A method for preparing an electroenzyme cascade self-supplying H2O2 cathode material and its application

Abstract

This invention relates to the fields of environmental pollution remediation and biocatalysis, and provides a method for preparing a self-supplied H2O2 cathode material via an electroenzyme cascade and its application. The cathode material is an ionic liquid-modified CPO-IL. EMB The bio-hybrid material formed by immobilizing molybdenum disulfide-modified MoS2@Co-CNNT composite material, namely CPO-IL EMB / MoS2@Co-CNNT. An electroenzyme cascade degradation system was constructed using this biohybrid material as the cathode. By controlling the electrode potential, controllable H2O2 generation was achieved while protecting the Fe(III) in the iron porphyrin ring of CPO from reduction, thus maintaining the intrinsic oxidative activity of the enzyme. The in-situ generated H2O2 activates CPO-IL. EMB It efficiently catalyzes the oxidative degradation of mesotrione. This invention requires no external CPO-IL. EMB It is green and environmentally friendly, with high degradation efficiency, and has promising applications in agricultural wastewater treatment and environmental remediation.

Description

Technical Field

[0001] This invention belongs to the field of environmental pollution remediation and biocatalysis technology, and particularly relates to a method for preparing an electroenzyme cascade self-supplying H2O2 cathode material and its application. Background Technology

[0002] Mesotrione is a selective HPPD inhibitor herbicide widely used in cornfields for weed control, playing a crucial role in ensuring crop yields. However, excessive use of mesotrione leads to elevated residual concentrations in soil and water, posing potential hazards to soil microorganisms and aquatic organisms, and becoming a significant source of agricultural non-point source pollution. Therefore, developing efficient, green, and economically feasible mesotrione degradation technologies has significant environmental importance and application value.

[0003] Currently, the main methods for degrading mesotrione include microbial degradation, advanced oxidation, and enzymatic catalysis. Microbial degradation utilizes specific strains or enzymes to degrade mesotrione, offering environmental advantages, but it suffers from drawbacks such as long degradation cycles, slow response to high concentrations of pollutants, and poor environmental adaptability. Advanced oxidation technologies can rapidly generate reactive species such as hydroxyl radicals, achieving efficient degradation of organic pollutants, but they typically require the addition of H₂O₂ or iron salts, increasing operating costs and the risk of secondary pollution.

[0004] Chloroperoxidase (CPO) is a heme enzyme with dual peroxidase and catalase activities, capable of catalyzing the oxidative degradation of various organic pollutants in the presence of H2O2. However, free CPO suffers from poor stability and difficulty in recycling, and a continuous supply of H2O2 is a major bottleneck for its industrial application. In recent years, the development of enzyme immobilization technology and electrochemical in-situ H2O2 production technology has provided new ideas for solving these problems, but existing systems generally suffer from shortcomings such as low enzyme loading, mismatch between H2O2 yield and enzyme activity, and lack of synergy between electrochemical and enzyme catalysis.

[0005] Therefore, developing a degradation system that can achieve in-situ self-supply of H2O2, high enzyme loading, and synergistic effect of electrochemistry and enzyme catalysis is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing an electroenzyme cascade self-supplying H2O2 cathode material and its application, aiming to solve the problems mentioned in the background art.

[0007] The present invention is implemented as follows: an electroenzyme cascade self-supplying H2O2 cathode material, wherein the cathode material is ion liquid-modified chloroperoxidase (CPO-IL). EMBA bio-hybrid material formed by immobilizing molybdenum disulfide-modified cobalt-doped carbon nitride nanotubes (denoted as MoS2@Co-CNNT) composite material, denoted as CPO-IL. EMB / MoS2@Co-CNNT.

[0008] In a further technical solution, in the MoS2@Co-CNNT composite material, MoS2 is modified on the surface of Co-CNNT in the form of nanoflowers, and Co-CNNT is a cobalt-doped carbon nitride nanotube structure.

