Space-time coordination dual-mode self-energized sensor of photo-assisted zinc air battery for gallic acid detection and preparation method of space-time coordination dual-mode self-energized sensor

Abstract

The invention belongs to the field of photoelectrochemical detection, and discloses a photo-assisted zinc-air battery space-time coordination dual-mode self-energized sensor for gallic acid detection and a preparation method of the photo-assisted zinc-air battery space-time coordination dual-mode self-energized sensor. The photocathode designed by the invention comprises a visual area and an electron injection area which are connected with each other through an electron transfer channel. Wherein the visual area is formed by modifying Prussian blue on the FTO conducting layer; the electron injection region is formed by sequentially modifying BiFeO3, AgBr and a molecularly imprinted polymer (MIP) on the conducting layer and is marked as MIP / AgBr / BiFeO3 / FTO; the electron transfer channel is an unmodified conducting layer. The zinc-air battery self-energized electrochemical sensor is constructed by taking eluted MIP / AgBr / BiFeO3 / FTO as a photocathode and a zinc plate as an anode, and is used for quantitative analysis of gallic acid (GA), and the self-energized electrochemical sensor is combined with an electrochromic technology, so that background interference is effectively eliminated, dual-mode sensing can be realized at the same time and in the same space, and the application prospect is wide. And the experiment operation process is simplified.

Description

Technical Field

[0001] The invention belongs to the field of photoelectrochemical detection, and specifically relates to a spatiotemporal coordinated dual-mode self-powered sensor of a light-assisted zinc-air battery for gallic acid detection and a preparation method thereof. Background Art

[0002] Oxidative stress plays an important role in the pathogenesis of many diseases such as atherosclerosis, Alzheimer's disease, and cancer. Therefore, over the past few decades, people have been interested in preventing or treating these diseases by supplementing antioxidants to counteract the effects of reactive oxygen species (ROS). Among the main antioxidants, polyphenols have high scavenging ability and antioxidant activity, and are ideal natural antioxidant sources for pharmacy. In particular, gallic acid (GA) is one of the representative components of polyphenols and is often used as a reference standard to determine whether it meets the standard. Many studies have confirmed that GA has a wide range of biological functions, including antioxidant, anti-inflammatory, and anti-tumor properties, and has been widely used in the pharmaceutical industry. The dosage of antioxidants is closely related to their antioxidant capacity. Therefore, the quantification of GA is crucial for drug safety. Over the past few decades, various technologies have witnessed substantial progress in GA determination, including traditional techniques such as chromatography and chemiluminescence, as well as emerging technologies such as electrochemical sensing technology. However, these methods have the disadvantages of complex instruments, high cost, poor selectivity and reproducibility. Therefore, the development of new detection technologies requires a lot of exploration.

[0003] Self-powered electrochemical sensors (SPES) have the advantages of not requiring an external power source, being easy to miniaturize, and having high detection sensitivity. Therefore, they have the advantage of developing a portable dual-mode sensing platform. The electrochromic method has attracted extensive attention in the field of target detection due to its convenience, simple operation, and the ability to generate visual signals without complex equipment. By combining SPES with electrochromic technology, the dual-mode sensing platform can simultaneously collect electrochemical signals (output power density) and visual signals (RGB values) at different target concentrations. These two types of signals are then used to cross-validate the detection results and improve the detection accuracy. This method allows dual-mode recognition of targets in the same space and time, greatly simplifies the structure of the sensing device, and shortens the detection time. However, the low energy conversion efficiency of SPES leads to insufficient electrochemical signal output, which not only limits the detection range of the sensor, but also limits the ability to achieve color changes through rapid electron injection in electrochromic technology. Therefore, how to improve the output signal is a key issue that needs to be addressed.

