Dual-ratio light-driven self-powered sensor, preparation method and application

Abstract

The application discloses a kind of dual-ratio light-driven self-powered sensors, preparation method and application, including anode, cathode, analog sunlight light source, anode and cathode are inserted into quartz reaction cell with electrolyte solution, and are communicated by external circuit, light source simultaneously irradiates anode and cathode, electrolyte solution is 0.1M PBS solution containing K2S2O8, anode has two anode sub-channel interfaces, two anode sub-channel interfaces are formed with cathode to form two parallel light-driven self-powered systems, two light-driven self-powered systems are driven by self-bias voltage generated under light irradiation condition to form current path, and generate electric energy.The dual-ratio light-driven self-powered sensor of the application is a new self-powered sensor precision enhancement technology with dual-signal analysis and signal amplification, and can be used for specific detection of small molecule target substances by introducing corresponding aptamer, with a minimum detection limit of pM level.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical detection, specifically relating to a dual-ratio light-driven self-powered sensor, its preparation method, and its application. Background Technology

[0002] As an emerging electrochemical detection method, light-driven self-powered sensors have attracted widespread research interest in the field of small molecule pollutant detection in recent years. Compared with traditional electrochemical sensors powered by batteries or external electricity, light-driven self-powered sensors have advantages such as low background noise, convenience, high efficiency, energy saving, environmental friendliness, and the ability to continuously detect in complex environments. Light-driven self-powered sensors are based on a dual-electrode system using a photocatalytic fuel cell, which can generate an electrical output related to the concentration of the analyte. However, in most reported light-driven self-powered sensors, target quantification relies solely on the weak, single electrical signal output of the designed dual-electrode system. This can be affected by errors caused by improper experimental procedures or operator differences, making it difficult to meet the requirements of high sensitivity and high accuracy.

[0003] Dual-signal analysis or dual-ratio analysis strategies can effectively improve the accuracy of self-powered sensors. They quantify the target based on two signals instead of a single signal, avoiding errors caused by improper experimental procedures or operator variations, such as inaccurate linear readings. Ratio analysis can also normalize environmental changes by comparing the ratio of the two signals, minimizing their impact on the detection results. Currently, common ratio analysis methods include: potassium ferricyanide ([Fe(CN)6]6) 3- / 4- Methods such as dual-detection site detection of Prussian blue analogues (NiFe-PBA) and dual-mode detection of photoelectrochemical (PEC) and electrochemical (EC) have drawbacks, including cumbersome operation, long detection time, limited performance enhancement, and single output signal.

[0004] Signal amplification strategies can effectively improve the sensitivity of self-powered sensors. Enhanced electrical output signals can lead to higher sensitivity. Signal amplification methods include developing novel nanostructures and external capacitor amplification modules. However, these methods suffer from drawbacks such as complex fabrication, high cost, or limited and singular performance enhancement. Therefore, developing a convenient and efficient new mechanism to improve upon and combine the advantages of both signal amplification and ratio analysis strategies is of great significance for light-driven self-powered sensors.

[0005] Potassium persulfate (K₂S₂O₈) is an inorganic compound, a white crystalline powder, soluble in water, almost non-hygroscopic, and possesses advantages such as good stability at room temperature, ease of storage, convenience, and safety. Compared to single-ratio analysis, dual-ratio analysis offers superior analytical performance and is an effective method for manufacturing high-precision self-powered sensors. Currently, there are no reports on self-powered sensors that accurately detect small molecule targets by incorporating a dual-ratio strategy based on a K₂S₂O₈ coupled dual-photoelectrode system to avoid changes in the sensor's output electrical signal caused by instability in K₂S₂O₈ factors (such as dosage). Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a dual-ratio light-driven self-powered sensor, its preparation method, and its application. This invention's dual-ratio light-driven self-powered sensor utilizes K2S2O8 to activate and excite a dual-photoelectrode self-powered system, generating a more sensitive electrical signal with a dual-power peak structure. This achieves signal amplification and dual-signal detection. Furthermore, spatial resolution technology is integrated into the dual-signal self-powered sensor, utilizing regionally separated dual photoelectrodes to generate two dual-power peak signals for dual-ratio detection. This effectively avoids variations in sensor output signal enhancement caused by instability in K2S2O8 factors (such as the amount added), and provides an effective method for manufacturing high-precision self-powered sensors. The constructed dual-ratio light-driven self-powered sensor, when used for the detection of the antibiotic chloramphenicol, exhibits high accuracy, high sensitivity, good selectivity, and low detection cost, with a minimum detection limit reaching the pM level.

[0007] One objective of this invention is to design a dual-ratio light-driven self-powered sensor, comprising a photoanode, a photocathode, a simulated sunlight source, a quartz reaction cell, and an electrolyte solution. The photoanode and photocathode are inserted into the quartz reaction cell containing the electrolyte solution and connected via an external circuit. The light source simultaneously irradiates the photoanode and photocathode. The electrolyte solution is a 0.1M PBS solution containing K2S2O8. The photoanode has two parallel photoanode sub-channel interfaces, which, together with the photocathode, form two parallel light-driven self-powered systems. Under the self-biased voltage generated by the light irradiation, the two light-driven self-powered systems form current paths and generate electrical energy.

[0008] The preferred technical solution is that the photoanode is a V2C and BiVO4 modified FTO electrode - V2C / BiVO4 / FTO photoanode, and the photocathode is a MoOHCF modified FTO electrode - MoOHCF / FTO photocathode.

[0009] The second objective of this invention is to design a method for fabricating a dual-ratio light-driven self-powered sensor. The fabrication of the aforementioned dual-ratio light-driven self-powered sensor includes the following steps:

[0010] S1: Preparation of photoanode: A BiOI film is electrodeposited on FTO conductive glass using a three-electrode system to form a BiOI / FTO electrode. Then, the BiOI / FTO electrode is sequentially placed in a solution of vanadium acetylacetone for chemical conversion, heat treatment, and alkaline washing to obtain a BiVO4 / FTO electrode. A V2C suspension is coated on the surface of the BiVO4 / FTO electrode and dried to obtain a V2C / BiVO4 / FTO photoanode.

[0011] S2: The photocathode is fabricated by electrodepositing a MoOHCF film on FTO conductive glass using a three-electrode system to form a MoOHCF / FTO photocathode;

[0012] S3: Preparation of the light-driven self-powered system: The above-mentioned V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode are inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy.

[0013] S4: Preparation of a dual-signal light-driven self-powered sensor: A certain amount of K2S2O8 reagent was added to the PBS solution in the quartz reaction cell and stirred evenly so that the output power-current correlation curve of the light-driven self-powered system formed two independent power peaks. The target material aptamer was then modified on the surface of the V2C / BiVO4 / FTO photoanode, incubated and cleaned to obtain a dual-signal light-driven self-powered sensor with specific recognition function.

[0014] S5: Fabrication of a dual-ratio light-driven self-powered sensor: The V2C / BiVO4 / FTO photoanode in step S4 is physically separated into a photoanode sub-channel interface PA1 and a photoanode sub-channel interface PA2, resulting in a dual-ratio light-driven self-powered sensor that generates two dual-power output peak signals by coupling two photoelectrodes with K2S2O8 and combining them with spatial resolution.

[0015] The preferred technical solution is that step S1 specifically involves the following steps: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 1.94–2.18 g of bismuth nitrate pentahydrate and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 20 mL of anhydrous ethanol solution containing 0.23–0.25 M p-benzoquinone to form electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A for electrodeposition, depositing the electrode onto the surface of the FTO conductive glass. A BiOI film was formed to obtain a BiOI / FTO electrode. Next, the BiOI / FTO electrode was chemically converted with a mixture containing 0.2M vanadium acetylacetone and 10mL dimethyl sulfoxide. The chemically converted electrode was then heat-treated at 450℃ for 2h at a heating rate of 2℃ / min. The heat-treated electrode was then washed with 1M sodium hydroxide solution for 30min to obtain a BiVO4 / FTO electrode. Finally, a V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode using a pipette, and the electrode was baked under an infrared lamp for 30min to obtain a V2C / BiVO4 / FTO photoanode.

[0016] A further preferred technical solution is that, in step S1: the electrodeposition method used is the constant potential method, and the voltage is set to -0.1V; the mass concentration of the V2C suspension used is 1mg / mL, and the drop volume of the V2C suspension is 10μL.

[0017] A preferred technical solution is that step S2 is specifically operated as follows: First, 0.165-0.175g of potassium ferricyanide, 0.620-0.660g of ammonium molybdate tetrahydrate and 3.728-3.748g of potassium chloride are added to 25mL of deionized water to prepare a mixed solution, and the solution is stirred continuously for 10min to obtain electrodeposition reserve solution B; Second, a three-electrode system consisting of FTO conductive glass as the working electrode, platinum electrode as the auxiliary electrode and Ag / AgCl electrode as the reference electrode is inserted into the above electrodeposition reserve solution B to perform electrodeposition, forming a MoOHCF film on the surface of FTO conductive glass to obtain a MoOHCF / FTO photocathode.

[0018] A further preferred technical solution is that, in step S2, the electrodeposition method used is cyclic voltammetry, the voltage window is set to -0.1 to 0.8V, the scan rate is 100mV / s, and the number of cycles is 90 to 100.

