A composite photoelectrode for glucose content detection, and a preparation method and application thereof

Abstract

The application discloses a composite photoelectrode for glucose content detection and a preparation method and application thereof, and belongs to the technical field of photoelectrochemical analysis. A BiOI film is electrochemically deposited on the surface of a conductive substrate (such as pretreated FTO conductive glass) in a nitric acid solution system; a bismuth vanadate photoelectrode is obtained by calcining and alkali treatment of the substrate on which dimethyl sulfoxide solution containing vanadyl acetylacetonate is dropped; a polyterthiophene (pTTH) layer is photoelectrodeposited on the surface of the bismuth vanadate by using acetonitrile electrolyte; a multistage composite structure is obtained by depositing a nickel oxide layer through an aqueous electrolyte and calcining treatment, so that the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode is obtained. In this way, the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode prepared by the application has high carrier separation efficiency and excellent catalytic stability, and provides an analysis method with simple steps for effective voltage detection of glucose.

Description

Technical Field

[0001] This invention belongs to the field of photoelectrochemical analysis technology, and particularly relates to a composite photoelectrode for glucose content detection, its preparation method, and its application. Background Technology

[0002] The increasing urgency brought about by rapid population growth and industrial development is exacerbating challenges related to global resource constraints, particularly water pollution. To control pollution, all domestic and industrial wastewater treatment plants now require regular water quality testing. Chemical oxygen demand (COD) is commonly used to reflect the organic matter content in wastewater and is a crucial indicator of the degree of organic pollution in water bodies. Rapid, accurate, and highly sensitive analysis of COD in water is essential for water quality assessment and pollution control. Therefore, to address the issue of pollutant content in water, glucose testing is being used as a substitute for pollutant content testing.

[0003] Despite the numerous methods currently available for glucose detection, these methods suffer from fatal drawbacks such as complex equipment, short lifespan, poor timeliness, and low sensitivity. Photoelectrochemical detection, as a next-generation detection technology, is gaining increasing attention due to its advantages, including low detection limits, low energy consumption, fast detection speed, and ability to quantify the degree of organic matter degradation. Its detection performance is primarily determined by the performance of the photoelectrode; however, existing photoelectrodes often suffer from drawbacks such as susceptibility to water electrolysis, low charge separation efficiency, and poor stability. Therefore, the design and fabrication of high-performance composite photoelectrode materials is a key issue in the photoelectrocatalytic detection of glucose content. It is necessary to provide a high-performance composite photoelectrode for glucose content detection. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a composite photoelectrode for glucose content detection, its preparation method, and its application. The composite photoelectrode of this invention can effectively detect voltage in glucose solutions of different concentrations and exhibits high stability.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] One of the technical solutions of the present invention:

[0007] This invention provides a composite photoelectrode for glucose content detection, wherein the composite photoelectrode is a nickel oxide (NiO) / polyterthiophene / bismuth vanadate composite photoelectrode.

[0008] The second technical solution of the present invention:

[0009] The present invention also provides a method for preparing the composite photoelectrode for glucose content detection, comprising the following steps:

[0010] (1) Potassium iodide and bismuth nitrate pentahydrate are added to nitric acid solution to obtain solution A; p-benzoquinone is added to ethanol to obtain solution B; solution A and solution B are mixed to obtain electrolyte A; using electrolyte A as electrolyte, an electrochemical deposition method is used to deposit a bismuth oxygen iodide thin film on the surface of a conductive substrate.

[0011] (2) Add acetylacetone vanadium oxide to dimethyl sulfoxide solution to obtain solution C; drop solution C onto the surface of the conductive substrate with bismuth oxy iodine film deposited in step (1), calcine, and after the calcine is completed, place the product in sodium hydroxide solution for immersion, and after washing and drying, obtain bismuth vanadate photoelectrode;

[0012] (3) Lithium perchlorate and terthiophene were added to an acetonitrile solution to obtain electrolyte B; using electrolyte B as electrolyte, photoelectrochemical deposition was performed on the surface of the bismuth vanadate photoelectrode by electrochemical deposition method. After washing and drying, a bismuth vanadate / polyterthiophene composite photoelectrode was obtained.