[0004] Light-assisted zinc-air battery (ZAB) is an innovative solar energy utilization technology that integrates the energy conversion processes of solar power generation and chemical power generation, thereby increasing the overall electrical energy output. The potential of using ZAB as an energy conversion device for dual-mode sensors has not yet been explored, which makes its application very promising. Light-assisted ZAB combines semiconductor materials, thereby improving the cathode reaction kinetics and overall battery performance. However, traditional semiconductor materials often suffer from low carrier separation efficiency and limited solar energy utilization. Therefore, improving the photoelectric conversion efficiency of semiconductors remains an important research area.

[0005] Engineered heterojunctions promote the efficient separation of photogenerated carriers. In addition, they also have excellent photocurrent response and photocatalytic effect, which is crucial to maximize the performance of the cell. Studies have shown that the charge transfer mechanism in the Z-type heterojunction can achieve efficient separation of electrons and holes while maintaining the redox ability of carriers. Therefore, constructing a Z-type heterojunction is a suitable strategy for developing light-assisted ZAB systems. Silver bromide (AgBr) is well known for its photosensitivity and has been widely used in the construction of engineered heterojunctions. In particular, AgBr particles are coated on certain semiconductor materials to form Z-type heterojunctions, such as AgBr / CuBi2O4, AgBr / BiOBr, AgBr / Bi2WO6, and Ag / AgBr / g-C3N4, which improves the photocatalytic activity and stability. The basis for constructing a Z-type heterojunction is to find materials with matching energy bands. As a member of the perovskite-type ABO3 semiconductor, bismuth ferrite (BiFeO3) has good visible light absorption (Eg ≈ 2.1 eV), excellent photoelectric properties, and good chemical stability. When constructing a Z-type heterojunction, whether the band structures of BiFeO3 and AgBr can be well matched remains to be studied, and whether they can be used to construct a sensor platform is a technical problem to be solved by the present invention. Summary of the invention

[0006] The purpose of the present invention is to provide a spatiotemporal coordinated dual-mode self-powered sensor for gallic acid detection based on a light-assisted zinc-air battery and a preparation method thereof. A sensitive dual-mode sensing platform was developed using Z-type heterojunction AgBr / BiFeO3 as the photocathode of a light-assisted zinc-air battery for the quantitative analysis of gallic acid (GA). Based on a light-assisted zinc-air battery (ZAB), the visualization mode is combined with the self-powered sensing mode, which not only effectively eliminates background interference, but also realizes dual-mode sensing in the same time and space, simplifying the experimental operation process.

[0007] The present invention first provides a spatiotemporal coordinated dual-mode self-powered sensor for a light-assisted zinc-air battery, wherein the photocathode of the sensor comprises a visualization region, an electron injection region and an electron transfer channel, wherein the left edge of the visualization region 1a is connected to the right edge of the electron injection region 1b through a first electron transfer channel 1-1; the upper side of the visualization region 1a is connected to a second electron transfer channel 1-2, and the upper side of the electron injection region 1b is connected to a third electron transfer channel 1-3, that is, the second electron transfer channel 1-2 and the third electron transfer channel 1-3 are arranged on the same side of a conductive glass 1; the visualization region is a fluorine-doped tin oxide (FTO) glass electrode conductive layer modified with Prussian blue; the electron injection region is a fluorine-doped tin oxide (FTO) glass electrode conductive layer modified with a Z-type heterojunction AgBr / BiFeO3 and a molecular imprinting polymer (MIP); and the electron transfer channel is an unmodified conductive layer.

[0008] Furthermore, the imprinted molecule in the molecular imprinted polymer (MIP) is gallic acid, and the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery is used to detect gallic acid.

[0009] The present invention also provides a method for preparing a light-assisted zinc-air battery self-powered sensor for detecting gallic acid, comprising the following steps: (1) Design of photocathode One side surface of the fluorine-doped tin oxide (FTO) conductive glass electrode has a visualization area 1a and an electron injection area 1b, the left edge of the visualization area 1a is connected to the right edge of the electron injection area 1b through the first electron transmission channel 1-1; the upper side of the visualization area 1a is connected to the second electron transmission channel 1-2, and the upper side of the electron injection area 1b is connected to the third electron transmission channel 1-3, that is, the second electron transmission channel 1-2 and the third electron transmission channel 1-3 are arranged on the same side of the conductive glass 1. Ultrasonic washing was performed with acetone, ethanol and ultrapure water for 10 minutes respectively, and then dried.