[0019] A preferred technical solution also includes: in step S3, the pH value of the PBS solution is 6.0 to 7.0; in step S4, the molar concentration of K2S2O8 in the PBS solution is 3 to 11 mM.

[0020] The third objective of this invention is to design an application of the aforementioned dual-ratio light-driven self-powered sensor for detecting small molecule target substances. This invention uses chloramphenicol as an example, but is not limited to chloramphenicol; it can be extended to all target analytes for which aptamers have been screened. Specifically, the following operational steps are included:

[0021] T1: Preparation of standard solutions containing different concentrations of the target substance: Accurately weigh the target substance and prepare a 1.0 × 10⁻⁶ standard solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. -12 mol / L~3.0×10 -9 Standard solutions of the target substance at different concentrations (mol / L);

[0022] T2: Establishment of the standard curve: The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor was incubated in a series of target substance standard solutions of known concentrations. Then, the photoanode sub-channel interface PA1 and the photocathode were placed in a quartz reaction cell in a 0.1M PBS solution containing K2S2O8 to simulate sunlight irradiation of the photoanode sub-channel interface PA1 and the photocathode. A series of target substance concentration-maximum output power correspondences and a series of corresponding dual-power output peak-to-peak values ​​P were obtained. Max1 P Max2 The photoanode subchannel interface PA2 of the prepared dual-ratio light-driven self-powered sensor was incubated in a standard solution of the target substance at a fixed concentration. Then, the photoanode subchannel interface PA2 and the photocathode were placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell to simulate sunlight irradiation of the photoanode subchannel interface PA2 and the photocathode. The correlation between the fixed concentration of the target substance and the maximum output power, as well as the corresponding peak-to-peak value P of the dual-power output, were obtained by testing. max3 P max4 ; Utilizing a series of target substance concentrations, dual-power output peak-to-peak values ​​P Max1 With P max3 The ratio P Max1 / P Max3 Dual power output peak-to-peak value P Max2 With P max4 The ratio P Max2 / P Max4 Two linear relationships were obtained between the peak-to-peak ratio of the maximum output power of the target substance and the logarithm of the target substance concentration, resulting in two different linear regression equations.

[0023] T3: Detection of target substance concentration in the sample: The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor was placed in the sample for incubation. Then, the photoanode sub-channel interface PA1 and the photocathode were placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell. The photoanode sub-channel interface PA1 and the photocathode were irradiated by a simulated sunlight source, and the peak-to-peak value P of the dual power output corresponding to the target substance was measured. max5 P max6 , will P max5 With P max3 The ratio P Max5 / P Max3 and P max6 With P max4 The ratio P Max6 / P Max4 Substitute the values ​​into the two linear regression equations in step T2 to calculate the two concentration values ​​of the target substance in the sample to be tested, and then compare the two concentration values ​​to perform self-calibration.

[0024] A further preferred technical solution is that, in steps T2 and T3, the incubation time of the photoanode sub-channel interface PA1 and the photoanode sub-channel interface PA2 in the solution is more than 60 minutes; step T3 also includes pretreatment of the sample to be tested before detection, specifically: take the original sample to be tested and let it stand for more than 1 hour, then place the original sample to be tested on a centrifuge for centrifugation, and take the supernatant as the sample to be tested.

[0025] The advantages and beneficial effects of this invention are as follows:

[0026] 1. This invention discloses a dual-ratio light-driven self-powered sensor, employing a V2C / BiVO4 / FTO photoelectrode as the photoanode, a MoOHCF / FTO photoelectrode as the photocathode, and a PBS mixed solution containing K2S2O8 as the electrolyte. A dual-signal light-driven self-powered sensor for a K2S2O8 coupled photocatalytic fuel cell is established. Using spatial resolution technology, the V2C / BiVO4 / FTO photoanode is physically divided into a photoanode sub-channel interface PA1 and a photoanode sub-channel interface PA2. A novel dual-ratio light-driven self-powered sensor is designed using the peak-to-peak power ratio of the dual photoanode sub-channels. This dual-ratio light-driven self-powered sensor exhibits excellent power generation performance, low manufacturing cost, and environmental friendliness.

[0027] 2. This invention discloses a dual-ratio light-driven self-powered sensor. By introducing potassium persulfate (K2S2O8), the power generation performance of the dual-photoelectrode system is enhanced. It not only acts as a supporting electrolyte to maintain the high open-circuit voltage (Voc) operation of the dual-photoelectrode system, but also acts as an electron acceptor or inorganic sacrificial agent to attract and eliminate transferred electrons and holes, suppressing electron-hole pair recombination. This amplifies the output electrical signal in the light-driven self-powered sensor, increasing the open-circuit voltage by approximately 2-3 times, the short-circuit current by approximately 3-5 times, and the maximum power by approximately 2-3 times. Simultaneously, the internal resistance of the K2S2O8-containing dual-photoelectrode system increases slightly at high potentials and decreases rapidly at low potentials, a faster change compared to the dual-photoelectrode system without K2S2O8. This results in two distinct output power signal peaks at low and high currents in the dual-photoelectrode system, enabling dual-signal analysis of the light-driven self-powered sensor. This is a novel self-powered sensor accuracy enhancement technology that combines dual-signal analysis and signal amplification.

[0028] 3. This invention provides a dual-ratio light-driven self-powered sensor that combines spatial resolution technology, ratiometric analysis, and dual-signal analysis. By separating the working electrode interface at the physical layer, and utilizing the two output electrical signals generated by the dual photoelectrodes and the dual power peaks of each signal, a dual-ratio light-driven self-powered sensor induced by spatial resolution has been successfully developed. This effectively avoids the detection inaccuracies caused by changes in the sensor's output electrical signal due to unstable K2S2O8 addition, providing an effective method for manufacturing high-precision self-powered sensors. Compared with traditional light-driven self-powered sensors, the dual-ratio light-driven self-powered sensor proposed in this invention is not only easy to operate but also has the characteristics of high sensitivity and high accuracy. When used for the detection of the antibiotic chloramphenicol, the constructed dual-ratio self-powered sensor has the characteristics of high accuracy, high sensitivity, good selectivity, and low detection cost.

[0029] 4. The dual-ratio light-driven self-powered sensor of the present invention can be used to specifically detect small molecule target substances by introducing a corresponding aptamer. The detection limit of the concentration of small molecule target substances in the solution reaches the pM level, and the operation steps for detecting small molecule target substances are simple and the application is highly feasible.

[0030] 5. The method for fabricating a dual-ratio light-driven self-powered sensor according to the present invention has simple operation steps, ensuring that the dual-ratio light-driven self-powered sensor of the present invention can be successfully fabricated and implemented. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a dual-ratio light-driven self-powered sensor according to the present invention;

[0032] Figure 2This is the peak-to-peak ratio P of the maximum output power in Example 1. Max1 / P Max3 and P Max2 / P Max4 With changes in K2S2O8 concentration;

[0033] Figure 3 The graph shows the correlation between chloramphenicol concentration and PI at the photoanode subchannel interface PA1 in the dual-ratio light-driven self-powered sensor of Example 1.

[0034] Figure 4 The graph shows the correlation between chloramphenicol concentration and PI at the photoanode subchannel interface PA2 in the dual-ratio light-driven self-powered sensor of Example 1.

[0035] Figure 5 The maximum output power ratio P after adding chloramphenicol in Example 1. Max1 / P Max3 Standard curve of chloramphenicol concentration;

[0036] Figure 6 The maximum output power ratio P after adding chloramphenicol in Example 1. Max2 / PMax4 Standard curve of chloramphenicol concentration;

[0037] Figure 7 To compare the correlation between chloramphenicol concentration and PI in the light-driven self-powered sensor in Example 4;

[0038] Figure 8 To compare the maximum output power P after adding chloramphenicol in Example 4 Max Standard curve of chloramphenicol concentration. Detailed Implementation

[0039] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0040] Comparative Example 2 and Comparative Example 3 are used to illustrate that the constructed dual-signal light-driven self-powered sensor will cause changes in the sensor's output electrical signal due to the unstable amount of K2S2O8 added, resulting in inaccurate detection results.

[0041] Example 1 is compared with Comparative Example 1 to illustrate whether the dual-ratio light-driven self-powered sensor proposed in this invention improves upon the dual-signal light-driven self-powered sensor the inaccurate detection results caused by changes in the sensor output electrical signal due to the unstable addition of K2S2O8.

[0042] Examples 1-3 are compared with Comparative Example 3 to illustrate that the dual-ratio optically driven self-powered sensor proposed in this invention has a lower detection limit than the single-signal optically driven self-powered sensor.

[0043] The samples used in Examples 1-3 and Comparative Examples 1-4 were wastewater from a pond in Changzhou and commercially available milk.

[0044] Example 1

[0045] like Figure 1 As shown, a dual-ratio light-driven self-powered sensor includes a photoanode, a photocathode, a simulated sunlight source, a quartz reaction cell, and an electrolyte solution. The photoanode and photocathode are inserted into the quartz reaction cell containing the electrolyte solution and are connected through an external circuit. The light source simultaneously irradiates the photoanode and photocathode. The electrolyte solution is a 0.1M PBS solution containing K2S2O8. The photoanode has two parallel photoanode sub-channel interfaces, which, together with the photocathode, form two parallel light-driven self-powered systems. Under the self-biased voltage generated by the light irradiation, the two light-driven self-powered systems form current paths and generate electrical energy.