[0013] (4) Dissolve nickel chloride in water to obtain electrolyte C; using electrolyte C as electrolyte, electrochemical deposition is used to deposit on the surface of the bismuth vanadate / polyterthiophene composite photoelectrode. After the deposition is completed, the photoelectrode is calcined, washed and dried to obtain nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode, which is the composite photoelectrode used for glucose content detection.

[0014] This invention first uses a constant potential deposition method to form a bismuth oxy iodine precursor film on a pretreated FTO surface, and then obtains a porous bismuth vanadate photoanode through high-temperature crystal phase transformation and alkali treatment; then, a polyterthiophene (pTTH) modification layer is generated in situ in a terthiophene monomer solution through photoelectrochemical polymerization; finally, a NiO surface modification structure is constructed through constant current deposition combined with thermal oxidation process, ultimately forming a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode (NiO / pTTH / BiVO4 composite photoelectrode).

[0015] Compared to patent CN 117169305 A, this invention focuses more on improving the selectivity of the modified BiVO4 photoanode surface by controlling surface hydrophobicity (changing the thickness of the heterojunction pTTH layer and increasing the NiO hydrophobic layer to make it more hydrophobic), thereby enhancing its selectivity for glucose oxidation and reducing the impact of water splitting reaction on the detection results. Furthermore, when the NiO / pTTH / BiVO4 composite photoelectrode prepared in this invention is used as a photoanode, the detection signal for different glucose concentrations is significantly higher than that of patent CN 117169305 A (for example, at the same 0.1M glucose concentration, the detection signal of the NiO / pTTH / BiVO4 composite photoelectrode in 0.8 vs. RHE is 1.11 mA·cm). -2In patent CN 117169305 A, the detection signal of the photoelectrode is only 0.6 mA·cm. -2 The NiO / pTTH / BiVO4 composite photoelectrode of this invention can detect higher concentrations (1M glucose) and more uniformly distributed glucose concentration gradients. The characteristic electrical signals generated by the NiO / pTTH / BiVO4 composite photoelectrode when oxidizing glucose of different concentrations enable quantitative detection of glucose. Therefore, this invention can achieve effective detection voltage in glucose solutions of different concentrations. While bismuth vanadate photoanodes are suitable for water splitting reactions, their structure is easily damaged by organic oxidation reactions during glucose dissolution, leading to reduced performance. This invention improves its detection performance and stability in glucose concentrations by constructing a heterojunction (pTTH) and adding a co-catalyst layer (NiO). Therefore, the NiO / pTTH / BiVO4 composite photoelectrode of this invention exhibits high stability.

[0016] Further, in step (1), the pH of the nitric acid solution is 1.65 to 1.75;

[0017] And / or, the molar ratio of potassium iodide, bismuth nitrate pentahydrate and p-benzoquinone is 4:0.4:2.3. When the ratio of the prepared solution is less than the above ratio, the electrodeposited BiOI film will be too thin, resulting in a decrease in detection performance; when the ratio of the prepared solution is higher than the above ratio, the electrodeposited BiOI film will be too thick, resulting in a decrease in detection performance.

[0018] And / or, the electrochemical deposition method is the time-current curve method; during the electrochemical deposition process, a conductive substrate is used as the working electrode, a platinum mesh is used as the counter electrode, and an Ag / AgCl electrode is used as the reference electrode.

[0019] Further, in step (1), the process parameters of the electrochemical deposition method are: initial voltage of -0.10 to -0.15V, sampling interval of 0.1s, deposition time of 150 to 200s, settling time of 0s, and sensitivity of 1×10⁻⁶. -3 A; the preferred initial voltage is -0.1V, the sampling interval is 0.1s, the deposition time is 180s, the settling time is 0s, and the sensitivity is 1×10⁻⁶. -3 A.

[0020] For example, the conductive substrate in step (1) is fluorine-doped tin oxide (FTO) conductive glass.

[0021] Furthermore, in step (2), the calcination temperature is 440–460°C, the time is 2 hours, and the heating rate is 2°C·min. -1 When the calcination temperature is below 440℃, BiVO4 crystallization will be incomplete, and sample preparation will fail; when the calcination temperature is above 460℃, BiVO4 will be burned black, and sample preparation will fail.

