Photo-assisted flexible electrode, preparation method and application

Abstract

The invention relates to the technical field of electroanalytical chemistry testing, in particular to a photo-assisted flexible electrode, a preparation method and application, the photo-assisted flexible electrode comprises a flexible electrode body and a photocatalyst loaded on the flexible electrode body, and the regeneration rate of the photo-assisted flexible electrode is 77-100%. Compared with the prior art, the flexible electrode is coated with the semiconductor with photoresponse, light energy is introduced into the sensor according to the photocatalytic characteristic of the semiconductor, electrode surface regeneration is achieved through illumination, and electrode pollution is avoided; the light-assisted flexible electrode is connected with the work station, so that the outdoor water matrix pollutant can be rapidly detected, the environment is protected, the cost is low, the reliability is high, secondary pollution is avoided, continuous operation is realized in the water quality monitoring period, the reliability of the electrode is improved, the service life of the electrode is prolonged, and a feasible solution is provided for rapid and accurate water detection in various environments.

Description

Technical Field

[0001] The present invention relates to the technical field of electroanalytical chemical testing, and in particular to a light-assisted flexible electrode, a preparation method and an application thereof. Background Art

[0002] The growing demand for effective outdoor water matrix detection has driven the development of sensor systems towards improved sensitivity, portability, rapid detection, and cost-effectiveness. Among them, electrochemical sensors have become a popular choice for food safety, medical diagnosis, and environmental monitoring due to their rapid response, high sensitivity, low cost, and easy operation. Traditional electrochemical detection platforms are complex in structure, high in operating cost, and require high technical skills of operators, making them unsuitable for rapid on-site water detection. In contrast, flexible electrochemical detection sensors have advantages in integration, portability, and cost-efficiency. However, both traditional and flexible electrochemical platforms suffer from a common challenge: electrode contamination. During the initial detection cycle, contaminants attached to the electrode surface can lead to irreversible surface contamination, which affects the reliability and lifetime of the sensor. To prevent severe signal fluctuations caused by electrode contamination, thorough surface cleaning and reconstruction of the sensor material and analyte are necessary for subsequent cycles.

[0003] Patent CN115704797A discloses an electrochemical detection method based on screen-printed electrodes, which fixes the protein sample on the electrode surface, and then captures the target molecule on the electrode surface through the specific recognition between biomolecules. The base electrode converts the concentration signal into current, and the measurable electrical signal is used as the corresponding signal, thereby achieving quantitative or qualitative analysis of the target analyte. However, the detection speed is not fast enough, the efficiency is not high, and the problem of electrode contamination is not solved.

[0004] Patent CN107238645A discloses a screen-printed electrode for glucose oxidase for online monitoring and its preparation method. The electrode uses a Prussian blue-doped carbon-based screen-printed electrode prepared by chemical deposition as an electrochemical transducer, modified with an immobilized glucose oxidase layer to form an enzyme biosensor, and uses the electrochemical reduction process of hydrogen peroxide for quantitative analysis to effectively avoid interference caused by easily oxidized components in the analysis sample. However, there is still the problem of electrode contamination, which limits its use.

[0005] In view of this, the present invention is proposed to avoid serious signal fluctuations caused by electrode contamination and improve the reliability of flexible electrode detection. Summary of the invention

[0006] In order to overcome the above technical defects, the present invention provides a light-assisted flexible electrode, preparation method and application thereof, which are used for effective and rapid detection of outdoor water matrix pollutants, and regenerate the electrode surface by light to avoid electrode contamination and achieve continuous operation during water quality monitoring.

[0007] One of the purposes of the present invention is to provide a light-assisted flexible electrode, comprising a flexible electrode body and a photocatalyst loaded on the flexible electrode body, wherein the regeneration rate of the light-assisted flexible electrode is 75-100%.

[0008] In some embodiments, the photocatalyst is TiO 2 , ZnO, CdS, BiOI, BiOBr, BiOCl, Bi 2 WO 6 , polythiophene, ZIF-8, Co 3 O 4 , gC 3 N 4 、ZIF-8@MoS 2 One of;

[0009] In some embodiments, the flexible electrode body includes a flexible substrate 1 and a reference electrode 2, a counter electrode 3 and a working electrode 4 (such as Figure 1 shown);

[0010] In some embodiments, the flexible substrate 1 is selected from a composite of one or more of polyvinyl chloride, polycarbonate, polyethylene terephthalate, polyester, paper, cardboard, ceramic, and regenerated silk fibroin.

