A light-driven self-powered sensor and its usage method

Abstract

The present invention discloses a light-driven self-powered sensor and its usage method. The present application utilizes the K2S2O8 activation technology to stimulate the self-powered system of a photo-assisted fuel cell (PFC) to generate more sensitive optoelectronic signals, enhancing its open-circuit voltage by approximately 2 to 3 times, short-circuit current by approximately 3 to 5 times, and maximum power by approximately 2 to 3 times. At the same time, K2S2O8 enables the PFC to form a double-power peak structure in two states of low voltage-high current and high voltage-low current, providing a basis for the development of a bilinear self-calibration function and improving the accuracy of the sensor. The sensor provided by the present invention not only has a novel mode, but also has a simple preparation process, low processing cost, extremely high sensitivity and accuracy, which plays a great role in promoting the development of light-driven self-powered sensors, especially in enhancing the detection accuracy of light-driven self-powered sensors.

Description

Technical Field

[0001] The present invention belongs to the field of light-driven self-powered sensors, and particularly relates to a light-driven self-powered sensor and a method for using the same. Background Art

[0002] Light-driven self-powered sensors have the advantages of low background, energy conservation and environmental protection, good stability, and continuous monitoring in complex environments, and have been widely used in the field of small molecule pollutant detection. The traditional design of light-driven self-powered sensors is based on a photo-assisted fuel cell system composed of a photoanode and a platinum wire as an electrical signal source and a target recognition platform, but the weak electrical signal is difficult to meet the high sensitivity and high accuracy requirements of high-precision detection fields. Therefore, it is of great significance to develop a high-precision light-driven self-powered sensor.

[0003] In the past few years, signal amplification and bilinear strategies have made great progress in improving the sensitivity and accuracy of self-powered sensors respectively. Signal amplification can effectively improve the detection sensitivity. It quantifies the target by enhancing the obvious change of the signal rather than the weak change of some original signals, so that the signal gap between adjacent gradient concentrations can be widened and the analysis of lower concentrations can be easier. When bilinear analysis cooperates with self-powered sensors, the self-calibration function can enable it to obtain higher accuracy. However, the signal amplification and bilinear detection of existing self-powered sensors seriously depend on material composites or dual detection modes, which affect the simplicity of assembly and the rapidity of detection. At the same time, the research on the synchronous improvement of the sensitivity and accuracy of self-powered sensors is not yet mature. Therefore, it is necessary to develop a new mechanism to further improve and balance the performance of signal amplification and bilinear measurement to achieve enhanced precision in self-powered sensors. Summary of the Invention

[0004] In order to solve the deficiencies existing in the prior art, the present application proposes a light-driven self-powered sensor and a method for using the same. The sensor designed by the present invention is simple to assemble, can ensure a low processing cost and can be quickly built in any occasion; the electrical signal is enhanced, so that the sensor has higher sensitivity, can obtain a wider detection limit and a lower detection limit; it also has a self-calibration function, avoiding errors caused by inaccurate linear reading due to non-standard experimental operations or operator differences, and making the sensor have a wide application prospect in the field of high-precision rapid detection.

[0005] In order to achieve the above object, the technical solutions adopted by the present invention are as follows:

[0006] A light-driven self-powered sensor, comprising: a photoanode, a photocathode, a K2S2O8 reagent, an electrolyte solution, a quartz single-chamber reaction cell, a simulated sunlight light source, and an electrochemical workstation:

[0007] The photoanode and photocathode are inserted into a quartz single-chamber reaction cell filled with an electrolyte solution. The photoanode and photocathode are connected through an external circuit to complete the construction of a dual-photoelectrode photo-assisted fuel cell system;

[0008] The K2S2O8 reagent is dissolved in the electrolyte solution;

[0009] The simulated light source is directly facing the surface of the dual-photoelectrodes;

[0010] The electrochemical workstation is connected to the photoanode and the photoanode circuit to obtain detection signals.

[0011] Further, the concentration of the K2S2O8 reagent dissolved in the electrolyte solution is in the range of 3 mM to 14 mM.