[0046] The preferred technical solution is that the photoanode is a V2C and BiVO4 modified FTO electrode - V2C / BiVO4 / FTO photoanode, and the photocathode is a MoOHCF modified FTO electrode - MoOHCF / FTO photocathode.

[0047] The above-mentioned dual-ratio light-driven self-powered sensor is prepared using the method of the present invention. The operation steps are as follows:

[0048] S1: Preparation of the photoanode: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 1.94 g of Bi(NO3)3·5H2O and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 20 mL of anhydrous ethanol solution containing 0.23 M p-benzoquinone (C6H4O2) as electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A, set a voltage of -0.1 V, and perform electrodeposition using a potentiostatic method to form BiOI on the surface of the FTO conductive glass. A BiOI / FTO electrode was obtained by forming a film. Next, the BiOI / FTO electrode was chemically converted using a mixture containing 0.2 M vanadium acetylacetone and 10 mL dimethyl sulfoxide (DMSO). The chemically converted electrode was then heat-treated at 450 °C for 2 h at a heating rate of 2 °C / min. The heat-treated electrode was then washed with 1 M sodium hydroxide solution for 30 min to obtain a BiVO4 / FTO electrode. Finally, 10 μL of a 1 mg / mL V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode using a pipette, and the electrode was baked under an infrared lamp for 30 min to obtain a V2C / BiVO4 / FTO photoanode.

[0049] S2: Preparation of the photocathode. First, 0.165 g of potassium ferricyanide, 0.620 g of ammonium molybdate tetrahydrate, and 3.728 g of potassium chloride were added to 25 mL of deionized water to prepare a mixed solution. The solution was stirred continuously for 10 min to obtain electrodeposition reserve solution B. Second, a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode was inserted into the above electrodeposition reserve solution B. Electrodeposition was performed using cyclic voltammetry to form a MoOHCF film on the surface of the FTO conductive glass to obtain a MoOHCF / FTO photocathode. The cyclic voltammetry settings were: voltage window set to -0.1 to 0.8 V, scan rate of 100 mV / s, and number of cycles of 90.

[0050] S3: Preparation of the light-driven self-powered system: The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode mentioned above were inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy. The pH value of the PBS solution is 7.0.

[0051] S4: Preparation of a dual-signal light-driven self-powered sensor: A certain amount of K2S2O8 reagent was added to the PBS solution in the quartz reaction cell to make the molar concentration of K2S2O8 in the PBS solution 11mM. The mixture was stirred evenly to make the output power-current correlation curve of the light-driven self-powered system form two independent power peaks. Chloramphenicol aptamers were then modified onto the surface of the V2C / BiVO4 / FTO photoanode, incubated, and cleaned to obtain a dual-signal light-driven self-powered sensor with specific recognition function. The nucleotide sequence of the chloramphenicol aptamer is: 5′-ACT TCA GTG AGT TGT CCC ACG GTC GGC GAGTCG GTG GTA G-3′, the concentration of the chloramphenicol aptamer is 5μmol / L, and the incubation condition is 60℃ for 5h.

[0052] S5: Fabrication of a dual-ratio light-driven self-powered sensor: The V2C / BiVO4 / FTO photoanode in step S4 is physically separated into a photoanode sub-channel interface PA1 and a photoanode sub-channel interface PA2, resulting in a dual-ratio light-driven self-powered sensor that generates two dual-power output peak signals by coupling two photoelectrodes with K2S2O8 and combining them with spatial resolution.

[0053] The prepared dual-ratio light-driven self-powered sensor was used to detect the concentration of chloramphenicol in wastewater and milk. The operation steps are as follows:

[0054] T1: Preparation of standard solutions containing different concentrations of chloramphenicol: Accurately weigh a certain mass of chloramphenicol and prepare a 1.0 × 10⁻⁶ solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. - 12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 - 9 Chloramphenicol standard solutions of different concentrations (mol / L);

[0055] T2: Establishment of the standard curve: The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor was placed in a series of known concentrations (0.5 × 10⁻⁶). -12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10-10 mol / L, 3.0×10 -9 The photoanode subchannel interface PA1 and photocathode were incubated in a chloramphenicol standard solution (mol / L) for 60 min. Then, the incubated photoanode subchannel interface PA1 and photocathode were placed in a quartz reaction cell in a 0.1 M PBS solution containing K2S2O8. The photoanode subchannel interface PA1 and photocathode were irradiated by a simulated sunlight source. A series of chloramphenicol concentration-maximum output power correspondences and a series of corresponding dual-power output peak-to-peak values ​​P were obtained. Max1 P Max2 The photoanode subchannel interface PA2 of the prepared dual-ratio light-driven self-powered sensor was placed in a solution with a concentration of 2.0 × 10⁻⁶. -12 The photoanode subchannel interface PA2 and photocathode were incubated in a mol / L chloramphenicol standard solution for 60 min. Then, the incubated photoanode subchannel interface PA2 and photocathode were placed in a quartz reaction cell in a 0.1 M PBS solution containing K2S2O8. The photoanode subchannel interface PA2 and photocathode were irradiated by a simulated sunlight source. The relationship between the fixed concentration of chloramphenicol and the maximum output power, as well as the corresponding peak-to-peak value P of the dual-power output, were obtained. max3 P max4 Using a series of chloramphenicol concentrations, dual-power output peak-to-peak values ​​P Max1 With P max3 The ratio P Max1 / P Max3 Dual power output peak-to-peak value P Max2 With P max4 The ratio P Max2 P Max4 Two standard curves were fitted to the peak-to-peak ratio of the maximum output power of chloramphenicol and the logarithm of the chloramphenicol concentration. Two linear relationships were established between the peak-to-peak ratio of the maximum output power of the dual-ratio light-driven self-powered sensor after the addition of chloramphenicol and the logarithm of the chloramphenicol concentration, resulting in two different linear regression equations.

[0056] T3: Detection of chloramphenicol concentration in the test sample: First, the test sample is pretreated by letting it stand for more than 1 hour. Then, the test sample is centrifuged and the supernatant is used as the test sample. The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor is placed in the test sample and incubated for 60 minutes. Then, the incubated photoanode sub-channel interface PA1 and photocathode are placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell. The photoanode sub-channel interface PA1 and photocathode are irradiated by a simulated sunlight source, and the peak-to-peak value of the dual power output P corresponding to chloramphenicol is measured. max5 P max6 , will P max5 With P max3 The ratio P Max5 / P Max3 and Pmax6 With P max4 The ratio P Max6 / P Max4 Substitute the values ​​into the two linear regression equations in step T2 to calculate the two concentration values ​​of chloramphenicol in the sample to be tested, and compare the two concentration values ​​to perform self-calibration. The results are shown in Table 1.

[0057] Figure 2 This is the peak-to-peak ratio P of the maximum output power in Example 1. Max1 / P Max3 and P Max2 / P Max4 As the concentration of K2S2O8 varies, with the molar concentration of K2S2O8 ranging from 3 to 11 mM, the peak-to-peak ratio of the maximum output power P can be observed from the figure. Max1 / P Max3 and P Max2 / P Max4 The signal magnitude remained essentially unchanged regardless of the amount of K2S2O8 added, indicating that the amount of K2S2O8 added did not affect the detection results of chloramphenicol within the molar concentration range of 3–11 mM.

[0058] Figure 3 This is a correlation graph of chloramphenicol concentration and PI at the photoanode sub-channel interface PA1 in the dual-ratio light-driven self-powered sensor of Example 1. The graph shows that the PI correlation curves of chloramphenicol standard solutions with different molar concentrations all exhibit a specific maximum output power peak-to-peak value P. max1 and P max2 Furthermore, as the molar concentration of chloramphenicol increases, the peak-to-peak value of the maximum output power P... max1 and P max2 They all gradually increase;

[0059] Figure 4 The graph shows the correlation between chloramphenicol concentration and PI at the photoanode subchannel interface PA2 in the dual-ratio light-driven self-powered sensor of Example 1. The graph indicates that the molar concentration is 2.0 × 10⁻⁶. -12 The PI correlation curve of 1 mol / L chloramphenicol standard solution exhibits a specific maximum output power peak-to-peak value P. max3 and P max4 ;

[0060] Figure 5 The maximum output power ratio P after adding chloramphenicol in Example 1. Max1 / P Max3 The standard curve of chloramphenicol concentration shows the peak-to-peak ratio P of the maximum output power for a series of chloramphenicol standard solutions with different molar concentrations. Max1 / P Max3The linear relationship between the molar concentration of chloramphenicol and the logarithmic value of chloramphenicol was well observed, and the corresponding linear regression equation was obtained.

[0061] Figure 6 The maximum output power ratio P after adding chloramphenicol in Example 1. Max2 / PMax4 The standard curve of chloramphenicol concentration shows the peak-to-peak ratio P of the maximum output power for a series of chloramphenicol standard solutions with different molar concentrations. Max2 / P Max4 The linear relationship between the molar concentration of chloramphenicol and the logarithmic value was well observed, and the corresponding linear regression equation was obtained.