[0009] Another objective of this invention is to provide a method for preparing an electroenzyme cascade self-supplying H2O2 cathode material, comprising the following steps: Step 1: Prepare cobalt-doped carbon nitride nanotube structures (Co-CNNT). Step 2: MoS2 nanoflowers are grown in situ on the surface of Co-CNNT via hydrothermal reaction to obtain MoS2@Co-CNNT composite material; Step 3: Modify chlorperoxidase (CPO) with an ionic liquid to obtain ionic liquid-modified chlorperoxidase (CPO-IL). EMB ); Step 4: Take the CPO-IL obtained in Step 3 EMB Immobilized on the MoS2@Co-CNNT composite material obtained in step 2, the bio-hybrid material CPO-IL was obtained after washing and drying. EMB / MoS2@Co-CNNT.

[0010] In a further technical solution, in step 2, the hydrothermal reaction conditions are: temperature 180~230℃, time 6~12 h, and the molar ratio of molybdenum source to sulfur source in the reaction system is 1:1~1:3.

[0011] In a further technical solution, the molybdenum source is ammonium molybdate or sodium molybdate, and the sulfur source is thiourea or L-cysteine.

[0012] In a further technical solution, the immobilization conditions in step 4 are: pH 5.0~6.0, temperature 20~30℃, and reaction time 2~4 h.

[0013] Another objective of this invention is the application of an electroenzyme cascade self-supplying H2O2 cathode material, based on the biohybrid material CPO-IL prepared by the above method. EMB / MoS2@Co-CNNT, the biohybrid material CPO-IL EMB / MoS2@Co-CNNT is used in the degradation of mesotrione.

[0014] A further technical solution, the application specifically being: Biohybrid material CPO-IL EMB The working electrode is made of / MoS2@Co-CNNT and placed in a solution containing mesotrione as the cathode. Oxygen is introduced and a potential is applied for electrolysis. The H2O2 generated in situ activates the chloroperoxidase in the cathode material to catalyze the oxidative degradation of mesotrione.

[0015] A further technical solution employs a three-electrode system, with the working electrode being the bio-hybrid material CPO-IL. EMB The electrode modified with / MoS2@Co-CNNT has a graphite electrode as the counter electrode and a saturated calomel electrode as the reference electrode.

[0016] A further technical solution involves controlling the potential of the working electrode to be no less than -0.25 V relative to the saturated calomel electrode, so that a two-electron oxygen reduction reaction occurs in situ at the cathode to generate H2O2, while avoiding the reduction of Fe(III) in CPO.

[0017] The present invention provides a method for preparing an electroenzyme cascade self-supplying H2O2 cathode material and its application, the beneficial effects of which are as follows: (1) Significant synergistic effect: Using MoS2@Co-CNNT composite material as a carrier, this material combines the ability of efficient two-electron oxygen reduction to produce H2O2 with excellent enzyme immobilization performance, realizing the cascade reaction pathway of "in-situ generation-immediate utilization" of H2O2, eliminating the need for exogenous addition of H2O2. Experiments show that the synergistic catalytic efficiency of this electroenzyme cascade system is 13.1 times higher than that of using MoS2@Co-CNNT material alone.

[0018] (2) Significantly increased enzyme loading: This invention significantly increases the specific surface area and enzyme binding sites of the carrier by modifying the surface of Co-CNNT with MoS2 nanoflowers, thereby increasing the enzyme loading capacity of CPO-IL. EMB The loading (92 mg / g) is about twice that of the unmodified MoS2 Co-CNNT support (45 mg / g), thereby increasing the catalytic activity density per unit electrode area.

[0019] (3) Precise potential matching to protect enzyme activity: By precisely controlling the cathode potential to be no less than -0.25 V (vs. SCE), this invention ensures efficient H2O2 generation while effectively preventing the reduction of Fe(III) in the heme center of CPO to Fe(II), thereby maintaining the intrinsic oxidation activity of CPO and solving the technical bottleneck of mismatch between electrochemical process and enzyme activity.