[0012] Further, the photoanode is a BiVO4-modified fluorine-doped SnO2 transparent conductive glass (FTO) electrode.

[0013] Further, the method for preparing the photoanode: Prepare a 0.4 M potassium iodide (KI) solution and adjust the pH to 1.7 with nitric acid (HNO3); Add 0.97 g of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), 0.23 M benzoquinone, and 20 mL of absolute ethanol to the aforementioned solution to make a BiOI electrodeposition solution; Use a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode for electrodeposition; After obtaining the BiOI / FTO electrode, chemically convert the BiOI / FTO electrode with a mixed solution of 5 mL of dimethyl sulfoxide (DMSO) and 0.2 M vanadyl acetylacetonate; After chemical conversion, perform heat treatment at 450 °C for 2 h with a heating rate of 2 °C / min; After heat treatment, wash with 1 M sodium hydroxide (NaOH) solution for 30 min to remove the vanadium pentoxide layer impurities formed on the surface; Finally, a yellow film is observed to form on the FTO substrate, completing the preparation of the BiVO4 / FTO photoanode.

[0014] Further, in the method for preparing the photoanode, the electrochemical deposition method specifically uses the potentiostatic method, where the voltage is -0.1 V.

[0015] Further, in the method for preparing the photoanode, a 5 μmol / L solution of a target aptamer modified with a thiol group is drop-coated on the outer surface of the BiVO4 / FTO electrode and incubated at 80 °C for 6 h to obtain the photoanode.

[0016] Further, the photocathode is an FTO electrode modified with molybdate ferrocyanide (MoOHCF).

[0017] Further, the method for preparing the photocathode: Add 0.165 g of K3Fe(CN)6, 0.620 g of H 24Mo7N6O 24 Dissolve 3.728 g of Mo7N6O·4H2O and 3.728 g of KCl in 25 mL of ultrapure water to prepare the MoOHCF electrodeposition solution; use a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode for electrodeposition; after electrodeposition, wash it repeatedly with deionized water three times, and finally observe that an orange-yellow film is deposited on the FTO substrate to complete the preparation of the photoanode.

[0018] Furthermore, in the method for preparing the photocathode, the electrochemical deposition method specifically uses cyclic voltammetry, where the voltage window is -0.1 to 0.8 V, the scanning rate is 100 mV / s, and the number of cycles is 80.

[0019] A method for using a light-driven self-powered sensor includes the following steps:

[0020] W1: Preparation work, dissolve the K2S2O8 reagent in the electrolyte, and connect the dual-photoelectrode photo-assisted fuel cell system to the electrochemical workstation to complete the construction of the light-driven self-powered sensor; configure blank control solutions and a series of analyte solutions with different concentration gradients;

[0021] W2: Design the signal extraction method: Measure and collect the V-I data of the dual-photoelectrode photo-assisted fuel cell system through the CPCR of the electrochemical workstation, perform power analysis, and extract the peak-to-peak power related to the analyte concentration at low current-high voltage and high current-low voltage respectively;

[0022] W3: Establish the standard linearity: Incubate the photoanode in analyte solutions with different concentration gradients for 30 min, collect the corresponding dual peak-to-peak powers, and perform data fitting to obtain two standard linearities related to the analyte concentration.

[0023] The beneficial effects of the present invention:

[0024] (1) The present invention selects BiVO4-modified FTO as the photoanode and MoOHCF-modified FTO as the photocathode to construct a novel dual-photoelectrode-driven photo-assisted fuel cell system. Compared with the traditional single-photoelectrode / platinum electrode system, the dual-photoelectrode system designed by the present invention is more conducive to environmental protection and cost reduction.

[0025] (2) The present invention enhances the electrical signal of the battery by coupling K2S2O8. The open-circuit voltage is enhanced by about 2 to 3 times, the short-circuit current is enhanced by about 3 to 5 times, and the maximum power is enhanced by about 2 to 3 times, greatly improving the sensitivity of the light-driven self-powered sensor.

