A single-atom-layer-based Ti 4 O 7 Composite electrode and preparation method thereof

Abstract

The present invention relates to the technical field of composite electrodes, and discloses a Ti4O7 composite electrode based on a single atomic layer and a preparation method thereof; the present invention provides a preparation method of a Ti4O7 composite electrode based on a single atomic layer, and this composite electrode has good removal rate and defluorination rate for perfluoro / polyfluoro compounds. Modifying the Ti4O7 electrode with MXene quantum dots can effectively enhance the interfacial electron transfer efficiency and its mechanical properties, and effectively inhibit the passivation of the electrode surface. Anchoring metal atoms on the defective Ti4O7 electrode in the form of a single-layer structure can maintain 100% metal utilization efficiency and overcome the disadvantage of easy aggregation of metal atoms.

Description

Technical Field

[0001] The present invention relates to the technical field of composite electrodes, and specifically to a Ti 4 O 7 composite electrode based on a single atomic layer and a preparation method thereof. Background Art

[0002] Perfluoro / polyfluoro compounds are a type of new persistent organic pollutants widely used in industry and human daily life. These compounds are prone to bioaccumulation and may cause characteristics such as hepatotoxicity, carcinogenicity, reproductive toxicity, and endocrine disruption. Due to the high electronegativity and small size of fluorine atoms, the C-F bonds formed with C have high stability. Therefore, traditional biological treatment technologies have little removal effect on perfluoro / polyfluoro compounds, resulting in these pollutants entering surface water and groundwater, posing a serious threat to the ecosystem and human health. Researchers have used a variety of advanced oxidation technologies to degrade perfluoro compounds and achieved certain results, but there has always been a problem of low defluorination rate of perfluoro / polyfluoro compounds.

[0003] Magnéli Ti 4 O 7 is a material with high electrochemical stability, good electrical conductivity, and resistance to various acid and alkali corrosions. At appropriate potentials, it can generate strongly oxidizing species to effectively degrade perfluoro / polyfluoro compounds. However, during the electrochemical oxidation process, an oxide film is easily formed on the electrode surface, causing electrode passivation and reducing its electrochemical activity. Chemically modifying and modifying the Ti 4 O 7 electrode is an effective method to inhibit its surface passivation. MXenes are a type of two-dimensional material with rich surface groups and a large specific surface area, which can provide rapid charge transfer in the two-dimensional nanosheets of SP2 hybridization and can be used as a chemical modification material for electrodes and a site for electrocatalytic reactions. MXenes materials with a lateral size less than 10 nm are called MXene quantum dots. MXene quantum dots have a quantum confinement effect and have more novel physical and chemical properties while retaining the advantages of MXenes themselves. Single-atom catalysts are a type of supported metal catalyst with extremely high atomic utilization efficiency. Its metal active components are anchored on the carrier in the form of isolated single atoms, with high atomic utilization efficiency and strong catalytic activity. However, it has the characteristics of high surface energy, thermodynamic instability, and easy agglomeration. Research has shown that building metal atoms in the form of a single-layer structure on a defective carrier can maintain 100% metal utilization efficiency, and at the same time, the metal atoms adjacent to the active sites can exhibit a synergistic effect, and it can also overcome the disadvantage of easy agglomeration of metal atoms, showing great advantages and good application prospects in the catalytic field.

[0004] Therefore, invent a Ti 4 O7 The composite electrode is of great significance. Summary of the Invention

[0005] An object of the present invention is to provide a Ti 4 O 7 -based composite electrode and a preparation method thereof to solve the problems raised in the above-mentioned background technology.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] A preparation method of a Ti 4 O 7 -based composite electrode, comprising the following steps:

[0008] S1: Mix Ti 4 O 7 powder and Ti 3 C 2 MXene quantum dot solution evenly, heat and evaporate to dryness, and dry to obtain Ti 4 O 7 mixed powder;

[0009] S2: High-temperature sinter the Ti 4 O 7 mixed powder to obtain a Ti 4 O 7 composite electrode;

[0010] S3: Calcinate the Ti 4 O 7 composite electrode in a reducing atmosphere to obtain a high-density defect Ti 4 O 7 composite electrode;

[0011] S4: Drop the single-atom precursor solution onto both sides of the high-density defect Ti 4 O 7 composite electrode, dry, and calcine to obtain a single-atom Ti 4 O 7 composite electrode;

[0012] S5: Calcinate the single-atom Ti 4 O 7 composite electrode in a reducing atmosphere to obtain a single-atom layer Ti 4 O 7 composite electrode.

