An electrode composite material, its preparation method and application

Abstract

This invention belongs to the field of electrocatalysis technology, specifically relating to an electrode composite material, its preparation method, and its application. The invention provides an electrode composite material comprising a carbon matrix and modified tin dioxide and cobalt tetroxide supported on the carbon matrix; the modified tin dioxide comprises tin dioxide and rare earth elements and zirconium doped into the tin dioxide. By doping the tin dioxide with rare earth elements and zirconium, this invention enables the formation of a solid solution oxide with the tin dioxide. The doping of rare earth elements and zirconium refines the tin dioxide grains, making the solid solution film more dense, uniform, and continuous, significantly improving the activity and stability of the catalyst. This invention modifies the carbon matrix with modified tin dioxide and cobalt tetroxide, resulting in fine, uniform, dense, and crack-free grains of the modifying material supported on the carbon matrix. Simultaneously, the carbon matrix material exhibits good conductivity. The synergistic effect of the modifying material and the carbon matrix improves the electrocatalytic degradation performance and catalyst stability of the composite material.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, specifically relating to an electrode composite material, its preparation method, and its application. Background Technology

[0002] Metal oxide anodes possess high catalytic performance, high current efficiency, and good stability; however, they still suffer from short lifespans and a decline in electrocatalytic activity with increasing electrolysis time. Therefore, further improving the performance of metal oxide anodes and developing anodes with long lifespans and high stability is of great significance.

[0003] The study of the failure mechanism of oxide anodes revealed a substrate modification approach: adding an intermediate layer between the substrate and the active coating. The addition of this intermediate layer increases the adhesion between the substrate and the coating, protects the substrate from passivation, improves anode performance, and thus extends the anode's lifespan. The material used as the intermediate layer must possess good conductivity and oxidation resistance. Research on intermediate electrode materials shows that metal doping with SnO2 can form a dense SnO2-based solid solution film. Its corrosion resistance at high potentials has achieved excellent results in previous work, with traditional doping metals including Mn, Cr, or Sb. However, to achieve industrialization, its stability needs further enhancement. Summary of the Invention

[0004] The purpose of this invention is to provide an electrode composite material, its preparation method, and its application. The electrode composite material provided by this invention has superior stability and catalytic activity.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides an electrode composite material comprising a carbon matrix and modified tin dioxide and cobalt tetroxide supported on the carbon matrix;

[0007] The modified tin dioxide comprises tin dioxide and rare earth elements and zirconium doped in the tin dioxide.

[0008] Preferably, the rare earth elements include one or more of cerium, lanthanum, gadolinium, neodymium, europium, and erbium.

[0009] Preferably, the rare earth element in the modified tin dioxide has a doping mass percentage of 1 to 10%.

[0010] The zirconium content in the modified tin dioxide is 1-10% by mass.

[0011] Preferably, the modified tin dioxide has a loading percentage of 10-20% on the electrode composite material;

[0012] The cobalt tetroxide is loaded with a mass percentage of 1-5% on the electrode composite material.

[0013] The present invention also provides a method for preparing the electrode composite material described in the above technical solution, comprising the following steps:

[0014] A precursor solution is obtained by mixing tin salt, rare earth element metal salt, zirconium salt, cobalt salt, binder and water;

[0015] The carbon matrix is ​​first impregnated in the precursor solution, then removed and sequentially dried and calcined to obtain the supported carbon matrix.

[0016] The supported carbon matrix is ​​subjected to a second impregnation in the precursor solution, and then subjected to a second drying and a second calcination to obtain the electrode composite material.

[0017] Preferably, the tin salt comprises tin dichloride and / or tin tetrachloride;

[0018] The rare earth element metal salts include one or more of rare earth element nitrates, rare earth element sulfates, and rare earth element chlorides.

[0019] The zirconium salts include one or more of zirconium oxychloride, zirconium nitrate, and zirconium sulfate;

[0020] The cobalt salt includes one or more of cobalt sulfate, cobalt nitrate, cobalt chloride, and cobalt acetate;

[0021] The adhesive includes polyvinylpyrrolidone and aluminosilicate sol.

