A single-atom confined carbon material composite electrode and its preparation method and application

Abstract

The present application proposes a single-atom confined carbon material composite electrode and its preparation method and application, wherein the single-atom confined carbon material composite electrode includes a substrate and a functional layer; the functional layer is distributed on the surface of the substrate; the material of the functional layer includes the following components in parts by weight: 0.05-1 parts of functional material, 0.075-0.375 parts of binder; the functional material is a single-atom confined carbon material composite material loaded with active components; the single-atom confined carbon material composite material is a composite material of single-atom transition metal, nitrogen and carbon, and the active component is a precious metal element or / and titanium element. The single-atom confined carbon material composite electrode described in this application has high stability due to the active component loaded on the single-atom confined carbon material.

Description

Technical Field

[0001] The present application relates to the field of material technology, and in particular to a single-atom confined carbon material composite electrode and a preparation method and application thereof. Background Art

[0002] Biomass, as a renewable energy source, is considered one of the most promising options for addressing current energy and environmental challenges. Biomass includes agricultural waste, crops, algae, and other materials. Biomass energy is considered to be the process of converting biomass into high-quality biofuels such as combustible gas, bio-oil, and biocoke through thermochemical processes including pyrolysis, combustion, and gasification. During biomass gasification or pyrolysis, organic compounds are produced, which condense into tar. This tar problem has limited the large-scale adoption of biomass gasification and pyrolysis technologies. Therefore, tar treatment has long been a major scientific challenge. Secondary removal is a key technology for tar treatment, commonly used to treat synthesis gas. It primarily utilizes physical purification methods, primarily spray water washing. However, this method suffers from the secondary pollution caused by the generated tar-washing wastewater. A key pollution indicator of tar-washing wastewater is high color. Electrochemical oxidation can clarify the tar-washing wastewater, providing theoretical and key technical support for addressing the tar problem in biomass gasification. Electrochemical oxidation is a highly effective method for treating high-salinity, highly toxic, and difficult-to-biodegrade organic wastewater. Its operating principles are categorized into two types: direct and indirect. Direct oxidation involves the degradation of organic matter at the anode surface. Indirect oxidation involves oxidation reactions occurring at the anode and on the surface of the filler particles, generating numerous intermediates such as ozone, [·HO₂], and [O₃]. These intermediates have a mineralizing effect on organic matter, converting recalcitrant macromolecules into small molecules. The efficiency of electrochemical oxidation in organic degradation is related to the anode material. High-quality electrode materials exhibit high electrochemical activity and organic degradation efficiency.

[0003] Compared to nanoscale catalysts, single atoms exhibit higher catalytic activity. Currently, researchers have used single-atom-confined carbon nanotube composite electrodes as anodes and titanium mesh as cathodes to degrade biomass gasification wastewater using electrochemical oxidation, attempting to enhance the electrode's catalytic activity through single-atom confinement. While this significant improvement in catalytic activity is achieved, the poor stability of the single-atom-confined carbon nanotube composite electrodes limits their application in water treatment. Summary of the Invention

[0004] In view of this, one object of the present application is to provide a single-atom confined carbon material composite electrode, which has high stability due to the active components loaded on the single-atom confined carbon material.

[0005] Another object of the present application is to provide a method for preparing a single-atom confined carbon material composite electrode.

[0006] Another object of the present application is to provide applications of single-atom confined carbon material composite electrodes.

[0007] Another object of the present application is to provide a method for treating biomass gasification coke washing wastewater.

[0008] To achieve the above objectives, the first embodiment of the present application provides a single-atom confined carbon material composite electrode, comprising:

[0009] substrate;

[0010] a functional layer, the functional layer being distributed on the surface of the substrate;

[0011] The material of the functional layer includes the following components in parts by weight: 0.05-1 part of functional material, 0.075-0.375 part of binder;

[0012] The functional material is a single-atom confined carbon material composite material loaded with active components; the single-atom confined carbon material composite material is a composite material of single-atom transition metal, nitrogen and carbon, and the active component is a noble metal element and / or titanium element.

[0013] In some embodiments, the loading amount of the active component is 0.5-1 wt%.

[0014] In some embodiments, when the active components are noble metal elements and titanium elements, the molar ratio of the noble metal elements to the titanium elements is (0.1-10): (10-0.1).

[0015] In some embodiments, in the single-atom confined carbon material, the molar ratio of the transition metal element, the carbon element, and the nitrogen element is 1:(16-24):(32-48).

[0016] In some embodiments, the binder is one or more of polytetrafluoroethylene, naphthol, and polypyrrole.

[0017] In some embodiments, the substrate is a metal plate structure having a plurality of through holes.

[0018] To achieve the above objectives, a second embodiment of the present application provides a method for preparing a single-atom confined carbon material composite electrode, comprising the following steps:

[0019] S1. Grinding a mixture containing a carbon source, a nitrogen source, an alcohol, and a transition metal salt into a slurry to obtain a first slurry;

[0020] S2. calcining the first slurry in an inert atmosphere to obtain a single-atom confined carbon material composite material;

[0021] S3, loading an active component on the single-atom confined carbon material composite material to obtain a single-atom confined carbon material composite material loaded with the active component;

[0022] S4, grinding the single-atom confined carbon material composite material loaded with active components into a powder, and then mixing it with a binder and an organic solvent to obtain a mixed solution;

[0023] S5, stirring and ultrasonically dispersing the mixed solution in sequence, and then drying it to a slurry to obtain a second slurry;

[0024] S6. Hot-press the second slurry onto the substrate while it is still hot to obtain the single-atom confined carbon material composite electrode.

