and 4.000g of potassium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12 hours, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.0804g (0.27mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.0303g (0.54mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 60 ℃, and filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

A TEM image of the nitrogen-doped carbon-zinc oxide composite in this example is shown in fig. 2.

As can be seen from fig. 2: the zinc oxide nano-particles in the nitrogen-doped carbon-zinc oxide composite material are uniformly dispersed and have small particle size of 10-20 nm.

Example 5:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 0.500g of glucose, 0.500g of melamine and 2.000g of lithium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 900 ℃ at a heating rate of 5 ℃/min, keeping the temperature for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring for 12 hours at the room temperature, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.0804g (0.27mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.015g (0.27mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 60 ℃, filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Example 6:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of sucrose, 1.000g of melamine and 4.000g of potassium carbonate, grinding, transferring to a tube furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2h, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12h, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.0804g (0.27mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.379g (0.675mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 60 ℃, and filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Example 7:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of glucose, 1.000g of melamine and 4.000g of sodium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12 hours, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.428g (1.4mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.157g (2.8mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 60 ℃, filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Example 8:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of glucose, 1.000g of melamine and 4.000g of potassium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12 hours, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.183g (0.6mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.069g (0.12mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2h at 60 ℃, and filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Example 9:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of glucose, 1.000g of melamine and 4.000g of potassium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12 hours, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.428g (1.4mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.157g (2.8mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 60 ℃, filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Example 10:

the preparation method of the nitrogen-doped carbon-zinc oxide composite material comprises the following steps:

1) mixing 1.000g of cellulose, 1.000g of melamine and 4.000g of potassium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2 hours, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12 hours, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet;

2) 0.31g (1.4mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of nitrogen-doped carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.196g (3.5mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2 hours at 60 ℃, filtering, washing and drying to obtain the nitrogen-doped carbon-zinc oxide composite material.

Comparative example 1:

a carbon-zinc oxide composite material is prepared by the following steps:

1) mixing 1.000g of glucose and 4.000g of potassium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2h, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12h, taking out the solid product, and washing, filtering and drying to obtain a carbon nanosheet;

2) 0.183g (0.6mmol) of Zn (NO)₃)₃·5H₂Dispersing O and 50mg of carbon nanosheets in 20mL of methanol to obtain a dispersion liquid A, dispersing 0.069g (1.2mmol) of KOH in 10mL of methanol to obtain a dispersion liquid B, adding the dispersion liquid B into the dispersion liquid A, reacting for 2h at 60 ℃, filtering, washing and drying to obtain the carbon-zinc oxide composite material.

The X-ray diffraction (XRD) pattern of the carbon-zinc oxide composite material of the present comparative example is shown in fig. 3.

As can be seen from fig. 3: in the figure, in addition to the characteristic peak of carbon, there is also a characteristic peak of ZnO, which illustrates the successful loading of zinc oxide. Comparative example 2:

a nitrogen-doped carbon nanosheet is prepared by the following steps:

mixing 1.000g of cellulose, 1.000g of melamine and 4.000g of potassium carbonate, grinding, transferring to a tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a heating rate of 5 ℃/min, preserving heat for 2h, naturally cooling to room temperature, adding the obtained solid product into a hydrochloric acid solution with the concentration of 6mol/L, stirring at room temperature for 12h, taking out the solid product, and washing, filtering and drying to obtain the nitrogen-doped carbon nanosheet.

And (3) performance testing:

1) nitrogen-doped carbon-zinc oxide composite material of example 8 and nitrogen-doped carbon nanosheet of comparative example 2 were used as catalysts for electrocatalysis of CO₂Reducing CO reaction, testing the obtained electrocatalytic CO₂The graph of faradaic efficiency of the reduced CO reaction is shown in fig. 4.

As can be seen from fig. 4: use of nitrogen-doped carbon nanosheets of comparative example 2 as catalysts for electrocatalysis of CO₂The CO production reaction by reduction is mainly hydrogen evolution reaction, and the nitrogen-doped carbon-zinc oxide composite material of the example 8 is used as a catalyst for electrocatalysis of CO₂The reduction of CO has the Faraday efficiency of over 90 percent, which shows that the existence of the zinc oxide nano-particles can obviously improve the electrocatalytic reduction of CO₂Faradaic efficiency for CO production.

2) Nitrogen-doped carbon-zinc oxide composite material of example 9 and nitrogen-doped carbon nanosheet of comparative example 2 were used as catalysts for electrocatalysis of CO₂Reducing CO reaction, testing the obtained electrocatalytic CO₂The current density profile of the reduced CO reaction is shown in fig. 5.

As can be seen from fig. 5: nitrogen-doped carbon-zinc oxide composite of example 9 as catalyst for electrocatalysis of CO₂The reduction and CO production reaction have the current density far higher than that of the nitrogen-doped carbon nano sheet in the comparative example 2, which shows that the existence of the zinc oxide nano particles can obviously improve the electrocatalytic reduction of CO₂Current density of the CO production reaction.

3) Referring to the above-mentioned various testing methods, the nitrogen-doped carbon-zinc oxide composite materials of examples 1 to 10 were subjected to a comprehensive performance test, and the test results show that: the nitrogen-doped carbon-zinc oxide composite material of examples 1 to 10, in which the thickness of the nitrogen-doped carbon nanosheet is within a range of 80nm to 120nm and the particle size of the supported zinc oxide nanoparticle is within a range of 10nm to 20nm, was used as a catalyst for electrocatalysis of CO₂The reduction produces CO reaction, and the Faraday efficiency can reach more than 90 percent.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.