[0020] (4) Green and environmentally friendly with broad application prospects: No external H2O2 or chemical oxidants are required, the degradation process is free of secondary pollution, and the operation is simple. This system has a high efficiency in degrading mesotrione and can be extended to the removal of other triketone herbicides, phenolic pollutants, antibiotics and dyes that are difficult to degrade organic pollutants. It has excellent application prospects in the fields of agricultural wastewater treatment and environmental remediation. Attached Figure Description

[0021] Figure 1 For CPO-IL EMB A schematic diagram of the electroenzyme cascade system of / MoS2@Co-CNNT biohybrid material degrading mesotrione; Figure 2 XRD patterns of Co-CNNT and MoS2@Co-CNNT (a), SEM image of MoS2@Co-CNNT (b), and TEM map of MoS2@Co-CNNT (c). Figure 3 For CPO-IL EMB Schematic diagram of the preparation of / MoS2@Co-CNNT biohybrid material (a), Rhodamine-labeled CPO-IL EMB Confocal laser scanning microscope image (b) of the / MoS2@Co-CNNT biohybrid material, CPO-IL EMB MoS2@Co-CNNT and CPO-IL EMB Fourier transform infrared spectra (c) of the / MoS2@Co-CNNT biohybrid material, and CPO-IL before and after loading on Co-CNNT and MoS2@Co-CNNT. EMB UV-Vis spectrum of the supernatant (d); Figure 4 Linear sweep voltammetry results of MoS2@Co-CNNT modified carbon cloth electrode (a), voltammetry results of rotating ring disk electrode (b), and Ce concentrations at different concentrations. 4+ UV-Vis spectra (c) of (0~0.333 mmol / L) and the yield and Faraday efficiency of the MoS2@Co-CNNT modified carbon cloth electrode for electrocatalytic reduction of O2 to H2O2 at different potentials (d). Figure 5 For Ce 4+ Standard curve; Figure 6 For CPO-IL EMB / MoS2@Co-CNNT biohybrids were in a 0.1 mol / L PBS solution containing 100 μmol / L mesotrione and saturated with oxygen, CPO-IL EMBThe electrolysis curves of / MoS2@Co-CNNT biohybrid materials at different potentials over 60 min; Figure 7 For using CPO-IL EMB UV-Vis spectra of the electrolyte before and after catalytic degradation of mesotrione at different potentials using the MoS2@Co-CNNT working electrode (a), and UV absorption change at 254.9 nm (b); using the MoS2@Co-CNNT working electrode and CPO-IL EMB The UV-Vis spectra of the electrolyte before and after catalytic degradation of mesotrione at the / MoS2@Co-CNNT working electrode at -0.25 V vs. SCE potential (c), and the change in UV-Vis absorbance at 254.9 nm (d). Figure 8 For MoS2@Co-CNNT working electrode and CPO-IL EMB Cyclic voltammetry curves of the / MoS2@Co-CNNT modified electrode in nitrogen-saturated 0.1 mol / L PBS solution (a), CPO-IL EMB Cyclic voltammetry curves (b) and linear relationship between peak current and scan rate (c) of the / MoS2@Co-CNNT modified electrode in nitrogen-saturated 0.1 mol / L PBS solution at different scan rates; CPO-IL EMB Cyclic voltammetry curves (d) of the / MoS2@Co-CNNT modified electrode in oxygen-saturated 0.1 mol / L PBS solution, with a potential range of -0.8 V to 0.4 V vs. SCE. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0024] One embodiment of the present invention provides a self-supplied H2O2 cathode material for an electroenzyme cascade, wherein the cathode material is chloroperoxidase modified with an ionic liquid (denoted as CPO-IL). EMB A bio-hybrid material formed by immobilizing molybdenum disulfide-modified cobalt-doped carbon nitride nanotubes (denoted as MoS2@Co-CNNT) composite material, denoted as CPO-IL. EMB / MoS2@Co-CNNT.

