CN112768712A

CN112768712A - Composite, preparation method thereof, catalyst containing composite and electrochemical neutralization energy battery

Info

Publication number: CN112768712A
Application number: CN201910998701.1A
Authority: CN
Inventors: 李燕; 温珍海
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Fujian Institute of Research on the Structure of Matter of CAS
Priority date: 2019-10-21
Filing date: 2019-10-21
Publication date: 2021-05-07
Anticipated expiration: 2039-10-21
Also published as: CN112768712B

Abstract

The application discloses a compound, which is a nitrogen-doped carbon nanosheet iron-carrying monatomic compound; the iron single atom is loaded in the two-dimensional structure of the nitrogen-doped carbon nanosheet. And an electrode catalyst comprising the composite, and an electrochemically neutralized energy cell using the electrode catalyst. In the electrochemical neutralization energy cell, the cathode end generates a reaction of reducing nitrogen into ammonia in an acidic solution, and the anode end generates a zinc oxidation reaction in an alkaline solution. The battery can provide an open-circuit voltage of 1.22V, and when the discharge current density reaches 12.7 mA-cm^‑2Then the maximum power density of the battery can reach 4.5mW cm^‑2The battery has good stability and potential application prospect in the synthetic ammonia industry.

Description

Composite, preparation method thereof, catalyst containing composite and electrochemical neutralization energy battery

Technical Field

The application relates to an electrochemical neutralization energy battery, belonging to the field of novel batteries and cheap catalysts.

Background

With the increasing global population, fossil fuels are about to be exhausted, global environmental problems are imminent, and the search for sustainable, renewable and eco-friendly energy sources is an urgent need for guaranteeing the future of our energy sources. Ammonia is not only used in the production of fertilizers to sustain the world population, but is also a green energy carrier. Currently, ammonia synthesis is dominated by the Haber-Bosch process of heterogeneous iron-based catalysts at high temperatures (300 ℃.) (500 ℃) and high pressures (150-. Therefore, there is an urgent need to develop an alternative process to overcome the limitations of the Haber-Bosch process such as harsh reaction conditions, complex plant infrastructure, centralized distribution, high energy consumption, environmental pollution, etc.

Disclosure of Invention

According to one aspect of the application, a composite is provided, and an electrochemical neutralization energy battery prepared by the composite as a catalyst has good reversibility and strong stability, and is easy for industrial production.

The novel electrochemical neutralization energy battery provided by the application is characterized in that acid and alkali asymmetric electrolytes are filled in a cathode pool and an anode pool, chemical neutralization of acid and alkali is prevented through a bipolar diaphragm, nitrogen is generated at the cathode to generate ammonia, zinc oxidation reaction is generated at the anode, a nitrogen-doped carbon nanosheet iron-loaded monatomic composite catalyst with excellent catalytic performance for ammonia reaction generated by reduction of nitrogen at the cathode is developed, and therefore the dischargeable battery taking nitrogen and zinc as raw materials is constructed.

During the discharge, the anode undergoes a zinc oxidation reaction:

3Zn+6OH^--6e^-→3ZnO+3H₂O E_a＝-1.285V(4.0M NaOH)

and (3) carrying out nitrogen reduction reaction on the cathode:

2N₂+6H⁺+6e^-1→2NH₃ E_c＝-0.00985V(0.1M HCl)

Na⁺and Cl^-The water layer which passes through the cation exchange membrane and the anion exchange membrane respectively and is transmitted to the middle forms a loop with an external circuit.

The overall reaction equation is:

3Zn+6OH^-+2N₂+6H⁺→3ZnO+2NH₃+3H₂O

the theoretical open circuit voltage of the cell is: v_cell＝E_c–E_a＝1.275V。

The composite provided by the application is a nitrogen-doped carbon nanosheet iron-loaded monatomic composite; the iron single atom is loaded in the two-dimensional structure of the nitrogen-doped carbon nanosheet.

Optionally, the structure of the composite is a three-dimensional porous structure.

Optionally, the weight content of iron in the compound is 0.1-1.0%; the thickness n of the carbon nano sheet is more than 0 and less than or equal to 5 nm; the coordination structure of the iron monoatomic in the compound is FeN_xO_y(ii) a Wherein x is 1-4, and y is 1-4.