[0025] In some embodiments, in step S1, the carbon source and nitrogen source are one or more of dicyandiamide, urea, and melamine, and the transition metal salt is one or more of sulfate, nitrate, chloride, and organic metal salt.

[0026] In some embodiments, in step S3, the method for loading the active component on the single-atom confined carbon material composite material is: uniformly mixing the low-molecular alcohol and the salt of the active component, and then adding the single-atom confined carbon material composite material.

[0027] In some embodiments, in step S3, the method of loading the active component on the single-atom confined carbon material composite material further comprises: drying a mixed solution of the low-molecular alcohol, the salt of the active component, and the single-atom confined carbon material composite material.

[0028] In some embodiments, in step S2, the calcination temperature is 750-850°C; in step S4, the organic solvent is one or more of ethanol, methanol, and N,N-dimethylacetamide; in step S5, the stirring time and ultrasonic dispersion time are both 15-45 minutes, and the drying temperature is 70-90°C; in step S6, the hot pressing pressure is between 10-30 MPa.

[0029] To achieve the above-mentioned purpose, the third aspect of the embodiment of the present application relates to the application of the single-atom confined carbon material composite electrode of the embodiment of the present application or the single-atom confined carbon material composite electrode prepared by the preparation method of the embodiment of the present application in the field of water treatment technology.

[0030] To achieve the above-mentioned purpose, the fourth aspect of the embodiment of the present application provides a method for treating biomass gasification and coke washing wastewater, wherein the biomass gasification and coke washing wastewater is treated by an electrochemical oxidation method, and the anode in the electrochemical oxidation treatment process adopts the single-atom confined carbon material composite electrode of the embodiment of the present application or the single-atom confined carbon material composite electrode prepared by the preparation method of the embodiment of the present application.

[0031] The single-atom confined carbon material composite electrode of the embodiment of the present invention can bring about the beneficial effect that the electrode has high stability because the active components are loaded on the single-atom confined carbon material.

[0032] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0034] Figure 1 Schematic diagram of the simple structure of a single-atom confined carbon material composite electrode according to one embodiment of the present invention.

[0035] Figure 2 Schematic diagram of the simple structure of a single-atom confined carbon material composite electrode according to another embodiment of the present invention.

[0036] Figure 3 This is a scanning electron microscope (SEM) comparison diagram of the materials of Comparative Example 2 and Examples 1-6, wherein:

[0037] (a) is the SEM image of Comparative Example 2 when the scale bar is 1 μm;

[0038] (b) is the SEM image of Comparative Example 2 when the scale bar is 200 mm;

[0039] (c) is the SEM image of Example 6, and (d) is the SEM image of Example 5;

[0040] (e) is the SEM image of Example 4;

[0041] (f) is the SEM image of Example 3;

[0042] (g) is the SEM image of Example 2;

[0043] (h) is the SEM image of Example 1.

[0044] Figure 4 The scanning transmission electron microscope (STEM) comparison diagram of the electrode of Example 2 under different scale conditions is shown in FIG.

[0045] (a) is the STEM image with a scale of 1 μm and a resolution of 10,000;

[0046] (b) is the STEM image with a scale of 50 nm and a resolution of 100,000;

[0047] (c) is the STEM image with a scale of 50 nm and a resolution of 100,000;

[0048] (d) is the STEM image with a scale of 2 nm and a resolution of 500,000.

[0049] Figure 5 Comparative X-ray diffraction (XRD) diagrams of the electrodes of Examples 1-6.

[0050] Figure 6 This is a comparison chart of the linear sweep voltammetry (LSV) curves of the single-atom confined carbon material composite electrodes of Examples 1-11 and Comparative Examples 1-8, wherein:

[0051] (a) Linear sweep voltammetry (LSV) curves of different metal single atom confined carbon material composite electrodes of Comparative Examples 1-4 in 10 mmol / L potassium ferrocyanide and 1 mol / L Na2SO4 solution;

[0052] (b) Linear sweep voltammetry (LSV) curves of single-atom confined carbon material composite electrodes with different PTFE contents in comparative examples 2 and 5-8 in 10 mmol / L potassium ferrocyanide and 1 mol / L Na2SO4 solutions;

[0053] (c) Linear sweep voltammetry (LSV) curves of ruthenium-titanium-supported single-atom confined carbon material composite electrodes (Ru:Ti=2:8) with different PTFE contents in 10 mmol / L potassium ferrocyanide and 1 mol / L Na2SO4 solutions of Examples 5 and 8-11;

[0054] (d) is the linear sweep voltammetry (LSV) curve of the single-atom confined carbon material composite electrode with different ruthenium-titanium loadings in Examples 1-7 in 10 mmol / L potassium ferrocyanide and 1 mol / L Na2SO4 solution.

[0055] Figure 7 This is a comparison chart of the impedance spectroscopy (EIS) of the single-atom confined carbon material composite electrodes of Examples 1-11 and Comparative Examples 1-8, wherein:

[0056] (a) Impedance spectra of different metal single-atom confined carbon material composite electrodes in 0.5 mol / L Na2SO4 solution in Comparative Examples 1-4;

[0057] (b) Impedance spectra of single-atom confined carbon material composite electrodes with different PTFE contents in comparative examples 2 and 5-8 in 0.5 mol / L Na2SO4 solution;

[0058] (c) Impedance spectra of ruthenium-titanium-loaded single-atom confined carbon material composite electrodes (Ru:Ti=2:8) with different PTFE contents in 0.5 mol / L Na2SO4 solution of Examples 5 and 8-11;

[0059] (d) is the impedance energy spectrum of the single-atom confined carbon material composite electrode with different ruthenium and titanium loadings in Examples 1-7 in 0.5 mol / L Na2SO4 solution.