[0010] (2) Preparation of the electron injection region of the photocathode Preparation of BiFeO3 / FTO: First, Bi(NO3)3⋅5H2O and Fe(NO3)3⋅9H2O are dissolved in 2-methoxyethanol, dissolved by ultrasonication, and then stirred to react to form a BiFeO3 precursor solution. The concentration of Bi(NO3)3⋅5H2O in the BiFeO3 precursor solution is 10 mg / mL, and the concentration of Fe(NO3)3⋅9H2O is 8 mg / mL. The obtained precursor solution is evenly dropped onto the electron injection region of the fluorine-doped tin oxide (FTO) glass electrode, and then pre-annealed at 350°C for 5 minutes, and then annealed at 500°C for 60 minutes to obtain BiFeO3 / FTO. The drop coating amount of the BiFeO3 precursor solution is 100µL / cm 2 .

[0011] Preparation of AgBr / BiFeO3 / FTO: AgBr was assembled on the BiFeO3 / FTO surface by chemical bath deposition (CBD). CBD solution was prepared by adding. The BiFeO3 / FTO electrode was exposed to only the electron injection region (1 cm×1 cm), and was immersed in 50 mL of CBD solution (containing AgNO3 (1 mM) and KBr (1 mM)) for 30-150 minutes. Finally, it was washed with distilled water and dried in a vacuum oven for 6 hours to obtain an AgBr / BiFeO3 / FTO electrode. Preferably, the CBD deposition time is 60-120 minutes, and most preferably 90 minutes.

[0012] Preparation of MIP / AgBr / BiFeO3 / FTO: A molecular imprinting polymer precursor solution was prepared, i.e., the original molecular imprinting polymer (MIP) solution contained methacrylic acid (MAA) (8 mM), ethylene glycol dimethacrylate (EDMA) (3 mM) and azobisisobutyronitrile (AIBN) (1 mM), and was mixed with 1 mM GA at a volume ratio of 2:1. The molar ratio of MAA, EDMA, AIBN and GA was 16:6:2:1. This mixed solution was then added dropwise to the modified area of ​​the semiconductor material. After UV-induced polymerization for 15 minutes, MIP / AgBr / BiFeO3 / FTO was obtained. Before use, the MIP / AgBr / BiFeO3 / FTO photocathode was eluted with a mixed solution of ethanol and 0.01 M NaOH at a volume ratio of 1:1 for more than 20 minutes.

[0013] (3) Preparation of the visualization area of ​​the photocathode: Preparation of Prussian blue (PB): In the construction of the three-electrode system, the FTO in the visualization area is the working electrode, the platinum sheet is the counter electrode, and the Ag / AgCl is the reference electrode. The PB is deposited on the visualization area of ​​the photocathode by constant potential deposition. The electrodeposition parameters are set to 0.4 V vs Ag / AgCl and the time is 50 s. After electrodeposition, the photocathode is dried in air.

[0014] The PB electrodeposition solution is a solution composed of 30mM KNO3, 3mM K3Fe(CN)6, 3mM Fe(NO3)3⋅9H2O, and 30mM HNO3. That is, in a 100 mL beaker, add KNO3 (100 mM), K3Fe(CN)6 (10 mM) and 30 mL of deionized water and stir until completely dissolved. In another 100 mL beaker, prepare a solution containing Fe(NO3)3⋅9H2O (10 mM), 2-4mL HNO3 (0.1M) and 30 mL of deionized water and stir well. Then mix these two solutions with 40 mL of deionized water to obtain the electrodeposition solution for preparing PB.