Preferably, FeN_xO_yWherein x is 2 and y is 4.

Preferably, the thickness n of the carbon nanoplatelets is 2.

Specifically, the catalytic active site in the nitrogen-doped carbon nanosheet iron-loaded monatomic composite is FeN₂O₄。

In particular, FeN₂O₄The structure of (1) is a structure in which an iron atom is a center and nitrogen and oxygen are coordinating elements.

According to an aspect of the present application, there is provided a method for preparing the complex including the steps of:

and calcining the mixture containing the iron source, the nitrogen source, the carbon source and the template agent in an inert atmosphere to obtain the compound.

Optionally, the mass ratio of the carbon source, the iron source, the nitrogen source and the template agent is 1-10: 0.1-2: 1-10: 0.1 to 5;

the iron source is selected from at least one of iron salts;

the nitrogen source is selected from at least one of ammonium salts;

the carbon source is at least one of citric acid and glucose;

the template agent is a hard template agent.

Optionally, the mass ratio of the carbon source, the iron source, the nitrogen source and the template agent is 4-6: 0.3-0.7: 4-6: 0.8 to 1.2.

Preferably, the mass ratio of the carbon source, the iron source, the nitrogen source and the template agent is 5: 0.5: 5: 1.

optionally, the ammonium salt is selected from at least one of ammonium chloride, ammonium carbonate, ammonium bicarbonate;

the ferric salt comprises at least one of ferric nitrate nonahydrate and ferric chloride;

the template agent is silicon dioxide.

Preferably, the iron source is ferric nitrate nonahydrate, the carbon source is citric acid, and the nitrogen source is ammonium chloride.

Specifically, the ammonium chloride is heated and decomposed to obtain ammonia gas, and the citric acid is calcined to obtain the carbon nanosheet.

Optionally, the inert atmosphere is selected from at least one of nitrogen and inert gas;

the calcining conditions are as follows: calcining at 400-1100 ℃ for 1-6 hours.

Alternatively, the upper limit of the calcination temperature is independently selected from 500 ℃, 600 ℃, 700 ℃, 800 ℃, 900 ℃, 1000 ℃, 1100 ℃; the lower limit is independently selected from 400 deg.C, 500 deg.C, 600 deg.C, 700 deg.C, 800 deg.C, 900 deg.C, 1000 deg.C.

Preferably, the calcination time is 2 to 4 hours.

Preferably, the inert atmosphere is argon.

Optionally, the preparation method comprises: drying a solution containing an iron source, a nitrogen source, a carbon source and a template agent, and calcining the solution in an inactive atmosphere to obtain the compound;

wherein the solvent in the solution comprises water.

Specifically, the purpose of forming the substance containing the iron source, the nitrogen source, the carbon source and the template agent into the solution is to uniformly disperse iron in the iron source in the solution, so that the loading of the nitrogen-doped carbon nanosheets is facilitated.

Preferably, the solution containing the iron source, the nitrogen source, the carbon source and the template is dried at 50-100 ℃.

Optionally, the water is deionized water, and the water is 1-30 ML.

Optionally, the water is 10-20 ML.

Preferably, the water is 15 ML.

According to another aspect of the present application, there is provided a catalyst comprising the composite, a method of preparing the composite.

Optionally, the catalyst is used for nitrogen reduction reactions.

According to another aspect of the present application, the electrochemically neutralized energy cell comprises a cathode, a catholyte, a separator, an anode, and an anolyte;

wherein the cathode contains a cathode catalyst;

the cathode catalyst comprises a nitrogen-doped ultrathin carbon nanosheet-supported iron monatomic composite.

Optionally, the battery is a zinc-nitrogen ammonia-making power generation battery;

the anode is metallic zinc;

the cathode catalyst is selected from at least one of the compound, the compound obtained by the preparation method and the catalyst.

Optionally, the catholyte is an acidic solution and the anolyte is an alkaline solution;

the anolyte and the catholyte are separated by the membrane.

Preferably, the catholyte concentration is 0-2M and the anolyte concentration is 0-5M.