[0025] In a preferred embodiment of the present invention, in the MoS2@Co-CNNT composite material, MoS2 is modified on the surface of Co-CNNT in the form of nanoflowers, and Co-CNNT is a cobalt-doped carbon nitride nanotube structure.

[0026] Another embodiment of the present invention provides a method for preparing an electroenzyme cascade self-supplying H2O2 cathode material, comprising the following steps: Step 1: Prepare cobalt-doped carbon nitride nanotube structures (Co-CNNT). Step 2: MoS2 nanoflowers are grown in situ on the surface of Co-CNNT via hydrothermal reaction to obtain MoS2@Co-CNNT composite material; Step 3: Modify chlorperoxidase (CPO) with an ionic liquid to obtain ionic liquid-modified chlorperoxidase (CPO-IL). EMB ); Step 4: Take the CPO-IL obtained in Step 3 EMB Immobilized on the MoS2@Co-CNNT composite material obtained in step 2, the bio-hybrid material CPO-IL was obtained after washing and drying. EMB / MoS2@Co-CNNT.

[0027] In a preferred embodiment of the present invention, in step 2, the hydrothermal reaction conditions are: temperature 180~230℃, time 6~12 h, and the molar ratio of molybdenum source to sulfur source in the reaction system is 1:1~1:3. The molybdenum source is ammonium molybdate or sodium molybdate, and the sulfur source is thiourea or L-cysteine.

[0028] In a preferred embodiment of the present invention, the immobilization conditions in step 4 are: pH 5.0~6.0, temperature 20~30℃, and reaction time 2~4 h.

[0029] like Figure 1 As shown, another embodiment of the present invention provides an application of an electroenzyme cascade self-supplying H2O2 cathode material, based on the bio-hybrid material CPO-IL prepared by the above method. EMB / MoS2@Co-CNNT, the biohybrid material CPO-IL EMB / MoS2@Co-CNNT is used in the degradation of mesotrione.

[0030] As a preferred embodiment of the present invention, the application is specifically as follows: Biohybrid material CPO-IL EMBThe working electrode is made of / MoS2@Co-CNNT and placed in a solution containing mesotrione as the cathode. Oxygen is introduced and a potential is applied for electrolysis. The H2O2 generated in situ activates the chloroperoxidase in the cathode material to catalyze the oxidative degradation of mesotrione.

[0031] In a preferred embodiment of the present invention, a three-electrode system is adopted, with the working electrode being the bio-hybrid material CPO-IL. EMB The electrode modified with / MoS2@Co-CNNT has a graphite electrode as the counter electrode and a saturated calomel electrode as the reference electrode.

[0032] In a preferred embodiment of the present invention, the potential of the working electrode is controlled to be no less than -0.25 V relative to the saturated calomel electrode so that H2O2 is generated in situ by a two-electron oxygen reduction reaction at the cathode, while avoiding the reduction of Fe(III) in CPO.

[0033] Several specific embodiments are provided below to verify the effectiveness of this method.

[0034] All reagents used in each example were commercially available analytical grade. Chloroperoxidase (CPO, derived from Caldariomyces fumago) was purchased from Sigma-Aldrich; 1-ethyl-3-methylimidazolium bromide (IL-1) was used. EMB The following were purchased from Shanghai Chengjie Chemical Co., Ltd.: melamine, cobalt nitrate hexahydrate, anhydrous ethanol, sulfuric acid, thiourea, sodium molybdate dihydrate, potassium dihydrogen phosphate, dipotassium hydrogen phosphate, hydrochloric acid, and mesotrione were purchased from Sinopharm Chemical Reagent Co., Ltd.; carbon cloth (WOS1009) was purchased from Suzhou Shengnuo Technology Co., Ltd.

