Composite cathode material integrating electro-catalysis and ozone oxidation functions, preparation method and application

Abstract

The invention discloses a composite cathode material integrating electrocatalysis and ozone oxidation functions, a preparation method and application. The composite cathode material is composed of oxidized carbon nanotubes, cuprous oxide and copper oxide. The copper loading capacity of the composite cathode material is 1-10wt.%; the diameter of the oxidized carbon nanotube is 5 to 10 nm; the mass ratio of the oxidized carbon nanotubes to the cuprous oxide to the copper oxide is (298-27): (3.0-2.5): (0-1). A composite cathode material integrating electrocatalysis and ozone oxidation functions is elaborately designed and prepared and is applied to an electrocatalytic ozone coupling system, and continuous and efficient attack on antibiotic molecules and degradation intermediates thereof is realized by utilizing multiple synergistic effects among all components of the material and in the electrocatalytic ozone process, so that the electrochemical performance of the composite cathode material is improved. Therefore, the technical bottleneck of low TOC removal rate in the traditional advanced oxidation process is broken through, and a new technical approach is provided for thoroughly eliminating the antibiotic risk in the water environment.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a composite cathode material integrating electrocatalysis and ozone oxidation functions, its preparation method, and its application. Background Technology

[0002] Electrocatalytic ozone oxidation, as an advanced water treatment process, aims to generate more potent oxidizing free radicals (such as hydroxyl radicals ·OH) through the coupling of electrochemical processes with ozone oxidation, thereby deeply degrading organic pollutants. However, the core effectiveness of this technology is highly dependent on the performance of the cathode material.

[0003] Antibiotics are a common organic pollutant in pharmaceutical wastewater, and their total organic matter (TOC) removal is generally much more difficult than that of the parent compound alone. Many advanced oxidation processes can rapidly degrade antibiotics, but TOC removal rates are often low, potentially leading to the accumulation of more toxic intermediates.

[0004] Currently, the existing technological level in this field and its key shortcomings are as follows: 1) Regarding ozone oxidation technology itself: Ozone is a strong oxidant, and its direct oxidation reaction has good chain-breaking and ring-opening effects on unsaturated aliphatic hydrocarbons and aromatic hydrocarbons (such as phenol), so it is widely used in the deep treatment of industrial wastewater. The shortcomings are: ozone's removal of TOC from organic pollutants is not thorough enough. It can destroy the parent structure of pollutants, but it is difficult to completely oxidize them into CO2 and H2O, resulting in a low total organic carbon removal rate. A large number of small-molecule intermediate products may remain in the treated water, and the toxicity and environmental risks of these products are unknown, potentially causing secondary pollution. 2) Regarding the application of carbon-based cathode materials in electrocatalytic ozone systems: Carbon materials (such as graphite, carbon felt, carbon cloth, carbon paper, etc.) are often used as cathode substrates in electrocatalytic systems due to their good conductivity and chemical stability. Researchers have also attempted to improve their performance by modifying or loading metal catalysts onto carbon substrates. Existing drawbacks: A. Limited intrinsic catalytic activity: Unmodified ordinary carbon materials exhibit low catalytic activity for ozone decomposition, primarily relying on the homogeneous pathway of electrochemical ozone reduction to generate free radicals, resulting in low efficiency and limited system oxidation capacity; B. Surface properties and stability issues: The surface chemical properties of carbon materials (such as hydrophobicity, type and number of functional groups) directly affect their catalytic performance and their binding ability with catalysts. Untreated carbon materials supporting metal catalysts are prone to detachment and loss during operation, leading to decreased activity and metal dissolution, affecting the long-term stability of the system. Furthermore, carbon materials may experience corrosion and structural collapse during long-term operation in highly oxidizing environments (ozone, free radicals), resulting in performance degradation. 3) Regarding the comprehensive performance of cathode materials: Existing technologies lack an ideal composite cathode that can achieve both high catalytic activity and excellent stability based on carbon materials. This limits the widespread application and effectiveness of electrocatalytic ozone coupling technology in treating recalcitrant organic wastewater, especially in scenarios requiring high mineralization. Summary of the Invention