Optionally, the catholyte is an acid solution;

the concentration of acid in the cathode electrolyte is 0.05-2M;

the anolyte is an alkali solution;

the concentration of alkali in the anolyte is 0.5-5M.

Optionally, the acid in the catholyte is selected from at least one of sulfuric acid and hydrochloric acid;

the alkali in the anolyte is at least one of sodium hydroxide and potassium hydroxide;

preferably, the catholyte is a HCl solution with a concentration of 0.1M; the anolyte is NaOH solution, and the concentration is 4M.

Optionally, the loading amount of the cathode catalyst on the cathode is 1-3 mg/cm²；

The substrate for loading the cathode catalyst is selected from one of carbon cloth and carbon paper;

preferably, the loading of the cathode catalyst on the substrate is 1mg/cm²。

Optionally, the area of the substrate is 1cm × 2cm to 2cm × 1 cm;

the substrate is a hydrophilic substrate;

the loading area of the cathode catalyst on the substrate is 1cm multiplied by 0.5-2 cm;

preferably, the resistance of the substrate is greater than 0 Ω and less than 5 Ω.

Preferably, the cathode catalyst is in a square shape of 1cm × 1cm on carbon paper.

Optionally, the membrane is a bipolar membrane; the diaphragm comprises an anion exchange membrane and a cation exchange membrane;

preferably, the substrate is rectangular, and the size of the substrate is 1cm × 2 cm.

Specifically, the loading of the catalyst supported on the substrate was 1 mg.

Optionally, the bipolar membrane has an anion exchange membrane facing the cathode and a cation exchange membrane facing the anode.

The beneficial effects that this application can produce include:

1) the application provides an electrochemistry neutralization energy battery, nitrogen gas can be reduced into ammonia as the cathode reactant, and metallic zinc is as anode reactant oxidation and provides electron for nitrogen gas reduction, has advantages such as reversibility is good, and stability is strong, and environmental protection effect is showing.

2) The electrochemical neutralization energy battery provided by the application is simple to assemble, high in practical value and easy for industrial production.

Drawings

Fig. 1 is a schematic diagram of the structure of an electrochemical neutralization energy cell of the present application.

Fig. 2 is a scanning electron microscope image of the nitrogen-doped carbon nanosheet iron-loaded monatomic composite catalyst prepared in example 1 of the present application.

Figure 3 is a graph of ammonia yield at different potentials and faradaic efficiency during electrochemical nitrogen reduction in 0.1M HCl at different potentials for catalysts prepared in example 1 of the present application.

FIG. 4 is a graph of stability of the catalyst prepared in example 1 of the present application during electrochemical nitrogen reduction in 0.1M HCl at different potentials.

Fig. 5 is a graph of power density in an electrochemical neutralization energy cell device assembled by the nitrogen-doped ultrathin carbon nanosheet iron-loaded monatomic composite catalyst synthesized by the present patent.

FIG. 6 shows an electrochemical neutralization energy cell of the present patent at 1mA cm^-2At 90 cycles of the constant current discharge-charge cycle plot.

FIG. 7 is a graph of the results of a space fit R of the x-ray absorption near edge structure (XANES) spectra of catalysts prepared in example 1 of the present patent application.

Fig. 8 is a scanning electron microscope image of the nitrogen-doped carbon nanosheet iron-supported monatomic composite catalyst prepared in examples 2,3, and 4 of the present application, corresponding to (a), (b), and (c), respectively.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

The raw materials in the examples of the present application were all purchased commercially, unless otherwise specified.

The electrochemical neutralization energy cell device of the present application has a schematic configuration as shown in fig. 1, wherein the cathode material is carbon paper carrying cathode catalyst, and the anode material is a metallic zinc sheet. The anode and cathode material electrodes were placed in the anode chamber (4M NaOH) for zinc oxidation and the cathode chamber (0.1M HCl) for catalytic nitrogen reduction, respectively, separated by a bipolar membrane.

The preparation method of the compound comprises the following steps: dissolving a mixture containing citric acid, an iron precursor, ammonium chloride and a hard template in deionized water, drying, and calcining in an inactive atmosphere to obtain the ultra-thin nitrogen-doped carbon nanosheet catalyst loaded with iron single atoms.