[0060] Figure 8 This is the EDS element distribution spectrum of the anode of Example 12 before and after the electrochemical oxidation reaction, where:

[0061] (i), (j), (k), and (l) are the EDS element distribution spectra of nickel, titanium, ruthenium, and carbon before electrochemical oxidation reaction, respectively;

[0062] (m), (n), (o), and (p) are the EDS element distribution spectra of nickel, titanium, ruthenium, and carbon after electrochemical oxidation reaction, respectively.

[0063] Figure 9 This is a test chart of the decolorization rate and anode stability of Example 12.

[0064] Figure 10 This is a test chart of the decolorization rate and anode stability of Example 13.

[0065] Figure 11 This is a test chart of the decolorization rate and anode stability of Comparative Example 9.

[0066] Figure 12 This is a test chart of the decolorization rate and anode stability of Comparative Example 10.

[0067] Figure 13 This is a comparison chart of the decolorization rates of biomass gasification coke washing wastewater at different treatment times according to the treatment methods of biomass gasification coke washing wastewater in Examples 13-20.

[0068] Reference numerals:

[0069] 1-substrate; 2-functional layer; 3-through hole. DETAILED DESCRIPTION

[0070] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present application, but should not be understood as limiting the present application.

[0071] Throughout this application, the disclosure of numerical ranges includes disclosure of all values ​​within the entire range and further subdivided ranges, including endpoints and subranges given within those ranges.

[0072] In the application, the raw materials, equipment, etc. involved, unless otherwise specified, are all raw materials and equipment that can be produced through commercial channels or known methods; the methods involved, unless otherwise specified, are all conventional methods.

[0073] A single-atom confined carbon material composite electrode according to an embodiment of the present application will be described below with reference to the accompanying drawings.

[0074] like Figure 1 As shown, the single-atom confined carbon material composite electrode of the embodiment of the present application includes a substrate 1 and a functional layer 2, and the functional layer 2 is distributed on the surface of the substrate 1; the material of the functional layer 2 includes the following components in parts by weight: 0.05-1 part of functional material, 0.075-0.375 part of binder; the functional material is a single-atom confined carbon material composite material loaded with active components; the single-atom confined carbon material composite material is a composite material of single-atom transition metal, nitrogen and carbon, and the active component is a precious metal element or / and titanium element.

[0075] The single-atom confined carbon material composite electrode of the embodiment of the present application has high stability because the active components are loaded on the single-atom confined carbon material.

[0076] In some embodiments, the substrate is a metal plate with conductive properties and a certain load-bearing capacity, including but not limited to one of iron plate, copper plate, titanium plate, etc.; in other embodiments, the substrate is a metal plate-like structure with conductive properties and a certain load-bearing capacity having several through holes 3, including but not limited to one of iron mesh, copper mesh, titanium mesh, etc.

[0077] It should be noted that the functional layer is distributed on at least one surface of the substrate, for example: Figure 1 As shown, it can be distributed on the upper surface; Figure 2 As shown, the functional layer can be distributed on two opposite surfaces of the substrate, such as the upper surface and the lower surface. When the substrate is a metal plate structure with a plurality of through holes 3, the functional layer can also be distributed on the surface of the through holes, such as Figure 1 and Figure 2 shown.

[0078] In some embodiments, the content of the functional material in the functional layer includes, but is not limited to, 0.05 parts by weight, 0.1 parts by weight, 0.15 parts by weight, 0.2 parts by weight, 0.3 parts by weight, 0.4 parts by weight, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight, or 1 part by weight. The content of the binder in the functional layer includes, but is not limited to, 0.075 parts by weight, 0.1 parts by weight, 0.15 parts by weight, 0.175 parts by weight, 0.2 parts by weight, 0.25 parts by weight, 0.275 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.375 parts by weight, etc.

[0079] In some embodiments, the thickness of the functional layer is between 0.5 nm and 1 nm.

[0080] In some embodiments, the loading amount of the active component is 0.5-1% of the mass of the single-atom confined carbon material composite material. As a non-limiting example, the loading amount of the active component is 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1.0% of the mass of the single-atom confined carbon material composite material. When the active component is a noble metal element and a titanium element, the molar ratio of the noble metal element to the titanium element is (0.1-10): (10-0.1), for example, including but not limited to 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 8:2, etc. Among them, the noble metal elements include but are not limited to one or more of ruthenium (Ru), palladium (Pd), platinum (Pt), gold and silver.

[0081] In some embodiments, the molar ratio of transition metal elements, carbon elements, and nitrogen elements in the single-atom confined carbon material composite material is 1:(16-24):(32-48), wherein the transition metal elements include, but are not limited to, one or more of iron, cobalt, nickel, copper, manganese, silver, strontium, and the like.

[0082] In some embodiments, the binder is one or more of polytetrafluoroethylene, naphthol, and polypyrrole.

[0083] The method for preparing the single-atom confined carbon material composite electrode of the embodiment of the present application comprises the following steps:

[0084] S1. Grinding a mixture containing a carbon source, a nitrogen source, an alcohol, and a transition metal salt into a slurry to obtain a first slurry;

[0085] S2. calcining the first slurry in an inert atmosphere to obtain a single-atom confined carbon material composite material;

[0086] S3, loading an active component on the single-atom confined carbon material composite material to obtain a single-atom confined carbon material composite material loaded with the active component;

[0087] S4, grinding the single-atom confined carbon material composite material loaded with active components into a powder, and then mixing it with a binder and an organic solvent to obtain a mixed solution;

[0088] S5, stirring and ultrasonically dispersing the mixed solution in sequence, and then drying it to a slurry to obtain a second slurry;

[0089] S6. Hot-press the second slurry onto the substrate while it is still hot to obtain a single-atom confined carbon material composite electrode.