[0005] Existing technologies use undesigned carbon-based materials (such as ordinary CNTs) as cathodes, which have limited intrinsic catalytic activity, single catalytic sites, and low electron transfer efficiency, making it difficult to continuously and efficiently catalyze the generation of sufficient free radicals from ozone. Furthermore, the catalyst-support bonding is weak, and active components are prone to detachment or deactivation during long-term operation. Additionally, the TOC removal rate of the catalytic material fluctuates significantly with pH changes. To address these issues, this invention employs a one-step thermal oxidation method for in-situ growth of the cathode material. This cathode material features a pioneering design of cuprous oxide / copper oxide heterojunction synergistic active site, constructing a dynamic Cu(I) / Cu(II) redox cycle, accelerating the electron transfer rate from the cathode to ozone. The mixed valence state of copper provides multiple catalytic pathways, acting as both a reduction site (Cu(I)) to directly activate ozone and an oxidation site (Cu(II)) to stabilize the cycle, synergistically promoting the chain generation of hydroxyl radicals. Strong interfacial coupling (Cu-OC bond) with carbon oxide nanotubes (OCNTs) ensures high dispersion and structural stability of the active sites. This method is simple, low-cost, and the catalyst material bonds firmly to the substrate, exhibiting good reproducibility and making it suitable for large-scale production.

[0006] According to a first aspect of the present invention, a composite cathode material integrating electrocatalysis and ozone oxidation functions is provided, the composite cathode material being composed of carbon oxide nanotubes, cuprous oxide and copper oxide; The copper loading of the composite cathode material is 1~10 wt.%; The diameter of the carbon oxide nanotubes is 5~10 nm; The cuprous oxide and copper oxide exist on the surface of the oxide nanotubes in the form of black crystalline particles with a particle size of 2-3 nm. The mass ratio of carbon oxide nanotubes, cuprous oxide, and copper oxide is 298~27:3.0~2.5:0~1.

[0007] Based on the above technical solution, the carbon oxide nanotubes have a grooved nanotube structure.

[0008] According to a second aspect of the present invention, a method for preparing a composite cathode material integrating electrocatalysis and ozone oxidation functions is provided, comprising the following steps: Step 1: Acidification treatment of carbon nanotubes to obtain carbon oxide nanotubes, i.e., OCNT catalyst precursor; Step 2: Copper acetylacetone and carbon oxide nanotubes obtained in Step 1 are dispersed in water, stirred at room temperature for 8-12 h, filtered, and freeze-dried at -80 to -50℃ for 8-12 h to form a black powder catalyst, which is then calcined in a tube furnace to obtain the composite material. Step 3: The composite material obtained in Step 2 is ultrasonically mixed with dispersant and binder for 30-45 min to form catalyst ink, which is then coated on the surface of carbon paper and dried for use as a cathode.

[0009] Based on the above technical solution, the acidification treatment in step 1 is specifically as follows: carbon nanotubes are mixed with a mixed acid solution, stirred at 80~90℃ for 1~1.5 h, cooled to room temperature, washed with water until neutral, and freeze-dried at -80~-50℃ for 8~12 h. The mixed acid solution is a mixture of concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3; The mass ratio of the carbon nanotubes to the mixed acid is 1~2.5:69.2~86.5.

[0010] Based on the above technical solution, in step 2, the mass ratio of copper acetylacetone to carbon oxide nanotubes is 0.0429~0.7003:1, and the concentration of copper acetylacetone is 0.1433~2.335 mg / mL. The calcination conditions described in step 2 are as follows: The calcination was carried out under argon protection; The heating rate of the calcination is 5~7℃ / min; The calcination temperature is 300~350℃; The calcination time is 1.2~1.5 h.

[0011] Based on the above technical solution, the dispersant in step 3 is selected from at least one of deionized water, PVP, and SDS. The binder in step 3 is selected from at least one of Nafion membrane solution, PVDF, and PEO, with a concentration of 3 to 5 wt.%. In step 3, the mixing mass ratio of the composite material, dispersant, and binder is 8~10:9~15:1~2; In step 3, the mass fraction of the composite material in the catalyst ink is 37.04 wt.% ~ 44.44 wt.%. In step 3, the working area of ​​the carbon paper is 6.25~9 cm². 2 .