[0022] Preferably, the molar concentration of tin salt in the precursor solution is 0.1–0.2 mol / L;

[0023] The molar concentration of rare earth metal salts in the precursor solution is 0.002–0.02 mol / L;

[0024] The molar concentration of zirconium salt in the precursor solution is 0.002–0.02 mol / L;

[0025] The molar concentration of cobalt salt in the precursor solution is 0.002–0.01 mol / L;

[0026] The ratio of water, polyvinylpyrrolidone, and aluminosilicate sol in the precursor solution is 100 mL: 0.2 g: 250 μL.

[0027] Preferably, the temperature of the first calcination is 400-550°C and the time is 10 minutes;

[0028] The first impregnation, first drying, and first calcination are repeated 5 to 7 times.

[0029] Preferably, the second calcination temperature is 450–550°C and the time is 30–180 min.

[0030] The present invention also provides the application of the electrode composite material described in the above technical solution or the electrode composite material prepared by the preparation method described in the above technical solution as a metal oxide anode.

[0031] This invention provides an electrode composite material comprising a carbon matrix and modified tin dioxide and cobalt tetroxide supported on the carbon matrix; the modified tin dioxide comprises tin dioxide and rare earth elements and zirconium doped into the tin dioxide. By doping the tin dioxide with rare earth elements and zirconium, this invention enables the formation of a solid solution oxide with the tin dioxide. The doping of rare earth elements and zirconium refines the tin dioxide grains, making the solid solution film denser, more uniform, and continuous, significantly improving the activity and stability of the catalyst. Furthermore, by modifying the carbon matrix with modified tin dioxide and cobalt tetroxide, this invention results in fine, uniform, dense, and crack-free grains of the modifying material supported on the carbon matrix. Simultaneously, the carbon matrix material exhibits good electrical conductivity. The synergistic effect of the modifying material and the carbon matrix improves the electrocatalytic degradation performance and catalyst stability of the composite material.

[0032] This invention also provides a method for preparing the electrode composite material described in the above technical solution, comprising the following steps: mixing tin salt, rare earth element metal salt, zirconium salt, cobalt salt, binder, and water to obtain a precursor solution; first impregnating a carbon matrix in the precursor solution, then removing it and sequentially performing a first drying and a first calcination to obtain a supported carbon matrix; second impregnating the supported carbon matrix in the precursor solution, then removing it and sequentially performing a second drying and a second calcination to obtain the electrode composite material. The preparation process provided by this invention is simple, convenient to operate, and suitable for large-scale production; this invention provides a new approach to catalyst preparation, and the catalyst synthesized by this method has small particle size and large specific surface area. More importantly, it successfully achieves the composite of metal oxide and carbon material matrix.

[0033] This invention also provides the application of the electrode composite material described above as a metal oxide anode. The composite material provided by this invention can be directly applied to the neutral electrolysis of water to degrade organic matter, can operate for a long time to exert the intrinsic catalytic performance of the catalyst, and has a simple process, reducing system complexity. It has more practical reference significance and value than the electrocatalytic anode catalysts currently reported in research. Attached Figure Description

[0034] Figure 1 SEM image of the electrode composite material obtained in Comparative Example 1

[0035] Figure 2 Here is a SEM image of the electrode composite material obtained in Example 1;

[0036] Figure 3 The XPS spectrum of the electrode composite material obtained in Example 1;

[0037] Figure 4 The images are SEM images of the electrode composite material obtained in Example 1 before and after the stability test, where (a) and (b) are before the test, and (c) and (d) are after the test.

[0038] Figure 5 The images show the XRD patterns of the electrode composite material obtained in Example 1 before and after stability testing.

[0039] Figure 6 The chronoamperometry (IT) plots of the electrode composite materials obtained in Comparative Example 1 and Example 1 are shown, where (a) is Comparative Example 1 and (b) is Example 1.