[0090] In the present application, a carbon source and a nitrogen source are used to produce carbon nanotubes, a transition metal provides single atoms, and an alcohol serves as a mixing medium.

[0091] In some embodiments, in step S1, the carbon source and the nitrogen source can be obtained from the same substance. For example, substances that can provide both the carbon source and the nitrogen source include, but are not limited to, one or more of dicyandiamide, urea, and melamine.

[0092] In some embodiments, the transition metal salt is one or more of sulfate, nitrate, chloride, and organic metal salts. The transition metal in the transition metal salt is as described above, including but not limited to one or more of iron, cobalt, nickel, copper, manganese, silver, strontium, etc.; the organic metal salt includes but is not limited to acetate, citrate, etc.

[0093] In some embodiments, in step S1, the alcohol includes but is not limited to ethanol, methanol, ethylene glycol, etc. The amount of alcohol is not limited as long as it can dissolve the carbon source, nitrogen source and transition metal salt. The carbon source, nitrogen source and transition metal salt only need to ensure that the molar ratio of transition metal element, carbon element and nitrogen element is 1: (16-24): (32-48).

[0094] In some embodiments, in step S2, the inert atmosphere includes but is not limited to nitrogen, helium, etc., and the calcination is carried out in a tube furnace at a calcination temperature of 750-850°C, preferably 800°C. In step S5, the stirring time and ultrasonic dispersion time are both 15-45 minutes, preferably 30 minutes; the drying includes but is not limited to forced air drying, oven drying, etc., and the drying temperature is 70-90°C, preferably 90°C. In step S6, hot pressing is performed using a single-chip microcomputer, and the hot pressing pressure is between 10-30 MPa, and the hot pressing pressure is preferably 20 MPa.

[0095] In some embodiments, in order to remove impurities on the surface of the calcined product and improve the purity of the single-atom confined carbon material composite material, in step S2, after the first slurry is calcined in an inert atmosphere, it is necessary to perform acid leaching and filtration. As a non-limiting example, the acid leaching can be performed by soaking in 0.3-0.8 mol / L H2SO4 for 2-6 hours, and the filtration can be performed using commonly used laboratory filtration equipment.

[0096] In some embodiments, in step S3, the method for loading the active component on the single-atom confined carbon material composite material includes but is not limited to an impregnation and roasting method. Specifically, the method for loading the active component on the single-atom confined carbon material composite material is: uniformly mix the low-molecular alcohol and the salt of the active component, then add the single-atom confined carbon material composite material, and then dry and roast. Among them, the method for uniformly mixing the low-molecular alcohol and the salt of the active component includes but is not limited to stirring and mixing, where the stirring speed is between 400-600r / min and the stirring time is between 20-40min; preferably, the stirring speed is between 500r / min and the stirring time is 30min. Drying here includes but is not limited to blast drying, oven drying, etc., the drying temperature is between 80-120℃, preferably 100℃; the drying overnight time is between 10-24h, preferably 12h and 24h. The roasting conditions are roasting at 500℃ for 2h under nitrogen protection.

[0097] In other embodiments, to improve electrode stability, in step S3, the method of loading the active component onto the single-atom confined carbon material composite material further includes drying the mixed solution of the low-molecular alcohol, the salt of the active component, and the single-atom confined carbon material composite material. Drying herein includes, but is not limited to, forced air drying, oven drying, etc., with a drying temperature between 80-120°C, preferably 100°C, and an overnight drying time between 10-24 hours, preferably 12 hours and 24 hours.

[0098] It should be noted that the purpose of grinding the single-atom confined carbon material composite material loaded with active components into powder in step S4 is to improve the stability of the material.

[0099] In some embodiments, grinding in steps S1 and S4 can be performed using a mortar or ball mill. In step S4, the binder is one or more of polytetrafluoroethylene, naphthol, and polypyrrole; and the organic solvent is one or more of ethanol, methanol, and N,N-dimethylacetamide.

[0100] The single-atom confined carbon material composite electrode of the embodiment of the present application or the single-atom confined carbon material composite electrode prepared by the preparation method of the embodiment of the present application can be widely used in the field of water treatment technology, including but not limited to the treatment of wastewater containing antibiotics and biomass gasification and coke washing wastewater. Among them, the main pollutant of biomass gasification and coke washing wastewater is tar, and one of its important pollution indicators is high chroma.

[0101] As a non-limiting example, the single-atom confined carbon material composite electrode of the embodiment of the present application or the single-atom confined carbon material composite electrode prepared by the preparation method of the embodiment of the present application can be used to treat biomass gasification and coke washing wastewater. The method for treating biomass gasification and coke washing wastewater of the embodiment of the present application adopts an electrochemical oxidation method to treat the gasification and coke washing wastewater, and the cathode in the electrochemical oxidation treatment process adopts the single-atom confined carbon material composite electrode of the embodiment of the present application or the single-atom confined carbon material composite electrode prepared by the preparation method of the embodiment of the present application.

[0102] As a possible example, in the method for treating biomass gasification and coke washing wastewater in the embodiment of the present application, an electrochemical oxidation method is used to treat the biomass gasification and coke washing wastewater. The anode in the electrochemical oxidation treatment process adopts the single-atom confined carbon material composite electrode of the embodiment of the present application or the single-atom confined carbon material composite electrode prepared by the preparation method of the embodiment of the present application, and the cathode adopts a titanium mesh. The distance between the anode and the cathode is 0.5-2 cm, and the current density is 1-6 mA / cm 2 , the reactor volume is 50-100mL.

[0103] It should be noted that the reactor in this application is a container that can accommodate the reaction liquid and the electrode sheet, and the electrode sheet is submerged in the reaction liquid. The reactor material is generally glass, acrylic or plastic, etc. Under laboratory conditions, the reactor can be a beaker, etc.