[0026] (3) For the first time, the present invention activates two power peaks of the battery (respectively at low current - high voltage and high current - low voltage) by coupling K2S2O8, realizing the self - calibration function of the light - driven self - powered sensor. Specifically, the dual - signal (bilinear) sensor of the present invention can obtain two concentrations in one measurement, and these two concentrations should be the same. If the difference between the two concentrations is large, it indicates that there is a problem with the measurement. The operator can thus check whether there are errors caused by inaccurate linear reading, such as non - standard experimental operations or operator differences, improving the accuracy of the light - driven self - powered sensor.

[0027] (4) The present invention proposes a new signal amplification and bilinear joint mechanism to improve the performance of the light - driven self - powered sensor, which has a great promoting effect on the development of the light - driven self - powered sensor, especially of great significance for enhancing the detection accuracy of the light - driven self - powered sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of the light - driven self - powered sensor in Example 1;

[0029] Figure 2 Performance comparison between the light - driven self - powered sensor in Example 1 and the traditional light - driven self - powered sensor;

[0030] Figure 3 Graph of the correlation between chloramphenicol concentration and V - I of the light - driven self - powered sensor in Example 1;

[0031] Figure 4 Graph of the correlation between chloramphenicol concentration and P - I of the light - driven self - powered sensor in Example 1;

[0032] Figure 5 For the two maximum powers (P max1 , P max2 ) and the linear correlation curve graph of the corresponding chloramphenicol concentration.

[0033] Figure 6 Graph of the correlation between chloramphenicol concentration and P - I of the light - driven self - powered sensor in Comparative Example 1;

[0034] Figure 7 For the maximum power P max and the linear correlation curve graph of the corresponding chloramphenicol concentration in Comparative Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not used to limit the present invention.

[0036] A light-driven self-powered sensor includes: a photoanode, a photocathode, a K2S2O8 reagent, an electrolyte solution, a quartz single-chamber reaction cell, a simulated sunlight source, and an electrochemical workstation. The photoanode and the photocathode are inserted parallelly into the quartz single-chamber reaction cell filled with the electrolyte solution and are connected through an external circuit. The K2S2O8 reagent is dissolved in the electrolyte solution. The simulated light source is directed at the surface of the dual photo electrodes. The electrochemical workstation is connected to the dual photo electrode system for collecting and analyzing detection signals.

[0037] In this embodiment, the electrolyte solution uses a phosphate buffer solution with a pH of 5 to 7. Driven by light and the Fermi level difference, the photoanode and the photocathode form a dual photo electrode photo-assisted fuel cell system, forming a current path to generate electrical energy. The K2S2O8 molecules act as both an electrolyte and an electron acceptor, making the voltage increase significantly at the low current of the battery and suppressing the electron-hole recombination reaction formed on the photo electrode to enhance the current at the low voltage, obtaining two power peaks at the low current-high voltage and high current-low voltage.

[0038] Example 1

[0039] 1. Preparation of photo electrodes

[0040] (1) Preparation of photoanode:

[0041] First, prepare a 0.4M potassium iodide (KI) solution and adjust the pH to 1.7 with nitric acid (HNO3). Secondly, add 0.97g of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), 0.23M of benzoquinone, and 20mL of absolute ethanol to the aforementioned solution to make a BiOI electrodeposition solution. Then, perform potentiostatic electrodeposition with a three-electrode system using FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode, with a voltage of -0.1V. After obtaining the BiOI / FTO electrode by electrodeposition, chemically convert the BiOI / FTO electrode with a mixed solution of 5mL of dimethyl sulfoxide (DMSO) and 0.2M of vanadyl acetylacetonate. After chemical conversion, perform heat treatment at 450°C for 2h with a heating rate of 2°C / min. After heat treatment, wash with 1M sodium hydroxide (NaOH) solution for 30min to remove the impurity of the vanadium pentoxide layer formed on the surface. Finally, observe that a yellow film is formed on the FTO substrate, completing the preparation of the BiVO4 / FTO photoanode.