[0013] Furthermore, the solute in the Ti 3 C 2 MXene quantum dot solution is Ti 3 C 2The solvent of MXene quantum dots is deionized water; wherein, Ti 3 C 2 The MXene quantum dots are prepared by the following method:

[0014] Disperse Ti 3 AlC 2 powder into hydrofluoric acid solution, etch, wash, and dry to obtain multi-layer Ti 3 C 2 MXenes powder; Disperse the multi-layer Ti 3 C 2 MXenes into deionized water by ultrasonic dispersion under N 2 atmosphere, add ammonia water to adjust the pH value, and then carry out hydrothermal reaction; After the reaction, centrifuge the mixture, collect the supernatant and freeze-dry to obtain Ti 3 C 2 MXene quantum dots.

[0015] Furthermore, the concentration of the Ti 3 C 2 MXene quantum dot solution is 2-10 mg / L; Add Ti 4 O 7 powder into the Ti 3 C 2 MXene quantum dot solution, stir at 800-850 rpm for 10-30 min, then ultrasonically mix for 10-30 min, heat to 60-65 °C and stir to dry until a slurry is formed, and then dry in an oven for 7-10 h to obtain Ti 4 O 7 mixed powder;

[0016] Among them, by mass percentage, Ti 4 O 7 powder is 90-95%, and Ti 3 C 2 MXene quantum dot solution is 5-10%.

[0017] Furthermore, the specific steps of the high-temperature sintering are as follows:

[0018] Put the Ti 4 O 7 mixed powder into a dual-power vacuum plasma sintering furnace, set the vacuum pressure to 20-50 Pa, the sintering temperature to 600-1200 °C, the sintering pressure to 1-3 MPa, and the sintering time to 30-40 min to obtain Ti 4 O 7 composite electrode.

[0019] Furthermore, the reducing atmosphere is 5-30% H 2and a 70 - 95% Ar mixed gas; Ti 4 O 7 The composite electrode is calcined at a high temperature in a reducing atmosphere of H 2 and Ar mixed gas, the temperature is 600 - 900 °C, the heating rate is 2 - 5 °C / min, and the time is 2 - 5 h, to obtain a high - density defect Ti 4 O 7 composite electrode.

[0020] Furthermore, the single - atom precursor solution is dropped onto both sides of the high - density defect Ti 4 O 7 composite electrode, then dried at 120 - 125 °C for 1 - 2 h, and then calcined in air at 400 - 700 °C for 1 - 3 h, with a heating rate of 2 - 5 °C / min, to obtain a single - atom Ti 4 O 7 composite electrode.

[0021] Furthermore, the solute in the single - atom precursor solution is a single - atom precursor and the solvent is deionized water; wherein, the mass ratio of the single - atom precursor to the high - density defect Ti 4 O 7 composite electrode is (0.1 - 1.0):(99.0 - 99.9); the single - atom precursor is any one of NiCl 2 , CuCl 2 , H 2 PtCl 6 , K 2 PdCl 6 , CoCl 2 , RuCl 3 , RhCl 3 .

[0022] Furthermore, the reducing atmosphere is 5 - 30% H 2 and 70 - 95% Ar mixed gas; the single - atom Ti 4 O 7 composite electrode is calcined at a high temperature in a reducing atmosphere of H 2 and Ar mixed gas, the temperature is 300 - 600 °C, the heating rate is 5 - 10 °C / min, and the time is 0.5 - 3 h, to obtain a single - atom layer Ti 4 O 7 composite electrode.

[0023] Compared with the prior art, the beneficial effects achieved by the present invention are: The present invention provides a single - atom layer - based Ti 4 O 7Preparation method of composite electrode, which has good removal rate and defluorination rate for perfluorinated / polyfluorinated compounds. Using MXene quantum dots to modify Ti 4 O 7 electrode can effectively enhance the interfacial electron transfer efficiency and its mechanical properties, and effectively inhibit the passivation of the electrode surface. Anchoring metal atoms in the form of a single-layer structure on the defective Ti 4 O 7 electrode can maintain 100% metal utilization efficiency, and at the same time, the metal atoms adjacent to the active sites show a synergistic effect, and overcome the disadvantage of easy agglomeration of metal atoms;