[0035] The preparation method of the molybdenum disulfide modified cobalt-doped carbon nitride nanotubes (MoS2@Co-CNNT) is as follows: thiourea is used as the sulfur source, and sodium molybdate dihydrate is used as the molar source, with a sulfur to molybdenum molar ratio of 3:1. A certain amount of Co-CNNT is weighed to make the mass ratio of sodium molybdate dihydrate to Co-CNNT 1:1, and deionized water is added and ultrasonically dispersed evenly. The mixture is transferred to a high-pressure reactor lined with polytetrafluoroethylene and hydrothermally reacted at 220 °C for 8 h. After the reaction is completed, it is naturally cooled, and the product is washed several times with ethanol and deionized water, and dried to obtain the MoS2@Co-CNNT composite material.

[0036] The CPO-IL used EMB The preparation method is as follows: CPO is dissolved in 0.1 mol / L PBS at pH 6.0, and IL is added. EMB To reach the appropriate concentration, stir the reaction at low temperature, then wash with ultrafiltration tube by centrifugation to remove unbound ILs. EMB CPO-IL was obtainedEMB Solution.

[0037] The carbon cloth pretreatment method used is as follows: the carbon cloth (1 cm × 1 cm) is ultrasonically cleaned in acetone, ethanol and deionized water for 15 min each, then soaked in 1 mol / L hydrochloric acid for 2 h, rinsed with deionized water until neutral, and vacuum dried at 60 ℃ for later use.

[0038] All electrochemical tests were performed on a CHI760E electrochemical workstation (Shanghai Chenhua Co., Ltd.) using a three-electrode system: the working electrode was a carbon cloth electrode modified with different materials, the counter electrode was a carbon rod, and the reference electrode was a SCE. All electrochemical tests were performed in 0.1 mol / L PBS (pH 5.0).

[0039] Example 1: Preparation and physical characterization of MoS2@Co-CNNT composite material; Co-CNNT and MoS2@Co-CNNT were prepared according to the method described above. The morphology and crystal structure of the materials were characterized by field emission scanning electron microscopy (FESEM, Quanta 200), transmission electron microscopy (TEM, JEM-2100), and X-ray powder diffraction (XRD, DX-2700). Figure 2 a shows the XRD patterns of Co-CNNT and MoS2@Co-CNNT. Co-CNNT exhibits characteristic diffraction peaks at 44.5°, 51.7°, and 75.9°, corresponding to the (111), (200), and (220) crystal planes of CoN (PDF#41-0943), indicating that cobalt is doped into the carbon-nitrogen framework in the form of nitrides. In addition to the aforementioned characteristic peaks of CoN, MoS2@Co-CNNT exhibits new diffraction peaks at 14.2°, 33.1°, and 58.6°, corresponding to the (002), (100), and (110) crystal planes of MoS2 (PDF#37-1492), proving that MoS2 was successfully loaded onto Co-CNNT. Figure 2 b is a SEM image of MoS2@Co-CNNT, showing that MoS2 is uniformly distributed on the surface of Co-CNNT in the form of nanoflowers. Figure 2 c is the TEM elemental mapping of MoS2@Co-CNNT, confirming that C, N, Co, Mo, and S elements are uniformly distributed.

[0040] Example 2: CPO-IL EMB Characterization of immobilized and biohybrid materials; The MoS2@Co-CNNT prepared according to the above method was dispersed in PBS (pH 5.0) at a concentration of 5 mg / mL. CPO-IL was then added. EMB The solution was incubated at 25 °C for 120 min. After the reaction was complete, the mixture was centrifuged, and the resulting precipitate was CPO-IL.EMB / MoS2@Co-CNNT biohybrid. The supernatant was used to determine the amount of unfixed enzyme. The absorbance change of CPO at 398 nm was determined by UV-Vis spectrophotometry (Cary 60), and the enzyme loading (unit mg / g) was calculated according to formula (1): (1) Where △A represents the absorbance change at 398 nm, V represents the total volume of the reaction system (L), and M represents the total volume of the reaction system (L). CPO Let ε be the molecular weight of CPO (42000 g / mol), ε be the molar absorptivity of CPO (91200 L / (mol·cm)), l be the optical path length of the cuvette (0.5 cm), and m be the mass (g) of MoS2@Co-CNNT. The calculated CPO-IL... EMB The loading capacity on MoS2@Co-CNNT was 92 mg / g, which is about 2.0 times higher than that of the unmodified MoS2 Co-CNNT vector (45 mg / g).