[0104] The following is a detailed description of the single-atom confined carbon material composite electrode, its preparation method, and its application.

[0105] 1. Examples and Comparative Examples

[0106] Example 1

[0107] like Figure 1 As shown, the single-atom confined carbon material composite electrode of this embodiment includes a substrate 1 and a functional layer 2, wherein the substrate 1 is a titanium mesh, the functional layer is distributed on the upper surface of the titanium mesh and the inner surface of the mesh, and the thickness of the functional layer is 0.5 nm; the material of the functional layer includes the following components in parts by weight: 0.85 parts of functional material and 0.15 parts of binder; the functional material is a single-atom confined carbon material composite material loaded with an active component, the single-atom confined carbon material composite material is a composite material of nickel, carbon and nitrogen, and the molar ratio of nickel, carbon and nitrogen is 1:20:40; the loading amount of the active component is 1wt% of the single-atom confined carbon material composite material, and the active component is ruthenium element; the binder is polytetrafluoroethylene (PVDF), and the organic solvent is ethanol.

[0108] The method for preparing the single-atom confined carbon material composite electrode of this embodiment includes the following steps:

[0109] S1. Put 3.5 mmol of nickel nitrate, 35 mmol of dicyandiamide, and 2 mL of ethanol into an agate mortar and grind them into a slurry to obtain a first slurry.

[0110] S2. The first slurry is placed in a tubular furnace and calcined at 800° C. in a nitrogen protective atmosphere for 2 h, then soaked in 0.5 mol / L H 2 SO 4 for 4 h, and then filtered to obtain a single-atom confined carbon material composite material.

[0111] S3. Add 3.1113 g of ruthenium chloride to 40 mL of ethanol and stir at 500 r / min for 30 min. Then add the single-atom confined carbon material composite material obtained in step S2. Dry the mixture in an oven at 100°C for 24 h to obtain a single-atom confined carbon material composite material loaded with ruthenium.

[0112] S4. Grind the single-atom confined carbon material composite material loaded with ruthenium into powder using a mortar, and then mix it with 0.15 mL of polytetrafluoroethylene and 10 mL of ethanol to obtain a mixed solution.

[0113] S5. Stir the mixed solution obtained in step S4 for 30 minutes, then ultrasonicate it for 30 minutes, and then dry it in an oven at 80° C. to a slurry to obtain a second slurry.

[0114] S6. The second slurry is hot pressed together with the titanium mesh by a tablet press at 20 MPa while it is still hot, thereby obtaining the single-atom confined carbon material composite electrode of this embodiment.

[0115] Example 2

[0116] This embodiment is basically the same as embodiment 1, except that:

[0117] In the single-atom confined carbon material composite electrode, the active components are ruthenium and titanium, and the molar ratio of ruthenium to titanium is 8:2.

[0118] In the preparation method of the single-atom confined carbon material composite electrode, step S3 is 2.4890g of ruthenium chloride and 1.05mL of tetrabutyl titanate.

[0119] Example 3

[0120] This embodiment is basically the same as embodiment 1, except that:

[0121] In the single-atom confined carbon material composite electrode, the active components are ruthenium and titanium, and the molar ratio of ruthenium to titanium is 6:4.

[0122] In the preparation method of the single-atom confined carbon material composite electrode, step S3 is 1.8668 g of ruthenium chloride and 2.05 mL of tetrabutyl titanate.

[0123] Example 4

[0124] This embodiment is basically the same as embodiment 1, except that:

[0125] In the single-atom confined carbon material composite electrode, the active components are ruthenium and titanium, and the molar ratio of ruthenium to titanium is 4:6.

[0126] In the preparation method of the single-atom confined carbon material composite electrode, step S3 is 1.2445 g of ruthenium chloride and 2.05 mL of tetrabutyl titanate.

[0127] Example 5

[0128] This embodiment is basically the same as embodiment 1, except that:

[0129] In the single-atom confined carbon material composite electrode, the active components are ruthenium and titanium, and the molar ratio of ruthenium to titanium is 2:8.

[0130] In the preparation method of the single-atom confined carbon material composite electrode, step S3 contains 0.628 g of ruthenium chloride and 4.08 mL of tetrabutyl titanate.

[0131] Example 6

[0132] This embodiment is basically the same as embodiment 1, except that:

[0133] In the single-atom confined carbon material composite electrode, the active component is titanium element.

[0134] In the preparation method of the single-atom confined carbon material composite electrode, step S3 is 5.15 mL of tetrabutyl titanate.

[0135] Example 7

[0136] This embodiment is basically the same as embodiment 1, except that:

[0137] In the single-atom confined carbon material composite electrode, the active components are ruthenium and titanium, and the molar ratio of ruthenium to titanium is 3:7.

[0138] In the preparation method of the single-atom confined carbon material composite electrode, step S3 contains 0.9333 g of ruthenium chloride and 1.55 mL of tetrabutyl titanate.

[0139] Example 8

[0140] This embodiment is substantially the same as embodiment 5, except that the amount of the binder polytetrafluoroethylene (PTFE) used is 0.05 mL (0.05 parts by weight).

[0141] Example 9

[0142] This embodiment is substantially the same as embodiment 5, except that the amount of the binder polytetrafluoroethylene (PTFE) used is 0.10 mL (0.10 parts by weight).

[0143] Example 10

[0144] This embodiment is substantially the same as embodiment 5, except that the amount of the binder polytetrafluoroethylene (PTFE) used is 0.20 mL (0.20 parts by weight).

