A method for in-situ anchoring transformation to prepare copper-iron coupled nanoszyme

Abstract

This invention belongs to the field of nanoenzyme materials technology, and discloses a method for preparing copper-iron coupled nanoenzymes through in-situ anchoring and transformation. Using L-cysteine-intercalated modified ZnFe-LDH as a functional platform, copper species are first stably immobilized on the ZnFe-LDH surface through coordination sites provided by the thiol and carboxyl groups in the L-cysteine ​​molecule. Subsequently, under low-temperature conditions, they are further in-situ transformed into copper peroxide nanoparticles, which then grow in situ on the carrier surface, thereby achieving stable loading and highly dispersed distribution of the active phase. In this system, L-cysteine ​​serves both as a coordination anchoring site for copper species and, through its thiol groups, supports some Fe... 3+ A reduction reaction is generated, thereby controlling the valence state of iron. The in-situ generated copper peroxide nanoparticles have both hydrogen peroxide-responsive release capability and peroxidase-like activity, forming a cascade catalytic system together with cysteine-intercalated ZnFe-LDH.

Description

Technical Field

[0001] This invention belongs to the field of nanoenzyme materials technology, and relates to a method for preparing copper-iron coupled nanoenzymes through in-situ anchoring and conversion. Background Technology

[0002] Peroxidase-like nanozymes have attracted widespread attention in recent years due to their good stability, low preparation cost, and tunable structure. These materials can catalyze the generation of reactive oxygen species from hydrogen peroxide, thereby achieving functions such as substrate oxidation and color development, and show promising applications in catalysis and detection.

[0003] Metal peroxide materials can decompose and release hydrogen peroxide under acidic conditions. Copper peroxide, in particular, can both supply hydrogen peroxide and provide copper active sites, making it a potential candidate for constructing self-supplied substrate catalytic systems. However, when copper peroxide is used alone as the active component, although it can provide hydrogen peroxide and participate in the catalytic reaction, its active sites are relatively singular and lack interfacial coupling with other metal sites, thus leaving room for improvement in overall catalytic efficiency.

[0004] Zinc-iron layered double hydroxides possess a large specific surface area and a tunable layered structure, with Fe active sites contributing to catalytic reactions. However, when unmodified ZnFe-LDH is combined with copper peroxide, the interfacial interaction between the copper component and the support is weak, which is detrimental to the interfacial stability of copper species and the enhancement of interfacial catalytic activity.

[0005] Therefore, developing a ZnFe-LDH composite material that can stabilize copper peroxide and significantly improve peroxidase-like activity is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the problems of unstable fixation of copper components on the carrier surface, limited interfacial interaction, and insufficient catalytic activity in existing technologies, this invention provides a method for in-situ anchoring and conversion to prepare copper-iron coupled nanozymes.

[0007] The technical solution of the present invention is as follows: A method for preparing copper-iron coupled nanozymes through in-situ anchoring and transformation includes the following steps: (1) Under inert atmosphere conditions, an alkaline solution containing L-cysteine ​​is reacted with a solution containing Zn. 2+ and Fe 3+ The mixed metal salt solution was reacted, and the pH of the reaction system was adjusted to 7.0-8.0 to allow L-cysteine ​​to be intercalated into the ZnFe-LDH interlayer structure, and thiol and carboxyl coordination sites were exposed in the ZnFe-LDH interlayer and on the surface, thus obtaining L-cysteine-intercalated modified ZnFe-LDH material. (2) Under low temperature conditions, the L-cysteine-intercalated modified ZnFe-LDH material was dispersed in deionized water, and copper salt precursor and dispersant were added. The coordination effect of the thiol and carboxyl groups in L-cysteine ​​molecules on copper ions was utilized to anchor copper species in situ on the ZnFe-LDH surface through coordination bonding, forming a coordination-mediated copper precursor pre-assembly system. (3) Continue to add alkaline solution and hydrogen peroxide solution to the coordination-mediated copper precursor pre-assembly system under low temperature conditions, so that the coordinated and anchored copper species are transformed into copper peroxide nanoparticles in situ on the ZnFe-LDH surface, and a stable copper-iron composite interface structure is formed during the in situ growth process, realizing the chemical configuration evolution of the copper / thiol and carboxyl coordination configuration to the copper peroxide active phase. After separation, washing and drying, copper-iron coupled nanozyme is obtained.