[0022] And / or, the drop volume of solution C is 35–50 μL·cm. -2 Preferably 40 μL·cm -2 Among them, when the dripping volume is less than 35 μL·cm -2 When the drop volume is less than 50 μL·cm, it will cause BiVO4 to be completely burned, resulting in sample preparation failure; -2 This will cause BiVO4 to burn black, resulting in sample preparation failure;

[0023] And / or, the concentration of the sodium hydroxide solution is 1M, and the soaking time is 15-25 min. In this invention, excess V2O5 is removed by soaking in sodium hydroxide solution. When the soaking time is less than 15 min, V2O5 will not be completely removed, resulting in reduced performance. When the soaking time is more than 25 min, BiVO4 will be alkalized and turn yellow, resulting in reduced performance.

[0024] For example, in step (2), the solution C is prepared by mixing 0.2M acetylacetonate vanadium with 5mL dimethyl sulfoxide and stirring until homogeneous to obtain solution C.

[0025] Furthermore, in step (3), the molar ratio of lithium perchlorate to terthiophene is 1:0.1;

[0026] And / or, the electrochemical deposition method is cyclic voltammetry; during the electrochemical deposition process, the bismuth vanadate photoelectrode is used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode, with a light intensity of 100 mW·cm. -2 .

[0027] Furthermore, in step (3), the electrochemical deposition process parameters are as follows: initial potential is 0V, upper limit potential is 0.85~0.95V, lower limit potential is 0V, termination voltage is 0.85~0.95V, initial scan direction is positive, and scan speed is 0.05V·s. -1 The scanning circle count is 3-5 circles, the sampling interval is 0.001V, the still time is 2s, and the sensitivity is 1×10⁻⁶. -3 A, where, when the electrodeposition parameters are lower than the above parameters, the pTTH loading will be too low and the performance will be reduced; when the electrodeposition parameters are higher than the above parameters, the pTTH loading will be too high and the performance will be reduced.

[0028] For example, in step (3), the washing is to rinse the bismuth vanadate / polyterthiophene composite photoelectrode with ethanol and tertiary water respectively.

[0029] Further, in step (4), the electrochemical deposition method is the time-current curve method; during the electrochemical deposition process, the bismuth vanadate / polyterthiophene composite photoelectrode (BiVO4 / pTTH composite photoelectrode) is used as the working electrode, the platinum mesh is used as the counter electrode, and the Ag / AgCl electrode is used as the reference electrode.

[0030] Furthermore, in step (4), the process parameters for electrochemical deposition using the time-current curve method are as follows: initial potential is the open-circuit voltage, sampling interval is 0.1s, deposition time is 600–1200s, settling time is 0s, and sensitivity is 1×10⁻⁶. -3 A; the preferred initial potential is the open-circuit voltage, the sampling interval is 0.1s, the deposition time is 900s, the settling time is 0s, and the sensitivity is 1×10⁻⁶. -3 A. When the deposition time is less than 600s, the NiOOH loading will be too low, resulting in reduced performance; when the deposition time is greater than 1200s, the NiOOH loading will be too high, resulting in reduced performance.

[0031] Further, in step (4), the calcination temperature is 250-350°C and the time is 1 hour; preferably, the calcination temperature is 300°C.

[0032] The third technical solution of the present invention:

[0033] The present invention also provides the application of the composite photoelectrode in the detection of glucose content.

[0034] Compared with the prior art, the present invention has the following advantages and technical effects:

[0035] This invention uses a conductive substrate (such as fluorine-doped tin oxide conductive glass) as the substrate and sequentially constructs a bismuth vanadate semiconductor layer, a polyterthiophene conductive layer, and a nickel oxide catalytic layer through an electrochemical deposition process. Specifically, firstly, a bismuth-oxy-iodine precursor film is formed on a pretreated FTO surface using a constant potential deposition method, followed by high-temperature crystal phase transformation and alkaline treatment to obtain a porous bismuth vanadate photoanode; then, a pTTH modification layer is generated in situ in a terthiophene monomer solution through photoelectrochemical polymerization; finally, a NiO surface modification structure is constructed through a constant current deposition combined with a thermal oxidation process, ultimately forming a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode.