[0011] Or the photocatalyst is BiOX wherein X=I, Br, Cl; or the photocatalyst is ZIF-8, gC 3 N 4 、ZIF-8@MoS 2 In some preferred embodiments, the photocatalyst is ZIF-8@MoS 2 .

[0012] The second object of the present invention is to provide a method for preparing a light-assisted flexible electrode, wherein a light-responsive semiconductor catalyst is ultrasonically mixed with isopropyl alcohol and naphthol and then coated on a flexible electrode body; wherein the photocatalyst is TiO 2 , ZnO, CdS, BiOI, BiOBr, BiOCl, Bi 2 WO 6 , polythiophene, ZIF-8, Co 3 O 4 , gC 3 N 4 、ZIF-8@MoS2 One of them.

[0013] In a preferred embodiment of the present invention, the photocatalyst is ZIF-8@MoS 2 .

[0014] In some embodiments, the mass volume ratio of the photoresponsive semiconductor catalyst to isopropanol and naphthol is (0-1) mg: (100-900) μL: (10-100) μL; for example, the mass volume ratio of the photoresponsive semiconductor catalyst to isopropanol and naphthol is (0.1-1) mg: (300-900) μL: (20-100) μL; or the mass volume ratio of the photoresponsive semiconductor catalyst to isopropanol and naphthol is (0.3-1) mg: (500-900) μL: (40-100) μL. )μL; or the mass volume ratio of the photoresponsive semiconductor catalyst to isopropanol and naphthol is (0.5-1)mg:(700-900)μL:(60~100)μL; or the mass volume ratio of the photoresponsive semiconductor catalyst to isopropanol and naphthol is (0.7-1)mg:(700-900)μL:(80~100)μL; or the mass volume ratio of the photoresponsive semiconductor catalyst to isopropanol and naphthol is (0.9-1)mg:(800-900)μL:(90~100)μL.

[0015] In some embodiments, the photoresponsive semiconductor catalyst is prepared by the following method: 2-methylimidazole and Zn(NO3) 2 6H 2 O were dissolved in methanol and mixed evenly, among which 2-methylimidazole and Zn(NO3) 2 6H 2 The molar ratio of O is 4:1. The mixed solution is aged at room temperature for 12-24 hours, and then centrifuged, washed, and dried to obtain ZIF-8.

[0016] In some embodiments, the photoresponsive semiconductor catalyst is prepared by the following method: placing melamine powder in an oven at 3-10°C min -1 The mixture was heated at a rate of 500-600 °C for 2-4 h, cooled to room temperature, and subjected to ultrasonic treatment to obtain g-C3N4.

[0017] In some embodiments, the photoresponsive semiconductor catalyst is prepared by the following method: ZIF-8 and ammonium tetrathiomolybdate in a mass ratio of (10-12):1 are added to dimethylformamide, ultrasonically dispersed, heated at 200-250°C for 12-20h, cooled to room temperature, and the product is centrifuged, washed, and dried to obtain ZIF-8@MoS 2 .

[0018] The third object of the present invention is to provide the above-mentioned light-assisted flexible electrode and the light-assisted flexible electrode prepared by the above-mentioned method for use in the rapid detection of outdoor water matrix pollutants.

[0019] In some embodiments, the light-assisted flexible electrode of the present invention uses the following steps to quickly detect outdoor water matrix pollutants: immerse the flexible electrode in the water to be detected, electrically connect the flexible electrode to the USB workstation, and use differential pulse voltammetry to perform electrochemical analysis on the collected data. The (electro)chemical reaction / interaction occurs and is converted into a detectable analytical signal, thereby achieving quantitative or qualitative analysis of the target analyte.

[0020] In some embodiments, the light-assisted flexible electrode is used to quickly detect outdoor water matrix pollutants. Before the detection, the flexible electrode is placed in a 1×10 -3 mol / L K 3 Fe(CN) 6 The phosphate buffer solution was scanned until reversible cathodic and anodic peaks appeared, indicating that the electrode surface was clean.

[0021] In some embodiments, during the rapid detection of outdoor water matrix pollutants by the light-assisted flexible electrode, the light source applied is natural light or sunlight simulated by a xenon lamp, and the light energy density is 10-100 mW / cm 2 .