[0024] Using Ti 3 C 2 MXene quantum dots to modify Ti 4 O 7 electrode has multiple advantageous effects. First of all, the interaction between Ti 4 O 7 and Ti 3 C 2 MXene quantum dots can effectively increase the rate of electron transfer, reduce the charge transfer resistance in the electrochemical reaction, and effectively prevent the passivation of Ti 4 O 7 . Secondly, the synergistic effect between Ti 4 O 7 and Ti 3 C 2 MXene quantum dots can increase the metal vacancies and oxygen vacancies on the interface, which helps to generate and expose more active sites. In addition, the coupling effect between Ti 4 O 7 and Ti 3 C 2 MXene quantum dots will cause changes in the coordination environment and structure during the electrochemical reaction process, adjust the electronic structure of the electrocatalyst, and promote electron transfer;

[0025] Anchoring metal atoms in the form of a single-layer structure on the defective Ti 3 C 2 MXene quantum dots / Ti 4 O 7 electrode can maintain 100% metal utilization efficiency, and at the same time, the metal atoms adjacent to the active sites show a synergistic effect, and can also overcome the disadvantage of easy agglomeration of metal atoms, showing great advantages and good application prospects in the catalytic field. Brief Description of the Drawings

[0026] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention. In the accompanying drawings:

[0027] Figure 1 is the scanning electron microscope image of the single-atom layer Ti 4 O 7 composite electrode prepared in Example 1 of the present invention. Detailed implementation manners

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] In the following examples, Ti 3 AlC 2 is provided by Jilin Yiyi Technology Co., Ltd.; the 48% hydrofluoric acid solution is provided by Shanghai Macklin Biochemical Co., Ltd., the 25-28% ammonia water and H 2 PtCl 6 is provided by Aladdin Reagent Co., Ltd.; Ti 4 O 7 is provided by Shandong Union Chemical Group; NiCl 2 , CuCl 2 , CoCl 2 and RhCl 3 are provided by Merck; K 2 PdCl 6 is provided by Kermel Reagent.

[0030] In the following examples, Ti 3 C 2 MXene quantum dots are prepared as follows:

[0031] Disperse 2 g of Ti 3 AlC 2 powder into 40 mL of 48% hydrofluoric acid solution, and stir for 36 h at 35 °C for etching. Then, the obtained dispersion is centrifugally washed repeatedly with deionized water until the pH of the dispersion reaches 5-6. The centrifugation condition for each time is 5000 rpm for 10 min, and it is dried at 80 °C for 12 h to obtain multi-layer Ti 3 C 2 MXenes powder.

[0032] Under N 2 atmosphere, 1 g of multi-layer Ti 3 C 2MXenes were ultrasonically dispersed in 20 mL of deionized water, and ammonia water was added to adjust the pH value of the mixture to 9. Then, hydrothermal reaction was carried out at 100 °C for 6 h. After the reaction, the mixture was centrifuged at 5000 rpm for 10 minutes. The supernatant was collected after centrifugation and freeze-dried to obtain Ti 3 C 2 MXene quantum dots.

[0033] Example 1

[0034] S1: Weigh Ti 4 O 7 powder and Ti 3 C 2 MXene quantum dot solution (5 mg / L) according to the mass ratio of 90 wt%:10 wt% respectively and mix them. Stir the mixture at 800 rpm for 20 min, then ultrasonically mix for 20 min. Stir and evaporate the mixture to dryness in a water bath at 60 °C until a slurry is formed, and then dry it in an oven for 10 h to obtain 2 g of Ti 4 O 7 mixed powder;

[0035] S2: Put the Ti 4 O 7 mixed powder into a circular graphite mold and then put it into a dual-power plasma sintering furnace. Set the vacuum pressure to about 25 Pa, the sintering temperature to 1100 °C, the sintering pressure to always remain at 1.5 MPa, and the sintering time to 35 min. After cooling for 2 h, obtain Ti 4 O 7 composite electrode;

[0036] S3: Calcinate the Ti 4 O 7 composite electrode in 10% H 2 / 90% Ar atmosphere at 750 °C for 2 h with a heating rate of 5 °C / min to obtain a high-density defect Ti 4 O 7 composite electrode;

[0037] S4: Drop the H 2 PtCl 6 aqueous solution evenly onto both sides of the high-density defect Ti 4 O 7 composite electrode, where the mass ratio of H 2 PtCl 6 : high-density defect Ti 4 O 7 composite electrode is 0.5:99.5. Then dry it at 120 °C for 1 h and calcinate it in air at 550 °C for 2 h with a heating rate of 5 °C / min to obtain single-atom Ti 4 O7 Composite electrode;

[0038] S5: Add single-atom Ti 4 O 7 The composite electrode is calcined in an atmosphere of 10% H 2 / 90% Ar at 400 °C for 1 h with a heating rate of 10 °C / min to obtain a single-atom layer Ti 4 O 7 composite electrode.