[0015] (4) Construction of spatiotemporal coordinated dual-mode self-powered sensor based on light-assisted zinc-air battery: The electron injection region MIP / AgBr / BiFeO3 / FTO electrode was immersed in the detection solution and reacted for 25 minutes to specifically capture GA. Then it was rinsed with 0.1 M PBS, and the MIP / AgBr / BiFeO3 / FTO electrode that specifically captured GA was used as the photocathode and the zinc plate as the photoanode to construct a light-assisted zinc-air battery self-powered electrochemical sensor (ZAB-SPES). Specifically, a xenon lamp was used as the light source, the distance between the photocathode and the photoanode was 20 mm, and the electrolyte was PBS buffer. The current potential curve of ZAB-SPES was collected; Electrochromic mode: After the OPD test, use a camera to photograph the visualization area under natural light, and use Colorcoll software to process and quantitatively analyze the captured images.

[0016] The present invention also provides the application of the spatiotemporal coordinated dual-mode self-powered sensor based on the light-assisted zinc-air battery in detecting gallic acid. The specific detection steps are as follows: S1. Prepare phosphate buffered saline (PBS) solution; S2, preparing PBS buffer solutions containing different concentrations of gallic acid and 0.1 mol / L; Accurately weigh gallic acid and prepare it with deionized water to 1.0×10 -2mol / L standard solution, the standard solution was diluted step by step with deionized water to obtain gallic acid standard solutions of different concentrations, the concentration range was 1.0×10 -9 mol / L~1.0×10 -4 mol / L; S3. Drawing of standard curve and presentation of electrochromic mode: The semiconductor material area of ​​the MIP / AgBr / BiFeO3 / FTO electrode was immersed in solutions with different gallic acid concentrations for 25 minutes to specifically capture GA. The FTO chip was then rinsed with 0.1 M PBS and used as a photocathode, a zinc plate as an anode, and a distance of 20 mm between the two electrodes to construct a zinc-air battery self-powered electrochemical sensor (ZAB-SPES); Electrochemical mode: Using a xenon lamp as the light source, the current potential curve of ZAB-SPES was collected. Specifically, it was recorded by collecting linear sweep voltammetry (LSV) in the potential range of -0.1 to 1 V. The calculation of the output power density (OPD) of ZAB-SPES can be expressed by the formula: OPD = UI / s, where OPD is the output power density, U and I are the potential and current of LSV, respectively, and s is the electrode surface area. The OPD value of the sensor changes with the concentration of GA and has a strong linear relationship with the logarithm of the target concentration; Electrochromic mode: After the OPD test, use a camera device (such as iPhone 13) to photograph the visualization area under natural light. Use Colorcoll software to process and quantitatively analyze the captured images. Each test area is tested three times and the average result is calculated.

[0017] S4. Actual sample testing: After filtering and removing impurities from the sample, the pH value is adjusted to 6.8, and the test is performed according to the above step S3 to obtain the OPD value. The obtained OPD value is calculated using the linear regression equation obtained in step S3 to obtain the concentration of gallic acid in the sample.

[0018] Preferably, the pH of the PBS buffer solution in step S1 is 6.8, and the concentration of the PBS buffer solution is 0.1 mol / L.

[0019] The beneficial effects of the present invention are: The present invention uses Z-type heterojunction AgBr / BiFeO3 as the photocathode of light-assisted zinc-air battery and develops a sensitive dual-mode sensing platform for quantitative analysis of gallic acid (GA). It has the following beneficial effects: (1) The present invention solves the bottleneck problems of low output voltage and low output power of self-powered sensors by introducing zinc-air batteries into self-powered sensors. The output signal of the sensor is further improved by accelerating the slow ORR reaction of the light-assisted zinc-air battery. The Z-type heterojunction AgBr / BiFeO3 is used as the photocathode of the light-assisted zinc-air battery to promote the effective separation of photogenerated carriers, and at the same time has excellent photocurrent response and photocatalytic effect.