Common nitrogen sources of ammonium chloride, ammonium carbonate and ammonium bicarbonate can be used in the application, and a person skilled in the art can select a proper nitrogen source according to actual production needs. Preferably, the nitrogen source is ammonium chloride. Example 1 nitrogen-doped ultrathin carbon nanosheet supportIron monatomic complex catalyst sample (1)^#) The preparation steps are as follows:

(1)5g of citric acid, 5g of ammonium chloride, 1g of silicon dioxide and 0.5g of ferric nitrate nonahydrate are dissolved in 15mL of water and sonicated for 30 minutes.

(2) The mixed solution was dried at 70 ℃.

(3) And (3) putting the dried sample into a tube furnace, and calcining the sample for 3 hours at 900 ℃ under argon to obtain a black sample.

(4) The resulting black sample was etched with hydrofluoric acid (5 wt%) to hard mask SiO₂Catalyst # 1 was obtained.

The carbon nanosheet in this example was measured by an AFM (atomic force microscope) instrument, and the thickness of the carbon nanosheet was found to be 2 nm.

Example 2 sample of nitrogen-doped ultrathin carbon nanosheet iron-loaded monatomic composite catalyst (2)^#) The preparation steps are as follows:

(2) The mixed solution was dried at 70 ℃.

(3) And (3) putting the dried sample into a tube furnace, and calcining the sample for 3 hours at 800 ℃ under argon to obtain a black sample.

(4) The resulting black sample was etched with hydrofluoric acid (5 wt%) to hard mask SiO₂Catalyst # 2 was obtained.

Example 3 sample of nitrogen-doped ultrathin carbon nanosheet iron-supported monatomic composite catalyst (3)^#) The preparation steps are as follows:

(2) The mixed solution was dried at 70 ℃.

(3) And (3) putting the dried sample into a tube furnace, and calcining for 3 hours at 1000 ℃ under argon to obtain a black sample.

(4) The resulting black sample was hard-etched with hydrofluoric acid (5 wt%) to form a hard filmPlate SiO₂Catalyst # 3 was obtained.

Example 4 preparation steps of a nitrogen-doped ultrathin carbon nanosheet-supported iron monatomic composite catalyst sample (4#) are as follows:

(1)6g glucose, 6g ammonium carbonate, 1.2g SiO₂0.7g of ferric chloride was dissolved in 15mL of water and sonicated for 30 minutes.

(2) The mixed solution was dried at 70 ℃.

(4) The resulting black sample was etched with hydrofluoric acid (5 wt%) to hard mask SiO₂Catalyst # 4 was obtained.

Example 5 structural characterization of iron-loaded monatomic composite of nitrogen-doped ultrathin carbon nanosheets

The catalyst sample (1) obtained in example 1 was used^#) Structural characterization was performed using x-ray absorption near edge structure (XANES) spectroscopy, and the results obtained, as shown in fig. 7, gave a fitted coordination structure of FeN₂O₄。

For the catalyst sample (2) obtained in example 2^#) The catalyst sample (3) obtained in example 3^#) And the catalyst sample (4) obtained in example 4^#) Structural characterization using x-ray absorption near edge structure (XANES) spectroscopy yielded a catalyst sample (1) similar to that of example 1^#) The x-ray pattern of (a) was similar, demonstrating that a composite with this structure was obtained.

Example 6 morphology characterization of iron-loaded monatomic composites of nitrogen-doped ultrathin carbon nanosheets

The catalyst sample (1) obtained in example 1 was used^#) And (3) performing morphology characterization, and scanning by using a scanning electron microscope to obtain a result shown in figure 2, wherein the compound has a three-dimensional porous reverse protein structure with regular arrangement.

For the catalyst sample (2) obtained in example 2^#) The catalyst sample (3) obtained in example 3^#) And the catalyst sample (4) obtained in example 4^#) Structural characterization was performed, as in FIG. 8, with the catalyst sample (1) of example 1^#) Similar to FIG. 2, all have three-dimensional porous and regularly arranged inverse protein structure, and the complex with the structure is proved to be obtained.