[0012] According to a third aspect of the present invention, a composite cathode material is provided for use in adsorption, electrocatalytic oxidation, ozone oxidation, catalytic ozone, and electrocatalytic ozone oxidation systems.

[0013] Based on the above technical solution, the electrocatalytic ozone oxidation system includes the following components: Cathode: Cuprous oxide / copper oxide supported carbon oxide electrode (Cu) x O / OCNT catalytic materials); Anode: Ruthenium-iridium-titanium electrode; Aeration device: Ozone aeration equipment located between the anode and cathode; Power supply system: Provides 25~75 mA DC power; Ozone generator: provides 10~30 mg / L of ozone; Reaction tank: Contains electrolytes and wastewater to be treated; Based on the above technical solution, the connection relationship of each component is as follows: the cathode and anode are placed in parallel opposite positions with a distance of 3cm; the aeration device is located in the middle of the two electrodes; the positive and negative terminals of the power supply are connected to the anode and cathode respectively; the ozone generator is connected to the aeration device through a pipeline.

[0014] Based on the above technical solution, Cu x The O / OCNT catalytic material consists of a substrate material (carbon nanotubes, OCNT) and active components (cuprous oxide / copper oxide Cu2O / CuO, generated by thermal oxidation).

[0015] The electrocatalytic ozone oxidation system disclosed in this invention achieves high-efficiency degradation through the following synergistic effect: (1) Cathode catalysis: Cuprous oxide / copper oxide supported carbon oxide cathode catalysis to generate ozone and other active oxygen species such as ·OH.

[0016] (2) Electrochemical enhancement: The electric field promotes electron transfer and accelerates the generation of free radicals.

[0017] (3) Optimization of free radical generation: Cu(I) / Cu(II) cycle ensures that free radicals such as ·OH are continuously produced.

[0018] (4) Electron transfer optimization: The excellent conductivity of OCNT ensures that cathode electrons can be transferred to Cu(I) / Cu(II) active sites quickly and without damage, maintaining the efficient operation of the above catalytic cycle.

[0019] According to a fourth aspect of the present invention, an application of a composite cathode material in the degradation of sulfamethoxazole is provided.

[0020] According to a fifth aspect of the present invention, an application of a composite cathode material in the removal of total organic carbon is provided.

[0021] Beneficial effects (1) The electrocatalytic ozone oxidation (ECO) system disclosed in this invention exhibits a synergistic degradation and mineralization capability for SMX that far exceeds that of a single technology path. Under optimal conditions, i.e., a cathode material with a copper mass fraction of 5% (5 wt.% Cu-OCNT), SMX is completely degraded within 2 minutes, and the TOC mineralization rate of SMX reaches approximately 86% within 90 minutes. Compared with electrocatalytic oxidation alone, ozone oxidation alone, and catalytic ozone oxidation, the mineralization rate of the ECO system is increased by 7.2 times, 3.9 times, and 1.4 times, respectively. This quantitative data strongly demonstrates the deep oxidation capability of the system and directly solves the common industry problem in advanced oxidation technologies that "antibiotic precursors are easily degraded but TOC is difficult to remove".

[0022] (2) The technical solution disclosed in this invention achieves the maximization of active sites and optimization of carrier function through acidification pretreatment and successful loading of copper oxide. Through systematic comparison, it is clear that 5% copper by mass is the optimal loading amount. Excessive loading (such as 10%) may lead to particle agglomeration, which will reduce the effective active area. XPS and other characterizations confirm that acidification successfully introduces oxygen-containing functional groups on the CNT surface to form OCNT. This not only improves hydrophilicity and dispersibility, but the C=O and other groups on its surface can also serve as anchoring points to form a strongly interacting Cu-OC interface with copper species, promoting electron transfer and stability. XRD and XPS confirm the successful loading of mixed-valence copper oxide (Cu(I) and Cu(II)). x This mixed valence system (O) is conducive to establishing an efficient catalytic cycle, overcoming key defects of traditional carbon-based materials such as insufficient catalytic active sites, easy agglomeration of metal particles, and weak binding force between active components and supports.