[0036] On the one hand, the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode prepared by this invention can effectively detect voltage in glucose solutions of different concentrations by combining photoelectric detection technology, and the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode has the advantage of high stability; on the other hand, the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode prepared by this invention provides a simple analytical method for effective voltage detection of glucose. This invention is easy and safe to operate, the materials are readily available, and it can be mass-produced. Attached Figure Description

[0037] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0038] Figure 1 The image shows a scanning electron microscope (SEM) image of the bismuth vanadate photoelectrode prepared in Example 1.

[0039] Figure 2 Transmission electron microscope (TEM) image of the bismuth vanadate photoelectrode prepared in Example 1;

[0040] Figure 3 SEM image of the poly(terthiophene) / bismuth vanadate composite photoelectrode prepared in Example 1;

[0041] Figure 4 TEM image of the poly(terthiophene) / bismuth vanadate composite photoelectrode prepared in Example 1;

[0042] Figure 5 SEM image of the nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode prepared in Example 1;

[0043] Figure 6 TEM image of the nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode prepared in Example 1;

[0044] Figure 7 X-ray diffraction (XRD) patterns of the bismuth vanadate photoelectrode, polyterthiophene / bismuth vanadate composite photoelectrode, and nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode prepared in Example 1;

[0045] Figure 8 The Fourier Transform Infrared (FT-IR) spectra of the poly(trithiophene) / bismuth vanadate composite photoelectrode and the nickel oxide / poly(trithiophene) / bismuth vanadate composite photoelectrode prepared in Example 1 are shown below.

[0046] Figure 9 Linear sweep voltammetry curves of poly(terthiophene) / bismuth vanadate photoelectrodes deposited at different potentials in 0.1 M Na2SO4 solution for application test example 1;

[0047] Figure 10 Linear sweep voltammetry curves of poly(terthiophene) / bismuth vanadate photoelectrodes deposited at different potentials in 0.1 M Na2SO4 + 0.1 M glucose solution for application test example 1;

[0048] Figure 11 Linear sweep voltammetric curves of poly(terthiophene) / bismuth vanadate photoelectrodes deposited at different potentials in test example 1 in 0.1M Na2SO4 + 0.1M hole trapping agent solution;

[0049] Figure 12 Linear sweep voltammetry curves of poly(terthiophene) / bismuth vanadate photoelectrodes with different deposition cycles in 0.1 M Na2SO4 solution for application test example 2;

[0050] Figure 13 Linear sweep voltammetry curves of poly(terthiophene) / bismuth vanadate photoelectrodes with different deposition cycles in 0.1 M Na2SO4 + 0.1 M glucose solution for application test example 2;

[0051] Figure 14 Linear sweep voltammetric curves of poly(terthiophene) / bismuth vanadate photoelectrodes with different deposition cycles in 0.1 M Na2SO4 + 0.1 M hole trapping agent solution for application test example 2;

[0052] Figure 15 Linear scan voltammetry curve of the bismuth vanadate photoelectrode in application test example 3;

[0053] Figure 16 Linear scan voltammetry curve of the poly(terthiophene) / bismuth vanadate composite photoelectrode in application test example 3;

[0054] Figure 17 Linear scan voltammetry curve of the nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode in application test example 3;

[0055] Figure 18 The time-current curve of the bismuth vanadate photoelectrode in application test example 4;

[0056] Figure 19 The time-current curve of the poly(trithiophene) / bismuth vanadate composite photoelectrode in application test example 4;

[0057] Figure 20 The time-current curve of the nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode in application test example 4;

[0058] Figure 21 This is a diagram of the optical contact angle measuring instrument for the bismuth vanadate photoelectrode in Example 1;

[0059] Figure 22 The image shows the optical contact angle measuring instrument for the poly(trithiophene) / bismuth vanadate composite photoelectrode in Example 1.