[0008] Preferably, in step (1), Zn 2+ with Fe 3+ The molar ratio of Zn in the reaction system is 1:1 to 5:1. 2+ The concentration is 5–30 mmol / L; Preferably, in step (1), L-cysteine ​​and Fe 3+ The molar ratio is 0.5:1 to 2:1 to regulate the intercalation density of L-cysteine ​​and the exposure of surface coordination sites; Preferably, in step (1), the alkaline solution is a sodium hydroxide solution with a concentration of 0.1 to 2.0 mol / L; Preferably, in step (1), the alkaline solution of L-cysteine ​​is added dropwise at a rate of 0.5 to 2 mL / min, the reaction time is 12 to 48 h, the reaction temperature is 15 to 35 °C, and the inert atmosphere is nitrogen or argon. Preferably, in step (1), the L-cysteine-intercalated modified ZnFe-LDH material is obtained by centrifugation, washing and freeze-drying; wherein the centrifugation speed is 5000-10000 rpm and the centrifugation time is 3-10 min; the washing is carried out until the pH of the supernatant is 6.5-7.5; and the freeze-drying temperature is -80 to -30℃.

[0009] Preferably, in step (2), the copper salt precursor is copper chloride, copper sulfate, copper nitrate or copper acetate, and the concentration of the copper salt precursor in the reaction system is 1 to 50 mmol / L; Preferably, in step (2), the L-cysteine-intercalated modified ZnFe-LDH material and the Cu in the copper salt precursor... 2+ The mass ratio is 1:0.2 to 1:0.8. By adjusting this mass ratio, the coordination occupancy rate and anchoring density of thiol and carboxyl groups can be adjusted, thereby controlling the multi-coordination spatial configuration of the copper precursor pre-assembled structure. Preferably, in step (2), the dispersant is polyvinylpyrrolidone, and the amount added is 5 to 20 times the mass of the L-cysteine-intercalated modified ZnFe-LDH material, and the in-situ coordination fixation time is 10 to 60 min.

[0010] Preferably, in step (3), the in-situ conversion is carried out at 2-8°C to control the formation rate and particle size of copper peroxide, and to improve its dispersibility and interfacial stability. Preferably, in step (3), the alkaline solution and hydrogen peroxide are added in steps, wherein sodium hydroxide alkaline solution is added slowly first, and then 30 wt% hydrogen peroxide is added slowly.

[0011] A copper-iron coupled nanozyme was prepared using the method described above. The copper-iron coupled nanozyme uses L-cysteine-intercalated ZnFe-LDH as a carrier platform. Copper species are first stably immobilized on the ZnFe-LDH surface through coordination sites provided by the thiol and carboxyl groups in the L-cysteine ​​molecule. Subsequently, under low-temperature conditions, it is further transformed in situ into copper peroxide nanoparticles, which then grow in situ on the carrier surface, thereby achieving stable loading and highly dispersed distribution of the active phase. In this system, L-cysteine ​​serves both as a coordination anchoring site for copper species and, through its thiol groups, influences some Fe... 3+ A reduction reaction is generated, thereby controlling the valence state of iron. The in-situ generated copper peroxide nanoparticles have both hydrogen peroxide-responsive release capability and peroxidase-like activity, and can form a cascade catalytic system with cysteine-intercalated ZnFe-LDH, thus enabling the material to exhibit high TMB oxidation color development capability under conditions without added hydrogen peroxide.