[0023] (3) The technical solution disclosed in this invention can maintain high catalytic activity in a wide pH range (such as pH=3~10), showing good adaptability and achieving the effect of "easy processing, operation, control and use".

[0024] (4) Cu prepared by the technical solution disclosed in this invention x The O / OCNT cathode material exhibits good catalytic and mechanical stability during repeated use. After multiple cycles, its TOC mineralization capacity for SMX did not decrease significantly, indicating that its lifespan meets practical requirements. The concentration of copper ions dissolved in the solution after the reaction remains at a low level, demonstrating the strong bond between the active component and the support. This effectively avoids secondary pollution and solves the problems of easy loss of active components and short service life of powder catalysts or traditional supported cathodes. Attached Figure Description

[0025] Figure 1 The Cu before and after CNT acidification and under different mass fractions of copper loading in Examples 1-5 of this inventionx SEM images of O / OCNT materials; Figure 2 This is a comparison of XPS images before and after CNT acidification as described in Example 1 of the present invention; Figure 3 Cu with different mass fractions of copper loading in Examples 1-5 of this invention x XPS comparison chart of O / OCNT materials; Figure 4 Cu with different mass fractions of copper loading in Examples 1-5 of this invention x Comparison of the degradation effect of O / OCNT cathode electrocatalytic ozone oxidation system on SMX; Figure 5 Cu with different mass fractions of copper loading in Examples 1-5 of this invention x Comparison of TOC removal effects of O / OCNT cathode electrocatalytic ozone oxidation system on SMX; Figure 6 Comparison of the degradation effects of the 5 wt.% Cu-OCNT cathode prepared in Example 3 of this invention on SMX under adsorption, electrocatalytic oxidation, ozone oxidation, catalytic ozone and electrocatalytic ozone conditions; Figure 7 Comparison of TOC removal effects of the 5 wt.% Cu-OCNT cathode prepared in Example 3 of this invention on SMX under adsorption, electrocatalytic oxidation, ozone oxidation, catalytic ozone and electrocatalytic ozone conditions; Figure 8 The TOC removal effect of the 5 wt.% Cu-OCNT cathode prepared in Example 3 of this invention on SMX under different pH conditions; Figure 9 The graph shows the TOC removal rate of SMX by the 5 wt.% Cu-OCNT cathode prepared in Example 3 of this invention in an electrocatalytic ozone oxidation system over 5 reaction cycles. Figure 10 The metal dissolution of the 5 wt.% Cu-OCNT cathode prepared for Example 3 of the present invention during 5 cycles of operation of the electrocatalytic ozone oxidation system. Detailed Implementation

[0026] To make the objectives and technical solutions of this invention clearer, the following embodiments are provided for further explanation. However, the scope of protection of this invention is not limited to these embodiments; the embodiments are merely for illustrative purposes. Those skilled in the art should understand that any changes or equivalent substitutions that do not depart from the concept of this invention are included within the scope of protection of this invention.

[0027] Unless otherwise specified, all reagents and raw materials used in this invention are obtained through purchase.

[0028] Example 1 Copper oxide supported carbon nanotubes (Cu) x Preparation of O / OCNT) electrode materials: Step 1, Preparation of OCNT catalyst precursor: Weigh 2.0 g of raw carbon nanotubes (CNTs, diameter 5-10 nm, purchased from Jiangsu Xianfeng Nanotechnology Co., Ltd., morphology shown in [reference needed]). Figure 1 The catalyst, exhibiting a smooth tubular structure, was uniformly dispersed in 80 ml of a mixed acid solution (concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3). The solution was continuously stirred at 80°C for 1 hour. After natural cooling to room temperature, the mixed suspension was diluted with ultrapure water and filtered. The resulting filter cake was repeatedly washed with ultrapure water and filtered until the pH of the filtrate was close to neutral. The collected catalyst was then dried in a vacuum freeze dryer at -60°C for 12 h to obtain the OCNT catalyst precursor (i.e., acidified OCNT, the substrate material). Its morphology is shown in […]. Figure 1 (OCNT), the tube wall becomes rougher and grooves appear, indicating that oxygen-containing functional groups have been successfully introduced; XPS comparison images before and after CNT acidification are shown below. Figure 2 .