[0041] Figure 3 a is the CPO-IL of this invention. EMB A schematic diagram of the preparation of the / MoS2@Co-CNNT biohybrid material. To visualize enzyme immobilization, Rhodamine B (Rh-B) was used to label CPO-IL. EMB : 100 μL of a certain concentration of CPO-IL EMB 50 μg of Rh-B was dispersed in 1 mL of PBS (pH 5.0) and reacted with shaking at 25 °C in the dark for 5 h to obtain Rh-B-CPO-IL. EMB Then, it was fixed onto MoS2@Co-CNNT using the same method. Excitation was performed with a 559 nm laser, and red fluorescence signals were collected in the 530–580 nm range. Confocal laser scanning microscopy (CLSM) images are shown below. Figure 3 b. The uniform red fluorescence distribution on the material surface proves that CPO-IL EMB Successfully fixed. Figure 3 c is CPO-IL EMB MoS2@Co-CNNT and CPO-IL EMB Fourier transform infrared spectrum of / MoS2@Co-CNNT biohybrid material, CPO-IL EMB / MoS2@Co-CNNT at 1650 cm⁻ 1 (Amide I band) and 1530 cm⁻ 1 The presence of a characteristic absorption peak in the amide II band confirms the presence of CPO. Figure 3 d represents CPO-IL before and after immobilization. EMB UV-Vis spectrum of the supernatant, CPO-ILEMB The absorbance of the supernatant immobilized with MoS2@Co-CNNT at 398 nm was significantly lower than that of the supernatant immobilized with Co-CNNT, indicating that MoS2 modification improved the enzyme loading.

[0042] Example 3: Electrochemical performance and H2O2 generation capacity of MoS2@Co-CNNT A MoS2@Co-CNNT modified carbon cloth electrode was used as the working electrode, and linear sweep voltammetry (LSV) was performed in 0.1 mol / L PBS (pH 5.0) saturated with oxygen or nitrogen at a scan rate of 10 mV / s. The results are as follows: Figure 4 As shown in Figure a: Under oxygen saturation conditions, the electrode exhibits a significant reduction current peak at approximately -0.15 V (vs. SCE), with an initial potential of approximately 0.182 V vs. SCE; under nitrogen saturation conditions, only a weak background current is observed, indicating that MoS2@Co-CNNT has good electrocatalytic activity for the oxygen reduction reaction.

[0043] A voltammetric scan was performed using a rotating ring-disc electrode (RRDE) in oxygen-saturated 0.1 mol / L PBS (pH 5.0) at 1600 rpm. The results are shown in the figure. Figure 4 b. Based on the ring disk current data, calculate the electron transfer number n and H2O2 selectivity according to formulas (2) and (3). : (2) = (3) Where N is the platinum ring collection efficiency (0.3), I D and I R These are the disk current and the ring current, respectively. Calculations show that n = 2.8 within the range of 0.15 V to -0.15 V vs. SCE potential. The result is above 61.0%, which proves that MoS2@Co-CNNT mainly catalyzes the two-electron oxygen reduction reaction (2e⁻ORR), which is suitable for in-situ generation of H2O2.