[0040] Figure 7 The curves showing the COD value of Rhodamine B at different times under a voltage of 2V are shown for the electrode composite material obtained in Example 1. Detailed Implementation

[0041] This invention provides an electrode composite material comprising a carbon matrix and modified tin dioxide and cobalt tetroxide supported on the carbon matrix;

[0042] The modified tin dioxide comprises tin dioxide and rare earth elements and zirconium doped in the tin dioxide.

[0043] In this invention, the rare earth elements preferably include one or more of cerium, lanthanum, gadolinium, neodymium, europium, and erbium. In this invention, the mass percentage of the rare earth element in the modified tin dioxide is preferably 1-10%, more preferably 2-8%, and even more preferably 5-6%. In this invention, rare earth elements are relatively reactive metals with good electrocatalytic performance. Adding rare earth elements can refine the surface layer grains, purify the crystal planes, reduce the internal stress of the electrode surface layer, enhance the electrode's corrosion resistance, and improve electrode stability. Ce, as one of the light rare earth elements, has advantages such as low density, abundant reserves, and high cost-effectiveness. When Ce, with its f-electron orbitals, is doped into the metal oxide coating, it can induce additional energy bands in the coating structure, which may help develop convenient electron transition channels and enhance the electrocatalytic characteristics of the anode. Furthermore, Ce also has a positive effect on improving corrosion resistance.

[0044] In this invention, the zirconium doping content in the modified tin dioxide is preferably 1-10%, more preferably 2-8%, and even more preferably 5-6%. In this invention, the transition metal Zr exhibits excellent corrosion resistance.

[0045] In this invention, the modified tin dioxide loading percentage on the electrode composite material is preferably 10-20%, more preferably 12-18%, and even more preferably 15-16%; the cobalt tetroxide loading percentage on the electrode composite material is preferably 1-5%, and even more preferably 2-3%.

[0046] In this invention, the carbon matrix preferably comprises a three-dimensional conductive carbon matrix; the three-dimensional conductive carbon matrix preferably comprises any one of conductive polyacrylonitrile carbon felt, conductive activated carbon felt, conductive viscose-based graphite felt, and conductive carbon fiber cloth; the diameter of the carbon fibers used in the three-dimensional conductive carbon matrix is ​​preferably 5-20 μm. The composite material matrix in this invention is selected from low-cost carbon matrices, which are widely available, acid and alkali resistant, chemically stable, and suitable for industrial applications.

[0047] The present invention also provides a method for preparing the electrode composite material described in the above technical solution, comprising the following steps:

[0048] A precursor solution is obtained by mixing tin salt, rare earth element metal salt, zirconium salt, cobalt salt, binder and water;

[0049] The carbon matrix is ​​first impregnated in the precursor solution, then removed and sequentially dried and calcined to obtain the supported carbon matrix.

[0050] The supported carbon matrix is ​​subjected to a second impregnation in the precursor solution, and then subjected to a second drying and a second calcination to obtain the electrode composite material.

[0051] In this invention, unless otherwise specified, all raw materials / components used in the preparation are commercially available products well known to those skilled in the art.

[0052] This invention involves mixing tin salt, rare earth element metal salt, zirconium salt, cobalt salt, binder, and water to obtain a precursor solution.

[0053] In this invention, the tin salt preferably includes tin dichloride and / or tin tetrachloride; the tin dichloride is preferably added in the form of tin dichloride dihydrate; the tin tetrachloride is preferably added in the form of tin tetrachloride pentahydrate. In this invention, the rare earth element-containing metal salt includes one or more of rare earth element-containing nitrates, rare earth element-containing sulfates, and rare earth element-containing chlorides; the types of rare earth elements in the rare earth element-containing metal salt are consistent with the types of rare earth elements defined in the above technical solutions, and will not be repeated here. In this invention, when the rare earth element is cerium, the rare earth element-containing metal salt preferably includes one or more of cerium nitrate, cerium sulfate, and cerium chloride; the cerium nitrate is preferably added in the form of cerium nitrate hexahydrate. In this invention, the zirconium salt preferably includes one or more of zirconium oxychloride, zirconium nitrate, and zirconium sulfate; the zirconium oxychloride is preferably added in the form of zirconium oxychloride octahydrate. In this invention, the cobalt salt preferably includes one or more of cobalt sulfate, cobalt nitrate, cobalt chloride, and cobalt acetate; the cobalt nitrate is preferably added in the form of cobalt nitrate hexahydrate.