[0029] Step 2, copper-doped carbon oxide nanotubes (Cu x Preparation of O / OCNT catalyst: 0.20 g of the OCNT catalyst precursor prepared in step 1 and 0.0086 g of copper acetylacetonate were weighed and uniformly dispersed in 60 ml of ultrapure water. The mixture was stirred continuously on a magnetic stirrer for 12 hours at room temperature. The catalyst cake was obtained by vacuum filtration and freeze-drying at -60℃ for 12 h to obtain a black powder. The obtained black powder catalyst was calcined in a vacuum tube furnace using argon (Ar) as a protective gas, heated to 350℃ for 1.5 hours at a heating rate of 5℃ / min, and then allowed to cool naturally to obtain copper-doped carbon oxide nanotube catalyst (Cu). x O / OCNT material, with a copper loading of 1 wt.% and an active component of Cu2O / CuO, wherein the Cu x XPS characterization results of O / OCNT material (1 wt.% Cu-OCNT) are shown in [reference needed]. Figure 3 The O 1s spectrum of OCNTs shows enhanced signals from oxygen-containing functional groups such as C=O and CO, while the Cu 2p spectrum shows characteristic peaks and satellite peaks of Cu(I) and Cu(II), confirming the presence of Cu at the surface chemical level. x Successful preparation of O / OCNT composite material.

[0030] Step 3, Preparation of the working electrode: 10.0 mg of Cu prepared in Step 2 was added... xThe O / OCNT material was uniformly dispersed in a mixture of 2.25 mL ultrapure water (dispersant) and 0.25 mL Nafion membrane solution (5 wt.%, purchased from Kawamori Corporation, binder). The mixture was sonicated for 30 minutes to obtain the catalyst ink, which was then coated onto carbon paper (working area 9 cm²). 2 ), to obtain Cu x O / OCNT working electrode (copper loading of 1 wt.%, cathode).

[0031] Example 2 The difference from Example 1 is that the amount of copper acetylacetone added is different, specifically 0.0282 g, resulting in a copper-doped carbon oxide nanotube catalytic material (copper loading of 3 wt.%). x XPS characterization results of O / OCNT material (3 wt.% Cu-OCNT) are shown in [reference needed]. Figure 3 The O 1s spectrum of OCNTs shows enhanced signals from oxygen-containing functional groups such as C=O and CO, while the Cu 2p spectrum shows characteristic peaks and satellite peaks of Cu(I) and Cu(II), confirming the presence of Cu at the surface chemical level. x The O / OCNT composite material was successfully prepared; the remaining steps were the same as in Example 1, yielding Cu. x O / OCNT working electrode (copper loading of 3 wt.%, cathode).

[0032] Example 3 The difference from Example 1 is that the amount of copper acetylacetone added is different, specifically 0.0519 g, resulting in a copper-doped carbon oxide nanotube catalytic material (copper loading of 5 wt.%, 5 wt.% Cu-OCNT, morphology shown in [reference needed]). Figure 1 Copper oxide particles are uniformly dispersed on the OCNT surface; the Cu x XPS characterization results of O / OCNT material (5 wt.% Cu-OCNT) are shown in [reference needed]. Figure 3 The O 1s spectrum of OCNTs shows enhanced signals from oxygen-containing functional groups such as C=O and CO, while the Cu 2p spectrum shows characteristic peaks and satellite peaks of Cu(I) and Cu(II), confirming the presence of Cu at the surface chemical level. x The O / OCNT composite material was successfully prepared; the remaining steps were the same as in Example 1, yielding Cu. x O / OCNT working electrode (copper loading of 5 wt.%, cathode), through Figure 1 The SEM characterization results show that acidification modifies the CNT surface, and the dispersion under different copper loading fractions proves that 5 wt.% is the optimal loading amount, which can achieve efficient dispersion of active sites.