[0062] Example 2

[0063] like Figure 1 As shown, a dual-ratio light-driven self-powered sensor includes a photoanode, a photocathode, a simulated sunlight source, a quartz reaction cell, and an electrolyte solution. The photoanode and photocathode are inserted into the quartz reaction cell containing the electrolyte solution and are connected through an external circuit. The light source simultaneously irradiates the photoanode and photocathode. The electrolyte solution is a 0.1M PBS solution containing K2S2O8. The photoanode has two parallel photoanode sub-channel interfaces, which, together with the photocathode, form two parallel light-driven self-powered systems. Under the self-biased voltage generated by the light irradiation, the two light-driven self-powered systems form current paths and generate electrical energy.

[0064] The preferred technical solution is that the photoanode is a V2C and BiVO4 modified FTO electrode - V2C / BiVO4 / FTO photoanode, and the photocathode is a MoOHCF modified FTO electrode - MoOHCF / FTO photocathode.

[0065] The above-mentioned dual-ratio light-driven self-powered sensor is prepared using the method of the present invention. The operation steps are as follows:

[0066] S1: Preparation of the photoanode: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 2.08 g of Bi(NO3)3·5H2O and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 20 mL of anhydrous ethanol solution containing 0.24 M p-benzoquinone (C6H4O2) as electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A, set a voltage of -0.1 V, and perform electrodeposition using a constant potential method to form BiOI on the surface of the FTO conductive glass. A BiOI / FTO electrode was obtained by forming a film. Next, the BiOI / FTO electrode was chemically converted using a mixture containing 0.2 M vanadium acetylacetone and 10 mL dimethyl sulfoxide (DMSO). The chemically converted electrode was then heat-treated at 450 °C for 2 h at a heating rate of 2 °C / min. The heat-treated electrode was then washed with 1 M sodium hydroxide solution for 30 min to obtain a BiVO4 / FTO electrode. Finally, 10 μL of a 1 mg / mL V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode using a pipette, and the electrode was baked under an infrared lamp for 30 min to obtain a V2C / BiVO4 / FTO photoanode.

[0067] S2: Preparation of the photocathode. First, 0.17 g of potassium ferricyanide, 0.64 g of ammonium molybdate tetrahydrate, and 3.738 g of potassium chloride were added to 25 mL of deionized water to prepare a mixed solution. The solution was stirred continuously for 10 min to obtain electrodeposition reserve solution B. Second, a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode was inserted into the above electrodeposition reserve solution B. Electrodeposition was performed using cyclic voltammetry to form a MoOHCF film on the surface of the FTO conductive glass to obtain a MoOHCF / FTO photocathode. The cyclic voltammetry settings were: voltage window set to -0.1 to 0.8 V, scan rate of 100 mV / s, and number of cycles of 95.

[0068] S3: Preparation of the light-driven self-powered system: The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode mentioned above were inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy. The pH value of the PBS solution is 6.0.

[0069] S4: Preparation of a dual-signal light-driven self-powered sensor: A certain amount of K2S2O8 reagent was added to the PBS solution in the quartz reaction cell to make the molar concentration of K2S2O8 in the PBS solution 7mM. The mixture was stirred evenly to make the output power-current correlation curve of the light-driven self-powered system form two independent power peaks. Chloramphenicol aptamers were then modified onto the surface of the V2C / BiVO4 / FTO photoanode, incubated, and cleaned to obtain a dual-signal light-driven self-powered sensor with specific recognition function. The nucleotide sequence of the chloramphenicol aptamer is: 5′-ACT TCA GTG AGT TGT CCC ACG GTC GGC GAGTCG GTG GTA G-3′, the concentration of the chloramphenicol aptamer is 5μmol / L, and the incubation condition is 60℃ for 5h.

[0070] S5: Fabrication of a dual-ratio light-driven self-powered sensor: The V2C / BiVO4 / FTO photoanode in step S4 is physically separated into a photoanode sub-channel interface PA1 and a photoanode sub-channel interface PA2, resulting in a dual-ratio light-driven self-powered sensor that generates two dual-power output peak signals by coupling two photoelectrodes with K2S2O8 and combining them with spatial resolution.

[0071] The prepared dual-ratio light-driven self-powered sensor was used to detect the concentration of chloramphenicol in wastewater and milk. The operation steps are as follows:

[0072] T1: Preparation of standard solutions containing different concentrations of chloramphenicol: Accurately weigh a certain mass of chloramphenicol and prepare a 1.0 × 10⁻⁶ solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. - 12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 - 9 Chloramphenicol standard solutions of different concentrations (mol / L);

[0073] T2: Establishment of the standard curve: The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor was placed in a series of known concentrations (0.5 × 10⁻⁶). -12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10-10 mol / L, 3.0×10 -9 The photoanode subchannel interface PA1 and photocathode were incubated in a chloramphenicol standard solution (mol / L) for 60 min. Then, the incubated photoanode subchannel interface PA1 and photocathode were placed in a quartz reaction cell in a 0.1 M PBS solution containing K2S2O8. The photoanode subchannel interface PA1 and photocathode were irradiated by a simulated sunlight source. A series of chloramphenicol concentration-maximum output power correspondences and a series of corresponding dual-power output peak-to-peak values ​​P were obtained. Max1 P Max2 The photoanode subchannel interface PA2 of the prepared dual-ratio light-driven self-powered sensor was placed in a solution with a concentration of 1×10⁻⁶. -11 The photoanode subchannel interface PA2 and photocathode were incubated in a mol / L chloramphenicol standard solution for 60 min. Then, the incubated photoanode subchannel interface PA2 and photocathode were placed in a quartz reaction cell in a 0.1 M PBS solution containing K2S2O8. The photoanode subchannel interface PA2 and photocathode were irradiated by a simulated sunlight source. The relationship between the fixed concentration of chloramphenicol and the maximum output power, as well as the corresponding peak-to-peak value P of the dual-power output, were obtained. max3 P max4 Using a series of chloramphenicol concentrations, dual-power output peak-to-peak values ​​P Max1 With P max3 The ratio P Max1 / P Max3 Dual power output peak-to-peak value P Max2 With P max4 The ratio P Max2 P Max4 Two standard curves were fitted to the peak-to-peak ratio of the maximum output power of chloramphenicol and the logarithm of the chloramphenicol concentration. Two linear relationships were established between the peak-to-peak ratio of the maximum output power of the dual-ratio light-driven self-powered sensor after the addition of chloramphenicol and the logarithm of the chloramphenicol concentration, resulting in two different linear regression equations.

[0074] T3: Detection of chloramphenicol concentration in the test sample: First, the test sample is pretreated by letting it stand for more than 1 hour. Then, the test sample is centrifuged and the supernatant is used as the test sample. The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor is placed in the test sample and incubated for 60 minutes. Then, the incubated photoanode sub-channel interface PA1 and photocathode are placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell. The photoanode sub-channel interface PA1 and photocathode are irradiated by a simulated sunlight source, and the peak-to-peak value of the dual power output P corresponding to chloramphenicol is measured. max5 P max6 , will P max5 With P max3 The ratio P Max5 / P Max3 and Pmax6 With P max4 The ratio P Max6 / P Max4 Substitute the values ​​into the two linear regression equations in step T2 to calculate the two concentration values ​​of chloramphenicol in the sample to be tested, and compare the two concentration values ​​to perform self-calibration. The results are shown in Table 1.

[0075] Example 3

[0076] like Figure 1 As shown, a dual-ratio light-driven self-powered sensor includes a photoanode, a photocathode, a simulated sunlight source, a quartz reaction cell, and an electrolyte solution. The photoanode and photocathode are inserted into the quartz reaction cell containing the electrolyte solution and are connected through an external circuit. The light source simultaneously irradiates the photoanode and photocathode. The electrolyte solution is a 0.1M PBS solution containing K2S2O8. The photoanode has two parallel photoanode sub-channel interfaces, which, together with the photocathode, form two parallel light-driven self-powered systems. Under the self-biased voltage generated by the light irradiation, the two light-driven self-powered systems form current paths and generate electrical energy.

[0077] The preferred technical solution is that the photoanode is a V2C and BiVO4 modified FTO electrode - V2C / BiVO4 / FTO photoanode, and the photocathode is a MoOHCF modified FTO electrode - MoOHCF / FTO photocathode.

[0078] The above-mentioned dual-ratio light-driven self-powered sensor is prepared using the method of the present invention. The operation steps are as follows:

[0079] S1: Preparation of the photoanode: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 2.18 g of Bi(NO3)3·5H2O and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 20 mL of anhydrous ethanol solution containing 0.25 M p-benzoquinone (C6H4O2) as electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A, set a voltage of -0.1 V, and perform electrodeposition using a constant potential method to form BiOI on the surface of the FTO conductive glass. A BiOI / FTO electrode was obtained by forming a film. Next, the BiOI / FTO electrode was chemically converted using a mixture containing 0.2 M vanadium acetylacetone and 10 mL dimethyl sulfoxide (DMSO). The chemically converted electrode was then heat-treated at 450 °C for 2 h at a heating rate of 2 °C / min. The heat-treated electrode was then washed with 1 M sodium hydroxide solution for 30 min to obtain a BiVO4 / FTO electrode. Finally, 10 μL of a 1 mg / mL V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode using a pipette, and the electrode was baked under an infrared lamp for 30 min to obtain a V2C / BiVO4 / FTO photoanode.