[0054] In this invention, the binder preferably comprises polyvinylpyrrolidone and aluminosilicate sol. This invention combines organic and inorganic binders, reducing the amount of organic binder and increasing the amount of inorganic aluminosilicate sol, thereby increasing the adhesion between catalyst grains, reducing cracks in the catalyst microcrystalline layer on the carbon fiber surface, and further increasing the stability of the electrocatalytic material.

[0055] In this invention, the molar concentration of tin salt in the precursor solution is preferably 0.1–0.2 mol / L; the molar concentration of rare earth element metal salt in the precursor solution is preferably 0.002–0.02 mol / L; the molar concentration of zirconium salt in the precursor solution is preferably 0.002–0.02 mol / L; the molar concentration of cobalt salt in the precursor solution is preferably 0.002–0.01 mol / L; and the preferred ratio of water, polyvinylpyrrolidone, and aluminosilicate sol in the precursor solution is 100 mL: 0.2 g: 250 μL.

[0056] In this invention, the mixing process is preferably as follows: dissolving tin salt, rare earth element metal salt, zirconium salt, and cobalt salt in water, and then adding a binder and stirring; the stirring time is preferably 30 minutes.

[0057] After obtaining the precursor solution, the present invention first impregnates the carbon matrix in the precursor solution, and then takes it out and performs a first drying and a first calcination in sequence to obtain the loaded carbon matrix.

[0058] Before performing the first impregnation, the present invention preferably includes pretreatment of the carbon matrix; the pretreatment preferably includes cutting, cleaning, drying and acidification in sequence.

[0059] In this invention, the carbon matrix is ​​preferably 1-4 cm long, 1-4 cm wide, and 0.3-1 cm high. In this invention, the cleaning is preferably performed by sequential ultrasonic cleaning in acetone, ethanol, and deionized water. In this invention, the acidification process is preferably performed by placing the dried carbon matrix in concentrated nitric acid for a hydrothermal reaction. In this invention, the hydrothermal reaction temperature is preferably 90-160°C, and the time is preferably 60-360 min. In this invention, acidification can improve the hydrophilicity of the carbon material, increase the number of oxygen-containing groups, and facilitate the loading of active components.

[0060] In this invention, the temperature of the first drying is preferably 120°C, and the time is preferably 2 hours. In this invention, the temperature of the first calcination is preferably 400–550°C, and the time is preferably 10 minutes. In this invention, the first impregnation, first drying, and first calcination are preferably repeated 5–7 times.

[0061] After obtaining the supported carbon matrix, the present invention performs a second impregnation in the supported carbon matrix precursor solution, and then performs a second drying and a second calcination in sequence to obtain the electrode composite material.

[0062] In this invention, the second drying process is the same as the first drying process, and will not be described again here. In this invention, the preferred temperature for the second calcination is 450–550°C, and the preferred time is 30–180 min.

[0063] The present invention also provides the application of the electrode composite material described in the above technical solution or the electrode composite material prepared by the preparation method described in the above technical solution as a metal oxide anode.

[0064] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, provides an electrode composite material, its preparation method, and its application, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] Carbon fiber cloth with a length of 4cm, a width of 3cm, and a thickness of 0.5cm was ultrasonically cleaned in acetone, ethanol, and deionized water in sequence and dried. Then it was placed in concentrated nitric acid and subjected to a hydrothermal reaction at 120℃ for 120min to obtain acidified carbon fiber cloth.