[0042] (2) Preparation of photocathode:

[0043] Dissolve 0.165g of K3Fe(CN)6, 0.620g of H 24 Mo7N6O 244H2O and 3.728gKCl were dissolved in 25mL ultrapure water to prepare MoOHCF electrodeposition solution; cyclic voltammetry electrodeposition was carried out in a three-electrode system with FTO conductive glass as working electrode, platinum wire as counter electrode and saturated Ag / AgCl as reference electrode, with a voltage window of -0.1 to 0.8V, a scan rate of 100mV / s and 80 cycles; after electrodeposition, the substrate was repeatedly washed with deionized water for 3 times, and finally an orange-yellow film was observed to be deposited on the FTO substrate, completing the preparation of the photoanode.

[0044] 2. Construction of light-driven self-powered sensors

[0045] (1) A 5 μmol / L thiol-modified target aptamer solution was drop-coated on the outer surface of the BiVO4 / FTO electrode and incubated at 80°C for 6 h to obtain the photoanode.

[0046] (2) The prepared photoanode and photocathode were inserted in parallel into a quartz reaction cell filled with a phosphate buffer solution of pH = 7 and connected through an external circuit; 11 mM K2S2O8 reagent was dissolved in the phosphate buffer solution; a simulated light source was directed toward the surface of the dual photoelectrode; and an electrochemical workstation was connected to the dual photoelectrode system to collect detection signals.

[0047] 3. Self-powered sensor for detecting chloramphenicol

[0048] (1) Introduction of the analyte: The photoanode is placed in a chloramphenicol solution with different concentration gradients and incubated for 30 minutes. Due to DNA matching, the aptamer accurately recognizes and captures the chloramphenicol molecule. As the number of chloramphenicol captured by the aptamer increases, a large number of aptamer-chloramphenicol complexes are fixed on the photoanode, resulting in a continuous increase in the open circuit voltage. At the same time, the aptamer-chloramphenicol complex can also be oxidized by photogenerated holes, thereby reducing the inhibitory effect of the aptamer on interfacial electron transfer and improving the electron separation efficiency, thereby gradually increasing the short-circuit current density and maximum power (P max ).

[0049] (2) Design of signal extraction method: The VI data of the dual-photoelectrode photo-assisted fuel cell system were collected by CPCR measurement of the electrochemical workstation, and power analysis was performed. The power peaks related to the concentration of the analyte were extracted at low current-high voltage (I=2μA, U=0.313V) and high current-low voltage (I=8μA, U=0.06156V). More specifically, combined with the attached Figure 2 In the UI diagram shown in 2a, since power = voltage × current, it is expressed as P Max1 =UI In the diagram, draw the area of ​​the rectangle formed by two vertical lines i=2, u=0.313; so P is obtained from UI, that is, the PI diagram is obtained from UI, as shown in 2b.

[0050] (3) Establish the standard linearity: Collect the corresponding double power peak-to-peak values, perform data fitting processing, and establish the corresponding relationship between the chloramphenicol concentration and P max1 and P max2 to obtain two standard curves for the sensitive detection of chloramphenicol by the self-powered method.

[0051] Figure 3 and Figure 4 are the relationship diagrams of the chloramphenicol concentration with the voltage-current curve and the power-current curve of the constructed light-driven self-powered sensor. As can be seen from the figure, the voltage, current, and two maximum powers (P max1 , P max2 ) of the light-driven self-powered sensor show a good linear relationship with the logarithm of the chloramphenicol concentration, and the results are as Figure 5 shown.