[0039] Example 2

[0040] S1: Weigh Ti 4 O 7 powder and Ti 3 C 2 MXenes quantum dot solution (5 mg / L) respectively according to the mass ratio of 95 wt%: 5 wt%, mix them, stir at 800 rpm for 30 min, then ultrasonically mix for 30 min, stir and evaporate the mixture to dryness in a water bath at 60 °C until a slurry is formed, and then dry it in an oven for 7 h to obtain 2 g of Ti 4 O 7 mixed powder;

[0041] S2: Put the Ti 4 O 7 mixed powder into a circular graphite mold and then put it into a dual-power plasma sintering furnace. Set the vacuum pressure to about 35 Pa, the sintering temperature to 1200 °C, keep the sintering pressure at 3 MPa all the time, the sintering time to 40 min, and cool down for 2 h to obtain Ti 4 O 7 composite electrode;

[0042] S3: Calcinate the Ti 4 O 7 composite electrode in an atmosphere of 20% H 2 / 80% Ar at 900 °C for 4 h with a heating rate of 3 °C / min to obtain a high-density defect Ti 4 O 7 composite electrode;

[0043] S4: Drop the H 2 PtCl 6 aqueous solution evenly onto both sides of the high-density defect Ti 4 O 7 composite electrode, where H 2 PtCl 6 : high-density defect Ti 4 O 7The mass ratio of the composite electrode is 1.0:99.0, and then it is dried at 120 °C for 1 h and calcined in air at 700 °C for 1 h with a heating rate of 3 °C / min to obtain single-atom Ti 4 O 7 Composite electrode;

[0044] S5: The single-atom Ti 4 O 7 Composite electrode is calcined in a 20% H 2 / 80% Ar atmosphere at 600 °C for 0.5 h with a heating rate of 5 °C / min to obtain a single-atom layer Ti 4 O 7 Composite electrode.

[0045] Example 3

[0046] S1: Weigh Ti 4 O 7 powder and Ti 3 C 2 MXenes quantum dot solution (5 mg / L) according to a mass ratio of 92 wt%:8 wt% respectively, mix them, stir at 800 rpm for 10 min, then ultrasonically mix for 10 min, stir and evaporate the mixture to dryness in a water bath at 60 °C until a slurry is formed, and then place it in an oven to dry for 8 h to obtain 2 g of Ti 4 O 7 Mixed powder;

[0047] S2: Load the Ti 4 O 7 mixed powder into a circular graphite mold and put it into a dual-power plasma sintering furnace. Set the vacuum pressure to about 20 Pa, the sintering temperature to 800 °C, the sintering pressure to always remain at 1 MPa, the sintering time to 30 min, and cool down for 2 h to obtain Ti 4 O 7 Composite electrode;

[0048] S3: Calcinate the Ti 4 O 7 composite electrode in a 5% H 2 / 95% Ar atmosphere at 600 °C for 3 h with a heating rate of 2 °C / min to obtain a high-density defect Ti 4 O 7 Composite electrode;

[0049] S4: Uniformly drip the H 2 PtCl 6 aqueous solution onto both sides of the high-density defect Ti 4 O 7 composite electrode, where H 2 PtCl 6: High-density defect Ti 4 O 7 The mass ratio of the composite electrode is 0.1:99.9, then it is dried at 120 °C for 2 h and calcined in air at 400 °C for 3 h with a heating rate of 2 °C / min to obtain single-atom Ti 4 O 7 composite electrode;

[0050] S5: The single-atom Ti 4 O 7 composite electrode is calcined in a 5% H 2 / 95% Ar atmosphere at 300 °C for 3 h with a heating rate of 7 °C / min to obtain a single-atom layer Ti 4 O 7 composite electrode.

[0051] Comparative Example 1

[0052] Without adding H 2 PtCl 6 (without single-atom layer structure); The remaining steps are the same as those in Example 1;

[0053] Comparative Example 2

[0054] Without adding Ti 3 C 2 MXenes quantum dots; The remaining steps are the same as those in Example 1.