[0044] Using Ce 4+ The amount of H₂O₂ generated was quantitatively determined by oxidation. Constant potential electrolysis was performed in an H-type electrolytic cell, with MoS₂@Co-CNNT modified carbon cloth as the working electrode. First, the electrolyte was electrolyzed for 30 min in nitrogen-saturated 0.1 mol / L PBS (pH 5.0) and the background current was measured. Then, the electrolyte was electrolyzed for 30 min in the same oxygen-saturated solution at different potentials (0.00 V to -0.15 V vs. SCE). After electrolysis, a portion of the electrolyte was collected, and Ce... 4+ It reacts with the electrically generated H2O2 (2Ce) 4++H₂O₂→2H + +2Ce 3+ +O2), leading to Ce 4+ The intensity of the characteristic absorption peak at 316 nm decreases. Figure 4 c represents different concentrations of Ce 4+ The UV-Vis spectrum curves (0~0.333 mmol / L) show that the absorbance increases with increasing concentration. Figure 5 For Ce 4+ The standard curve and linear regression equation are y = 2.434x (mmol / L) + 0.00498, R0. 2 =0.999. Figure 4 d represents the H2O2 production yield and Faraday efficiency of MoS2@Co-CNNT at different potentials, where the H2O2 production yield at -0.05 V is 20.1 μmol / (g·s) and the Faraday efficiency of H2O2 is 93.46%.

[0045] Example 4: Optimization of conditions and performance evaluation of electroenzymatic cascade degradation of mesotrione; With CPO-IL EMB A MoS2@Co-CNNT modified carbon cloth electrode was used as the working electrode, a carbon rod as the counter electrode, and SCE as the reference electrode to construct an electroenzyme cascade degradation system. The electrolyte was 0.1 mol / L PBS (pH 5.0) saturated with oxygen containing 100 μmol / L mesotrione. Electrolysis was performed at different potentials (-0.10 V, -0.15 V, -0.20 V, -0.25 V, -0.30 V vs. SCE) for 60 min at a constant potential, and the current-time (it) curves were recorded. The results are shown below. Figure 6 As the potential shifts negative, the reduction current first increases and then decreases.

[0046] Samples were taken before and after electrolysis, and the change in absorbance at 254.9 nm was measured using a UV-Vis spectrophotometer to characterize the degradation rate of mesotrione. Figure 7 a is for using CPO-IL EMB UV-Vis spectra of the / MoS2@Co-CNNT working electrode before and after decomposition at different potentials. Figure 7 b shows the absorbance change at 254.9 nm. The results show that the degradation rate is close to 100% at -0.25 V; however, the degradation rate drops sharply when the potential decreases to -0.30 V. This is because Fe(III) in CPO is reduced below -0.25 V, leading to enzyme inactivation. Therefore, the optimal potential window was determined to be -0.15 V to -0.25 V (vs. SCE).

[0047] Figure 7c compares the performance of the MoS2@Co-CNNT working electrode alone and CPO-IL at a potential of -0.25 V. EMB UV-Vis spectra of mesotrione before and after degradation at the / MoS2@Co-CNNT working electrode. Figure 7 d represents the absorbance change at 254.9 nm. (CPO-IL) EMB The degradation rate of the / MoS2@Co-CNNT working electrode is 13.1 times that of the MoS2@Co-CNNT alone.

[0048] Example 5: Electrochemical behavior and direct electron transfer mechanism; CPO-IL was recorded at a scan rate of 50 mV / s in nitrogen-saturated 0.1 mol / L PBS (pH 5.0). EMB Cyclic voltammetry curves for the / MoS2@Co-CNNT electrode are shown in [the table below]. Figure 8 a. Compared to the MoS2@Co-CNNT working electrode (only bilayer capacitance current is shown), CPO-IL EMB The / MoS2@Co-CNNT electrode exhibits a pair of distinct redox peaks with peak potentials of -0.30 V and -0.27 V vs. SCE, corresponding to the redox couple of Fe(III) / Fe(II) at the CPO heme center. This indicates that the ionic liquid modification promotes direct electron transfer between CPO and the electrode.

[0049] Cyclic voltammetry curves were measured at different scan rates, and the results are shown in the figure. Figure 8 b. Figure 8 c is a linear relationship between the reduction peak current and the oxidation peak current and the scan rate. The two show a good linear relationship, indicating that the electrochemical reaction is controlled by the surface.