[0012] The beneficial effects of this invention: The nanozyme of this invention uses L-cysteine-intercalated modified ZnFe-LDH as a functional platform. Copper species are first immobilized on the ZnFe-LDH surface through coordination sites provided by L-cysteine, and then in situ converted into copper peroxide nanoparticles and grown in situ, thereby forming a copper-iron coupled nanozyme composite material. The resulting composite material is denoted as Cys-ZnFe-LDH / CuO2, abbreviated as CLDH / CuO2. Unless otherwise specified, CLDH / CuO2 refers to the L-cysteine-intercalated modified ZnFe-LDH / copper peroxide composite material. Attached Figure Description

[0013] Figure 1 XRD patterns of ZnFe-LDH before and after cysteine ​​intercalation; Figure 2XPS spectra of ZnFe-LDH and Cys-ZnFe-LDH; where (a) is the high-resolution Fe 2p spectrum of ZnFe-LDH and Cys-ZnFe-LDH; and (b) is the high-resolution S 2p spectrum of Cys-ZnFe-LDH. Figure 3 The images are SEM and EDS plots of CLDH / CuO2; where (a) is the SEM plot of CLDH / CuO2, (b) is the Cu element distribution plot, and (c) is the S element distribution plot. Figure 4 The Fourier transform infrared spectrum of CLDH / CuO2; Figure 5 XPS spectra of Cys-ZnFe-LDH and CLDH / CuO2 are shown below; (a) is the full spectrum; (b) is the high-resolution C 1s spectrum; (c) is the high-resolution S 2p spectrum; (d) is the high-resolution O 1s spectrum of CLDH / CuO2; (e) is the high-resolution Cu 2p spectrum of CLDH / CuO2; and (f) is the Cu LMM Auger spectrum of CLDH / CuO2. Figure 6 The image shows the TMB colorimetric results of CLDH / CuO2 under conditions without added H2O2. Detailed Implementation

[0014] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0015] Example 1 Preparation of CLDH / CuO2: (1) Preparation of cysteine-intercalated ZnFe-LDH; Preferably, Zn(NO3)2·6H2O and Fe(NO3)3·9H2O are dissolved in 20 mL of deionized water to obtain a mixed metal salt solution A, wherein Zn 2+ The concentration was 15 mmol / L, Fe 3+ The concentration was 5 mmol / L. L-cysteine ​​was dissolved in 1.0 M sodium hydroxide solution to obtain cysteine ​​alkaline solution B, in which L-cysteine ​​reacted with Fe... 3+ The molar ratio was 1:1. Under a nitrogen atmosphere and with vigorous stirring, cysteine ​​alkaline solution B was slowly added dropwise to mixed metal salt solution A at a rate of 1 mL / min, adjusting the pH of the system to 7.6, and reacted at room temperature for 24 h. The precipitate was then collected by centrifugation at 8000 rpm for 5 min, and washed with deionized water until the pH of the supernatant was approximately 7. Finally, it was freeze-dried under vacuum at -50 °C for 24 h to obtain Cys-ZnFe-LDH.

[0016] (2) Preparation of CLDH / CuO2 composite material; 100 mg Cys-ZnFe-LDH, 106.56 mg CuCl2·2H2O, and 1 g polyvinylpyrrolidone were added to 100 mL of deionized water and stirred to disperse them evenly. The L-cysteine-intercalated ZnFe-LDH material was then mixed with CuCl2·2H2O. 2+ The mass ratio of the CLDH to CuO2 was approximately 1:0.4, and the mass ratio of the CLDH to polyvinylpyrrolidone was approximately 1:10. The system was placed in an ice-water bath at 4°C, and in-situ coordination fixation was first performed for 30 min under continuous stirring. Then, 25 mL of 0.05 M sodium hydroxide solution was slowly added dropwise to form a coordination-mediated copper precursor pre-assembly system. After the addition was complete, 1.25 mL of 30 wt% hydrogen peroxide solution was slowly added dropwise under continuous stirring and low temperature conditions, and the system gradually turned into a dark brown suspension. After the reaction was complete, the solid was collected by centrifugation, repeatedly washed with cold deionized water, and freeze-dried for 20 h to obtain CLDH / CuO2 composite powder.