Example 7 test of nitrogen-doped ultrathin carbon nanosheet iron-loaded monatomic composite catalyst sample for electrochemical catalysis of nitrogen reduction performance

Test of nitrogen-doped ultrathin carbon nanosheet iron-loaded monatomic composite catalyst sample (1#) for electrochemical catalysis of nitrogen reduction performance

The method comprises the following steps: the loading of the catalyst-containing material is 0.25 mg-cm-²50uL of the dispersion (water/ethanol/Nafion volume ratio 4:6:1) was applied dropwise to an area of 1 × 1cm²And naturally drying the carbon paper electrode. And the nitrogen-doped ultrathin carbon nanosheet iron-carrying monatomic composite (1#) is used as a working electrode. The nitrogen reduction of the material is tested by using a three-electrode system, the nitrogen-doped ultrathin carbon nanosheet iron-loaded monatomic composite catalyst (1#) is used as a working electrode, a platinum net is used as a counter electrode, silver/silver chloride is used as a reference electrode, and the tested solution is a solution containing 0.1M HCl. The material was subjected to an i-t test using an electrochemical workstation (Chenghua CHI 760E). The electrochemical test conditions were: before electrochemical reaction, nitrogen is introduced into the reaction system for 0.5 hour, so that the nitrogen in the reaction system is saturated, the electrode modified by the catalyst is a working electrode, silver/silver chloride is a reference electrode, a platinum net is a counter electrode, the test voltage is-0.3V, -0.4V, -0.5V, -0.6V (relative to a silver/silver chloride reference electrode), and the test time is 2 hours.

The test results are shown in figures 3 and 4, and the results show that the nitrogen-doped ultrathin carbon nanosheet-supported iron monatomic composite catalyst has excellent catalytic activity for nitrogen reduction, and the average ammonia yield (namely the ammonia yield obtained per milligram of raw material per hour) is 31.85 mug.h-¹·mg-¹The Faraday efficiency reaches 11.79%, and the catalyst has good stability.

Test of nitrogen-doped ultrathin carbon nanosheet iron-loaded monatomic composite catalyst sample (2#) for electrochemical catalysis of nitrogen reduction performance

The procedure for testing the electrochemical catalytic nitrogen reduction performance of the catalyst sample (2#) is similar to that of the catalyst sample (1#), and the description thereof is not repeated here. The test results were as follows: under the condition of-0.4V, the average ammonia yield is 11.85 mu g.h-¹·mg-¹The Faraday efficiency reaches 3.56%.

Test of nitrogen-doped ultrathin carbon nanosheet iron-loaded monatomic composite catalyst sample (3#) for electrochemical catalysis of nitrogen reduction performance

The procedure for testing the electrochemical catalytic nitrogen reduction performance of the catalyst sample (3#) is similar to that of the catalyst sample (1#), and the description thereof is not repeated here. The test results were as follows: the average ammonia yield was 9.9. mu.g.h at a voltage of-0.4V^-1·mg^-1The Faraday efficiency reaches 0.95%.

Testing the electrochemical catalytic nitrogen reduction performance of a nitrogen-doped ultrathin carbon nanosheet iron-loaded monatomic composite catalyst sample (No. 4),

the procedure for testing the electrochemical catalytic nitrogen reduction performance of the catalyst sample (4#) is similar to that of the catalyst sample (1#), and the description thereof is not repeated here. The test results were as follows: the average ammonia yield was 12.23. mu.g.h at a voltage of-0.4V^-1·mg^-1The Faraday efficiency reaches 7.5%.

Example 8 assembly of an electrochemically neutralized energy cell M1

Comprises a cathode, a catholyte, a diaphragm, an anode and an anolyte.

Cathode catalyst: Fe-NCNs (1)^#)

Cathode electrode: 5mg Fe-NCNs (1)^#) Dispersing the catalyst in 1mL of water/ethanol/Nafion mixed solution (volume ratio of water/ethanol/Nafion is 4:6:1), ultrasonically dispersing uniformly, dripping 0.05mL of suspension liquid on hydrophilic carbon paper with the area of 1cm multiplied by 1cm, and placing the prepared cathode electrode on an infrared lampAnd (4) baking and drying the mixture for assembling the electrochemical neutralization energy battery.