[0033] Example 4 The difference from Example 1 is that the amount of copper acetylacetone added is different, specifically 0.0810 g, resulting in a copper-doped carbon oxide nanotube catalytic material (copper loading of 7 wt.%, cathode, 7 wt.% Cu-OCNT, morphology shown in [reference needed]). Figure 1 With increased loading, the particle distribution remained relatively uniform; the Cu x XPS characterization results of O / OCNT material (7 wt.% Cu-OCNT) are shown in [reference needed]. Figure 3 The O 1s spectrum of OCNTs shows enhanced signals from oxygen-containing functional groups such as C=O and CO, while the Cu 2p spectrum shows characteristic peaks and satellite peaks of Cu(I) and Cu(II), confirming the presence of Cu at the surface chemical level. x Successful preparation of O / OCNT composite material; the remaining steps are the same as in Example 1, yielding Cu x O / OCNT working electrode (copper loading of 7 wt.%).

[0034] Example 5 The difference from Example 1 is that the amount of copper acetylacetone added is different, specifically 0.1401 g, resulting in a copper-doped carbon oxide nanotube catalytic material (copper loading of 10 wt.%, cathode, 10 wt.% Cu-OCNT, morphology shown in [reference needed]). Figure 1 The particles clearly agglomerated, forming large aggregates; the Cu x XPS characterization results of O / OCNT material (10 wt.% Cu-OCNT) are shown in [reference needed]. Figure 3 The O 1s spectrum of OCNTs shows enhanced signals from oxygen-containing functional groups such as C=O and CO, while the Cu 2p spectrum shows characteristic peaks and satellite peaks of Cu(I) and Cu(II), confirming the presence of Cu at the surface chemical level. x The O / OCNT composite material was successfully prepared; the remaining steps were the same as in Example 1, yielding Cu. x O / OCNT working electrode (copper loading of 10 wt.%).

[0035] Example 6 Cu with different copper loadings prepared in Examples 1-5 xThe O / OCNT working electrode is used in an electrocatalytic ozone oxidation system to degrade SMX solution (sulfamethoxazole) and remove TOC (total organic carbon) from the solution (electrocatalytic ozone). Specifically, it is used to treat a 20 mg / L sulfamethoxazole (SMX) solution for 90 min. The treatment parameters are: ozone concentration of 10-30 mg / L (preferably 20 mg / L), ozone flow rate of 0.1 L / min (aeration device: 20 mg / L ozone), current intensity of 25-75 mA (preferably 50 mA), electrode spacing of 3 cm, initial pH of 3-10 (preferably 5), electrolyte of 0.05 M Na2SO4, and cathode of Cu with mass fractions of 1 wt.%, 3 wt.%, 5 wt.%, 7 wt.%, and 10 wt.%. x O / OCNT cathode (3cm×3cm), anode: ruthenium-iridium-titanium electrode (3 ×3×0.15 cm) 3 The effect of SMX degradation is as follows Figure 4 As shown, the TOC removal effect of SMX is shown in the figure. Figure 5 The results showed that Cu x The O / OCNT working electrode (copper loading of 5 wt.%) used in the electrocatalytic ozone oxidation system achieved the highest degradation rate of SMX and TOC removal rate, with a removal rate of 86%.

[0036] Example 7 Cu with different copper loadings prepared in Example 3 x The O / OCNT working electrode was used to adsorb and degrade SMX solution (sulfamethoxazole, concentration 20 mg / L) and remove TOC (total organic carbon) from the solution. The adsorption conditions were as follows: initial pH 5, treatment time 90 min. The SMX degradation effect is shown in [reference needed]. Figure 6 The TOC removal effect in SMX solution is shown in [reference needed]. Figure 7 .

