Preparation method of self-breathing photoelectric self-powered sensor and application thereof in detection of microcystin-rr

Abstract

The application belongs to the technical field of photoelectrochemical detection, and particularly relates to a preparation method of a self-breathing photoelectric self-powered sensor and application thereof in detection of microcystin-RR. Ti3C2 dispersion liquid is coated on ITO, Ag3BiO3 nanoparticle dispersion liquid is coated on the electrode to prepare a photoanode, a porous gas diffusion electrode treated by PTFE hydrophobicity is used as an air self-breathing cathode, then the air self-breathing cathode, a single-chamber quartz electrolytic cell and the photoanode apta / Ag3BiO3 / Ti3C2 / ITO are assembled together to construct the self-breathing photoelectric self-powered sensor. The sensor constructed by the application has a wide detection range, high sensitivity and low detection limit, and has important significance for detection of microcystin.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photoelectrochemical detection, and particularly relates to a preparation method of a self-breathing photoelectrochemical self-powered sensor and application in microcystin-RR detection. BACKGROUND

[0002] Microcystins (MC) is a kind of biologically active cyclic heptapeptide toxin, which is the most widely distributed hepatotoxin. It is produced as a secondary metabolite of Microcystis cyanobacteria during algal blooms in eutrophic waters worldwide. It is mainly produced by freshwater algae Microcystis aeruginosa. It has relative stability, can strongly inhibit the activity of protein phosphatase, and is also a strong liver tumor promoter. One of the toxic variants in its structure has arginine amino acids at positions X and Z, which is called microcystin-RR.

[0003] Currently, the commonly used methods for detecting and quantifying microcystins include protein phosphatase inhibition assay (PPIA) and enzyme-linked immunosorbent assay (ELISA) in biochemistry, high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) in physical chemistry, and biosensor-based strategies. These methods have the disadvantages of high technical requirements, time-consuming, expensive equipment, or low detection sensitivity. Therefore, it is of great significance to find a high-efficiency and convenient method for detecting the content of microcystins in the environment.

[0004] Self-powered photoelectrochemical (PEC) sensors have attracted extensive attention due to their simple construction, small size, and low cost. A typical self-powered sensor is composed of a photoanode and a cathode. Under light conditions, the semiconductor material generates electrons and holes. The electrons can be transferred to the cathode through an external circuit, and a reduction reaction occurs at the cathode.

[0005] It is mainly applied in the field of electroanalytical chemistry and is usually constructed in a three-electrode system. The sensitivity and selectivity are improved mainly through material strategies. In the field of fuel cells, it is mainly constructed in a two-electrode mode, focusing on generating a large open-circuit potential and a large short-circuit current. Through the improvement of catalysts, materials, interfaces, and battery design, the maximum power density is achieved. At present, according to the different primary batteries, self-powered sensors based on enzyme biological fuel cells, microbial fuel cells, and light fuel cells have been researched and proposed. However, the low solubility of oxygen in the electrolyte greatly limits the performance of the cathode. The expensive Pt electrode requires additional oxygen supply equipment, which increases the cost of practical application. In recent years, a new type of air-breathing cathode loaded with Pt / C has replaced the Pt electrode to construct a self-breathing light-responsive self-powered sensor platform, which is an effective method to improve energy utilization and reduce cost. SUMMARY

[0006] In order to make up for the shortcomings of the prior art, the present application provides a preparation method of a self-breathing photoelectrochemical self-powered sensor and application in detecting microcystin-RR, which realizes the construction of a self-powered sensor to detect microcystin-RR in the environment by taking Ag3BiO3 / Ti3C2 nanomaterial as a light anode electrode and Pt / C as an air cathode. Compared with Ag3BiO3 monomer, the introduction of Ti3C2 MXene forms a Schottky junction, which can promote the separation of electron-hole pairs and broaden light absorption, so as to obtain a higher photoelectric conversion frequency. The air self-breathing cathode directly uses oxygen in the air instead of dissolved oxygen, enhances the interface reaction of the cathode, induces the transmission of electrons from the external circuit to the cathode, and further promotes the separation of electron-hole pairs of the light anode semiconductor material.