[0080] S2: Preparation of the photocathode. First, 0.175 g of potassium ferricyanide, 0.66 g of ammonium molybdate tetrahydrate, and 3.748 g of potassium chloride were added to 25 mL of deionized water to prepare a mixed solution. The solution was stirred continuously for 10 min to obtain electrodeposition reserve solution B. Second, a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode was inserted into the above electrodeposition reserve solution B. Electrodeposition was performed using cyclic voltammetry to form a MoOHCF film on the surface of the FTO conductive glass to obtain a MoOHCF / FTO photocathode. The cyclic voltammetry settings were: voltage window set to -0.1 to 0.8 V, scan rate of 100 mV / s, and number of cycles of 100.

[0081] S3: Preparation of the light-driven self-powered system: The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode mentioned above were inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy. The pH value of the PBS solution is 5.0.

[0082] S4: Preparation of a dual-signal light-driven self-powered sensor: A certain amount of K2S2O8 reagent was added to the PBS solution in the quartz reaction cell to make the molar concentration of K2S2O8 in the PBS solution 3mM. The mixture was stirred evenly to make the output power-current correlation curve of the light-driven self-powered system form two independent power peaks. Chloramphenicol aptamers were then modified onto the surface of the V2C / BiVO4 / FTO photoanode, incubated, and cleaned to obtain a dual-signal light-driven self-powered sensor with specific recognition function. The nucleotide sequence of the chloramphenicol aptamer is: 5′-ACT TCA GTG AGT TGT CCC ACG GTC GGC GAGTCG GTG GTA G-3′, the concentration of the chloramphenicol aptamer is 5μmol / L, and the incubation condition is 60℃ for 5h.

[0083] S5: Fabrication of a dual-ratio light-driven self-powered sensor: The V2C / BiVO4 / FTO photoanode in step S4 is physically separated into a photoanode sub-channel interface PA1 and a photoanode sub-channel interface PA2, resulting in a dual-ratio light-driven self-powered sensor that generates two dual-power output peak signals by coupling two photoelectrodes with K2S2O8 and combining them with spatial resolution.

[0084] The prepared dual-ratio light-driven self-powered sensor was used to detect the concentration of chloramphenicol in wastewater and milk. The operation steps are as follows:

[0085] T1: Preparation of standard solutions containing different concentrations of chloramphenicol: Accurately weigh a certain mass of chloramphenicol and prepare a 1.0 × 10⁻⁶ solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. - 12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 - 9 Chloramphenicol standard solutions of different concentrations (mol / L);

[0086] T2: Establishment of the standard curve: The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor was placed in a series of known concentrations (0.5 × 10⁻⁶). -12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10-10 mol / L, 3.0×10 -9 The photoanode subchannel interface PA1 and photocathode were incubated in a chloramphenicol standard solution (mol / L) for 60 min. Then, the incubated photoanode subchannel interface PA1 and photocathode were placed in a quartz reaction cell in a 0.1 M PBS solution containing K2S2O8. The photoanode subchannel interface PA1 and photocathode were irradiated by a simulated sunlight source. A series of chloramphenicol concentration-maximum output power correspondences and a series of corresponding dual-power output peak-to-peak values ​​P were obtained. Max1 P Max2 The photoanode subchannel interface PA2 of the prepared dual-ratio light-driven self-powered sensor was placed in a solution with a concentration of 5.0 × 10⁻⁶. -11 The photoanode subchannel interface PA2 and photocathode were incubated in a mol / L chloramphenicol standard solution for 60 min. Then, the incubated photoanode subchannel interface PA2 and photocathode were placed in a quartz reaction cell in a 0.1 M PBS solution containing K2S2O8. The photoanode subchannel interface PA2 and photocathode were irradiated by a simulated sunlight source. The relationship between the fixed concentration of chloramphenicol and the maximum output power, as well as the corresponding peak-to-peak value P of the dual-power output, were obtained. max3 P max4 Using a series of chloramphenicol concentrations, dual-power output peak-to-peak values ​​P Max1 With P max3 The ratio P Max1 / P Max3 Dual power output peak-to-peak value P Max2 With P max4 The ratio P Max2 P Max4 Two standard curves were fitted to the peak-to-peak ratio of the maximum output power of chloramphenicol and the logarithm of the chloramphenicol concentration. Two linear relationships were established between the peak-to-peak ratio of the maximum output power of the dual-ratio light-driven self-powered sensor after the addition of chloramphenicol and the logarithm of the chloramphenicol concentration, resulting in two different linear regression equations.

[0087] T3: Detection of chloramphenicol concentration in the test sample: First, the test sample is pretreated by letting it stand for more than 1 hour. Then, the test sample is centrifuged and the supernatant is used as the test sample. The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor is placed in the test sample and incubated for 60 minutes. Then, the incubated photoanode sub-channel interface PA1 and photocathode are placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell. The photoanode sub-channel interface PA1 and photocathode are irradiated by a simulated sunlight source, and the peak-to-peak value of the dual power output P corresponding to chloramphenicol is measured. max5 P max6 , will P max5 With P max3 The ratio P Max5 / P Max3 and Pmax6 With P max4 The ratio P Max6 / P Max4 Substitute the values ​​into the two linear regression equations in step T2 to calculate the two concentration values ​​of chloramphenicol in the sample to be tested, and compare the two concentration values ​​to perform self-calibration. The results are shown in Table 1.

[0088] Comparative Example 1

[0089] A dual-ratio optically driven self-powered sensor was fabricated, and the operation steps are as follows:

[0090] S1: Preparation of the photoanode: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 1.94 g of Bi(NO3)3·5H2O and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 20 mL of anhydrous ethanol solution containing 0.23 M p-benzoquinone (C6H4O2) as electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A, set a voltage of -0.1 V, and perform electrodeposition using a potentiostatic method to form BiOI on the surface of the FTO conductive glass. A BiOI / FTO electrode was obtained by forming a film. Next, the BiOI / FTO electrode was chemically converted using a mixture containing 0.2 M vanadium acetylacetone and 10 mL dimethyl sulfoxide (DMSO). The chemically converted electrode was then heat-treated at 450 °C for 2 h at a heating rate of 2 °C / min. The heat-treated electrode was then washed with 1 M sodium hydroxide solution for 30 min to obtain a BiVO4 / FTO electrode. Finally, 10 μL of a 1 mg / mL V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode using a pipette, and the electrode was baked under an infrared lamp for 30 min to obtain a V2C / BiVO4 / FTO photoanode.

[0091] S2: Preparation of the photocathode. First, 0.165 g of potassium ferricyanide, 0.620 g of ammonium molybdate tetrahydrate, and 3.728 g of potassium chloride were added to 25 mL of deionized water to prepare a mixed solution. The solution was stirred continuously for 10 min to obtain electrodeposition reserve solution B. Second, a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode was inserted into the above electrodeposition reserve solution B. Electrodeposition was performed using cyclic voltammetry to form a MoOHCF film on the surface of the FTO conductive glass to obtain a MoOHCF / FTO photocathode. The cyclic voltammetry settings were: voltage window set to -0.1 to 0.8 V, scan rate of 100 mV / s, and number of cycles of 90.

[0092] S3: Preparation of the light-driven self-powered system: The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode mentioned above were inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy. The pH value of the PBS solution is 7.0.

[0093] S4: Preparation of a dual-signal light-driven self-powered sensor: A certain amount of K2S2O8 reagent was added to the PBS solution in the quartz reaction cell to make the molar concentration of K2S2O8 in the PBS solution 8mM. The mixture was stirred evenly to make the output power-current correlation curve of the light-driven self-powered system form two independent power peaks. Chloramphenicol aptamers were then modified onto the surface of the V2C / BiVO4 / FTO photoanode, incubated, and cleaned to obtain a dual-signal light-driven self-powered sensor with specific recognition function. The nucleotide sequence of the chloramphenicol aptamer is: 5′-ACT TCA GTG AGT TGT CCC ACG GTC GGC GAGTCG GTG GTA G-3′, the concentration of the chloramphenicol aptamer is 5μmol / L, and the incubation condition is 60℃ for 5h.

[0094] S5: Fabrication of a dual-ratio light-driven self-powered sensor: The V2C / BiVO4 / FTO photoanode in step S4 is physically separated into a photoanode sub-channel interface PA1 and a photoanode sub-channel interface PA2, resulting in a dual-ratio light-driven self-powered sensor that generates two dual-power output peak signals by coupling two photoelectrodes with K2S2O8 and combining them with spatial resolution.