And (3) cathode electrolyte: 0.1M aqueous HCl.

A diaphragm: a bipolar membrane.

Anode catalyst: using a 1X 1cm²The zinc plate of (1).

Anolyte: 4M aqueous NaOH solution

Respectively using the prepared electrodes as cathode and anode, separating catholyte and anolyte by bipolar membrane, the anion exchange membrane of bipolar membrane is faced to cathode chamber, the cation exchange membrane is faced to anode chamber, and mixing them^.And (3) injecting 0.1M HCl into a cathode chamber and injecting 4M NaOH into an anode chamber to build a zinc-nitrogen battery M1.

Example 9 Assembly of Zinc-Nitrogen cell M2

Comprises a cathode, a catholyte, a diaphragm, an anode and an anolyte.

Cathode catalyst: Fe-NCNs (2)^#)

Cathode electrode: 5mg Fe-NCNs (2)^#) Dispersing the catalyst in 1mL of water/ethanol/Nafion mixed solution (volume ratio of water/ethanol/Nafion is 4:6:1), ultrasonically dispersing uniformly, dripping 0.05mL of suspension liquid on 1cm multiplied by 2cm of hydrophilic carbon paper, wherein the area of the catalyst is 1cm multiplied by 1cm, baking and drying the prepared cathode electrode under an infrared lamp, and using the baked and dried cathode electrode for assembling an electrochemical neutralization energy battery.

And (3) cathode electrolyte: 0.1M aqueous HCl.

A diaphragm: a bipolar membrane.

Anode catalyst: using a 1X 1cm²The zinc plate of (1).

Anolyte: 4M aqueous NaOH solution

Respectively using the prepared electrodes as cathode and anode, separating catholyte and anolyte by bipolar membrane, the anion exchange membrane of bipolar membrane is faced to cathode chamber, the cation exchange membrane is faced to anode chamber, and mixing them^.And (3) injecting 0.1M HCl into a cathode chamber and injecting 4M NaOH into an anode chamber to build a zinc-nitrogen battery M2.

Example 10 Assembly of Zinc-Nitrogen cell M3

Comprises a cathode, a catholyte, a diaphragm, an anode and an anolyte.

Cathode catalyst: Fe-NCNs (3)^#)

Cathode electrode: 5mg Fe-NCNs (3)^#) Dispersing the catalyst in 1mL of water/ethanol/Nafion mixed solution (volume ratio of water/ethanol/Nafion is 4:6:1), ultrasonically dispersing uniformly, dripping 0.05mL of suspension liquid on 1cm multiplied by 2cm of hydrophilic carbon paper, wherein the area of the catalyst is 1cm multiplied by 1cm, baking and drying the prepared cathode electrode under an infrared lamp, and using the baked and dried cathode electrode for assembling an electrochemical neutralization energy battery.

And (3) cathode electrolyte: 0.1M aqueous HCl.

A diaphragm: a bipolar membrane.

Anode catalyst: using a 1X 1cm²The zinc plate of (1).

Anolyte: 4M aqueous NaOH solution

Respectively using the prepared electrodes as cathode and anode, separating catholyte and anolyte by bipolar membrane, the anion exchange membrane of bipolar membrane is faced to cathode chamber, the cation exchange membrane is faced to anode chamber, and mixing them^.And (3) injecting 0.1M HCl into a cathode chamber and injecting 4M NaOH into an anode chamber to build a zinc-nitrogen battery M3.

Example 11 electrochemical neutralization of energy cell electrochemical Performance testing

The electrochemical workstation (Shanghai Chen Hua CHI760E) and the New Willer cell tester (Shenzhen) were used to perform electrochemical and charge-discharge energy tests on the fresh air. And (3) testing conditions are as follows: under normal temperature and pressure, the voltage range is 1.5V-0.2V, and the sweep rate is 0.005mV^-1；1mA·cm^-2At 90 cycles of constant current discharge.