[0055] Experiment: Conducted in a 100 mL electrochemical reactor for 2 h. A simulated wastewater solution containing 10 mg / L of the target pollutant and 40 mM Na 2 SO 4 as a supporting electrolyte was placed in the electrochemical reactor. The prepared single-atom layer Ti 4 O 7 composite electrode was used as the anode and cathode. A stabilized DC power supply provided a constant current for the reaction device. Approximately 1 mL of the solution was sampled regularly during the reaction and filtered through a 0.22 μm polytetrafluoroethylene membrane. High-performance liquid chromatography (HPLC) was used to measure the degradation degree of the target pollutant, and ion chromatography was used to measure the fluoride ion concentration in the solution to investigate the defluorination rate of the single-atom layer Ti 4 O 7 composite electrode for the pollutant. The target pollutants were perfluorooctanoic acid, perfluorooctane sulfonic acid, hexafluoropropylene dimer acid, and hexafluoropropylene tetramer acid. The test results are shown in Table 1.

[0056] Table 1

[0057]

[0058]

[0059] Conclusion: From the data of Examples 1 to 3, it can be seen that the prepared single-atom layer Ti 4 O 7 composite electrode has high degradation efficiency and defluorination efficiency for refractory pollutants perfluorooctanoic acid, perfluorooctane sulfonic acid, hexafluoropropylene dimer acid and hexafluoropropylene tetramer acid. Within 2 h, the degradation efficiency of the above pollutants can reach more than 87%, and the defluorination efficiency is above 58%. Moreover, a higher content of the single-atom layer is beneficial to the defluorination of target pollutants.

[0060] Comparing with Comparative Example 1, it can be found that when there is no single-atom layer structure in the composite electrode, both the degradation rate and the defluorination efficiency decrease, and the decrease in the defluorination rate is more obvious. The reason is that: in the composite electrode, the single-atom layer structure can effectively break the carbon-fluorine bond. Pt is a particularly strong metal, and it can decompose hydrogen into single hydrogen atoms, which is a key step in breaking the carbon-fluorine bond. The Pt single-atom layer can not only maintain 100% metal utilization efficiency, but also show a synergistic effect with the metal atoms adjacent to the active sites, and can also overcome the disadvantage of easy agglomeration of metal atoms, greatly improving the hydrodefluorination effect. Therefore, when there is no single-atom layer structure in the composite electrode, the removal efficiency of the target pollutants will be reduced.

[0061] Comparing with Comparative Example 2, it can be found that when there is no Ti 3 C 2 MXenes quantum dots modification, the degradation rate and the defluorination efficiency decrease sharply. The reason is that: the interaction between Ti 4 O 7 and Ti 3 C 2 MXene quantum dots can effectively improve the rate of electron transfer, reduce the charge transfer resistance in the electrochemical reaction, and effectively prevent the passivation of Ti 4 O 7 . Secondly, the synergistic effect between Ti 4 O 7 and Ti 3 C 2 MXenes quantum dots can increase the metal vacancies and oxygen vacancies on the interface, which helps to generate and expose more active sites. In addition, the coupling effect between Ti 4 O 7 and Ti 3 C 2 MXenes will cause changes in the coordination environment and structure during the electrochemical reaction process, adjust the electronic structure of the electrocatalyst, and promote electron transfer. Therefore, when there is no Ti 3 C 2 MXenes quantum dots modification in the composite electrode will lead to a decrease in the removal efficiency of the target pollutants.

[0062] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a composite electrode based on single-atom-layer Ti 4 O 7 composite electrode, It is characterized in that: It includes the following steps: S1: Mix the Ti 4 O 7 powder and the Ti 3 C 2 MXene quantum dot solution evenly, heat to evaporate to dryness, and dry to obtain the Ti 4 O 7 mixed powder; S2: Mix Ti 4 O 7 mixed powder by high-temperature sintering to obtain Ti 4 O 7 composite electrode; S3: Calcinate the Ti 4 O 7 composite electrode in a reducing atmosphere to obtain a high-density defective Ti 4 O 7 composite electrode; S4: Drop the single-atom precursor solution onto both sides of the high-density defect Ti 4 O 7 composite electrode, dry, and calcine to obtain the single-atom Ti 4 O 7 composite electrode; S5: Calcinate the single-atom Ti 4 O 7 composite electrode under a reducing atmosphere to obtain a single-atom-layer Ti 4 O 7 composite electrode.