[0060] Figure 23 This is a diagram of the optical contact angle measuring instrument for the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode in Example 1;

[0061] Figure 24The steady-state fluorescence spectra of the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode, the polyterthiophene / bismuth vanadate composite photoelectrode, and the bismuth vanadate photoelectrode in Example 1 are shown. Detailed Implementation

[0062] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0063] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0064] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0065] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0066] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0067] This invention electrochemically deposits a BiOI thin film onto a conductive substrate (such as pretreated FTO conductive glass) using a nitric acid solution system. A bismuth vanadate photoelectrode is obtained by calcining and alkali-treating the substrate with a solution of vanadium acetylacetonate in dimethyl sulfoxide. A poly(pTTH) layer is photoelectrochemically deposited on the bismuth vanadate surface using acetonitrile electrolyte. A multi-level composite structure is obtained by depositing a nickel oxide layer in an aqueous electrolyte and calcining it, thus yielding a nickel oxide / poly(pTTH) / bismuth vanadate composite photoelectrode. Therefore, the nickel oxide / poly(pTTH) / bismuth vanadate composite photoelectrode prepared by this invention is a high-performance photoelectrode that combines high carrier separation efficiency and excellent catalytic stability, providing a simple analytical method for the effective voltage detection of glucose.

[0068] "Grade III water" refers to a type of experimental water with an electrical conductivity of no more than 0.50 mS / m (i.e., 5.0 μS / cm) at 25℃ and a resistivity of no less than 0.2 MΩ·cm.

[0069] In the electrodeposition process, the settling time represents the waiting time before deposition, and 0s means no waiting is required and deposition proceeds directly.

[0070] Unless otherwise specified, the room temperature in this invention is 25±2℃.

[0071] All raw materials used in the embodiments of this invention were obtained through commercial purchase.

[0072] It should be noted that all aspects not described in detail in this invention are conventional operating methods in the field and are not the focus of this invention. For example, the specific methods such as the preparation method of nitric acid solution with pH 1.7 are all completed using conventional methods.

[0073] The technical solution of the present invention will be further illustrated by the following embodiments.

[0074] Example 1

[0075] This embodiment provides a composite photoelectrode for glucose content detection, which is a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode, consisting of FTO conductive glass and a bismuth vanadate layer, a polyterthiophene layer and a nickel oxide layer sequentially loaded on the FTO conductive glass.

[0076] The preparation process of the above-mentioned nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode is as follows:

[0077] Step 1: Preparation of bismuth vanadate photoelectrode:

[0078] Take a 20cm×15cm piece of FTO conductive glass, cut it into 2cm×3cm dimensions using a glass cutting table, and then ultrasonically wash it with acetone, ethanol and grade III water for 15 minutes each. After washing, put it in an oven to dry to obtain pretreated FTO conductive glass.

[0079] Prepare a nitric acid solution with a pH of 1.7 and transfer it to a brown wide-mouth bottle for storage away from light. Take 25 mL of the above nitric acid solution and place it in a 100 mL beaker. Add 0.4 M potassium iodide (KI) and 0.04 M bismuth nitrate pentahydrate (Bi(NO3)3·5H2O) and stir thoroughly until the solution is clear and transparent to obtain solution A. Take 10 mL of anhydrous ethanol and place it in a beaker. Add 0.23 M p-benzoquinone and sonicate until the precipitate is completely dissolved to obtain solution B. Mix the above solutions A and B and stir vigorously (at a speed of 450 rpm) to make them fully miscible to obtain electrolyte A.

[0080] Using the obtained electrolyte A as the electrolyte, the pretreated FTO conductive glass as the working electrode, a platinum mesh as the counter electrode, and Ag / AgCl as the reference electrode, electrodeposition was performed using the time-current curve method. The electrodeposition conditions were: initial voltage -0.1V, sampling interval 0.1s, deposition time 180s, settling time 0s, and sensitivity 1×10⁻⁶. -3 A.

[0081] After electrodeposition, the glass is rinsed with tertiary water and dried to obtain FTO conductive glass with a bismuth oxygen iodine film deposited on it. The glass is then cut into 2cm×1cm dimensions using a glass cutting table.