[0017] Example 2 Except for Zn 2+ with Fe 3+ Except for adjusting the molar ratio to 1:1, the remaining steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0018] Example 3 Except for Zn 2+ with Fe 3+ Except for adjusting the molar ratio to 5:1, the remaining steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0019] Example 4 In addition to L-cysteine ​​and Fe 3+ Except for adjusting the molar ratio to 0.5:1, the remaining steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0020] Example 5 In addition to L-cysteine ​​and Fe 3+ Except for adjusting the molar ratio to 2:1, the remaining steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0021] Example 6 Except for adjusting the concentration of sodium hydroxide solution used to prepare L-cysteine ​​alkaline solution in step (1) to 0.1 mol / L, the remaining steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0022] Example 7 Except for adjusting the concentration of sodium hydroxide solution used to prepare L-cysteine ​​alkaline solution in step (1) to 2.0 mol / L, the other steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0023] Example 8 Except for adjusting the dropping rate of L-cysteine ​​alkaline solution in step (1) to 0.5 mL / min, the other steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0024] Example 9 Except for adjusting the dropping rate of L-cysteine ​​alkaline solution in step (1) to 2 mL / min, the other steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0025] Example 10 Except for adjusting the pH of the reaction system in step (1) to 7.0, the other steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0026] Example 11 Except for adjusting the pH of the reaction system in step (1) to 8.0, the other steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0027] Example 12 In addition to the L-cysteine-intercalated ZnFe-LDH material and the Cu in the copper salt precursor 2+ Except for adjusting the mass ratio to 1:0.8, the remaining steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0028] Example 13 In addition to the L-cysteine-intercalated ZnFe-LDH material and the Cu in the copper salt precursor 2+ Except for adjusting the mass ratio to 1:0.2, the remaining steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0029] Example 14 Except for adjusting the amount of polyvinylpyrrolidone added to 5 times the mass of the L-cysteine-intercalated ZnFe-LDH material, the remaining steps and conditions were the same as in Example 1, and the CLDH / CuO2 composite material was obtained.

[0030] Example 15 Except for adjusting the amount of polyvinylpyrrolidone added to 20 times the mass of the L-cysteine-intercalated ZnFe-LDH material, the remaining steps and conditions were the same as in Example 1, and the CLDH / CuO2 composite material was obtained.

[0031] Example 16 Except for adjusting the in-situ coordination fixation time in step (2) to 10 min, the other steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0032] Example 17 Except for adjusting the in-situ coordination fixation time in step (2) to 60 min, the other steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0033] Example 18 Except for adjusting the in-situ conversion temperature in step (3) to 2℃, the other steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0034] Example 19 Except for adjusting the in-situ conversion temperature in step (3) to 8°C, the remaining steps and conditions are the same as in Example 1, and the CLDH / CuO2 composite material is obtained.

[0035] Example 20 Except for changing the copper salt precursor from copper chloride dihydrate to copper sulfate, the other steps and conditions were the same as in Example 1, and the CLDH / CuO2 composite material was obtained.

[0036] Example 21 Except for changing the copper salt precursor from copper chloride dihydrate to copper nitrate, the remaining steps and conditions were the same as in Example 1, and the CLDH / CuO2 composite material was obtained.

[0037] Example 22 Except for changing the copper salt precursor from copper chloride dihydrate to copper acetate, the remaining steps and conditions were the same as in Example 1, and the CLDH / CuO2 composite material was obtained.

[0038] Comparative Example 1 Without adding L-cysteine, ZnFe-LDH precursor was prepared under the same conditions as step (1) in Example 1; then, copper salt precursor was introduced and low-temperature in-situ conversion was carried out under the same conditions as step (2) in Example 1 to obtain ZnFe-LDH / CuO2 control material.

[0039] Comparative Example 2 Preparation of CuO2 material: CuO2 material was prepared under the same low-temperature conditions as the subsequent conversion steps in Example 1, without the addition of ZnFe-LDH support.

[0040] Comparative Example 3 Preparation of ZnFe-LDH: ZnFe-LDH was prepared using the same method and conditions as step (1) in Example 1 without the addition of L-cysteine.

[0041] Structural characterization (1) X-ray diffraction (XRD) - Comparison before and after cysteine ​​intercalation X-ray diffraction was used to characterize the ZnFe-LDH obtained in Comparative Example 3 and the Cys-ZnFe-LDH precursor obtained in Example 1. The results showed that both exhibited typical diffraction peaks characteristic of LDH layered structures, indicating that cysteine ​​intercalation did not disrupt the crystal structure of ZnFe-LDH. Figure 1 Meanwhile, compared with Comparative Example 3, the diffraction peak of the 003 crystal plane of the Cys-ZnFe-LDH precursor obtained in the preparation process of Example 1 shifted to a lower angle, indicating that cysteine ​​was successfully intercalated and affected the interlayer structure, thus proving its stable existence in LDH.