[0007] The scheme adopted by the present application to solve its technical problems is:

[0008] A preparation method of a self-breathing photoelectrochemical self-powered sensor for detecting microcystin, which takes apta / Ag3BiO3 / Ti3C2 / ITO as a light anode electrode and Pt / C as an air cathode to construct a self-powered sensor, wherein the preparation method of the apta / Ag3BiO3 / Ti3C2 / ITO light anode electrode comprises the following steps:

[0009] (1) Coating Ti3C2 dispersion liquid on the surface of pre-cleaned ITO and drying; then coating Ag3BiO3 dispersion liquid on the surface of ITO and vacuum drying, denoted as Ag3BiO3 / Ti3C2 / ITO light anode;

[0010] (2) Dropping microcystin-RR aptamer solution on the surface of the Ag3BiO3 / Ti3C2 / ITO light anode and naturally airing to dry, to obtain the apta / Ag3BiO3 / Ti3C2 / ITO light anode.

[0011] Further, the preparation of Ag3BiO3 nanomaterial: dissolving AgNO3 in pure water to form a colorless solution, denoted as solution A; under stirring conditions, adding concentrated nitric acid and Bi(NO3)3 5H2O into pure water, denoted as solution B; mixing solution A and solution B to obtain a mixed solution; dropping NaOH solution into the mixed solution, heating at 180℃ for 12 h, naturally cooling, centrifuging to collect the precipitate, washing and drying to obtain Ag3BiO3 nanoparticles; wherein the molar ratio of AgNO3 to Bi(NO3)3 5H2O is 3:1.

[0012] Further, the preparation of the air cathode: platinum black, Nafion perfluorinated resin solution and ethanol and pure water mixed solution are uniformly ultrasonically mixed to obtain a spraying solution; the spraying solution is sprayed on the carbon paper loaded with carbon nanoparticles by using a pneumatic spray gun, and heated at 80℃ for 30 min to obtain a Pt / C air cathode; wherein the mass ratio of platinum black, Nafion perfluorinated resin, ethanol and pure water mixed solution is 0.1:0.5:5; the mass concentration of the Nafion perfluorinated resin solution is 5wt.%, and the mass ratio of ethanol and pure water is 1:1; the loading amount of platinum black in the prepared air cathode is 1.0 mg / cm 2 .

[0013] Further, the concentration of the Ag3BiO3 dispersion solution is 2 mg / mL; the drop coating amount of the Ag3BiO3 dispersion solution is 30~50 μL / cm 2 , preferably 40 μL / cm 2 .

[0014] Further, the concentration of the Ti3C2 dispersion solution is 0.5 mg / mL; the drop coating amount of the Ti3C2 dispersion solution is 8~40 μL / cm 2 , preferably 32 μL.

[0015] Further, the concentration of the MC-RR aptamer solution is 0.5~4 μmol / L, preferably 2 μmol / L; the modification amount is 10~30 μL / cm 2 ; preferably 20 μL / cm 2 .

[0016] Further, the nucleotide sequence of the microcystin-RR aptamer is as follows: 5'-CAG CTC AGA AGC TTG ATC CTA CTG CCC TTC AAT GTT CAC TCC TGT TTC CTG ATC TTT GTC GAC TCG AAG TCG TGC ATC TG-3'.

[0017] The application of the self-breathing photoelectric self-powered sensor in detecting microcystin-RR by photoelectrochemical method, and the specific detection method comprises the following steps:

[0018] S1, preparing a phosphate (PBS) buffer solution;

[0019] S2, preparing microcystin-RR with different concentrations;

[0020] A certain amount of microcystin-RR is accurately weighed, and by dilution, a microcystin-RR standard solution with a concentration of 0.5~4 μmol / L is obtained, and the concentration range is 1.0×10 -15 mol / L~1.0×10-10 mol / L;

[0021] S3, drawing of a standard curve:

[0022] A series of microcystin-RR standard solutions with known concentrations are selected and dropped on the prepared electrode apta / Ag3BiO3 / Ti3C2 / ITO, and naturally dried at room temperature to obtain a modified electrode marked as MC-RR / apta / Ag3BiO3 / Ti3C2 / ITO;

[0023] MC-RR / apta / Ag3BiO3 / Ti3C2 / ITO is used as a photoanode for photoelectrochemical testing, Pt / C is used as an air cathode, a photoelectrochemical self-powered system is formed, PBS buffer salt solution is used as an electrolyte, the current of a xenon lamp light source is kept at 20 A, the horizontal distance between the light source outlet and the ITO conductive surface is kept at 10 cm, the electric power density is tested at a test potential of 0 V, a series of corresponding relationships between microcystin-RR concentrations and photoelectric power densities are obtained, and a standard curve of microcystin-RR is calculated to establish a linear relationship between the photoelectric power density output value after adding microcystin-RR and the logarithm of the concentration of microcystin-RR, and a corresponding linear regression equation is obtained.