[0067] Tin tetrachloride pentahydrate, cerium nitrate hexahydrate, zirconium oxychloride octahydrate, and cobalt nitrate hexahydrate were dissolved in 100 mL of deionized water to obtain a mixed salt solution, wherein the concentration of tin tetrachloride pentahydrate was 0.175 mol / L, the concentration of cerium nitrate hexahydrate was 0.014 mol / L, the concentration of zirconium oxychloride octahydrate was 0.006 mol / L, and the concentration of cobalt nitrate hexahydrate was 0.006 mol / L. Then, 0.2 g of polyvinylpyrrolidone and 250 μL of aluminosilicate sol were added, and the mixture was magnetically stirred for 30 min to obtain a precursor solution.

[0068] The acidified carbon fiber cloth was immersed in the precursor solution, removed and dried, placed in an oven at 120°C for 2 hours, and then placed in a muffle furnace and calcined at 500°C for 10 minutes. The above steps were repeated 4 times to obtain the supported carbon matrix.

[0069] The obtained supported carbon matrix was immersed in the precursor solution, removed and dried, placed in an oven at 120℃ for 2 hours, and then placed in a muffle furnace and calcined at 500℃ for 60 minutes to obtain the electrode composite material, denoted as SnO2-Ce(7)-Zr(3)-Co3O4@GF.

[0070] Example 2

[0071] Carbon fiber cloth with a length of 4cm, a width of 3cm, and a thickness of 0.5cm was ultrasonically cleaned in acetone, ethanol, and deionized water in sequence and dried. Then it was placed in concentrated nitric acid and subjected to a hydrothermal reaction at 120℃ for 120min to obtain acidified carbon fiber cloth.

[0072] Tin tetrachloride pentahydrate, cerium nitrate hexahydrate, zirconium oxychloride octahydrate, and cobalt nitrate hexahydrate were dissolved in 100 mL of deionized water to obtain a mixed salt solution, wherein the concentration of tin tetrachloride pentahydrate was 0.175 mol / L, the concentration of cerium nitrate hexahydrate was 0.016 mol / L, the concentration of zirconium oxychloride octahydrate was 0.017 mol / L, and the concentration of cobalt nitrate hexahydrate was 0.004 mol / L. Then, 0.2 g of polyvinylpyrrolidone and 250 μL of aluminosilicate sol were added, and the mixture was magnetically stirred for 30 min to obtain a precursor solution.

[0073] The acidified carbon fiber cloth was immersed in the precursor solution, removed and dried, placed in an oven at 120°C for 2 hours, and then placed in a muffle furnace and calcined at 500°C for 10 minutes. The above steps were repeated 4 times to obtain the supported carbon matrix.

[0074] The obtained supported carbon matrix was immersed in the precursor solution, removed and dried, placed in an oven at 120℃ for 2 hours, and then placed in a muffle furnace and calcined at 500℃ for 60 minutes to obtain the electrode composite material, denoted as SnO2-Ce(8)-Zr(2)-Co3O4@GF.

[0075] Example 3

[0076] Carbon fiber cloth with a length of 4cm, a width of 3cm, and a thickness of 0.5cm was ultrasonically cleaned in acetone, ethanol, and deionized water in sequence and dried. Then it was placed in concentrated nitric acid and subjected to a hydrothermal reaction at 120℃ for 120min to obtain acidified carbon fiber cloth.

[0077] Tin tetrachloride pentahydrate, cerium nitrate hexahydrate, zirconium oxychloride octahydrate, and cobalt nitrate hexahydrate were dissolved in 100 mL of deionized water to obtain a mixed salt solution, wherein the concentration of tin tetrachloride pentahydrate was 0.175 mol / L, the concentration of cerium nitrate hexahydrate was 0.010 mol / L, the concentration of zirconium oxychloride octahydrate was 0.010 mol / L, and the concentration of cobalt nitrate hexahydrate was 0.006 mol / L. Then, 0.2 g of polyvinylpyrrolidone and 250 μL of aluminosilicate sol were added, and the mixture was magnetically stirred for 30 min to obtain a precursor solution.