[0042] (2) X-ray photoelectron spectroscopy (XPS) – Comparison before and after cysteine ​​intercalation X-ray photoelectron spectroscopy was used to characterize the ZnFe-LDH obtained in Comparative Example 3 and the Cys-ZnFe-LDH precursor obtained in Example 1. The results showed that, compared with Comparative Example 3, the Fe 2p spectrum of the Cys-ZnFe-LDH precursor obtained in Example 1 contained higher Fe content. 2+ / Fe 3+ The ratio increased from 1.42 to 3.27, indicating that the thiol group partially inhibited Fe during the reaction. 3+ This process generates a reducing effect, thereby regulating the distribution of iron species valence states. Figure 2 a); Simultaneously, the characteristic peak corresponding to the thiol group appeared in the S 2p spectrum of the Cys-ZnFe-LDH precursor obtained during the preparation process in Example 1, further proving that cysteine ​​successfully intercalated and provided a stable coordination site ( Figure 2 b).

[0043] (3) Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) The morphology of the CLDH / CuO2 composite material obtained in Example 1 was observed using scanning electron microscopy. The results showed that relatively uniformly distributed nanoparticles were visible on the sample surface. Energy dispersive spectroscopy (EDS) indicated a good spatial correspondence between the distributions of Cu and S elements in the sample, suggesting that a copper-related active phase had formed and was loaded onto the material surface. Figure 3 ).

[0044] (4) Fourier transform infrared spectroscopy (FTIR) analysis Fourier transform infrared spectroscopy was used to analyze the changes in surface functional groups of CLDH / CuO2 obtained in Example 1. The characteristic peaks of the carboxylate group in the Cys-ZnFe-LDH precursor obtained in the preparation process of Example 1 are located at 1577 cm⁻¹. -1 and 1401 cm -1 After the introduction of copper species, these two peaks shifted to 1600 cm⁻¹. -1 and 1396 cm -1 This indicates that the interfacial chemical environment changes after the introduction of copper species, and that carboxyl groups participate in copper species fixation. Figure 4 ).

[0045] (5) X-ray photoelectron spectroscopy (XPS) X-ray photoelectron spectroscopy was used to analyze the surface elemental composition and valence state of the CLDH / CuO2 obtained in Example 1. Compared with the Cys-ZnFe-LDH precursor, the CLDH / CuO2 sample obtained in Example 1 showed a significant Cu signal ( Figure 5 a) Positive shift of carboxyl-related peaks in C1s ( Figure 5 b), the CS double peaks in S 2p shift positively simultaneously overall ( Figure 5 c), indicating that the copper species interacts with the carboxyl and thiol modification sites; peroxide-related components appear in O 1s ( Figure 5 d) indicates the presence of a copper peroxide-related phase in the material; Cu 2p and Cu LMM together support the presence of Cu on the sample surface. + / Cu 2+ Active site ( Figure 5 e and Figure 5 f).

[0046] Peroxidase-like activity assay under conditions without added hydrogen peroxide: The activity differences of CLDH / CuO2 obtained in Example 1, ZnFe-LDH / CuO2 obtained in Comparative Example 1, and CuO2 obtained in Comparative Example 2 were evaluated using the TMB colorimetric method. 50 μL of a 0.5 mg / mL material dispersion and 50 μL of a 10 mM TMB solution were added to 900 μL of HAc / NaAc buffer. After reacting at 37°C for 20 min, the absorbance was measured in the range of 500 to 800 nm, and the absorbance at 652 nm was recorded.