[0024] S4, actual sample detection:

[0025] The actual sample is pretreated before detection, and then the pH value is adjusted, and the linear regression equation in step S3 is calculated.

[0026] As preferred: in step S3, the pH value of the PBS buffer salt solution is 6, the concentration is 0.1 mol / L, and the binding time of the detection substance of the modified electrode apta / Ag3BiO3 / Ti3C2 / ITO and the aptamer is 5-40 min.

[0027] The minimum detection limit of the microcystin-RR solution concentration detected by the sensor is 1.05*10 -16 mol / L.

[0028] The beneficial effects of the present application are as follows:

[0029] The present application will prepare an Ag3BiO3 material, introduce Ti3C2 MXene, form a Schottky junction, promote the separation of electron-hole pairs, broaden light absorption, and thus obtain a higher photoelectric conversion frequency.

[0030] The application uses air self-breathing cathode to directly use oxygen in air instead of dissolved oxygen, enhances the interface reaction of the cathode, induces the transmission of electrons from the external circuit to the cathode, and further promotes the separation of the electron-hole pairs of the photoanode semiconductor material. Meanwhile, the introduction of the aptamer makes the sensor have the effect of specific detection of microcystin.

[0031] (3) The self-powered sensor prepared in the application has high stability, high sensitivity, wide linear range, good reproducibility, and can realize simple, rapid, efficient and specific detection when used for microcystin-RR detection. BRIEF DESCRIPTION OF DRAWINGS

[0032] The application will be further described below in combination with the drawings and examples.

[0033] Figure 1 is the flow chart of the preparation of the sensor in the application and the detection of microcystin-RR.

[0034] Figure 2 is the Pmax of the Ag3BiO3 / Ti3C2 / ITO photoanode with different Ti3C2 proportions in the sensor.

[0035] Figure 3 is the scanning electron microscope image of the Ag3BiO3 / Ti3C2 / ITO photoanode in the sensor.

[0036] Figure 4 is the power density curve of the sensor for different concentrations of MC-RR.

[0037] Figure 5 is the standard curve of the photoelectric power size of the sensor for different concentrations of MC-RR and the logarithm of the concentration of MC-RR.

[0038] Figure 6 is the output voltage curve (B) power density curve of the sensor in air (a) and nitrogen (b) using Ag3BiO3 / Ti3C2 as the photoanode and Pt / C air-breathing cathode (A).

[0039] Figure 7 is the P-I curve of the sensor using different photoanodes: Ag3BiO3 / Ti3C2 / ITO (a), apta / Ag3BiO3 / Ti3C2 / ITO (b) and MC-RR / apta / Ag3BiO3 / Ti3C2 / ITO (c). DETAILED DESCRIPTION

[0040] The application will be further described below in combination with the drawings and examples.

[0041] As Figure 1The application discloses a preparation method of a self-breathing photoelectrochemical self-powered sensor and application of the self-breathing photoelectrochemical self-powered sensor in microcystin-RR detection, and the self-breathing photoelectrochemical self-powered sensor is composed of Ag3BiO3 / Ti3C2 / ITO as a light anode, Pt / C as an air cathode and a self-powered system. Example 1

[0042] A preparation method of a self-breathing photoelectrochemical self-powered sensor has the following steps:

[0043] (1) Preparation of Ag3BiO3 nanomaterials

[0044] First, 3 mmol of AgNO3 is dissolved in 30 mL of pure water to form a colorless solution, which is denoted as solution A. Next, 2 mL of concentrated nitric acid (15 mol / L) and 1 mmol of Bi(NO3)3 5H2O in 10 mL of pure water are added under stirring conditions, which is denoted as solution B. Then, the two solutions are mixed, and 10 mL of 5M NaOH solution is gently dropped into the mixed solution. Then, the suspension is placed in a stainless steel high-pressure reaction kettle, heated at 180°C for 12 h, and then naturally cooled to room temperature and all the deposits are collected. After being washed with pure water and anhydrous ethanol for several times, vacuum drying at 60°C for 12 h, the final Ag3BiO3 solid powder is obtained.