[0078] The acidified carbon fiber cloth was immersed in the precursor solution, removed and dried, placed in an oven at 120°C for 2 hours, and then placed in a muffle furnace and calcined at 500°C for 10 minutes. The above steps were repeated 4 times to obtain the supported carbon matrix.

[0079] The obtained supported carbon matrix was immersed in the precursor solution, removed and dried, placed in an oven at 120℃ for 2 hours, and then placed in a muffle furnace and calcined at 500℃ for 60 minutes to obtain the electrode composite material, denoted as SnO2-Ce(5)-Zr(5)-Co3O4@GF.

[0080] Comparative Example 1

[0081] Carbon fiber cloth with a length of 4cm, a width of 3cm, and a thickness of 0.5cm was ultrasonically cleaned in acetone, ethanol, and deionized water in sequence and dried. Then it was placed in concentrated nitric acid and subjected to a hydrothermal reaction at 120℃ for 120min to obtain acidified carbon fiber cloth.

[0082] Tin tetrachloride pentahydrate, antimony trichloride, and cobalt nitrate hexahydrate were dissolved in 100 mL of LDM to obtain a mixed salt solution, wherein the concentration of tin tetrachloride pentahydrate was 0.178 mol / L, the concentration of antimony trichloride was 0.020 mol / L, and the concentration of cobalt nitrate hexahydrate was 0.002 mol / L. Then, 1 g of polyvinylpyrrolidone was added, and the mixture was magnetically stirred for 30 min to obtain a precursor solution.

[0083] The acidified carbon fiber cloth was immersed in the precursor solution, removed and dried, placed in an oven at 120°C for 2 hours, and then placed in a muffle furnace and calcined at 500°C for 10 minutes. The above steps were repeated 4 times to obtain the supported carbon matrix.

[0084] The obtained supported carbon matrix was immersed in the precursor solution, removed and air-dried, placed in an oven at 120℃ for 2 hours, and then placed in a muffle furnace and calcined at 500℃ for 120 minutes to obtain the electrode composite material, denoted as SnO2-Sb-Co3O4@GF.

[0085] Performance testing

[0086] Test Example 1

[0087] Figures 1-2 SEM images of SnO2-Sb-Co3O4@GF obtained in Comparative Example 1 and SnO2-Ce(7)-Zr(3)-Co3O4@GF obtained in Example 1; wherein Figure 1 For Comparative Example 1, Figure 2 Example 1;

[0088] Depend on Figures 1-2 As can be seen, compared with Comparative Example 1, the carbon fiber surface of the electrode composite material obtained in this invention is covered by a continuous and dense film, with fewer exposed carbon fibers. This indicates that the doping of Ce and Zr and the addition of aluminum silicate sol make the microcrystalline particles smaller, denser, and more continuous, increasing the solid solubility of the metal oxide and improving the stability of the catalyst.

[0089] Test Example 2

[0090] Figure 3 XPS spectra of SnO2-Ce(7)-Zr(3)-Co3O4@GF prepared in Example 1, wherein (a) is the full XPS spectrum of SnO2-Ce(7)-Zr(3)-Co3O4@GF, (b) is the high-resolution spectrum of Zr element, and (c) is the high-resolution spectrum of Ce element;

[0091] from Figure 3 As can be seen in the high-resolution XPS spectrum of Zr, there are two peaks at 182.25 eV and 185.24 eV, corresponding to Zr 3d5 / 2 and Zr 3d3 / 2 respectively. Their binding energies are consistent with those reported in the literature, indicating the presence of ZrO2. Ce 3dXPS shows Ce 3+ / Ce 4+ Mixed peaks.

[0092] Test Example 3

[0093] Figure 4 These are SEM images of the composite electrode material SnO2-Ce(7)-Zr(3)-Co3O4@GF prepared in Example 1 before and after stability testing; where (a) and (b) are before testing, and (c) and (d) are after testing.