[0050] Cyclic voltammetry curves were recorded at a scan rate of 100 mV / s in oxygen-saturated 0.1 mol / L PBS (pH 5.0). The results are shown in [Figure number missing]. Figure 8 d. An irreversible reduction current peak appears, with an initial potential of approximately 0.154 V vs. SCE, corresponding to the oxygen reduction reaction, demonstrating that in the presence of oxygen, both oxygen reduction to H2O2 and CPO-mediated substrate oxidation processes occur simultaneously on the electrode surface.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A self-supplied H2O2 cathode material for an electroenzyme cascade, characterized in that, The cathode material is CPO-IL modified with an ionic liquid. EMB The bio-hybrid material formed by immobilizing molybdenum disulfide-modified MoS2@Co-CNNT composite material, namely CPO-IL EMB / MoS2@Co-CNNT.

2. The electroenzyme cascade self-supplying H2O2 cathode material according to claim 1, characterized in that, In the MoS2@Co-CNNT composite material, MoS2 is modified on the surface of Co-CNNT in the form of nanoflowers, and Co-CNNT is a cobalt-doped carbon nitride nanotube structure.

3. A method for preparing the electroenzyme cascade self-supplying H2O2 cathode material as described in claim 2, characterized in that, Includes the following steps: Step 1: Preparation of Co-CNNT; Step 2: MoS2 nanoflowers are grown in situ on the surface of Co-CNNT via hydrothermal reaction to obtain MoS2@Co-CNNT composite material; Step 3: Modify CPO with an ionic liquid to obtain ionic liquid-modified CPO-IL. EMB ; Step 4: Take the CPO-IL obtained in Step 3 EMB Immobilized on the MoS2@Co-CNNT composite material obtained in step 2, the bio-hybrid material CPO-IL was obtained after washing and drying. EMB / MoS2@Co-CNNT.

4. The method for preparing the electroenzyme cascade self-supplying H2O2 cathode material according to claim 3, characterized in that, In step 2, the hydrothermal reaction conditions are: temperature 180~230℃, time 6~12 h, and the molar ratio of molybdenum source to sulfur source in the reaction system is 1:1~1:

3.

5. The method for preparing the electroenzyme cascade self-supplying H2O2 cathode material according to claim 4, characterized in that, The molybdenum source is ammonium molybdate or sodium molybdate, and the sulfur source is thiourea or L-cysteine.

6. The method for preparing the electroenzyme cascade self-supplying H2O2 cathode material according to claim 3, characterized in that, In step 4, the immobilization conditions are: pH 5.0~6.0, temperature 20~30℃, and reaction time 2~4 h.

7. The application of the electroenzyme cascade self-supplying H2O2 cathode material as described in claim 1 or 2, characterized in that, The biohybrid material CPO-IL EMB / MoS2@Co-CNNT is used in the degradation of mesotrione.

8. The application of the electroenzyme cascade self-supplying H2O2 cathode material according to claim 7, characterized in that, The specific application is as follows: Biohybrid material CPO-IL EMB The working electrode was fabricated using / MoS2@Co-CNNT and placed in a solution containing mesotrione as the cathode. Oxygen was introduced, and electrolysis was performed by applying a potential. The H2O2 generated in situ activated the CPO-IL in the cathode material. EMB Catalytic oxidation degradation of mesotrione.

9. The application of the electroenzyme cascade self-supplying H2O2 cathode material according to claim 8, characterized in that, A three-electrode system is adopted, with the working electrode being the bio-hybrid material CPO-IL. EMB The electrode modified with / MoS2@Co-CNNT has a graphite electrode as the counter electrode and a saturated calomel electrode as the reference electrode.

10. The application of the electroenzyme cascade self-supplying H2O2 cathode material according to claim 9, characterized in that, The potential of the working electrode is controlled to be no less than -0.25 V relative to the saturated calomel electrode so that a two-electron oxygen reduction reaction occurs at the cathode to generate H2O2 in situ.

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