[0047] TMB results indicate that under conditions without added H2O2 ( Figure 6The absorbance of the TMB+CLDH / CuO2 system obtained in Example 1 at 652 nm was 1.85, which was significantly higher than that of the TMB+ZnFe-LDH / CuO2 (1.28) obtained in Comparative Example 1 and the TMB+CuO2 (0.24) control system obtained in Comparative Example 2. The color intensity was increased by about 44% compared with ZnFe-LDH / CuO2. The above results indicate that the composite material obtained after cysteine ​​intercalation has higher peroxidase-like activity. The interfacial intercalation of cysteine ​​provides thiol active groups, which is beneficial to improving the copper species immobilization effect and interfacial catalytic activity.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent substitutions, improvements, and modifications made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing copper-iron coupled nanozymes through in-situ anchoring and transformation, characterized in that, The steps are as follows: (1) Under inert atmosphere conditions, an alkaline solution containing L-cysteine ​​is reacted with a solution containing Zn. 2+ and Fe 3+ The mixed metal salt solutions were mixed, and the pH of the reaction system was adjusted to 7.0-8.

0. The reaction caused L-cysteine ​​to be intercalated into the ZnFe-LDH interlayer structure, and thiol and carboxyl coordination sites were exposed in the ZnFe-LDH interlayer and on the surface, thus obtaining L-cysteine ​​intercalated modified ZnFe-LDH material. (2) Under low temperature conditions, the L-cysteine-intercalated modified ZnFe-LDH material was dispersed in deionized water, and copper salt precursor and dispersant were added. The coordination effect of the thiol and carboxyl groups in L-cysteine ​​molecules on copper ions was utilized to anchor copper species in situ on the ZnFe-LDH surface through coordination bonding, forming a coordination-mediated copper precursor pre-assembly system. (3) Continue to add alkaline solution and hydrogen peroxide solution to the coordination-mediated copper precursor pre-assembly system under low temperature conditions, so that the coordinated and anchored copper species are transformed into copper peroxide nanoparticles in situ on the ZnFe-LDH surface, and a stable copper-iron composite interface structure is formed during the in situ growth process, realizing the chemical configuration evolution of the copper / thiol and carboxyl coordination configuration to the copper peroxide active phase. After separation, washing and drying, copper-iron coupled nanozymes are obtained.

2. The method for preparing copper-iron coupled nanozymes by in-situ anchoring transformation according to claim 1, characterized in that, In step (1), Zn 2+ with Fe 3+ The molar ratio of Zn in the reaction system is 1:1 to 5:

1. 2+ The concentration is 5–30 mmol / L; L-cysteine ​​and Fe 3+ The molar ratio is 0.5:1 to 2:1 to regulate the intercalation density of L-cysteine ​​and the exposure of surface coordination sites; The alkaline solution is a sodium hydroxide solution with a concentration of 0.1–2.0 mol / L; The alkaline solution of L-cysteine ​​was added dropwise at a rate of 0.5–2 mL / min, the reaction time was 12–48 h, the reaction temperature was 15–35 °C, and the inert atmosphere was nitrogen or argon. The L-cysteine ​​intercalation-modified ZnFe-LDH material was obtained by centrifugation, washing and freeze-drying. The centrifugation speed was 5000–10000 rpm, and the centrifugation time was 3–10 min; the washing was carried out until the pH of the supernatant was 6.5–7.5; and the freeze-drying temperature was -80 to -30℃.

3. The method for preparing copper-iron coupled nanozymes by in-situ anchoring transformation according to claim 1, characterized in that, In step (2), The copper salt precursor is copper chloride, copper sulfate, copper nitrate or copper acetate, and the concentration of the copper salt precursor in the reaction system is 1-50 mmol / L; L-cysteine-intercalated ZnFe-LDH material and Cu in copper salt precursor 2+ The mass ratio is 1:0.2 to 1:0.8; The dispersant was polyvinylpyrrolidone, and the amount added was 5 to 20 times the mass of the L-cysteine-intercalated ZnFe-LDH material. The in-situ coordination fixation time was 10 to 60 min.

4. The method for preparing copper-iron coupled nanozymes by in-situ anchoring transformation according to claim 1, characterized in that, In step (3), The in-situ conversion was carried out at 2–8°C to control the formation rate and particle size of copper peroxide. The alkaline solution and hydrogen peroxide are added in steps, with sodium hydroxide alkaline solution added slowly first, followed by 30 wt.% hydrogen peroxide added slowly.

5. A copper-iron coupled nanozyme obtained by the method according to any one of claims 1-4.

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