[0094] As shown in (a) and (b), the carbon fibers are covered by a thin film composed of nanoscale particles of varying sizes. Electron microscopy images reveal that the addition of rare earth element Ce and transition metal Zr resulted in finer, denser catalyst coating grains, forming a stable and continuous film that encapsulates the carbon fibers, significantly reducing their susceptibility to voltage corrosion. Furthermore, the addition of aluminosilicate sol resulted in a continuous, crack-free catalyst layer that tightly binds the catalyst grains together, improving catalyst stability. After a prolonged degradation experiment of 360 hours, electron microscopy images of the material, as shown in (c) and (d), show no significant change in catalyst morphology, although the number of catalyst grains increased, possibly due to a reduction in the amount of aluminosilicate sol.

[0095] Test Example 4

[0096] Figure 5 The XRD patterns of SnO2-Ce(7)-Zr(3)-Co3O4@GF before and after stability testing obtained in Example 1 are shown in the figure. It can be seen from the figure that SnO2-Ce(7)-Zr(3)-Co3O4@GF has obvious characteristic peaks at 26.0° and 43.4°, which corresponds to the presence of carbon as indicated in standard card PDF#26-1079. Diffraction peaks appear at 26.6°, 33.9° and 51.8°, which correspond to the (110), (101) and (211) crystal planes of tetragonal rutile SnO2. No characteristic diffraction peaks of crystalline substances containing Ce and Zr elements appear in the figure, indicating that they are doped into the SnO2 lattice by substitution. This indicates that the impregnation pyrolysis method successfully achieved the composite of SnO2-Ce(7)-Zr(3)-Co3O4 and the matrix carbon fiber to form an integrated electrode for degrading organic matter. After 360 hours of electrode stability testing, the diffraction peaks of SnO2 did not decrease significantly, indicating that the electrode has good stability.

[0097] Test Example 5

[0098] The electrode composite material and original felt prepared in Example 1 and Comparative Example 1 were both cut into 3*4*0.5cm pieces. A polytetrafluoroethylene electrode clamp was used to fix the electrode composite material as the anode and the original felt as the cathode, with an electrode spacing of 1cm. The two electrodes were used to degrade Rhodamine B solution. The electrolyte solution was 0.1mol / L Na₂SO₄ + 100mg / L RhB solution. A constant voltage mode was used, with a fixed applied potential of 2V. Long-term time-lapse current degradation was performed under a fixed bias voltage in a neutral electrolysis environment, and the change in current density over time was detected. Samples were taken at intervals for COD testing, and a COD curve of the solution over time was plotted.

[0099] Figure 6Chronoamperometry (ChRM) plots of SnO2-Sb-Co3O4@GF obtained in Comparative Example 1 and SnO2-Ce(7)-Zr(3)-Co3O4@GF prepared in Example 1 are shown; where (a) is Comparative Example 1 and (b) is Example 1; Figure 6 It can be seen that at a relatively high voltage of 2V, SnO2-Ce(7)-Zr(3)-Co3O4@GF can react for a long time of 360h, which is nearly 160h longer than SnO2-Sb-Co3O4@GF. Under neutral electrolysis conditions, SnO2-Ce(7)-Zr(3)-Co3O4@GF can maintain the current without decay for a long time when directly used as an anode for catalytic degradation, which shows high stability and has important guiding significance for the actual development of catalysts.

[0100] Figure 7 The curves showing the COD values ​​of Rhodamine B over time at different times and with a voltage of 2V are shown for SnO2-Ce(7)-Zr(3)-Co3O4@GF obtained in Example 1. Figure 7 It was observed that the degradation rate of Rhodamine B was relatively rapid in the first 24 hours, decreasing from an initial 192.6 mg / L to 54.18 mg / L. The degradation trend then slowed down, and after 72 hours, its COD value was 34.61 mg / L. The solution gradually lightened from its initial red color, showing a slight green tinge in the later stages of degradation, before becoming colorless and transparent. Throughout subsequent tests, the electrolyte solution remained colorless and transparent. With continued time, the COD value increased slightly, but remained relatively stable around 40 mg / L with minor fluctuations.