[0082] FTO conductive glass sheets with a bismuth oxyiodine film deposited on them, each measuring 2 cm × 1 cm, were placed on a high-temperature resistant corundum sheet, with a 2 mm distance between the sheets. 5 mL of dimethyl sulfoxide (DMSO) was added to 0.2 M acetylacetonate vanadyl oxyacetate, and the mixture was stirred vigorously (450 rpm) until no obvious precipitate was observed, yielding solution C. Solution C was obtained by pipetting using a 100 μL pipette at a rate of 40 μL·cm⁻¹. -2 To standardize the process, solution C was dropped onto the surface of a bismuth-oxygen-iodine film. Then, a corundum sheet was placed in a muffle furnace and heated at 2°C / min. -1 The temperature was increased to 450℃ at a certain heating rate, and calcined for 2 hours.

[0083] After the muffle furnace cools down to room temperature, remove the corundum sheet, place the fired FTO conductive glass in a petri dish, add 1M NaOH solution, soak for 20 minutes, rinse with tertiary water, and air dry to obtain the bismuth vanadate photoelectrode (BiVO4 photoelectrode).

[0084] The scanning image of the bismuth vanadate photoelectrode under a scanning electron microscope (SEM) is shown below. Figure 1 As shown, bismuth vanadate crystals are worm-shaped and approximately 50-100 nm in size.

[0085] The scanning image of the bismuth vanadate photoelectrode under a transmission electron microscope (TEM) is shown below. Figure 2 As shown, the lattice spacing of bismuth vanadate is 0.314 nm, corresponding to the 107 crystal plane.

[0086] Step 2, Preparation of the poly(terthiophene) / bismuth vanadate composite photoelectrode:

[0087] 0.1 M lithium perchlorate and 0.01 M terthiophene were added to 50 mL of acetonitrile and sonicated until the precipitate was completely dissolved to obtain electrolyte B. Electrolyte B was then used as the electrolyte for photoelectrodeposition of a bismuth vanadate photoelectrode. The specific steps were as follows: using electrolyte B as the electrolyte, the bismuth vanadate photoelectrode obtained above as the working electrode, a platinum mesh as the counter electrode, and Ag / AgCl as the reference electrode, with a light intensity of 100 mW·cm⁻¹. -2 Electrodeposition was performed using cyclic voltammetry under the following conditions: initial potential 0V, upper limit potential 0.9V, lower limit potential 0V, termination voltage 0.9V, initial scan direction positive, and scan rate 0.05V / s. -1 The scanning circle count is 4, the sampling interval is 0.001V, the still time is 2s, and the sensitivity is 1×10⁻⁶. -3 A.

[0088] After electrodeposition, the electrodepositor was rinsed with ethanol and tertiary water, and then dried to obtain the poly(terthiophene) / bismuth vanadate composite photoelectrode (pTTH / BiVO4 composite photoelectrode).

[0089] The scanning electron microscope (SEM) image of the poly(terthiophene) / bismuth vanadate composite photoelectrode is shown below. Figure 3 As shown; the scanning image of the poly(terthiophene) / bismuth vanadate composite photoelectrode under a transmission electron microscope (TEM) is as follows. Figure 4 As shown, the lattice spacing of bismuth vanadate is 0.274 nm, corresponding to the -220 crystal plane. The amorphous thin film polyterthiophene and bismuth vanadate are separated by short white dashed lines, thus confirming the successful loading of polyterthiophene.

[0090] Step 3: Preparation of the nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode:

[0091] 0.001M nickel chloride was added to 50mL of tertiary water and sonicated until the precipitate was completely dissolved. The resulting solution was used as electrolyte C for photoelectrodeposition of the poly(terthiophene / bismuth vanadate) composite photoelectrode. Specifically, electrolyte C was used as the electrolyte, the poly(terthiophene / bismuth vanadate) composite photoelectrode obtained above was used as the working electrode, a platinum mesh was used as the counter electrode, and Ag / AgCl was used as the reference electrode. Electrodeposition was performed using the time-current curve method. The electrodeposition conditions were: initial voltage was open-circuit voltage, sampling interval was 0.1s, deposition time was 900s, settling time was 0s, and sensitivity was 1×10⁻⁶. -3 A.

[0092] After electrodeposition, the glass was rinsed with tertiary water and dried. FTO conductive glass sheets with a 2cm × 1cm diameter and deposited with nickel oxide / poly(terthiophene) / bismuth vanadate layers were then placed on high-temperature resistant corundum sheets, with a 2mm distance between the sheets. The corundum sheets were then placed in a muffle furnace and heated at 2℃·min. -1 The temperature was increased to 300℃ at a certain heating rate, and calcined for 1 hour.