[0052] Example 2

[0053] 1. Preparation of the photo-electrode

[0054] (1) Preparation of the photoanode:

[0055] First, prepare a 0.4 M potassium iodide (KI) solution and adjust the pH to 1.7 with nitric acid (HNO3); second, add 0.97 g of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), 0.23 M benzoquinone, and 20 mL of absolute ethanol to the aforementioned solution to make a BiOI electrodeposition solution; then, perform potentiostatic electrodeposition in a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode, with a voltage of -0.1 V; after obtaining the BiOI / FTO electrode by electrodeposition, chemically transform the BiOI / FTO electrode with a mixed solution of 5 mL of dimethyl sulfoxide (DMSO) and 0.2 M vanadyl acetylacetonate; after chemical transformation, perform heat treatment at 450 °C for 2 h with a heating rate of 2 °C / min; after heat treatment, wash with 1 M sodium hydroxide (NaOH) solution for 30 min to remove the impurity of the vanadium pentoxide layer formed on the surface; finally, observe that a yellow film is formed on the FTO substrate to complete the preparation of the BiVO4 / FTO photoanode.

[0056] (2) Preparation of the photocathode:

[0057] Dissolve 0.181 g of K3Fe(CN)6, 0.686 g of H 24 Mo7N6O 24· 4H2O and 3.8 g KCl were dissolved in 27.5 mL of ultrapure water to prepare the MoOHCF electrodeposition solution; a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode was used for cyclic voltammetry electrodeposition. The voltage window was -0.1 to 0.8 V, the scan rate was 100 mV / s, and the number of cycles was 80; after electrodeposition, it was repeatedly washed 3 times with deionized water, and finally an orange-yellow film was observed to be deposited on the FTO substrate, completing the preparation of the photoanode.

[0058] 2. Construction of a light-driven self-powered sensor

[0059] (1) A target analyte solution modified with 3 μmol / L mercapto was drop-coated on the outer surface of the BiVO4 / FTO electrode and incubated at 80 °C for 6 h to obtain the photoanode.

[0060] (2) The prepared photoanode and photocathode were inserted parallel into a quartz reaction cell containing a phosphate buffer solution with pH = 6 and connected through an external circuit; 3 mM K2S2O8 reagent was dissolved in the phosphate buffer solution; the simulated light source was directly opposite the surface of the double photo electrodes; the electrochemical workstation was connected to the double photo electrode system for collecting and analyzing detection signals.

[0061] 3. The self-powered sensor is used for detecting chloramphenicol

[0062] (1) Introducing the analyte to be measured: The photoanode was incubated in chloramphenicol solutions with different concentration gradients for 30 min. Due to DNA matching, the aptamer precisely recognized and captured chloramphenicol molecules. As the number of chloramphenicol molecules captured by the aptamer increased, a large number of aptamer-chloramphenicol complexes were immobilized on the photoanode, resulting in a continuous increase in the open-circuit voltage. At the same time, the aptamer-chloramphenicol complex could also be oxidized by photo-generated holes, thereby reducing the inhibitory effect of the aptamer on interfacial electron transfer and improving the electron separation efficiency, thus gradually increasing the short-circuit current density and the maximum power (P max ).

[0063] (2) Designing a signal extraction method: The V-I data of the double photo electrode photo-assisted fuel cell system were measured and collected through the CPCR of the electrochemical workstation for power analysis, and power peaks related to the concentration of the analyte to be measured were extracted at low current-high voltage and high current-low voltage respectively.

[0064] (3) Establishing a standard linear relationship: The corresponding double power peak values were collected and subjected to data fitting to establish the corresponding relationship between the chloramphenicol concentration and P max1 and P max2 to obtain two standard curves for the sensitive detection of chloramphenicol by the self-powered method.

[0065] Example 3

[0066] 1. Preparation of Photoelectrode

[0067] (1) Preparation of Photoanode:

[0068] Firstly, prepare a 0.44 M potassium iodide (KI) solution and adjust the pH to 1.7 with nitric acid (HNO3). Secondly, add 1.06 g of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), 0.25 M benzoquinone, and 22 mL of absolute ethanol into the aforementioned solution to prepare a BiOI electrodeposition solution. Then, perform potentiostatic electrodeposition using a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode at a voltage of -0.1 V. After obtaining the BiOI / FTO electrode, chemically transform the BiOI / FTO electrode with a mixed solution of 6 mL of dimethyl sulfoxide (DMSO) and 0.24 M vanadyl acetylacetonate. After chemical transformation, conduct heat treatment at 450 °C for 2 h with a heating rate of 2 °C / min. After heat treatment, wash with 1 M sodium hydroxide (NaOH) solution for 30 min to remove the vanadium pentoxide layer impurities formed on the surface. Finally, observe that a yellow film is formed on the FTO substrate, and the preparation of the BiVO4 / FTO photoanode is completed.