[0101] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An electrode composite material, characterized in that, It includes a carbon matrix and modified tin dioxide and cobalt tetroxide supported on the carbon matrix; the carbon matrix is ​​any one of conductive polyacrylonitrile carbon felt, conductive activated carbon felt, conductive adhesive-based graphite felt, and conductive carbon fiber cloth. The modified tin dioxide comprises tin dioxide and rare earth elements and zirconium doped in the tin dioxide; the rare earth elements and zirconium are doped in the crystal lattice of the tin dioxide; The preparation method of the electrode composite material includes the following steps: A precursor solution is obtained by mixing tin salt, rare earth element metal salt, zirconium salt, cobalt salt, binder and water; The carbon matrix is ​​first impregnated in the precursor solution, then removed and sequentially dried and calcined to obtain the supported carbon matrix. The supported carbon matrix is ​​subjected to a second impregnation in the precursor solution, and then removed and subjected to a second drying and a second calcination to obtain the electrode composite material. The electrode composite material is used directly as a metal oxide anode in neutral water electrolysis to degrade organic matter.

2. The electrode composite material according to claim 1, characterized in that, The rare earth elements include one or more of cerium, lanthanum, gadolinium, neodymium, europium, and erbium.

3. The electrode composite material according to claim 1, characterized in that, The rare earth element in the modified tin dioxide has a doping mass percentage of 1-10%; The zirconium content in the modified tin dioxide is 1-10% by mass.

4. The electrode composite material according to claim 1, characterized in that, The modified tin dioxide has a loading percentage of 10-20% on the electrode composite material. The cobalt tetroxide has a loading percentage of 1-5% on the electrode composite material.

5. The method for preparing the electrode composite material according to any one of claims 1 to 4, characterized in that, Includes the following steps: A precursor solution is obtained by mixing tin salt, rare earth element metal salt, zirconium salt, cobalt salt, binder and water; The carbon matrix is ​​first impregnated in the precursor solution, then removed and sequentially dried and calcined to obtain the supported carbon matrix. The supported carbon matrix is ​​subjected to a second impregnation in the precursor solution, and then subjected to a second drying and a second calcination to obtain the electrode composite material.

6. The preparation method according to claim 5, characterized in that, The tin salt includes tin dichloride and / or tin tetrachloride; The rare earth element metal salts include one or more of rare earth element nitrates, rare earth element sulfates, and rare earth element chlorides. The zirconium salts include one or more of zirconium oxychloride, zirconium nitrate, and zirconium sulfate; The cobalt salt includes one or more of cobalt sulfate, cobalt nitrate, cobalt chloride, and cobalt acetate; The adhesive includes polyvinylpyrrolidone and aluminosilicate sol.

7. The preparation method according to claim 6, characterized in that, The molar concentration of tin salt in the precursor solution is 0.1~0.2 mol / L; The molar concentration of rare earth element metal salt in the precursor solution is 0.002~0.02 mol / L; The molar concentration of zirconium salt in the precursor solution is 0.002~0.02 mol / L; The molar concentration of cobalt salt in the precursor solution is 0.002~0.01 mol / L; The ratio of water, polyvinylpyrrolidone, and aluminosilicate sol in the precursor solution is 100 mL: 0.2 g: 250 μL.

8. The preparation method according to claim 5, characterized in that, The first calcination temperature is 400~550℃, and the time is 10min; The first impregnation, first drying, and first calcination are repeated 5 to 7 times.

9. The preparation method according to claim 5, characterized in that, The second calcination temperature is 450~550℃ and the time is 30~180min.

10. The application of the electrode composite material according to any one of claims 1 to 4 or the electrode composite material prepared by the preparation method according to any one of claims 5 to 9 as a metal oxide anode.

Images