[0095] The prepared dual-ratio light-driven self-powered sensor was used to detect the concentration of chloramphenicol in wastewater and milk. The operation steps are as follows:

[0096] T1: Preparation of standard solutions containing different concentrations of chloramphenicol: Accurately weigh a certain mass of chloramphenicol and prepare a 1.0 × 10⁻⁶ solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. - 12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 -9 Chloramphenicol standard solutions of different concentrations (mol / L);

[0097] T2: Establishment of the standard curve: The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor was placed in a series of known concentrations (0.5 × 10⁻⁶). -12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 -9 The photoanode subchannel interface PA1 and photocathode were incubated in a chloramphenicol standard solution (mol / L) for 60 min. Then, the incubated photoanode subchannel interface PA1 and photocathode were placed in a quartz reaction cell in a 0.1 M PBS solution containing K2S2O8. The photoanode subchannel interface PA1 and photocathode were irradiated by a simulated sunlight source. A series of chloramphenicol concentration-maximum output power correspondences and a series of corresponding dual-power output peak-to-peak values ​​P were obtained. Max1 P Max2 The photoanode subchannel interface PA2 of the prepared dual-ratio light-driven self-powered sensor was placed in a solution with a concentration of 2.0 × 10⁻⁶. -12 The photoanode subchannel interface PA2 and photocathode were incubated in a mol / L chloramphenicol standard solution for 60 min. Then, the incubated photoanode subchannel interface PA2 and photocathode were placed in a quartz reaction cell in a 0.1 M PBS solution containing K2S2O8. The photoanode subchannel interface PA2 and photocathode were irradiated by a simulated sunlight source. The relationship between the fixed concentration of chloramphenicol and the maximum output power, as well as the corresponding peak-to-peak value P of the dual-power output, were obtained. max3 P max4 Using a series of chloramphenicol concentrations, dual-power output peak-to-peak values ​​P Max1 With P max3 The ratio P Max1 / P Max3 Dual power output peak-to-peak value P Max2 With P max4 The ratio P Max2 P Max4 Two standard curves were fitted to the peak-to-peak ratio of the maximum output power of chloramphenicol and the logarithm of the chloramphenicol concentration. Two linear relationships were established between the peak-to-peak ratio of the maximum output power of the dual-ratio light-driven self-powered sensor after the addition of chloramphenicol and the logarithm of the chloramphenicol concentration, resulting in two different linear regression equations.

[0098] T3: Detection of chloramphenicol concentration in the test sample: First, the test sample is pretreated by letting it stand for more than 1 hour. Then, the test sample is centrifuged and the supernatant is used as the test sample. The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor is placed in the test sample and incubated for 60 minutes. Then, the incubated photoanode sub-channel interface PA1 and photocathode are placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell. The photoanode sub-channel interface PA1 and photocathode are irradiated by a simulated sunlight source, and the peak-to-peak value of the dual power output P corresponding to chloramphenicol is measured. max5 P max6 , will P max5 With P max3 The ratio P Max5 / P Max3 and P max6 With P max4 The ratio P Max6 / P Max4 Substitute the values ​​into the two linear regression equations in step T2 to calculate the two concentration values ​​of chloramphenicol in the sample to be tested, and compare the two concentration values ​​to perform self-calibration. The results are shown in Table 1.

[0099] Comparative Example 2

[0100] A dual-signal optically driven self-powered sensor is fabricated, and the operation steps are as follows:

[0101] S1: Preparation of the photoanode: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 1.94 g of Bi(NO3)3·5H2O and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 20 mL of anhydrous ethanol solution containing 0.23 M p-benzoquinone (C6H4O2) as electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A, set a voltage of -0.1 V, and perform electrodeposition using a potentiostatic method to form BiOI on the surface of the FTO conductive glass. A BiOI / FTO electrode was obtained by forming a film. Next, the BiOI / FTO electrode was chemically converted using a mixture containing 0.2 M vanadium acetylacetone and 10 mL dimethyl sulfoxide (DMSO). The chemically converted electrode was then heat-treated at 450 °C for 2 h at a heating rate of 2 °C / min. The heat-treated electrode was then washed with 1 M sodium hydroxide solution for 30 min to obtain a BiVO4 / FTO electrode. Finally, 10 μL of a 1 mg / mL V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode using a pipette, and the electrode was baked under an infrared lamp for 30 min to obtain a V2C / BiVO4 / FTO photoanode.

[0102] S2: Preparation of the photocathode. First, 0.165 g of potassium ferricyanide, 0.620 g of ammonium molybdate tetrahydrate, and 3.728 g of potassium chloride were added to 25 mL of deionized water to prepare a mixed solution. The solution was stirred continuously for 10 min to obtain electrodeposition reserve solution B. Second, a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode was inserted into the above electrodeposition reserve solution B. Electrodeposition was performed using cyclic voltammetry to form a MoOHCF film on the surface of the FTO conductive glass to obtain a MoOHCF / FTO photocathode. The cyclic voltammetry settings were: voltage window set to -0.1 to 0.8 V, scan rate of 100 mV / s, and number of cycles of 90.

[0103] S3: Preparation of the light-driven self-powered system: The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode mentioned above were inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy. The pH value of the PBS solution is 7.0.

[0104] S4: Preparation of a dual-signal light-driven self-powered sensor: A certain amount of K2S2O8 reagent was added to the PBS solution in the quartz reaction cell to make the molar concentration of K2S2O8 in the PBS solution 11mM. The mixture was stirred evenly to make the output power-current correlation curve of the light-driven self-powered system form two independent power peaks. Chloramphenicol aptamers were then modified onto the surface of the V2C / BiVO4 / FTO photoanode, incubated, and cleaned to obtain a dual-signal light-driven self-powered sensor with specific recognition function. The nucleotide sequence of the chloramphenicol aptamer is: 5′-ACT TCA GTG AGT TGT CCC ACG GTC GGC GAGTCG GTG GTA G-3′, the concentration of the chloramphenicol aptamer is 5μmol / L, and the incubation condition is 60℃ for 5h.

[0105] The prepared dual-signal optically driven self-powered sensor was used to detect the concentration of chloramphenicol in wastewater and milk. The operation steps are as follows:

[0106] T1: Preparation of standard solutions containing different concentrations of chloramphenicol: Accurately weigh a certain mass of chloramphenicol and prepare a 1.0 × 10⁻⁶ solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. - 12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 - 9 Chloramphenicol standard solutions of different concentrations (mol / L);

[0107] T2: Establishment of the standard curve: The V2C / BiVO4 / FTO photoanode of the prepared dual-signal light-driven self-powered sensor was placed in a series of known concentrations (0.5 × 10⁻⁶). -12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 -9The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode were incubated in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell for 60 min. The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode were then irradiated with simulated sunlight. A series of chloramphenicol concentration-maximum output power correlations and a series of corresponding dual-power output peak-to-peak values ​​(P0) were obtained. Max1 P Max2 Two standard curves were fitted to the peak-to-peak value of the maximum output power of chloramphenicol and the logarithm of chloramphenicol concentration. Two linear relationships were established between the peak-to-peak value of the maximum output power of the dual-signal light-driven self-powered sensor after the addition of chloramphenicol and the logarithm of chloramphenicol concentration, resulting in two different linear regression equations.

[0108] T3: Detection of chloramphenicol concentration in the test sample: First, the test sample is pretreated by letting it stand for more than 1 hour. Then, the test sample is centrifuged and the supernatant is used as the test sample. The V2C / BiVO4 / FTO photoanode of the prepared dual-signal light-driven self-powered sensor is incubated in the test sample for 60 minutes. Then, the incubated V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode are placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell. The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode are illuminated by simulated sunlight. The peak-to-peak value of the dual power output P corresponding to chloramphenicol is measured. max5 P max6 , will P max5 and P max6 Substitute the values ​​into the two linear regression equations in step T2 to calculate the two concentration values ​​of chloramphenicol in the sample to be tested, and compare the two concentration values ​​to perform self-calibration. The results are shown in Table 1.

[0109] Comparative Example 3

[0110] A dual-signal optically driven self-powered sensor is fabricated, and the operation steps are as follows:

[0111] S1: Preparation of the photoanode: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 1.94 g of Bi(NO3)3·5H2O and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 20 mL of anhydrous ethanol solution containing 0.23 M p-benzoquinone (C6H4O2) as electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A, set a voltage of -0.1 V, and perform electrodeposition using a potentiostatic method to form BiOI on the surface of the FTO conductive glass. A BiOI / FTO electrode was obtained by forming a film. Next, the BiOI / FTO electrode was chemically converted using a mixture containing 0.2 M vanadium acetylacetone and 10 mL dimethyl sulfoxide (DMSO). The chemically converted electrode was then heat-treated at 450 °C for 2 h at a heating rate of 2 °C / min. The heat-treated electrode was then washed with 1 M sodium hydroxide solution for 30 min to obtain a BiVO4 / FTO electrode. Finally, 10 μL of a 1 mg / mL V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode using a pipette, and the electrode was baked under an infrared lamp for 30 min to obtain a V2C / BiVO4 / FTO photoanode.

[0112] S2: Preparation of the photocathode. First, 0.165 g of potassium ferricyanide, 0.620 g of ammonium molybdate tetrahydrate, and 3.728 g of potassium chloride were added to 25 mL of deionized water to prepare a mixed solution. The solution was stirred continuously for 10 min to obtain electrodeposition reserve solution B. Second, a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode was inserted into the above electrodeposition reserve solution B. Electrodeposition was performed using cyclic voltammetry to form a MoOHCF film on the surface of the FTO conductive glass to obtain a MoOHCF / FTO photocathode. The cyclic voltammetry settings were: voltage window set to -0.1 to 0.8 V, scan rate of 100 mV / s, and number of cycles of 90.

[0113] S3: Preparation of the light-driven self-powered system: The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode mentioned above were inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy. The pH value of the PBS solution is 7.0.