[0037] Example 8 Cu with different copper loadings prepared in Example 3 x The O / OCNT working electrode was used for the electrocatalytic oxidation degradation of SMX solution (sulfamethoxazole, concentration 20 mg / L) and removal of TOC (total organic carbon) from the solution. The electrocatalytic oxidation conditions were as follows: current intensity 50 mA, electrode spacing 3 cm, initial pH 5, electrolyte 0.05 M Na2SO4, anode ruthenium-iridium-titanium electrode, and treatment time 90 min. The degradation effect of SMX is shown in […]. Figure 6 The TOC removal effect in SMX solution is shown in [reference needed]. Figure 7 The TOC removal rate was only 10.4%, which is a limited TOC removal rate, leading to the accumulation of intermediate products.

[0038] Example 9 Pure ozone oxidation was used to degrade SMX solution (sulfamethoxazole, concentration 20 mg / L) and remove TOC (total organic carbon) from the solution. The ozone oxidation conditions were as follows: ozone concentration 20 mg / L, ozone flow rate 0.1 L / min, initial pH 5, and treatment time 90 min. The SMX degradation effect is shown in [the figure]. Figure 6 The TOC removal effect in SMX solution is shown in [reference needed]. Figure 7 The TOC removal rate was only 17.4%, which is limited and leads to the accumulation of intermediate products.

[0039] Example 10 Cu with different copper loadings prepared in Example 3 x The O / OCNT working electrode was used to catalyze the ozone degradation of SMX solution (sulfamethoxazole, concentration 20 mg / L) and remove TOC (total organic carbon) from the solution. The catalytic ozone conditions were as follows: ozone concentration 20 mg / L, ozone flow rate 0.1 L / min, initial pH 5, and treatment time 90 min. The SMX degradation effect is shown in [the figure]. Figure 6 The TOC removal effect in SMX solution is shown in [reference needed]. Figure 7 The TOC removal rate was 35.7%, which is limited, leading to the accumulation of intermediate products.

[0040] Example 11 Cu with different copper loadings prepared in Example 3 x The O / OCNT working electrode was used for electrocatalytic ozone degradation of SMX solution (sulfamethoxazole, concentration 20 mg / L) and removal of TOC (total organic carbon) from the solution. The electrocatalytic ozone conditions were as follows: ozone concentration 20 mg / L, ozone flow rate 0.1 L / min, current intensity 50 mA, electrode spacing 3 cm, initial pH 5, electrolyte 0.05 M Na₂SO₄, anode ruthenium-iridium-titanium electrode, and treatment time 90 min. The degradation effect of SMX is shown in […]. Figure 6 The TOC removal effect in SMX solution is shown in [reference needed]. Figure 7 The results showed that the TOC removal rate of SMX by electrocatalytic ozone was 7.2 times, 3.9 times, and 1.4 times higher than that of electrocatalytic oxidation, ozone oxidation, and catalytic ozone, respectively, demonstrating the superior performance and synergistic effect of the 5 wt.% Cu-OCNT cathode in the electrocatalytic ozone system.

[0041] Example 12 Testing Cu prepared in Example 3 under different pH conditions xThe TOC removal efficiency of the O / OCNT working electrode (copper loading of 5 wt.%) for SMX solution (concentration of 20 mg / L) was investigated under the following conditions: ozone concentration of 20 mg / L, ozone flow rate of 0.1 L / min, current intensity of 50 mA, electrode spacing of 3 cm, initial pH values ​​of 3, 5, 8, and 10, electrolyte of 0.05 M Na₂SO₄, anode of ruthenium-iridium-titanium electrode, and treatment time of 90 min. The removal results are shown in [Figure number missing]. Figure 8 This demonstrates that the 5 wt.% Cu-OCNT cathode exhibits highly efficient TOC removal capability in SMX solutions under different pH conditions within the electrocatalytic ozone system.

[0042] Example 13 Test Example 3 prepared Cu x The TOC removal efficiency of the O / OCNT working electrode (copper loading of 5 wt.%) on SMX (concentration of 20 mg / L) over 5 reaction cycles was evaluated. The cycling conditions were the same as in Example 11, with 5 cycles. The removal results are shown in [Figure 1]. Figure 9 ,Depend on Figure 9 It can be seen that the TOC removal rate curve remained stable after multiple cycles without significant decrease; the metal leaching situation after 5 cycles is shown in the figure. Figure 10 ,Depend on Figure 10 It can be seen that the amount of copper ions dissolved remains at a low level, proving that the prepared Cu x The O / OCNT cathode material and the electrocatalytic ozone system constructed therefrom exhibit good long-term operational stability and environmental safety.