[0020] (2) Compared with traditional detection methods, the present invention combines SPES with electrochromic technology, and the dual-mode sensing platform can simultaneously collect electrochemical signals (output power density) and visual signals (RGB values) at different target concentrations. These two types of signals are then used to cross-validate the detection results, which not only effectively eliminates background interference, but also realizes dual-mode sensing at the same time and space, simplifying the experimental operation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the design drawing of the photocathode; Figure 2 The photocathode preparation process (A); the response mechanism of the dual-mode sensing platform: a brief flow chart of the self-powered sensing mode (B) and the visual detection mode (C); and the distribution size diagram of the conductive layer of FTO conductive glass (D); Figure 3 It is the optimization of chemical deposition time of AgBr; Figure 4 It is the molecular imprinting elution time optimization diagram; Figure 5 The OPD values ​​of AgBr, BiFeO3 monomer materials and AgBr / BiFeO3 composite materials are compared; Figure 6 This is the OPD response diagram of different concentrations of gallic acid. The concentration of gallic acid changes from top to bottom according to the OPD value of 1×10 -9 mol / L, 1×10 -8 mol / L, 1×10 -7 mol / L, 1×10 -6 mol / L, 1×10 -5 mol / L, 1×10 -4 mol / L; Figure 7 is the linear calibration curve of OPD response after adding gallic acid; Figure 8 is the RGB (blue) value of different concentrations of gallic acid; Fig. 9 is the linear calibration curve of RGB (blue) values ​​after adding gallic acid. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the embodiments.

[0023] The preparation process of the photocathode of the present invention and the brief flow chart of the dual-mode sensing mode are as follows: Figure 2 As shown; the fluorine-doped tin oxide (FTO) glass (2 cm × 2 cm) used in the following specific examples has a specific structural distribution of the conductive layer as shown Figure 2 As shown in D. Example 1

[0024] like Figure 2 As shown in A, a Z-type heterojunction AgBr / BiFeO3 was modified on the electron injection region. In addition, Prussian blue (PB) was electrodeposited on the visualization region of the chip. Molecular imprinting polymer (MIP) was formed on the AgBr / BiFeO3 surface for specific recognition of GA. The visualization region and the electron injection region were integrated on a chip as the cathode of a light-assisted zinc-air battery, achieving dual-mode detection of gallic acid. Figure 2 B shows that after MIP elution, a larger output power density (OPD) value was obtained (Ⅰ), and only the target molecules entered the MIP cavity and affected the OPD of the sensor (Ⅱ), thus achieving specific and sensitive GA detection. Figure 2 C shows that electrons can be injected quickly after MIP elution, and the PB in the visualization area quickly turns into Prussian white (PW). After GA incubation, the imprint cavity is selectively filled with GA, which hinders electron transfer and produces a color change of PB, thereby achieving detection (II).

[0025] The preparation method of the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery comprises the following steps: (1) Design of photocathode The conductive layer (2 cm × 2 cm) of the fluorine-doped tin oxide (FTO) glass electrode consists of three parts: the visualization area, the electron transfer channel, and the electron injection area. The three areas are interconnected. Then, ultrasonic cleaning was performed with acetone, ethanol, and ultrapure water for 10 minutes respectively, and then dried.

[0026] (2) Preparation of the electron injection region of the photocathode: Preparation of BiFeO3 / FTO: First, 100 mg Bi(NO3)3⋅5H2O and 80 mg Fe(NO3)3⋅9H2O were dissolved in 10 mL 2-methoxyethanol, dissolved by ultrasonication, and then stirred for 60 minutes to form a precursor solution. 100 µL of the obtained precursor solution was evenly dropped onto the semiconductor material area of ​​a 1 cm × 1 cm chip. Then, BiFeO3 / FTO was obtained by pre-annealing at 350°C for 5 minutes and then annealing at 500°C for 60 minutes.