[0069] (2) Preparation of Photocathode:

[0070] Dissolve 0.165 g of K3Fe(CN)6, 0.620 g of H 24 Mo7N6O 24 ·4H2O and 3.728 g of KCl in 25 mL of ultrapure water to prepare a MoOHCF electrodeposition solution. Perform cyclic voltammetry electrodeposition using a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode, with a voltage window of -0.1 to 0.8 V, a scan rate of 100 mV / s, and 80 cycles. After electrodeposition, wash repeatedly with deionized water three times. Finally, observe that an orange-yellow film is deposited on the FTO substrate, and the preparation of the photoanode is completed.

[0071] 2. Construction of Light-Driven Self-Powered Sensor

[0072] (1) Dropwise coat a 6 μmol / L solution of the target analyte aptamer modified with a thiol group on the outer surface of the BiVO4 / FTO electrode and incubate at 80 °C for 6 h to obtain the photoanode described above.

[0073] (2) Insert the prepared photoanode and photocathode parallelly into a quartz reaction cell filled with a phosphate buffer solution at pH = 5 and connect them through an external circuit. Dissolve 14 mM of K2S2O8 reagent in the phosphate buffer solution. Align the simulated light source with the surface of the double photoelecrode. Connect the electrochemical workstation to the double photoelecrode system for collecting and analyzing detection signals.

[0074] 3. The self-powered sensor is used to detect chloramphenicol.

[0075] (1) Introduction of the analyte: The photoanode is incubated in chloramphenicol solutions with different concentration gradients for 30 min. Due to DNA matching, the aptamer precisely recognizes and captures chloramphenicol molecules. As the number of chloramphenicol molecules captured by the aptamer increases, a large number of aptamer-chloramphenicol complexes are immobilized on the photoanode, resulting in a continuous increase in the open-circuit voltage. At the same time, the aptamer-chloramphenicol complex can also be oxidized by photo-generated holes, thereby reducing the inhibition of the aptamer on interfacial electron transfer and improving the electron separation efficiency, gradually increasing the short-circuit current density and the maximum power (P max ).

[0076] (2) Design of the signal extraction method: The V-I data of the dual-photoelectrode photo-assisted fuel cell system are measured and collected by an electrochemical workstation CPCR, and power analysis is performed. Power peaks related to the analyte concentration are extracted at low current-high voltage and high current-low voltage, respectively.

[0077] (3) Establishment of the standard linearity: The corresponding peak values of the dual power peaks are collected, and data fitting is performed to establish the corresponding relationship between the chloramphenicol concentration and P max1 and P max2 , obtaining two standard curves for the sensitive detection of chloramphenicol by the self-powered method.

[0078] Comparative Example 1

[0079] 1. Preparation of the photoelectrode

[0080] (1) Preparation of the photoanode:

[0081] First, prepare a 0.4 M potassium iodide (KI) solution and adjust the pH to 1.7 with nitric acid (HNO3). Secondly, add 0.97 g of bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), 0.23 M benzoquinone, and 20 mL of absolute ethanol to the aforementioned solution to make a BiOI electrodeposition solution. Then, a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode is used for potentiostatic electrodeposition at a voltage of -0.1 V. After obtaining the BiOI / FTO electrode, the BiOI / FTO electrode is chemically transformed with a mixed solution of 5 mL of dimethyl sulfoxide (DMSO) and 0.2 M vanadyl acetylacetonate. After chemical transformation, heat treatment is performed at 450 °C for 2 h with a heating rate of 2 °C / min. After heat treatment, it is washed with 1 M sodium hydroxide (NaOH) solution for 30 min to remove the impurity of the vanadium pentoxide layer formed on the surface. Finally, a yellow film is observed to form on the FTO substrate, completing the preparation of the BiVO4 / FTO photoanode.