[0145] Example 11

[0146] This embodiment is substantially the same as embodiment 5, except that the amount of the binder polytetrafluoroethylene (PTFE) used is 0.25 mL (0.25 parts by weight).

[0147] Example 12

[0148] This embodiment is basically the same as embodiment 1, except that:

[0149] In the single-atom confined carbon material composite electrode, the active components are ruthenium and titanium, and the molar ratio of ruthenium to titanium is 1:9.

[0150] In the preparation method of the single-atom confined carbon material composite electrode, step S3 contains 0.3111 g of ruthenium chloride and 4.60 mL of tetrabutyl titanate.

[0151] Example 13

[0152] The treatment method of biomass gasification coke washing wastewater in this embodiment is as follows: biomass gasification coke washing wastewater with a tar content of 600 mg / L and a chroma of 600 is added to a 100 mL beaker and treated by electrochemical oxidation, wherein the anode is the single-atom confined carbon material composite electrode of Example 1, the cathode is a titanium mesh, the distance between the anode and the cathode is 1 cm, and the current density is 4 mA / cm 2 , the processing time is 60min.

[0153] Example 14

[0154] The treatment method of biomass gasification coke washing wastewater in this embodiment is basically the same as that in Example 13, except that the anode adopts the single-atom confined carbon material composite electrode of Example 2.

[0155] Example 15

[0156] The treatment method of biomass gasification coke washing wastewater in this embodiment is basically the same as that in Example 13, except that the anode adopts the single-atom confined carbon material composite electrode of Example 3.

[0157] Example 16

[0158] The treatment method of biomass gasification coke washing wastewater in this embodiment is basically the same as that in Example 13, except that the anode adopts the single-atom confined carbon material composite electrode of Example 4.

[0159] Example 17

[0160] The treatment method of biomass gasification coke washing wastewater in this embodiment is basically the same as that in Example 13, except that the anode adopts the single-atom confined carbon material composite electrode of Example 5.

[0161] Example 18

[0162] The treatment method of biomass gasification coke washing wastewater in this embodiment is basically the same as that in Example 13, except that the anode adopts the single-atom confined carbon material composite electrode of Example 6.

[0163] Example 19

[0164] The treatment method of biomass gasification coke washing wastewater in this embodiment is basically the same as that in Example 13, except that the anode adopts the single-atom confined carbon material composite electrode of Example 7.

[0165] Example 20

[0166] The treatment method of biomass gasification coke washing wastewater in this embodiment is basically the same as that in Example 13, except that the anode adopts the single-atom confined carbon material composite electrode of Example 12.

[0167] Comparative Example 1

[0168] The single-atom confined carbon material composite electrode of this comparative example is basically the same as that of Example 1, except that the functional material is commercial carbon nanotubes.

[0169] Comparative Example 2

[0170] This comparative example is basically the same as Example 1, except that the functional material is the single-atom confined carbon material composite material in Example 1 (ie, single-atom nickel-modified carbon nanotubes), and no ruthenium is loaded.

[0171] Comparative Example 3

[0172] This comparative example is substantially the same as comparative example 2, except that nickel is replaced by cobalt, and nickel nitrate is replaced by cobalt nitrate.

[0173] Comparative Example 4

[0174] This comparative example is substantially the same as comparative example 2, except that nickel is replaced by iron, and nickel nitrate is replaced by ferric nitrate.

[0175] Comparative Example 5

[0176] This comparative example is substantially the same as comparative example 2, except that the amount of the binder polytetrafluoroethylene (PTFE) used is 0.05 mL (0.05 parts by weight).

[0177] Comparative Example 6

[0178] This comparative example is substantially the same as comparative example 2, except that the amount of the binder polytetrafluoroethylene (PTFE) used is 0.10 mL (0.1 parts by weight).

[0179] Comparative Example 7

[0180] This comparative example is substantially the same as comparative example 2, except that the amount of the binder polytetrafluoroethylene (PTFE) used is 0.20 mL (0.2 parts by weight).

[0181] Comparative Example 8

[0182] This comparative example is substantially the same as comparative example 2, except that the amount of the binder polytetrafluoroethylene (PTFE) used is 0.25 mL (0.25 parts by weight).

[0183] Comparative Example 9

[0184] The treatment method of biomass gasification coke washing wastewater in this comparative example is basically the same as that in Example 12, except that the anode adopts the electrode of Comparative Example 1.

[0185] Comparative Example 10

[0186] The treatment method of biomass gasification coke washing wastewater in this comparative example is basically the same as that in Example 12, except that the anode adopts the electrode of Comparative Example 2.

[0187] 2. Performance Testing

[0188] (1) Appearance

[0189] The surface morphology of the single-atom confined carbon material composite material of Comparative Example 2 and the single-atom confined carbon material composite electrode of Examples 1-6 was tested using a scanning electron microscope (SEM). The test results are as follows: Figure 3 As shown. Figure 3 It can be seen that there are obvious bamboo-shaped carbon nanotubes, and the active components are evenly loaded on the carbon nanotubes.

[0190] The bulk morphology of the single-atom confined carbon material composite electrode of Example 1 was tested using a scanning transmission electron microscope (STEM). The test results are as follows: Figure 4 As shown. Figure 4 It can be seen that Figure 4In (a), when the scale bar is 1 μm, numerous crisscrossing carbon nanotubes can be seen. When magnified as shown in 4 (b) and (c), it can be seen that when the scale bar is 50 nm, there is a clear bamboo-like morphology, which confirms the existence of carbon nanotubes. Figure 4 In (d), under the condition of a scale of 2 nm, the white bright spots circled in red in the figure are single atoms, and their distribution is relatively uniform, indicating the presence of high-density dispersed single atomic nickel in the carbon nanotubes, further confirming the successful preparation of single-atom-modified carbon nanotube electrode materials.