[0027] Preparation of AgBr / BiFeO3 / FTO: AgBr was assembled on the BiFeO3 / FTO surface by chemical bath deposition (CBD). 50 mL of CBD solution was prepared by adding AgNO3 (1 mM) and KBr (1 mM). The photocathode surface was covered with tape, exposing only the electron injection area (1 cm × 1 cm). Subsequently, the BiFeO3 / FTO chip was immersed in the CBD solution for 30-150 min. Finally, the obtained AgBr / BiFeO3 / FTO chip was washed with distilled water and dried in a vacuum oven for 6 h.

[0028] Figure 3 The effect of AgBr deposition time on SPES performance was studied. As shown in the figure, as the AgBr deposition time increases from 30 min to 90 min, the OPD value continues to increase, and when the deposition time exceeds 90 min, the OPD value decreases. Therefore, the optimal deposition time of AgBr is 90 min.

[0029] The original solution of molecular imprinting polymer (MIP) contained methacrylic acid (MAA) (8 mM), ethylene glycol dimethacrylate (EDMA) (3 mM) and azobisisobutyronitrile (AIBN) (1 mM), and the molar ratio of MAA / EDMA / AIBN was 8:3:1. -3 MGA was mixed in a volume ratio of 2:1. Then 30uL of this mixed solution was dripped onto the modified area of ​​the semiconductor material. After 15 minutes of UV-induced polymerization, MIP / AgBr / BiFeO3 / FTO was obtained. Before use, the MIP / AgBr / BiFeO3 / FTO photocathode was eluted with a mixed solution of ethanol and 0.01 M NaOH in a volume ratio of 1:1 for 5-25 minutes. Figure 4 It can be seen that after elution for more than 20 minutes, the OPD value reaches a stable equilibrium.

[0030] (3) Preparation of the visualization area of ​​the photocathode: Preparation of Prussian blue (PB): In a 100 mL beaker, add 100 mM KNO3, 10 mM K3Fe(CN)6, and 30 mL of deionized water and stir until completely dissolved. In another 100 mL beaker, prepare a solution containing 10 mM Fe(NO3)3⋅9H2O, 30 mL of deionized water, and 0.1 M HNO3 and stir thoroughly. Then mix these two solutions with 40 mL of deionized water to obtain the electrodeposition solution for preparing PB. Using this electrodeposition solution, PB was electrodeposited on the visible area of ​​the photocathode by constant potential deposition in a typical three-electrode system. The electrodeposition parameters were set to 0.4 V vs Ag / AgCl and the time was 50 s. After electrodeposition, the photocathode was dried in air.

[0031] (4) Construction of spatiotemporal coordinated dual-mode self-powered sensor based on light-assisted zinc-air battery: GA was dissolved in 0.1 M phosphate buffer (PBS). The semiconductor material area of ​​the MIP / AgBr / BiFeO3 / FTO electrode was immersed in solutions with different GA concentrations and reacted for 25 minutes to specifically capture GA. The FTO chip was then rinsed with 0.1 M PBS as a photocathode, the zinc plate was used as an anode, the distance between the two electrodes was 20 mm, and 0.1 M PBS buffer solution (pH 6.8) was used as the electrolyte to construct a zinc-air battery self-powered electrochemical sensor (ZAB-SPES). Using a xenon lamp as the light source, the current potential curve of the ZAB-SPES was collected; Electrochromic mode: The visualization area was photographed under natural light using an iPhone 13. The captured images were processed and quantitatively analyzed using Colorcoll software.