[0082] (2) Preparation of the photocathode:

[0083] Dissolve 0.181 g of K3Fe(CN)6, 0.686 g of H 24 Mo7N6O 24 ·4H2O and 3.8 g of KCl in 27.5 mL of ultrapure water to prepare a MoOHCF electrodeposition solution; use a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode for cyclic voltammetry electrodeposition. The voltage window is -0.1 to 0.8 V, the scanning rate is 100 mV / s, and the number of cycles is 80; after electrodeposition, wash it repeatedly with deionized water three times. Finally, an orange-yellow film is deposited on the FTO substrate, completing the preparation of the photoanode.

[0084] 2. Construction of the light-driven self-powered sensor

[0085] (1) Dropwise coat a solution of the target analyte modified with thiol at a concentration of 3 μmol / L on the outer surface of the BiVO4 / FTO electrode and incubate it at 80 °C for 6 h to obtain the photoanode.

[0086] (2) Insert the prepared photoanode and photocathode parallelly into a quartz reaction cell filled with a phosphate buffer solution with pH = 6 and connect them through an external circuit; the simulated light source is directly facing the surface of the double photo electrodes; the electrochemical workstation is connected to the double photo electrode system for collecting and analyzing detection signals.

[0087] 3. Use of the self-powered sensor for detecting chloramphenicol

[0088] (1) Introduction of the analyte to be detected: Place the photoanode in chloramphenicol solutions with different concentration gradients and incubate for 30 min. Due to DNA matching, the aptamer precisely recognizes and captures chloramphenicol molecules. As the number of chloramphenicol molecules captured by the aptamer increases, a large number of aptamer-chloramphenicol complexes are fixed on the photoanode, resulting in a continuous increase in the open-circuit voltage. At the same time, the aptamer-chloramphenicol complex can also be oxidized by photogenerated holes, thereby reducing the inhibition of the aptamer on interfacial electron transfer and improving the electron separation efficiency, gradually increasing the short-circuit current density and the maximum power (P max ).

[0089] (2) Design of the signal extraction method: Measure and collect the V-I data of the double photo electrode photo-assisted fuel cell system through the electrochemical workstation CPCR, perform power analysis, and extract the power peak related to the concentration of the analyte to be detected.

[0090] (3) Establishment of the standard linear relationship: Collect the peak values of the corresponding power peaks, perform data fitting, establish the corresponding relationship between the chloramphenicol concentration and P max , and obtain a standard curve for the sensitive detection of chloramphenicol by the self-powered method.

[0091] Combined with Figure 6 and 7 it can be seen that the maximum value of its base power is small. Therefore, after adding the target substance, the change in the maximum power value is small, so the slope of the line is very low, the sensitivity of the sensor is low, and there is only one peak without bilinearity. Therefore, the accuracy of the sensor in Comparative Example 1 is not as high as that of the present invention.

[0092] From Figure 1 the perspective of, after adding potassium persulfate to the electrolyte solution in this application, the maximum power value (quantifying the signal of the target substance) becomes higher and two maximum power values appear (because there are two peaks). The increase in the quantified signal is the signal amplification strategy, which increases the sensitivity. Because after adding the target substance, the change in the large quantified signal is greater, and the greater the change, the clearer the change, that is, the more sensitive the sensor; the second peak is the dual-signal (bilinear) strategy, which enables the sensor to obtain two data in one measurement, and these two data can be self-calibrated to enhance the accuracy of the sensor measurement result.

[0093] In the above embodiments, only chloramphenicol is used as the detection object for illustration. However, the light-driven self-powered sensor designed by the present invention and its use method are not limited to the detection of chloramphenicol, but also applicable to other detection objects.

[0094] The above embodiments are only used to illustrate the design concept and characteristics of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made according to the principles and design ideas disclosed by the present invention are within the protection scope of the present invention.