[0114] S4: Preparation of a dual-signal light-driven self-powered sensor: A certain amount of K2S2O8 reagent was added to the PBS solution in the quartz reaction cell to make the molar concentration of K2S2O8 in the PBS solution 8mM. After stirring evenly, the output power-current correlation curve of the light-driven self-powered system formed two independent power peaks. Chloramphenicol aptamers were then modified onto the surface of the V2C / BiVO4 / FTO photoanode, incubated, and cleaned to obtain a dual-signal light-driven self-powered sensor with specific recognition function. The nucleotide sequence of the chloramphenicol aptamer is: 5′-ACT TCA GTG AGT TGT CCC ACG GTC GGC GAGTCG GTG GTA G-3′, the concentration of the chloramphenicol aptamer is 5μmol / L, and the incubation condition is 60℃ for 5h.

[0115] The prepared dual-signal optically driven self-powered sensor was used to detect the concentration of chloramphenicol in wastewater and milk. The operation steps are as follows:

[0116] T1: Preparation of standard solutions containing different concentrations of chloramphenicol: Accurately weigh a certain mass of chloramphenicol and prepare a 1.0 × 10⁻⁶ solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. - 12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 - 9 Chloramphenicol standard solutions of different concentrations (mol / L);

[0117] T2: Establishment of the standard curve: The V2C / BiVO4 / FTO photoanode of the prepared dual-signal light-driven self-powered sensor was placed in a series of known concentrations (0.5 × 10⁻⁶). -12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 -9The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode were incubated in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell for 60 min. The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode were then irradiated with simulated sunlight. A series of chloramphenicol concentration-maximum output power correlations and a series of corresponding dual-power output peak-to-peak values ​​(P0) were obtained. Max1 P Max2 Two standard curves were fitted to the peak-to-peak value of the maximum output power of chloramphenicol and the logarithm of chloramphenicol concentration. Two linear relationships were established between the peak-to-peak value of the maximum output power of the dual-signal light-driven self-powered sensor after the addition of chloramphenicol and the logarithm of chloramphenicol concentration, resulting in two different linear regression equations.

[0118] T3: Detection of chloramphenicol concentration in the test sample: First, the test sample is pretreated by letting it stand for more than 1 hour. Then, the test sample is centrifuged and the supernatant is used as the test sample. The V2C / BiVO4 / FTO photoanode of the prepared dual-signal light-driven self-powered sensor is incubated in the test sample for 60 minutes. Then, the incubated V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode are placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell. The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode are illuminated by simulated sunlight. The peak-to-peak value of the dual power output P corresponding to chloramphenicol is measured. max5 P max6 , will P max5 and P max6 Substitute the values ​​into the two linear regression equations in step T2 to calculate the two concentration values ​​of chloramphenicol in the sample to be tested, and compare the two concentration values ​​to perform self-calibration. The results are shown in Table 1.

[0119] Comparative Example 4

[0120] The following are the steps for fabricating a light-driven self-powered sensor:

[0121] S1: Preparation of the photoanode: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 1.94 g of Bi(NO3)3·5H2O and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 40 mL of anhydrous ethanol solution containing 0.46 M p-benzoquinone (C6H4O2) as electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A, set a voltage of -0.1 V, and perform electrodeposition using a potentiostatic method to form BiOI on the surface of the FTO conductive glass. A BiOI / FTO electrode was obtained by forming a film. Next, the BiOI / FTO electrode was chemically converted using a mixture containing 0.2 M vanadium acetylacetone and 10 mL dimethyl sulfoxide (DMSO). The chemically converted electrode was then heat-treated at 450 °C for 2 h at a heating rate of 2 °C / min. The heat-treated electrode was then washed with 1 M sodium hydroxide solution for 30 min to obtain a BiVO4 / FTO electrode. Finally, 10 μL of a 1 mg / mL V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode using a pipette, and the electrode was baked under an infrared lamp for 30 min to obtain a V2C / BiVO4 / FTO photoanode.

[0122] S2: Preparation of the photocathode. First, 0.165 g of potassium ferricyanide, 0.620 g of ammonium molybdate tetrahydrate, and 3.728 g of potassium chloride were added to 25 mL of deionized water to prepare a mixed solution. The solution was stirred continuously for 10 min to obtain electrodeposition reserve solution B. Second, a three-electrode system consisting of FTO conductive glass as the working electrode, a platinum electrode as the auxiliary electrode, and an Ag / AgCl electrode as the reference electrode was inserted into the above electrodeposition reserve solution B. Electrodeposition was performed using cyclic voltammetry to form a MoOHCF film on the surface of the FTO conductive glass to obtain a MoOHCF / FTO photocathode. The cyclic voltammetry settings were: voltage window set to -0.1 to 0.8 V, scan rate of 100 mV / s, and number of cycles of 90.

[0123] S3: Preparation of the light-driven self-powered system: The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode mentioned above were inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy. The pH value of the PBS solution is 7.0.

[0124] S4: Fabrication of a light-driven self-powered sensor: A chloramphenicol aptamer was modified on the surface of a V2C / BiVO4 / FTO photoanode, incubated, and cleaned to obtain a signal light-driven self-powered sensor with specific recognition function. The nucleotide sequence of the chloramphenicol aptamer is: 5′-ACT TCA GTG AGT TGT CCC ACG GTC GGC GAG TCG GTG GTA G-3′, the concentration of the chloramphenicol aptamer is 5 μmol / L, and the incubation condition is 60℃ for 5 h.

[0125] The prepared light-driven self-powered sensor was used to detect the concentration of chloramphenicol in wastewater and milk. The operation steps are as follows:

[0126] T1: Preparation of standard solutions containing different concentrations of chloramphenicol: Accurately weigh a certain mass of chloramphenicol and prepare a 1.0 × 10⁻⁶ solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. - 12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 -10 mol / L, 5.0×10 -10 mol / L, 3.0×10 - 9 Chloramphenicol standard solutions of different concentrations (mol / L);

[0127] T2: Establishment of the standard curve: The V2C / BiVO4 / FTO photoanode of the prepared light-driven self-powered sensor was placed in a series of known concentrations (0.5 × 10⁻⁶). -12 mol / L, 2.0×10 -12 mol / L, 2.0×10 -11 mol / L, 1.0×10 - 10 mol / L, 5.0×10 -10 mol / L, 3.0×10 -9 The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode were incubated in a 1 mol / L chloramphenicol standard solution for 60 min. Then, the incubated V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode were placed in a PBS solution within a quartz reaction cell to simulate sunlight irradiation. A series of chloramphenicol concentration-maximum output power correlations were obtained, and the peak-to-peak value P of the maximum output power of chloramphenicol was fitted. MaxBy using a standard curve of the logarithm of chloramphenicol concentration, a linear relationship was established between the peak-to-peak value of the maximum output power of the light-driven self-powered sensor after the addition of chloramphenicol and the logarithm of chloramphenicol concentration, thus obtaining a linear regression equation.

[0128] T3: Detection of chloramphenicol concentration in the test sample: First, the test sample is pretreated by letting it stand for more than 1 hour. Then, the test sample is centrifuged and the supernatant is used as the test sample. The V2C / BiVO4 / FTO photoanode of the prepared signal light-driven self-powered sensor is incubated in the test sample for 60 minutes. Then, the incubated V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode are placed in a quartz reaction cell in a 0.1M PBS solution containing K2S2O8. The V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode are simulated by sunlight. The peak-to-peak power output P corresponding to chloramphenicol is measured. max5 , will P max5 Substituting the values ​​into the linear regression equation in step T2, the concentration of chloramphenicol in the sample to be tested was calculated, and the results are shown in Table 1.

[0129] Figure 7 To compare the correlation between chloramphenicol concentration and PI in the light-driven self-powered sensor of Example 4, it can be seen from the figure that the PI correlation curves of chloramphenicol standard solutions with different molar concentrations all exhibit a specific peak-to-peak value of maximum output power P. max And P max As the molar concentration of chloramphenicol increases;

[0130] Figure 8 To compare the maximum output power P after adding chloramphenicol in Example 4 Max The standard curve of chloramphenicol concentration shows the peak-to-peak value of the maximum output power P corresponding to a series of chloramphenicol standard solutions with different molar concentrations. Max The linear relationship between the molar concentration of chloramphenicol and the logarithmic value was well observed, and the corresponding linear regression equation was obtained.

[0131] Table 1. Experimental results of Examples 1-3 and Comparative Examples 1-3

[0132]

[0133] Experimental results show that the light-driven self-powered sensor in Comparative Example 4 failed to detect the concentration of chloramphenicol in the sample, while the dual-ratio light-driven self-powered sensors in Examples 1-3 and Comparative Example 1, and the dual-signal light-driven self-powered sensors in Examples 2-3 were able to detect the concentration of chloramphenicol in the sample. This indicates that the detection limits of the dual-ratio light-driven self-powered sensor and the dual-signal light-driven self-powered sensor are better than those of the light-driven self-powered sensor in Comparative Example 4. However, the detection results of Comparative Example 2 and Comparative Example 3 are significantly different, indicating that the constructed dual-signal light-driven self-powered sensor is prone to inaccurate detection results due to changes in the sensor output electrical signal caused by unstable K2S2O8 addition. However, the detection results of Example 1 and Comparative Example 1 are almost identical, demonstrating that the dual-ratio light-driven self-powered sensor proposed in this invention improves upon the shortcomings of the dual-signal light-driven self-powered sensor, which suffers from inaccurate detection results due to changes in the sensor output electrical signal caused by unstable K2S2O8 addition.