[0043] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A composite cathode material having both functions of collecting electrons and ozone oxidation, characterized in that, The composite cathode material is composed of oxidized carbon nanotubes, cuprous oxide and copper oxide; The copper loading of the composite cathode material is 1-10 wt.%; The diameter of the oxidized carbon nanotubes is 5-10 nm; The cuprous oxide and copper oxide exist in the form of black crystal particles on the surface of the oxidized nanotubes, and the particle size of the black crystal particles is 2-3 nm.

2. The composite cathode material of claim 1, wherein, The oxidized carbon nanotubes have a gully-shaped nanotube structure; The mass ratio of the oxidized carbon nanotubes, cuprous oxide and copper oxide is 298-27:3.0-2.5:0-1.

3. A method for producing the composite cathode material according to any one of claims 1 or 2, characterized in that, The method comprises the following steps: Step 1: acidizing carbon nanotubes to obtain oxidized carbon nanotubes, i.e. OCNT catalyst precursor; Step 2: dispersing copper acetylacetonate and the oxidized carbon nanotubes obtained in step 1 in water, stirring at room temperature for 8-12 hours, suction filtering, freeze-drying at-80--50℃ for 8-12 hours to form a black powder catalyst, and calcining the black powder catalyst in a tube furnace to obtain a composite material; Step 3: ultrasonically mixing the composite material obtained in step 2 with a dispersant and a binder for 30-45 minutes to form a catalyst ink, coating the catalyst ink on the surface of carbon paper, and drying to obtain a cathode.

4. The preparation method according to claim 3, characterized in that, The acidizing treatment in step 1 is specifically as follows: mixing carbon nanotubes with a mixed acid solution, stirring at 80-90℃ for 1-1.5 hours, cooling to room temperature, washing with water until neutral, and freeze-drying at-80--50℃ for 8-12 hours; The mixed acid solution is a mixed solution of concentrated nitric acid and concentrated sulfuric acid with a volume ratio of 1:3; The mixing mass ratio of the carbon nanotubes and the mixed acid is 1-2.5:69.2-86.

5.

5. The preparation method according to claim 3, characterized in that, In step 2, the mass ratio of copper acetylacetonate and the oxidized carbon nanotubes is 0.0429-0.7003:1, wherein the concentration of copper acetylacetonate is 0.1433-2.335 mg / mL; The calcining conditions in step 2 are as follows: The calcining is performed under argon protection; The heating rate of the calcining is 5-7℃ / min; The temperature of the calcining is 300-350℃; The time of the calcining is 1.2-1.5 hours.

6. The preparation method according to claim 3, characterized in that, The dispersant in step 3 is selected from at least one of deionized water, PVP and SDS; The binder in step 3 is selected from at least one of Nafion membrane liquid, PVDF and PEO, and the concentration is 3-5 wt%; The mixing mass ratio of the composite material, the dispersant and the binder in step 3 is 8-10:9-15:1-2; The mass fraction of the composite material in the catalyst ink in step 3 is 37.04 wt.%-44.44 wt.%; The working area of the carbon paper in step 3 is 6.25~9.00 cm 2 .

7. The composite cathode material according to any one of claims 1-2 and / or the composite cathode material prepared by the preparation method according to any one of claims 3-6 is applied in adsorption, electrocatalytic oxidation, ozone oxidation, catalytic ozone and electrocatalytic ozone oxidation systems.

8. The composite cathode material according to any one of claims 1-2 and / or the composite cathode material prepared by the preparation method according to any one of claims 3-6 is applied in sulfamethoxazole degradation.

9. Use of the composite cathode material according to any one of claims 1 to 2 and / or of the composite cathode material obtained by the production process according to any one of claims 3 to 6 for the removal of total organic carbon.

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