[0045] (2) Preparation of photoanode

[0046] The Ti3C2 dispersion liquid is purchased from Guangzhou Foshan Xinyan Technology Co., Ltd., with a purity of ≥99.9%, a specification of 2 mg / ml and a dispersion system of water. The Ti3C2 dispersion liquid is diluted to 0.5 mg / ml for standby use;

[0047] 2 mg of Ag3BiO3 is dispersed in a DMF solution to prepare an Ag3BiO3 dispersion liquid with a concentration of 2 mg / mL;

[0048] ITO electrodes (1 cm²) are ultrasonically cleaned in a 1 M NaOH solution for 30 min, and then heated and boiled for 30 min, and then cleaned in ultrapure water and ethanol for 30 min, respectively, to obtain a plurality of pre-cleaned ITO electrodes for standby use. 8 μL, 16 μL, 24 μL, 32 μL and 40 μL of the Ti3C2 dispersion liquid with a concentration of 0.5 mg / ml are coated on the surface of the ITO, and then 40 μL of the Ag3BiO3 dispersion liquid with a concentration of 2 mg / ml is coated on the surface of the ITO, and vacuum drying is performed, which is denoted as an Ag3BiO3 / Ti3C2 / ITO light anode.

[0049] From Figure 2It can be seen that the Pmax of the power density continues to increase as the proportion of Ti3C2 increases from 5% to 20%. When the proportion of Ti3C2 increases from 20% to 25%, Pmax no longer changes significantly, and the material is obviously peeled off. Ag3BiO3 / Ti3C2 / ITO with a Ti3C2 proportion of 20% is used for subsequent experiments.

[0050] The scanning electron microscope image of the Ag3BiO3 / Ti3C2 / ITO photoanode is shown in Figure 6. Figure 3 It can be seen that the Ag3BiO3 material introduced into the Ti3C2 MXene forms a Schottky junction.

[0051] (3) Preparation of air cathode

[0052] A porous gas diffusion electrode treated with polytetrafluoroethylene (PTFE) hydrophobicity is used as an air self-breathing cathode. First, 0.1 g of platinum black, 0.5 g of Nafion perfluoro resin, and 5 g of ethanol and pure water (mass ratio of ethanol to pure water 1:1) are mixed and ultrasonically vibrated for 30 minutes. The prepared solution is completely sprayed on the carbon paper (Japan Toray carbon paper) loaded with carbon nanoparticles using a pneumatic spray gun, and then the sample is heated at 80°C for 30 min to prepare a Pt / C air self-breathing cathode with a platinum black loading of 1 mg / cm 2

[0053] (4) Preparation of self-powered aptamer sensor detection

[0054] The prepared Ag3BiO3 / Ti3C2 / ITO photoanode is added with 20 μL of 2 μM MC-RR aptamer solution, and the sensor is incubated at room temperature overnight to obtain the photoanode apta / Ag3BiO3 / Ti3C2 / ITO. Then the Pt / C air self-breathing cathode, single-chamber quartz electrolytic cell, and photoanode apta / Ag3BiO3 / Ti3C2 / ITO are assembled together to construct a self-powered sensor.

[0055] The aptamer sequence of the above sensor is as follows: aptamer: 5'-CAG CTC AGA AGC TTG ATC CTA CTG CCC TTC AAT GTT CAC TCC TGT TTC CTG ATC TTT GTC GAC TCG AAG TCG TGC ATC TG-3'.

[0056] (5) Drawing of standard curve:

[0057] Prepare a microcystin-RR standard solution: Dissolve a certain amount of microcystin-RR in deionized water and dilute it step by step to obtain microcystin-RR with concentrations of 1.0 x 10​-15 1.0 x 10 -14 -1.0 x 10 -13 -1.0 x 10 -12 -1.0 x 10 -11 -1.0 x 10 -10 -1.0 x 10

[0058] -1.0 x 10 Figure 4 -1.0 x 10 Figure 5 -1.0 x 10 -15 -1.0 x 10 -10 -1.0 x 10 -16 -1.0 x 10

[0059] As shown in Figure 4 , wherein the concentration curve peak of microcystin-RR from top to bottom in turn is: 1.0 x 10 -15 -1.0 x 10 -14 -1.0 x 10 -13 -1.0 x 10 -12 -1.0 x 10 -11 -1.0 x 10 -10 -1.0 x 10