[0032] (5) Drawing of standard curve: Prepare gallic acid solution. Accurately weigh a certain amount of gallic acid and use deionized water to prepare 1.0×10 -2mol / L standard solution, the standard solution was diluted step by step with deionized water to obtain a series of gallic acid standard solutions with different concentrations; the semiconductor material area of ​​the MIP / AgBr / BiFeO3 / FTO electrode was immersed in solutions with different gallic acid concentrations and reacted for 25 minutes to specifically capture GA. Then the FTO chip was rinsed with 0.1 M PBS as a photocathode, the zinc plate was used as an anode, and the distance between the two electrodes was 20 mm to construct a zinc-air battery self-powered electrochemical sensor (ZAB-SPES). Using a xenon lamp as a light source, the current potential curve of ZAB-SPES was collected. The calculation of the output power density (OPD) of ZAB-SPES can be expressed by the formula: OPD = UI / s, where OPD is the output power density, U and I are the potential and current of LSV, respectively, and s is the electrode surface area. The OPD value of the sensor changes with the concentration of GA and has a strong linear relationship with the logarithm of the target concentration; such as Figure 6 As shown, the concentration of gallic acid is as follows from top to bottom according to the peak value of the curve: 1×10 -9 mol / L, 1×10 -8 mol / L, 1×10 -7 mol / L, 1×10 -6 mol / L, 1×10 -5 mol / L,1×10 -4 mol / L.

[0033] The dual-mode electrochemical / electrochromic method was used to detect GA at different concentrations and its analytical performance was investigated. Figure 6 It can be seen that in 10 -9 M ~ 10 -4 Within the M range, the OPD value of the sensor decreases with the increase of GA concentration and has a strong linear relationship with the logarithm of the target concentration ( Figure 7 ). The linear equation is OPD (μW / cm 2 ) = -27.04 log C GA (M) +67.39, correlation coefficient was 0.9954, and detection limit was 1.2 × 10 -10 M (S / N = 3).

[0034] In electrochromic mode ( Figure 8 ), with the increase of GA concentration, the degree of electrode discoloration gradually decreased. The corresponding RGB (blue) value decreased and showed a good linear relationship with the logarithm of GA concentration ( Fig. 9 ). The linear equation of RGB is calculated as RGB = -30.73 log C GA(M) - 77.12, correlation coefficient 0.9936, detection limit 1.9 × 10 -10 M. Comparative Example 1

[0035] Referring to the method of Example 1, AgBr was chemically bath deposited on the pretreated FTO for 90 minutes to prepare AgBr / FTO. Comparative Example 2

[0036] BiFeO3 / FTO was prepared by referring to the method of Example 1.

[0037] Figure 5 The output power density (OPD) of AgBr / FTO, BiFeO3 / FTO and AgBr / BiFeO3 / FTO electrodes under illumination conditions shows that the OPD response of AgBr / BiFeO3 reaches 484 µW / cm 2 , which is significantly higher than the OPD value of AgBr or BiFeO3 alone.

[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A time-space coordinated dual-mode self-powered sensor of a light-assisted zinc-air battery, characterized in that: The self-powered sensor includes a zinc anode and a photocathode; the photocathode includes a visualization area, an electron injection area and an electron transfer channel, the left edge of the visualization area is connected to the right edge of the electron injection area through a first electron transfer channel; the upper side of the visualization area is connected to a second electron transfer channel, and the upper side of the electron injection area is connected to a third electron transfer channel; the visualization area is a conductive layer modified with Prussian blue; the electron injection area is a conductive layer modified with AgBr / BiFeO3 and molecular imprinting polymer; the electron transfer channel is an unmodified conductive layer.

2. The time-space coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 1, characterized in that: The imprinted molecule in the molecularly imprinted polymer is gallic acid.