[0022] Beneficial effects: Compared with the prior art, the present invention coats a light-responsive semiconductor on a flexible electrode body, introduces light energy into the semiconductor photocatalytic properties into the sensor, and realizes electrode surface regeneration through illumination to avoid electrode contamination; the light-assisted flexible electrode of the present invention is connected to a workstation to achieve rapid detection of outdoor water matrix pollutants, which is environmentally friendly, low-cost, highly reliable, and has no secondary pollution. Continuous operation is achieved during water quality monitoring, which improves the reliability and life of the electrode, and provides a feasible solution for rapid and accurate water detection in various environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of the flexible electrode body of the present invention;

[0024] Figure 2 This is a current detection diagram of the flexible electrode of Example 1 at different SMX concentrations;

[0025] Among them, 2a-1st run with different SMX concentrations; 2b-6th run with different SMX concentrations (DPV response at the 6th measurement after xenon lamp irradiation); 2c-Δi of DPV at different SMX concentrations pRelationship with the number of runs; 2d - 6-cycle DPV response of the flexible electrode at 30μM SMX (the 1st to 5th curves are continuous DPV responses, and the 6th curve is the DPV response after 10 minutes of xenon lamp illumination); 2e - Corresponding curves of anodic oxidation current density and SMX concentration;

[0026] Figure 3 This is a current detection diagram of the flexible electrode of Example 2 at different SMX concentrations;

[0027] Among them, 3a-the first run of different SMX concentrations; 3b-the sixth run of different SMX concentrations (DPV response at the sixth measurement after xenon lamp irradiation); 3c-Δi of DPV at different SMX concentrations p Relationship with the number of runs; 3d - 6-cycle DPV response of the flexible electrode at 30μM SMX (the 1st to 5th curves are continuous DPV responses, and the 6th curve is the DPV response after 10 minutes of xenon lamp illumination); 3e - Corresponding curves of anodic oxidation current density and SMX concentration;

[0028] Figure 4 This is a current detection diagram of the flexible electrode of Example 3 at different SMX concentrations;

[0029] Among them, 4a-DPV response of the flexible electrode in 30μM SMX (the 1st to 5th curves are continuous DPV responses, and the 6th curve is the DPV response after 10 minutes of xenon light irradiation); 4b-DPV response of the flexible electrode under 30μM SMX (the 1st to 5th curves are continuous DPV responses, and the 6th curve is the DPV response after 13 minutes of natural light irradiation); 4c-Δi of different SMX concentrations and running times p ; 4d - 1st run at different SMX concentrations; 4e - 6th run at different SMX concentrations (DPV response at the 6th measurement after xenon lamp irradiation);

[0030] Figure 5 This is a current detection diagram of the flexible electrode of Example 3 at different bending angles;

[0031] Figure 6 is the detection limit of the flexible electrode in Example 3;

[0032] Among them, 6a-DPV response of flexible electrode at different SMX concentrations; 6b-corresponding graph of current density and SMX concentration;

[0033] Figure 7 Reliability test of the flexible electrode of Example 3;

[0034] Among them, 7a-continuous DPV test diagram of flexible electrode under sunlight; 7b-Δi pCorresponding curve graph with the number of cycles;

[0035] Figure 8 This is a current detection diagram of the flexible electrode of Example 3 in the presence of multiple antibiotics;

[0036] Among them, 8a-the first DPV response test diagram of the flexible electrode; 8b-multiple DPV response diagrams of the flexible electrode (the 1st to 5th operation curves are continuous DPV responses, and the 6th operation is sunlight irradiation for 13 minutes). DETAILED DESCRIPTION

[0037] In order to make those skilled in the art better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with specific embodiments. The experimental methods in the following examples that do not specify specific conditions are usually based on conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, percentages and parts are calculated by weight. Unless otherwise defined, all professional and scientific terms used in the text have the same meanings as those familiar to those skilled in the art. In addition, any method and material similar or equivalent to the recorded content can be applied to the present invention. The preferred implementation methods and materials described in the text are for demonstration purposes only.

[0038] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0039] Example 1

[0040] The light-assisted flexible electrode was prepared by the following method: (1) 2-methylimidazole (10 mmol) and Zn(NO 3 ) 2 6H 2 O (2.5 mmol) was added to methanol (50 mL) and stirred until completely dissolved; then, the two solutions were mixed into a uniform mixture; after aging at room temperature for 24 h, the mixture was heated at 3000 r min -1 The mixture was centrifuged at 400 °C, then washed with methanol and dried at 65 °C for 12 h to obtain ZIF-8. (2) 1 mg ZIF-8, 900 μL isopropanol and 100 μL naphthol were weighed and ultrasonicated for 3 h. After complete dissolution, 5 μl of the prepared sample was vertically dropped on the surface of the flexible electrode body (TC201, purchased from Weihai Boteng Technology Co., Ltd.) and dried at room temperature for later use.