Claims

1. A method for using a light-driven self-powered sensor, characterized in that, It includes the following steps: W1: Construct a light-driven self-powered sensor, including: a photoanode, a photocathode, a K2S2O8 reagent, an electrolyte solution, a quartz single-chamber reaction cell, a simulated sunlight source, and an electrochemical workstation: The photoanode and the photocathode are inserted into the quartz single-chamber reaction cell filled with the electrolyte solution, and the photoanode and the photocathode are connected through an external circuit to complete the construction of a two-photoelectrode photo-assisted fuel cell system; The K2S2O8 reagent is dissolved in the electrolyte solution; The simulated sunlight source is directly opposite the surface of the two-photoelectrode; The electrochemical workstation is connected to the photoanode and the photocathode circuits to obtain detection signals; The concentration of the K2S2O8 reagent in the electrolyte solution is 3 mM to 14 mM; Prepare a blank control solution and a series of analyte solutions with different concentration gradients; W2: Design a signal extraction method: Measure and collect the V-I data of the two-photoelectrode photo-assisted fuel cell system by the CPCR of the electrochemical workstation, perform power analysis, and extract the peak-to-peak power related to the analyte concentration at low current-high voltage and high current-low voltage respectively; W3: Establish a standard linearity: Incubate the photoanode in analyte solutions with different concentration gradients for 30 min, collect the corresponding double peak-to-peak powers, and perform data fitting to obtain two standard linearities related to the analyte concentration.

2. The usage method of an optically driven self-powered sensor according to claim 1, characterized in that The photoanode is an FTO electrode modified with BiVO4.

3. The usage method of a light-driven self-powered sensor according to claim 2, characterized in that, Method for preparing the photoanode: Prepare a 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; Add 0.97 g of bismuth nitrate pentahydrate, 0.23 M of benzoquinone, and 20 mL of absolute ethanol to the above solution to make a BiOI electrodeposition solution; Perform electrodeposition using a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode; After the BiOI / FTO electrode was obtained by electrodeposition, the BiOI / FTO electrode was chemically transformed with a mixed solution of 5 mL of dimethyl sulfoxide and 0.2 M vanadyl acetylacetonate; after chemical transformation, heat treatment was carried out at 450 o °C for 2 h, and the heating rate was 2 o °C / min; after heat treatment, it was washed with 1 M sodium hydroxide solution for 30 min to remove the impurity of the vanadium pentoxide layer formed on the surface; finally, a yellow film was observed to form on the FTO substrate, and the preparation of the BiVO4 / FTO photoanode was completed.

4. The method for using a light-driven self-powered sensor according to claim 3, characterized in that In the method for preparing the photoanode, the electrochemical deposition method specifically uses the potentiostatic method, where the voltage is -0.1 V.

5. The usage method of a light-driven self-powered sensor according to claim 3, wherein In the method for preparing a photoanode, a target aptamer solution modified with thiol at a concentration of 5 μmol / L is drop-coated on the outer surface of a BiVO4 / FTO electrode and incubated at 80 o °C for 6 h to obtain the photoanode.

6. The method for using a light-driven self-powered sensor according to claim 1, characterized in that The photocathode is an FTO electrode modified with MoOHCF.

7. The method of using a light-driven self-powered sensor according to claim 6, characterized in that Method for preparing a photocathode: Dissolve 0.165 g of K3Fe(CN)6, 0.620 g of H 24 Mo7N6O 24 ·4H2O and 3.728 g of KCl in 25 mL of ultrapure water to prepare a MoOHCF electrodeposition solution; perform electrodeposition using a three-electrode system with an FTO conductive glass as the working electrode, a platinum wire as the counter electrode, and a saturated Ag / AgCl as the reference electrode; after electrodeposition, wash it repeatedly with deionized water three times, and finally observe that an orange-yellow film is deposited on the FTO substrate to complete the preparation of the photocathode.

8. The method for using a light-driven self-powered sensor according to claim 7, characterized in that In the method for preparing the photocathode, the electrochemical deposition method specifically uses cyclic voltammetry, where the voltage window is -0.1 to 0.8 V, the scan rate is 100 mV / s, and the number of cycles is 80.

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