[0191] (2) Crystal phase

[0192] The crystal phase composition of Examples 1-6 was tested by X-ray diffractometer, and the test results are as follows: Figure 5 As shown. Figure 5 It can be seen that the single-atom confined carbon nanotube composite electrode materials with different metal ruthenium / titanium ratios correspond to the peaks of anatase-type titanium dioxide and elemental ruthenium, indicating that ruthenium and titanium have been successfully loaded onto the surface of the single-atom confined carbon nanotube electrode. Figure 5 It can also be seen that with the increase of titanium content, the corresponding anatase titanium dioxide peak becomes more obvious, and conversely, with the decrease of ruthenium content, the peak of ruthenium element becomes weaker. Figure 9 ) It can be inferred that ruthenium plays a role in providing more catalytic active sites in the entire reaction process.

[0193] (3) Electrochemical performance

[0194] The materials of Examples 1-11 and Comparative Examples 1-8 were subjected to linear sweep voltammetry (LSV) curve and impedance spectroscopy analysis, wherein the linear sweep voltammetry (LSV) curve test was carried out in 10 mmol / L potassium ferrocyanide and 1 mol / L Na2SO4 solution at a scan rate of 50 mV / s.

[0195] Figure 6 The linear sweep voltammetry (LSV) curves of the single-atom confined carbon material composite electrodes of Examples 1-11 and Comparative Examples 1-8 are compared. Figure 6 It can be seen that in the process of electrooxidation, the oxygen evolution potential (OEP) determines the amount of hydroxyl radicals produced and the current efficiency. A higher oxygen evolution potential (OEP) can reduce the oxygen evolution side reaction, increase the current efficiency, and thus improve the ability to degrade pollutants. Figure 6 As shown in (a), after the addition of single atoms, the oxygen evolution potential (OEP) increased from 0.900 V to 0.930 V, which shows that the introduction of single atoms provides a certain amount of active sites for the degradation of pollutants. Figure 6(c) also shows the linear sweep voltammetry (LSV) curves of Ru-Ti-supported single-atom confined carbon composite electrodes with different PTFE contents when Ru:Ti=2:8, and the trend is similar to Figure 6 (b) is consistent, and the oxygen evolution potential (OEP) increases to 1.197 V after the addition of ruthenium titanium. It can be seen that ruthenium titanium and its oxides provide a certain amount of active components for the electrode, reducing the oxygen release side reaction, thereby improving the degradation effect of biomass gasification coke washing wastewater. Figure 6 In (d), linear sweep voltammetry (LSV) curves were tested on single-atom confined carbon material composite electrodes with different ruthenium-titanium loadings. The results showed that when the loading was Ru:Ti = 0:10, the oxygen evolution potential (OEP) could reach 1.400 V, indicating that at this ratio, ruthenium and its oxide provided reactive components for the entire reaction, reduced the generation of oxygen-evolving side reactions, improved current efficiency, and thus improved the ability to degrade pollutants.

[0196] Figure 7 The linear sweep voltammetry (LSV) curves of the single-atom confined carbon material composite electrodes of Examples 1-11 and Comparative Examples 1-8 are compared. The small diameter of the arc shows a lower charge transfer resistance, indicating that this electrode has a higher electron transfer efficiency. Figure 7 As shown in (a), the radius of the arc becomes smaller after the addition of single atoms, which shows that the introduction of single atoms improves the electron transfer efficiency. Figure 7 (c) also shows the impedance spectroscopy analysis of Ruthenium-Titanium loaded single-atom confined carbon nanotube composite electrodes with different PTFE contents when Ru:Ti=2:8, and the trend is similar to Figure 7 (b) is consistent, and the arc diameter decreases after the addition of ruthenium titanium. It can be seen that ruthenium titanium and its oxides provide a certain amount of active components for the electrode, which improves the electron transfer efficiency and thus has a better tar degradation effect. Figure 7 (d) Impedance spectroscopy analysis of single-atom confined carbon nanotube composite electrodes with varying ruthenium-titanium loadings reveals that when the Ru:Ti ratio is 0:10, the arc radius is significantly smaller than that of the other electrodes, resulting in higher electron transfer efficiency and, therefore, superior pollutant degradation. Furthermore, it is clear that at this ratio, ruthenium and its oxide provide the active components for the reaction, thereby enhancing pollutant degradation.

[0197] The test results of electrochemical impedance spectroscopy are consistent with the results of cyclic voltammetry curves and linear voltammetry curves, both of which prove that reducing the PTFE content and loading ruthenium and / or titanium can significantly improve the electrochemical performance of the battery.

[0198] (4) Electrode stability

[0199] 1) The element distribution of the anode before and after the electrochemical oxidation reaction treatment of Example 13 was tested by X-ray energy dispersive spectroscopy (EDS) to evaluate the stability of the anode (i.e., the single-atom confined carbon material composite electrode of Example 2). The results are as follows: Figure 8 shown.

[0200] from Figure 8 It can be seen that there is no obvious change in the element distribution before and after the electrochemical oxidation reaction, indicating that the electrode is relatively stable before and after the reaction.

[0201] 2) According to the "Dilution Multiple Method for Determination of Water Color" (HJ 1182-2021), the chroma of the biomass gasification and coke washing wastewater treatment methods of Example 13, Example 14, Comparative Example 9 and Comparative Example 10 at different treatment times was measured, and the chroma of the biomass gasification and coke washing wastewater at different time periods in Example 13 was repeatedly degraded by the corresponding anodes for 6 times. The stability of the anode was evaluated based on the performance of the chroma decolorization rate when the electrode was reused. The results are as follows: Figure 9-12 shown.