[0041] Example 2

[0042] The light-assisted flexible electrode was prepared by the following method: (1) 10.0 g of melamine powder was placed on a semi-covered Al 2 O 3 Crucible, in a muffle oven at 5℃min -1 The sample was heated at a rate of 500 °C and kept at 550 °C for 3 h, then cooled to room temperature, and then ultrasonicated for 3 h to form gC 3 N 4 ; (2) Weigh 1 mg gC 3 N 4 , 900 μL isopropanol, 100 μL naphthol, ultrasonic for 3 h, after complete dissolution, take 5 μl of the prepared sample and drop it vertically on the surface of the flexible electrode body (TC201, purchased from Weihai Boteng Technology Co., Ltd.), dry it at room temperature for use.

[0043] Example 3

[0044] The light-assisted flexible electrode was prepared by the following method: (1) 2-methylimidazole (10 mmol) and Zn(NO 3 ) 2 6H 2 O (2.5 mmol) was added to methanol (50 mL) and stirred until completely dissolved; then, the two solutions were mixed into a uniform mixture; after aging at room temperature for 24 h, the mixture was heated at 3000 r min -1 The mixture was centrifuged at 220 °C, washed with methanol, and finally dried at 65 °C for 12 h to obtain ZIF-8. 0.36 g of the prepared ZIF-8 and 0.032 g of ammonium tetrathiomolybdate were added to 60 mL of dimethylformamide (DMF) and ultrasonicated for 30 min. After that, the mixture was heated at 220 °C for 12 h. After the temperature dropped to room temperature, the product was taken out and heated at 4000 r min. -1 After centrifugation at 40 °C and then washing with ethanol, ZIF-8@MoS 2 (2) Weigh 1 mg ZIF-8, 900 μL isopropanol, and 100 μL naphthol, and sonicate for 3 h. After complete dissolution, take 5 μl of the prepared sample and drop it vertically on the surface of the flexible electrode body (TC201, purchased from Weihai Boteng Technology Co., Ltd.), and dry it at room temperature for later use.

[0045] Example 4 Investigation of the regeneration rate of light-assisted flexible electrodes

[0046] Prepare the working electrolyte: weigh Na 2 HPO 4 (4.2978 g), NaH 2 PO 4(13.7288g) is placed in a corresponding beaker and sufficient deionized water is added. After the solution is dissolved, it is transferred to a volumetric flask with a glass rod. The beaker is rinsed with deionized water in small amounts and multiple times, and then the volume is adjusted to the scale line with deionized water to obtain a phosphate buffer solution. Sulfamethoxazole (SMX) is weighed and added to a beaker, and the phosphate buffer solution is poured into the beaker. Ultrasonication is performed for 3 hours. After the solid particles in the beaker are completely dissolved, a 10-50μM SMX solution is obtained.

[0047] Before detection, the light-assisted flexible electrode was placed in a 1×10 -3 mol / L K 3 Fe(CN) 6 Scan in phosphate buffer solution until reversible cathode and anode peaks appear (at this point, indicating that the electrode surface has been cleaned); under natural light (1sun), immerse the cleaned light-assisted flexible electrode in antibiotic solution, connect it to the flexible electrode through a USB workstation, and use differential pulse voltammetry to perform electrochemical analysis on the collected data.

[0048] like Figure 2 It can be seen that at 50μM, 40μM, 30μM, 20μM and 10μM SMX concentrations, the regeneration rate signal recovery rates of ZIF-8 were 77-79%, respectively. p It has a linear relationship with concentration and a high correlation coefficient.

[0049] like Figure 3 It can be seen that the signal recovery rates of g-C3N4 were 87-89% at 50μM, 40μM, 30μM, 20μM and 10μM SMX concentrations, respectively. p It has a linear relationship with concentration and a high correlation coefficient.

[0050] according to Figure 4 It can be seen that the signal recovery rates of ZIF-8 were 99-100% at 50μM, 40μM, 30μM, 20μM and 10μM SMX concentrations, respectively. p It has a linear relationship with concentration and a high correlation coefficient.

[0051] It can be seen that the flexible electrode of the present invention accelerates the separation of electrons and holes in the photoresponsive semiconductor under light irradiation, and utilizes the synergistic effect of photothermal and photocatalytic processes to perform sensitive, rapid and renewable electrochemical detection of antibiotics.

[0052] Example 5 Investigation of the detection performance of light-assisted flexible electrodes

[0053] The USB workstation was connected to the flexible electrode, and differential pulse voltammetry (DPV) was used to perform electrochemical analysis on the collected data. At a concentration of 50 μM SMX, the detection performance of the flexible electrode at different bending angles and its reliability in repeated use were tested. At a concentration of 30 μM SMX, the mixed detection of the flexible electrode in the presence of multiple antibiotics was tested. In addition, the detection limit of the flexible electrode was tested at concentrations of 0 to 65.64 μM SMX.