3. The method for preparing the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 1 or 2, characterized in that: The specific steps include: (1) Designing a conductive layer on a glass substrate, wherein the conductive layer is fluorine-doped tin oxide (FTO), to obtain FTO conductive glass; cleaning and drying the FTO conductive glass for later use; (2) Preparation of electron injection region: BiFeO3 thin film was deposited on the electron injection region of FTO conductive glass by drop coating and annealing method to obtain BiFeO3 / FTO; AgBr was assembled on the BiFeO3 / FTO surface by chemical bath deposition method to obtain AgBr / BiFeO3 / FTO; a mixed solution of molecular imprinting polymer functional monomer, crosslinker and initiator with imprinting molecules was drop coated on the AgBr / BiFeO3 / FTO surface, ultraviolet light was used to initiate polymerization, and the imprinting molecules were eluted to obtain the electron injection region, which was marked as MIP / AgBr / BiFeO3 / FTO; (3) Preparation of the visualization area: A three-electrode system was constructed using the FTO in the visualization area as the working electrode, and Prussian blue was deposited on the conductive layer in the visualization area by constant potential deposition. (4) The electron injection area is immersed in the detection solution to specifically capture the imprinted molecules. Under light conditions, MIP / AgBr / BiFeO3 / FTO that specifically captures the imprinted molecules is used as the photocathode and the zinc plate is used as the photoanode to construct a light-assisted zinc-air battery self-powered electrochemical sensor for electrochemical mode detection; or the photoinduced electrons generated by AgBr / BiFeO3 are injected into Prussian blue to cause its reduction and color change, which is used for electrochromic mode detection.

4. The method for preparing the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 3, characterized in that: Preparation method of BiFeO3 / FTO in step (2): dissolving Bi(NO3)3⋅5H2O and Fe(NO3)3⋅9H2O in 2-methoxyethanol to obtain a BiFeO3 precursor solution, wherein the concentration of Bi(NO3)3⋅5H2O in the BiFeO3 precursor solution is 10 mg / mL, and the concentration of Fe(NO3)3⋅9H2O is 8 mg / mL; uniformly dropping the BiFeO3 precursor solution into the electron injection region of the fluorine-doped tin oxide conductive glass, and then pre-annealing at 350°C for 5 minutes, and then annealing at 500°C for 60 minutes to obtain BiFeO3 / FTO, wherein the drop coating amount of the BiFeO3 precursor solution is 100 µL / cm 2 .

5. The method for preparing the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 3, characterized in that: The chemical bath deposition method described in step (2) is: immersing BiFeO3 / FTO in a CBD solution for 30-150 minutes; the CBD solution contains 1mmol / L AgNO3 and 1mmol / L KBr.

6. The method for preparing the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 3, characterized in that: In the mixed solution of the molecular imprinting polymer functional monomer, cross-linking agent, initiator and imprinting molecule in step (2), the molar ratio of the functional monomer, the cross-linking agent, the initiator and the imprinting molecule is 16:6:2:

1.

7. The method for preparing the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 3, characterized in that: The elution time of the imprinted molecules in step (2) is more than 20 minutes.

8. The method for preparing the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 3, characterized in that: In the constant potential electrodeposition method described in step (3), the electrodeposition solution is a solution composed of 30 mM KNO3, 3 mM K3Fe(CN)6, 3 mM Fe(NO3)3⋅9H2O, and 30 mM HNO3; the electrodeposition parameters are set to 0.4 V vs Ag / AgCl and the time is 50 s.

9. Application of the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 1 or 2 in photoelectrochemical detection, characterized in that: The photoelectrochemical detection includes an electrochemical mode and an electrochromic mode. The electrochemical mode is: using a xenon lamp as a light source with a wavelength range of 200-1100nm, adopting linear sweep voltammetry to record the current potential curve, calculating the output power density (OPD), establishing a linear relationship between the OPD value and the logarithm of the concentration of the detection object, and calculating the concentration of the detection object; the electrochromic mode is to take a visual area image after the electrochemical reaction, use Colorcoll software to process the captured image, establish a linear relationship between the RGB value and the logarithm of the concentration of the detection object, and calculate the concentration of the detection object.

10. The application of the spatiotemporal coordinated dual-mode self-powered sensor of the light-assisted zinc-air battery according to claim 9 in photoelectrochemical detection, characterized in that: The electrolyte in the photoelectrochemical detection was PBS buffer solution with a pH of 6.8 and a concentration of 0.1 mol / L.

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