The test result shows that, as shown in fig. 5, the zinc-nitrogen assembled by the applied technical scheme has higher current density and power density than M2 and M3, M1, and it can be seen from the figure that the zinc-nitrogen provided by the applied technical scheme can provide 1.22V open circuit voltage, and when the discharge current density reaches 12.7 mA-cm^-2Then the maximum power density of the battery can reach 4.5mW cm^-2. The performance of M1 using Fe-NCNs (1#) prepared in example 1 as the catalyst was better than that of M2 using Fe-NCNs (2#,3#) prepared in examples 2 and 3 as the catalystAnd M3 properties.

Fig. 6 is a graph of constant current discharge-charge cycle for a zinc-nitrogen cell M1, under test conditions: 1 mA-cm at normal temperature and normal pressure^-2And the constant current charging and discharging for 90 periods shows that the zinc-nitrogen battery prepared by the technology has good stability and cycle performance.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. A composite, wherein the composite is a nitrogen-doped carbon nanosheet iron-loaded monatomic composite;

the iron single atom is loaded in the two-dimensional structure of the nitrogen-doped carbon nanosheet.

2. The compound of claim 1, wherein the iron content of the compound is between 0.1% and 1.0% by weight;

the thickness n of the carbon nano sheet is more than 0 and less than or equal to 5 nm;

the coordination structure of the iron monoatomic in the compound is FeN_xO_y(ii) a Wherein x is 1-4, and y is 1-4.

3. A method for preparing a compound according to claim 1 or 2, comprising the steps of:

4. The production method according to claim 3,

the mass ratio of the carbon source, the iron source, the nitrogen source and the template agent is 1-10: 0.1-2: 1-10: 0.1 to 5; the iron source is selected from at least one of iron salts; the nitrogen source is selected from at least one of ammonium salts; the carbon source is at least one of citric acid and glucose; the template agent is a hard template agent;

preferably, the ammonium salt is selected from at least one of ammonium chloride, ammonium carbonate and ammonium bicarbonate; the ferric salt comprises at least one of ferric nitrate nonahydrate and ferric chloride; the hard template agent is silicon dioxide.

5. The production method according to claim 3,

the inert atmosphere is selected from at least one of nitrogen and inert gas;

6. The production method according to claim 3, characterized by comprising: drying a solution containing an iron source, a nitrogen source, a carbon source and a template agent, and calcining the solution in an inactive atmosphere to obtain the compound;

wherein the solvent in the solution comprises water.

7. A catalyst comprising at least one of the composite of claim 1 or 2, a composite prepared according to the method of any one of claims 3 to 6.

8. The catalyst of claim 7, wherein the catalyst is used in a nitrogen reduction reaction.

9. An electrochemical neutralization energy cell, comprising a cathode, a catholyte, a separator, an anode, and an anolyte;

wherein the cathode contains a cathode catalyst;

the cathode catalyst comprises a nitrogen-doped carbon nanosheet-supported iron monatomic composite;

preferably, the battery is a zinc-nitrogen ammonia-making power generation battery; the anode is metallic zinc; the cathode catalyst is selected from at least one of the composite of claim 1 or 2, the composite prepared by the method of any one of claims 3 to 6, and the catalyst of claim 7 or 8.

10. The electrochemically neutralized energy cell according to claim 9, wherein the catholyte is an acidic solution and the anolyte is an alkaline solution;

the anolyte and the catholyte are separated by the membrane;

preferably, the catholyte is an acid solution; the concentration of acid in the cathode electrolyte is 0.05-2M; the anolyte is an alkali solution; the concentration of alkali in the anolyte is 0.5-5M;

preferably, the acid in the catholyte is selected from at least one of sulfuric acid and hydrochloric acid; the alkali in the anolyte is at least one of sodium hydroxide and potassium hydroxide;

preferably, the load capacity of the cathode catalyst on the cathode is 1-3 mg/cm²(ii) a The substrate for loading the cathode catalyst is selected from one of carbon cloth and carbon paper;

preferably, the area of the substrate is 1cm × 2cm to 2cm × 1 cm; the substrate is a hydrophilic substrate; the loading area of the cathode catalyst on the substrate is 1cm multiplied by 0.5-2 cm;

preferably, the membrane is a bipolar membrane; the diaphragm comprises an anion exchange membrane and a cation exchange membrane;

preferably, the anion exchange membrane of the bipolar membrane faces the cathode and the cation exchange membrane faces the anode.