[0060] (6) Detection of actual samples

[0061] A certain amount of wastewater (in the table, the sample is added with MC-RR) is dropped on the electrode apta / Ag3BiO3 / Ti3C2 / ITO to obtain a working electrode, a Pt / C is used as a light cathode, a photoelectrochemical self-powered system is formed, a PBS with a pH value of 6 and a concentration of 0.1 M is used as an electrolyte, photoelectrochemical detection is carried out according to the above standard solution detection method, the sample is detected in parallel for 3 times, and the concentration of microcystin-RR in the sample to be detected is calculated according to the regression equation corresponding to the above standard curve, and the results are listed in Table 1. Example 2

[0062] Comparison of self-powered systems prepared by using Ag3BiO3 / Ti3C2 as a light anode and Pt / C air-breathing cathode under air and nitrogen.

[0063] The preparation steps of Ag3BiO3 / Ti3C2 light anode and Pt / C air-breathing cathode are the same as those in Example 1.

[0064] The Ag3BiO3 / Ti3C2 / ITO is used as a photoanode for photoelectrochemical testing, the Pt / C is used as an air cathode, a photoelectrochemical self-powered system is formed, a PBS buffer salt solution is used as an electrolyte, nitrogen is passed into the electrolyte or not, the xenon lamp light source current is kept at 20 A, the horizontal distance between the light source outlet and the ITO conductive surface is kept at 10 cm, the photoelectric current size and the electric power density are tested at a test potential of 0 V, and the (A) V-I and (B) P-I curves of the self-powered system prepared by using Ag3BiO3 / Ti3C2 as a light anode and Pt / C air-breathing cathode are as shown in Figure 6 From top to bottom in air (a) and nitrogen (b), it can be seen from the figure that there is a higher electric power density in air. Example 3

[0065] Comparison of self-powered systems prepared by using MC-RR and apta before and after binding with light anode and Pt / C air-breathing cathode.

[0066] The preparation steps of Ag3BiO3 / Ti3C2, apta / Ag3BiO3 / Ti3C2 / ITO, MC-RR / apta / Ag3BiO3 / Ti3C2 / ITO and Pt / C air-breathing cathode are the same as those in Example 1.

[0067] The photoanode of the photoelectrochemical test was respectively Ag3BiO3 / Ti3C2 / ITO (a), apta / Ag3BiO3 / Ti3C2 / ITO (b), MC-RR / apta / Ag3BiO3 / Ti3C2 / ITO (c), the air cathode was Pt / C, the photoelectrochemical self-powered system was composed, the PBS buffer salt solution was used as the electrolyte, the current of the xenon lamp light source was kept at 20 A, the horizontal distance between the light source outlet and the ITO conductive surface was kept at 10 cm, the electric power density was tested under the test potential of 0 V, and the photoelectric power density output value was seen from Table 2. Figure 7 .

[0068] Table 1 Determination results of MC-RR in water samples

[0069]

[0070] As shown in Table 1, two groups of samples were detected, the sample was detected in parallel for 3 times, the relative standard deviation was less than 4.9%, and the recovery rate of the standard addition was 96% to 104%. The above results show that the electrode modified by Ag3BiO3 / ITO or Ti3C2 / ITO alone cannot detect microcystin-RR, but apta / Ag3BiO3 / Ti3C2 / ITO can realize specific detection of microcystin-RR, and the present application can realize detection of microcystin-RR in the environment.

Claims

1. A method for preparing a self-breathing optoelectronic self-powered sensor, characterized in that, A self-powered sensor is constructed with apta / Ag3BiO3 / Ti3C2 / ITO as a photoanode electrode and Pt / C as an air cathode; the photoanode electrode is prepared as follows: (1) Ti3C2 dispersion liquid is coated on the surface of pre-cleaned ITO and dried; then Ag3BiO3 dispersion liquid is coated on the surface of ITO, and vacuum dried, denoted as Ag3BiO3 / Ti3C2 / ITO photoanode; (2) Microcystin-RR aptamer solution is added dropwise on the surface of Ag3BiO3 / Ti3C2 / ITO photoanode, and naturally dried, to obtain apta / Ag3BiO3 / Ti3C2 / ITO photoanode; The Ag3BiO3 nanomaterial is prepared as follows: AgNO3 is dissolved in pure water to form a colorless solution, denoted as solution A; Under stirring, concentrated nitric acid and Bi(NO3)3·5H2O are added into pure water, denoted as solution B; solution A and solution B are mixed to obtain a mixed solution; NaOH solution is added dropwise into the mixed solution, heated at 180℃ for 12 h, naturally cooled, and the precipitate is collected by centrifugation, washed and dried to obtain Ag3BiO3 nanoparticles; wherein the molar ratio of AgNO3 to Bi(NO3)3·5H2O is 3:

1.