[0054] Figure 5 The detection performance of the light-assisted flexible electrode of Example 3 at different bending angles is shown. It can be seen that the detection performance of the flexible electrode at different bending angles (0°, 45°, 90°, 135°, 180°) does not change significantly.

[0055] Figure 6 The detection limit of the light-assisted flexible electrode of Example 3 is shown. It can be seen that nearly 100% regeneration can be achieved under sunlight irradiation, achieving a low detection limit of about 12 nM.

[0056] Figure 7 The continuous DPV test and Δi of the light-assisted flexible electrode of Example 3 under light irradiation are shown. p From the corresponding graph with the number of cycles, it can be seen that the light-assisted flexible electrode can be reused for up to 24 cycles, which can achieve continuous operation during water quality monitoring and improve the reliability and life of the electrode.

[0057] Figure 8 The mixed detection results of the light-assisted flexible electrode in Example 3 in the presence of multiple antibiotics are shown. It can be seen that the flexible electrode shows good selectivity for multiple antibiotic pollutants such as ciprofloxacin, sulfamethoxazole, tetracycline, and ofloxacin, which fully proves the detection selectivity and photoregeneration versatility of the flexible electrode.

[0058] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Under the guidance of the present invention, those skilled in the art can make a variety of similar expressions without violating the purpose and claims of the present invention. Such changes all fall within the scope of protection of the present invention.

Claims

1. Light-assisted flexible electrode, characterized in that: It comprises a flexible electrode body and a photocatalyst loaded on the flexible electrode body. The regeneration rate of the light-assisted flexible electrode is 77-100%.

2. The light-assisted flexible electrode according to claim 1, characterized in that: The photocatalyst is one of TiO2, ZnO, CdS, BiOI, BiOBr, BiOCl, Bi2WO6, polythiophene, ZIF-8, Co3O4, g-C3N4, and ZIF-8@MoS2; or the photocatalyst is BiOX, wherein X=I, Br, Cl; or the photocatalyst is one of ZIF-8, g-C3N4, and ZIF-8@MoS2.

3. The method for preparing a light-assisted flexible electrode according to claim 1, characterized in that: The photoresponsive semiconductor catalyst is ultrasonically mixed with isopropanol and naphthol and then coated on a flexible electrode body; wherein the photocatalyst is one of TiO2, ZnO, CdS, BiOI, BiOBr, BiOCl, Bi2WO6, polythiophene, ZIF-8, Co3O4, g-C3N4, and ZIF-8@MoS2.

4. The preparation method according to claim 3, characterized in that: The mass volume ratio of the photoresponsive semiconductor catalyst to isopropanol and naphthol is (0-1) mg: (100-900) μL: (10-100) μL.

5. The preparation method according to claim 3, characterized in that: The photoresponsive semiconductor catalyst is prepared by the following method: 2-methylimidazole and Zn(NO3)2·6H2O are dissolved in methanol respectively and mixed evenly, wherein the molar ratio of 2-methylimidazole to Zn(NO3)2·6H2O is 4:1, and the mixed solution is aged at room temperature for 12-24 hours, and then centrifuged, washed, and dried to obtain ZIF-8.

6. The preparation method according to claim 3, characterized in that: The photoresponsive semiconductor catalyst is prepared by the following method: placing melamine powder in an oven at 3-10°C min -1 The mixture was heated at a rate of 500-600 °C for 2-4 h, cooled to room temperature, and subjected to ultrasonic treatment to obtain g-C3N4.

7. The preparation method according to claim 3, characterized in that: ZIF-8 and ammonium tetrathiomolybdate in a mass ratio of (10-12):1 were added to dimethylformamide, ultrasonically dispersed, heated at 200-250°C for 12-20h, cooled to room temperature, and the product was centrifuged, washed, and dried to obtain ZIF-8@MoS2.

8. Use of the light-assisted flexible electrode described in claims 1-2 and the light-assisted flexible electrode prepared by the method described in claims 3-7 in rapid detection of outdoor water matrix pollutants.

9. The use according to claim 8, characterized in that: During the detection process, differential pulse voltammetry was used to perform electrochemical analysis on the collected data.

10. The use according to claim 8, characterized in that: During the test, the light source is natural light or sunlight simulated by a xenon lamp, and the light energy density is 10-100mW / cm 2 .

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