[0134] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dual-ratio light-driven self-powered sensor, comprising a photoanode, a photocathode, a simulated sunlight source, a quartz reaction cell, and an electrolyte solution, wherein the photoanode and photocathode are inserted into the quartz reaction cell containing the electrolyte solution and are connected via an external circuit, and the light source simultaneously illuminates the photoanode and photocathode, characterized in that, The electrolyte solution is a 0.1M PBS solution containing K2S2O8. The photoanode has two independent photoanode sub-channel interfaces arranged in parallel. The two photoanode sub-channel interfaces are respectively inserted into the same quartz reaction cell containing the electrolyte solution with the same photocathode to form two parallel light-driven self-powered systems. The two light-driven self-powered systems form current paths under the self-bias voltage generated under light irradiation conditions, thereby generating electrical energy.

2. The dual-ratio optically driven self-powered sensor as described in claim 1, characterized in that, The photoanode is a V2C and BiVO4 modified FTO electrode - V2C / BiVO4 / FTO photoanode, and the photocathode is a MoOHCF modified FTO electrode - MoOHCF / FTO photocathode.

3. A method for fabricating a dual-ratio light-driven self-powered sensor, characterized in that, The fabrication of the dual-ratio light-driven self-powered sensor according to claim 2 includes the following steps: S1: Preparation of photoanode: A BiOI film is electrodeposited on FTO conductive glass using a three-electrode system to form a BiOI / FTO electrode. Then, the BiOI / FTO electrode is sequentially placed in a solution of vanadium acetylacetone for chemical conversion, heat treatment, and alkaline washing to obtain a BiVO4 / FTO electrode. A V2C suspension is coated on the surface of the BiVO4 / FTO electrode and dried to obtain a V2C / BiVO4 / FTO photoanode. S2: The photocathode is fabricated by electrodepositing a MoOHCF film on FTO conductive glass using a three-electrode system to form a MoOHCF / FTO photocathode; S3: Preparation of the light-driven self-powered system: The above-mentioned V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode are inserted into a quartz reaction cell containing 0.1M PBS solution and connected through an external circuit to form a light-driven self-powered system. The system simulates sunlight irradiating the V2C / BiVO4 / FTO photoanode and MoOHCF / FTO photocathode, so that the constructed light-driven self-powered system forms a current path under the self-bias voltage generated under the light irradiation condition, and generates electrical energy. S4: Preparation of a dual-signal light-driven self-powered sensor: A certain amount of K2S2O8 reagent was added to the PBS solution in the quartz reaction cell and stirred evenly so that the output power-current correlation curve of the light-driven self-powered system formed two independent power peaks. The target material aptamer was then modified on the surface of the V2C / BiVO4 / FTO photoanode, incubated and cleaned to obtain a dual-signal light-driven self-powered sensor with specific recognition function. S5: Fabrication of a dual-ratio light-driven self-powered sensor: The V2C / BiVO4 / FTO photoanode in step S4 is physically separated into a photoanode sub-channel interface PA1 and a photoanode sub-channel interface PA2, resulting in a dual-ratio light-driven self-powered sensor that generates two dual-power output peak signals by coupling two photoelectrodes with K2S2O8 and combining them with spatial resolution.

4. The method for fabricating a dual-ratio optically driven self-powered sensor as described in claim 3, characterized in that, The specific operation of step S1 is as follows: First, prepare 50 mL of 0.4 M potassium iodide solution and adjust the pH to 1.7 with nitric acid; second, add 1.94–2.18 g of bismuth nitrate pentahydrate and stir to obtain a homogeneous solution; then, mix the prepared homogeneous solution with 20 mL of anhydrous ethanol solution containing 0.23–0.25 M p-benzoquinone to obtain electrodeposition reserve solution A; insert a three-electrode system consisting of FTO conductive glass as the working electrode, platinum electrode as the auxiliary electrode, and Ag / AgCl electrode as the reference electrode into the electrodeposition reserve solution A to perform electrodeposition, forming Bi on the surface of the FTO conductive glass. OI film was used to obtain BiOI / FTO electrode; then, the BiOI / FTO electrode was chemically converted with a mixture containing 0.2M vanadium acetylacetone and 10mL dimethyl sulfoxide. The chemically converted electrode was then heat-treated at 450℃ for 2h at a heating rate of 2℃ / min. The heat-treated electrode was then washed with 1M sodium hydroxide solution for 30min to obtain BiVO4 / FTO electrode; finally, V2C suspension was uniformly drop-coated onto the surface of the BiVO4 / FTO electrode with a pipette, and the electrode was baked under an infrared lamp for 30min to obtain V2C / BiVO4 / FTO photoanode.

5. The method for fabricating a dual-ratio optically driven self-powered sensor as described in claim 4, characterized in that, In step S1: the electrodeposition method used is the constant potential method, and the voltage is set to -0.1V; the mass concentration of the V2C suspension used is 1mg / mL, and the drop volume of the V2C suspension is 10μL.

6. The method for fabricating a dual-ratio optically driven self-powered sensor as described in claim 3, characterized in that, The specific operation of step S2 is as follows: First, 0.165-0.175g of potassium ferricyanide, 0.620-0.660g of ammonium molybdate tetrahydrate and 3.728-3.748g of potassium chloride are added to 25mL of deionized water to prepare a mixed solution, and the solution is stirred continuously for 10min to obtain electrodeposition reserve solution B; Second, a three-electrode system consisting of FTO conductive glass as the working electrode, platinum electrode as the auxiliary electrode and Ag / AgCl electrode as the reference electrode is inserted into the above electrodeposition reserve solution B to perform electrodeposition, forming a MoOHCF film on the surface of FTO conductive glass to obtain a MoOHCF / FTO photocathode.

7. The method for fabricating a dual-ratio optically driven self-powered sensor as described in claim 6, characterized in that, In step S2, the electrodeposition method used is cyclic voltammetry, with a voltage window set to -0.1 to 0.8 V, a scan rate of 100 mV / s, and a cycle count of 90 to 100.

8. The method for fabricating a dual-ratio optically driven self-powered sensor as described in claim 3, characterized in that, In step S3, the pH value of the PBS solution is 6.0 to 7.0; in step S4, the molar concentration of K2S2O8 in the PBS solution is 3 to 11 mM.

9. An application of the dual-ratio optically driven self-powered sensor as described in claim 1 or 2, characterized in that, The procedure for detecting small molecule target substances includes the following steps: T1: Preparation of standard solutions containing different concentrations of the target substance: Accurately weigh the target substance and prepare a 1.0 × 10⁻⁶ standard solution using deionized water. -6 A standard solution of mol / L was prepared by serially diluting the standard solution with deionized water to obtain a 0.5 × 10⁻⁶ mol / L solution. -12 mol / L~3.0×10 -9 Standard solutions of the target substance at different concentrations (mol / L); T2: Establishment of the standard curve: The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor was incubated in a series of target substance standard solutions of known concentrations. Then, the photoanode sub-channel interface PA1 and the photocathode were placed in a quartz reaction cell in a 0.1M PBS solution containing K2S2O8 to simulate sunlight irradiation of the photoanode sub-channel interface PA1 and the photocathode. A series of target substance concentration-maximum output power correspondences and a series of corresponding dual-power output peak-to-peak values ​​P were obtained. Max1 P Max2 The photoanode subchannel interface PA2 of the prepared dual-ratio light-driven self-powered sensor was incubated in a standard solution of the target substance at a fixed concentration. Then, the photoanode subchannel interface PA2 and the photocathode were placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell to simulate sunlight irradiation of the photoanode subchannel interface PA2 and the photocathode. The correlation between the fixed concentration of the target substance and the maximum output power, as well as the corresponding peak-to-peak value P of the dual-power output, were obtained by testing. max3 P max4 ; Utilizing a series of target substance concentrations, dual-power output peak-to-peak values ​​P Max1 With P max3 The ratio P Max1 / P Max3 Dual power output peak-to-peak value P Max2 With P max4 The ratio P Max2 / P Max4 Two linear relationships were obtained between the peak-to-peak ratio of the maximum output power of the target substance and the logarithm of the target substance concentration, resulting in two different linear regression equations. T3: Detection of target substance concentration in the sample: The photoanode sub-channel interface PA1 of the prepared dual-ratio light-driven self-powered sensor was placed in the sample for incubation. Then, the photoanode sub-channel interface PA1 and the photocathode were placed in a 0.1M PBS solution containing K2S2O8 in a quartz reaction cell. The photoanode sub-channel interface PA1 and the photocathode were irradiated by a simulated sunlight source, and the peak-to-peak value P of the dual power output corresponding to the target substance was measured. max5 P max6 , will P max5 With P max3 The ratio P Max5 / P Max3 and P max6 With P max4 The ratio P Max6 / P Max4 Substitute the values ​​into the two linear regression equations in step T2 to calculate the two concentration values ​​of the target substance in the sample to be tested, and then compare the two concentration values ​​to perform self-calibration.

10. The application of the dual-ratio optically driven self-powered sensor as described in claim 9, characterized in that, In steps T2 and T3, the incubation time of the photoanode sub-channel interface PA1 and the photoanode sub-channel interface PA2 in the solution is more than 60 minutes. Step T3 also includes pretreatment of the sample to be tested before detection. The specific operation is as follows: take the original sample to be tested and let it stand for more than 1 hour, then place the original sample to be tested on a centrifuge for centrifugation, and take the supernatant as the sample to be tested.

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