[0202] from Figure 9 and Figure 10 It can be seen that when the ruthenium-titanium ratio is 10:0, the current density is 4 mA / cm 2 When the ruthenium-titanium ratio is 8:2, the current density is 4 mA / cm 2 When the biomass gasification wastewater is decolorized for 6 cycles, the decolorization rate can reach 70%, demonstrating the high electrochemical oxidation activity of the prepared single-atom confined carbon material composite electrode. When the biomass gasification coke washing wastewater in Example 13 was repeatedly degraded for 6 cycles, the decolorization rate of the anode with a ruthenium-to-titanium ratio of 10:0 in Example 13 remained relatively stable, essentially maintaining at 70% after 3 cycles, while the decolorization rate of the anode with a ruthenium-to-titanium ratio of 8:2 in Example 14 decreased slightly. However, after 3 to 6 cycles, the decolorization rate of the anode with a ruthenium-to-titanium ratio of 10:0 in Example 13 gradually decreased, reaching a minimum of 50%, while the decolorization rate of the anode with a ruthenium-to-titanium ratio of 8:2 in Example 14 remained relatively stable, consistently maintaining above 50%. Therefore, from the perspective that more cycles lead to better stability, a ruthenium-to-titanium ratio of 8:2 exhibits superior stability.

[0203] from Figure 11 and Figure 12 It can be seen that when the electrode of Comparative Example 1 (commercial carbon nanotubes) is used as the anode, the decolorization rate of the biomass gasification wastewater is always below about 20%. When the electrode of Comparative Example 2 (commercial carbon nanotubes) is used as the anode, the decolorization rate of the biomass gasification wastewater is also lower than that in Examples 13 and 14.

[0204] (5) Decolorization rate

[0205] According to the "Dilution Multiple Method for Determination of Water Color" (HJ 1182-2021), the color of the biomass gasification and coke washing wastewater of Example 13-20 was measured at different treatment times. The results are as follows: Figure 13 shown.

[0206] from Figure 13 It can be seen that the degradation effects of carbon nanotube composite electrodes with different ruthenium-titanium ratios on biomass gasification wastewater are slightly different, among which the degradation effect is best when the ruthenium-titanium ratio is 10:0.

[0207] In this application, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0208] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A single-atom confined carbon material composite electrode, characterized in that: include: substrate; a functional layer, the functional layer being distributed on the surface of the substrate; The material of the functional layer includes the following components in parts by weight: 0.05-1 part of functional material, 0.075-0.375 part of binder; The functional material is a single-atom confined carbon material composite material loaded with an active component; the single-atom confined carbon material composite material is a composite material of single-atom transition metal, nitrogen and carbon, and the active component is a noble metal element and titanium element; in the single-atom confined carbon material, the molar ratio of the transition metal element, carbon element and nitrogen element is 1:(16-24):(32-48); The single-atom confined carbon material composite electrode is used as the anode when treating biomass gasification coke washing wastewater using an electrochemical oxidation method.

2. The single-atom confined carbon material composite electrode according to claim 1, characterized in that: The loading amount of the active component is 0.5-1wt%; And / or, when the active components are noble metal elements and titanium elements, the molar ratio of the noble metal elements to the titanium elements is (0.1-10): (10-0.1).

3. The single-atom confined carbon material composite electrode according to claim 1, characterized in that: The binder is one or more of polytetrafluoroethylene, naphthol and polypyrrole; And / or, the substrate is a metal plate structure having a plurality of through holes.

4. A method for preparing a single-atom confined carbon material composite electrode according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Grinding a mixture containing a carbon source, a nitrogen source, an alcohol, and a transition metal salt into a slurry to obtain a first slurry; S2. calcining the first slurry in an inert atmosphere to obtain a single-atom confined carbon material composite material; S3, loading an active component on the single-atom confined carbon material composite material to obtain a single-atom confined carbon material composite material loaded with the active component; S4, grinding the single-atom confined carbon material composite material loaded with active components into a powder, and then mixing it with a binder and an organic solvent to obtain a mixed solution; S5, stirring and ultrasonically dispersing the mixed solution in sequence, and then drying it to a slurry to obtain a second slurry; S6. Hot-press the second slurry onto the substrate while it is still hot to obtain the single-atom confined carbon material composite electrode.

5. The preparation method according to claim 4, characterized in that In step S1, the carbon source and nitrogen source are one or more of dicyandiamide, urea, and melamine, and the transition metal salt is one or more of sulfate, nitrate, chloride, and organic metal salt.

6. The preparation method according to claim 4, characterized in that In step S3, the method of loading the active component on the single-atom confined carbon material composite material is: uniformly mixing the low-molecular alcohol and the salt of the active component, and then adding the single-atom confined carbon material composite material; In step S3, the method for loading active components on the single-atom confined carbon material composite material further comprises: drying a mixed solution of low-molecular alcohol, the salt of the active component, and the single-atom confined carbon material composite material.

7. The preparation method according to claim 4, characterized in that In step S2, the calcination temperature is 750-850°C; And / or, in step S4, the organic solvent is one or more of ethanol, methanol, and N,N-dimethylacetamide; And / or, in step S5, the stirring time and ultrasonic dispersion time are both 15-45 min, and the drying temperature is 70-90° C.; And / or, in step S6, the hot pressing pressure is between 10-30 MPa.

8. A method for treating biomass gasification coke washing wastewater, characterized in that: The biomass gasification coke washing wastewater is treated by an electrochemical oxidation method, and the anode in the electrochemical oxidation treatment process adopts the single-atom confined carbon material composite electrode as described in any one of claims 1 to 3 or the single-atom confined carbon material composite electrode prepared by the preparation method as described in any one of claims 4 to 7.

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