2. The preparation method of a single-atom-layer-based Ti 4 O 7 composite electrode It is characterized in that: The Ti 3 C 2 The solute in the MXene quantum dot solution is Ti 3 C 2 The solvent of the MXene quantum dots is deionized water; among them, Ti 3 C 2 The MXene quantum dots are prepared by the following method: Disperse Ti 3 AlC 2 powder into hydrofluoric acid solution, etch, wash, and dry to obtain multi-layered Ti 3 C 2 MXenes powder; Disperse multi-layered Ti 3 C 2 MXenes into deionized water by ultrasonic dispersion under N 2 atmosphere, add ammonia water to adjust the pH value, and then carry out hydrothermal reaction; After the reaction, centrifuge the mixture, collect the supernatant and freeze-dry to obtain Ti 3 C 2 MXenes quantum dots.

3. A preparation method of a single-atom-layer-based Ti 4 O 7 composite electrode, It is characterized in that: In step S1, the Ti 3 C 2 concentration of the MXene quantum dot solution is 2 - 10 mg / L; add the Ti 4 O 7 powder into the Ti 3 C 2 MXene quantum dot solution, stir at 800 - 850 rpm for 10 - 30 min, then ultrasonically mix for 10 - 30 min, heat to 60 - 65 °C and stir to dryness until a slurry is formed, and then place it in an oven to dry for 7 - 10 h to obtain the Ti 4 O 7 mixed powder; Among them, by mass percentage, the Ti 4 O 7 powder is 90 - 95%, and the Ti 3 C 2 MXenes quantum dot solution is 5 - 10%.

4. The preparation method of a single-atom-layer-based Ti 4 O 7 composite electrode It is characterized in that: In step S2, the specific steps of the high-temperature sintering are as follows: Put the Ti 4 O 7 mixed powder into a dual-power vacuum plasma sintering furnace, set the vacuum pressure to 20 - 50 Pa, the sintering temperature to 600 - 1200 °C, the sintering pressure to 1 - 3 MPa, and the sintering time to 30 - 40 min, to obtain the Ti 4 O 7 composite electrode.

5. A preparation method of a Ti 4 O 7 composite electrode based on a single atomic layer It is characterized in that: In step S3, the reducing atmosphere is a mixed gas of 5-30% H 2 and 70-95% Ar; Ti 4 O 7 The composite electrode is calcined at a high temperature in a reducing atmosphere of a mixed gas of H 2 and Ar. The temperature is 600-900 °C, the heating rate is 2-5 °C / min, and the time is 2-5 h to obtain a high-density defect Ti 4 O 7 composite electrode.

6. A preparation method of a Ti 4 O 7 composite electrode based on a single atomic layer It is characterized in that: In step S4, the single-atom precursor solution is dropped onto both sides of the high-density defect Ti 4 O 7 composite electrode, then dried at 120 - 125 °C for 1 - 2 h, and then calcined in air at 400 - 700 °C for 1 - 3 h with a heating rate of 2 - 5 °C / min to obtain the single-atom Ti 4 O 7 composite electrode.

7. A preparation method of a single-atom-layer-based Ti 4 O 7 composite electrode, It is characterized in that: In step S4, the solute in the single-atom precursor solution is a single-atom precursor and the solvent is deionized water; wherein, the single-atom precursor: high-density defect Ti 4 O 7 The mass ratio of the composite electrode is (0.1 - 1.0):(99.0 - 99.9); the single-atom precursor is NiCl 2 , CuCl 2 , H 2 PtCl 6 , K 2 PdCl 6 , CoCl 2 , RuCl 3 , RhCl 3 Any one of them.

8. A preparation method of a Ti 4 O 7 composite electrode based on a single atomic layer It is characterized in that: In step S5, the reducing atmosphere is a mixed gas of 5-30% H 2 and 70-95% Ar; the single-atom Ti 4 O 7 composite electrode is calcined at a high temperature in the reducing atmosphere of the mixed gas of H 2 and Ar. The temperature is 300-600 °C, the heating rate is 5-10 °C / min, and the time is 0.5-3 h to obtain the single-atom layer Ti 4 O 7 composite electrode.

9. A single-atom-layer Ti 4 O 7 composite electrode prepared by the preparation method of the composite electrode according to any one of claims 1-8 4 O 7 composite electrode.

Images