2. The method for the fabrication of a self-breathing photoelectric self- supplied sensor according to claim 1, characterized in that, Preparation of the air cathode: platinum black, Nafion perfluorinated resin solution and a mixed solution of ethanol and pure water were uniformly mixed by ultrasonic to obtain a spraying solution; the spraying solution was sprayed on the carbon paper loaded with carbon nanoparticles by using a pneumatic spray gun, and then heated at 80°C for 30 min to obtain a Pt / C air cathode; wherein the mass ratio of platinum black, Nafion perfluorinated resin solution, ethanol and the mixed solution of pure water was 0.1:0.5:5; the mass concentration of the Nafion perfluorinated resin solution was 5 wt.%; the mass ratio of ethanol and pure water was 1:1; the loading amount of platinum black in the prepared air cathode was 1.0 mg / cm 2 .

3. The method for the fabrication of a self-breathing optoelectronic self- powered sensor according to claim 1, characterized in that, The concentration of the Ag3BiO3 dispersion liquid is 2 mg / mL; the drop coating amount of the Ag3BiO3 dispersion liquid is 30-50 μL / cm 2 .

4. The method of claim 1, wherein the self-breathing opto-electronic self- powered sensor is prepared by the steps of: The concentration of the Ti3C2 dispersion liquid is 0.5 mg / mL; the drop coating amount of the Ti3C2 dispersion liquid is 8~40 μL / cm 2 .

5. The method of claim 1, wherein the self-breathing opto-electronic self- powered sensor is prepared by the steps of: The concentration of the MC-RR aptamer solution is 0.5-4 μmol / L, and the modification amount is 10-30 μL / cm 2 .

6. The method of claim 1, wherein the self-breathing opto-electronic self- powered sensor is prepared by the steps of: The nucleotide sequence of microcystin-RR aptamer is as follows: 5'-CAGCTCAGAAGCTTGATCCTACTGCCCTTCAATGTTCACTCCTGTTTCCTGATCTTTGTCGACTCGAAGTCGTGCATCTG-3'.

7. Use of the self-breathing photoautonomous sensor prepared according to the method of any one of claims 1 to 6 for the detection of microcystin-RR by means of photoelectrochemical methods, characterized in that, The specific detection method comprises the following steps: S1, preparing a phosphate buffered saline solution; S2, preparing microcystin-RR with different concentrations; Accurately weigh a certain amount of microcystin-RR, and dilute to obtain a microcystin-RR standard solution with a concentration of 0.5-4 μmol / L, and the concentration range is 1.0×10 -15 mol / L-1.0×10 -10 mol / L; S3, drawing a standard curve: A series of microcystin-RR standard solutions with known concentrations are selected and drop-coated on the prepared electrode apta / Ag3BiO3 / Ti3C2 / ITO, and naturally dried at room temperature to obtain a modified electrode marked as MC-RR / apta / Ag3BiO3 / Ti3C2 / ITO; MC-RR / apta / Ag3BiO3 / Ti3C2 / ITO is used as a photoanode for photoelectrochemical test, Pt / C is used as an air cathode to form a photoelectrochemical self-powered system, PBS buffer solution is used as an electrolyte, the current of a xenon lamp light source is kept at 20 A, the horizontal distance between the light source outlet and the ITO conductive surface is kept at 10 cm, the electric power density is tested at a test potential of 0 V, a series of corresponding relationships between microcystin-RR concentration and photoelectric power density are obtained, and a standard curve of microcystin-RR is calculated to establish a linear relationship between the photoelectric power density output value after adding microcystin-RR and the logarithm of microcystin-RR concentration, and a corresponding linear regression equation is obtained; S4, actual sample detection: Actual samples are pretreated before detection, and then the pH value is adjusted, and the linear regression equation in step S3 above is calculated.

8. Use of the self-breathing photoelectric self-powered sensor according to claim 7 for detecting microcystin-RR by photoelectrochemical method, characterized in that, The PBS buffer solution has a pH value of 6 and a concentration of 0.1 mol / L; the binding time of the modified electrode apta / Ag3BiO3 / Ti3C2 / ITO with the detection object and the aptamer is 5-40 min.

Images