[0093] After the muffle furnace is cooled to room temperature, it is rinsed with three stages of water and dried to obtain a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode (NiO / pTTH / BiVO4 composite photoelectrode).

[0094] The scanning electron microscope (SEM) image of the nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode is shown below. Figure 5 As shown; the scanning image of the nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode under a transmission electron microscope (TEM) is as follows. Figure 6 As shown, the lattice spacing of bismuth vanadate is 0.323 nm, corresponding to the 026 crystal plane. The amorphous thin film polyterthiophene is separated from bismuth vanadate by short white dashed lines, and the nickel oxide particles are separated from polyterthiophene by long white dashed lines, thus confirming the successful loading of nickel oxide.

[0095] The X-ray diffraction (XRD) patterns of the bismuth vanadate photoelectrode, the poly(terthiophene) / bismuth vanadate composite photoelectrode, and the nickel oxide / poly(terthiophene) / bismuth vanadate composite photoelectrode prepared in this embodiment are shown below. Figure 7 As shown, the successful preparation of bismuth vanadate crystals is due to the absence of XRD peaks in the polymer, the absence of peaks for polyterthiophene in this figure, and the fact that nickel oxide is an electrodeposition product, so it also lacks corresponding characteristic peaks.

[0096] The Fourier Transform Infrared (FT-IR) spectra of the poly(trithiophene / bismuth vanadate) composite photoelectrode and the nickel oxide / poly(trithiophene / bismuth vanadate) composite photoelectrode prepared in this embodiment are shown in the figure below. Figure 8 As shown, 688cm -1 790cm -1 1031cm -1 1120cm -1 The characteristic peak of poly(terthiophene) crystals is 496 cm⁻¹. -1 1031cm -1 1384cm -1 3448cm -1 These are characteristic peaks of nickel oxide.

[0097] Application Test Example 1

[0098] Linear scanning voltammetry was selected, with chopping under AM 1.5G illumination at a rate of 1 s / s. The pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1 M Na2SO4. The initial potential was 0.3 V vs. RHE, the termination potential was 1.3 V vs. RHE, the scan rate was 0.025 V / s, the sampling interval was 0.001 V, the settling time was 0 s, and the sensitivity was 1 × 10⁻⁶. -3 A. The photocurrent of pTTH / BiVO4 composite photoelectrodes deposited at potentials of 0.80V, 0.85V, 0.90V, 0.95V, 1.00V, 1.05V, 1.10V, 1.15V, and 1.20V in 0.1M Na2SO4 solution was measured as a function of potential. The performance of the material in pure water was evaluated based on this photocurrent density change. The obtained linear sweep voltammetry curves are shown below. Figure 9 As shown.

[0099] Linear scanning voltammetry was selected. Under chopping light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1M Na2SO4 + 0.1M glucose. The initial potential was 0.3V vs. RHE, the termination potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A. The photocurrent of pTTH / BiVO4 composite photoelectrodes deposited at potentials of 0.80V, 0.85V, 0.90V, 0.95V, 1.00V, 1.05V, 1.10V, 1.15V, and 1.20V was measured as a function of potential in 0.1M Na2SO4 + 0.1M glucose. This photocurrent density change was used to evaluate the material's performance in glucose content detection. The resulting linear sweep voltammetric curves are shown below. Figure 10 As shown.

[0100] Linear scanning voltammetry was selected. Under chopping light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1M Na2SO4 + 0.1M hole scavenger. The initial potential was 0.3V vs. RHE, the termination potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3A. The photocurrent of pTTH / BiVO4 composite photoelectrodes deposited at potentials of 0.80V, 0.85V, 0.90V, 0.95V, 1.00V, 1.05V, 1.10V, 1.15V, and 1.20V was measured in 0.1M Na2SO4 + 0.1M hole scavenger (Na2SO3). The change in photocurrent density was used to evaluate the charge separation performance of the material. The resulting linear sweep voltammetric curves are shown below. Figure 11 As shown.

[0101] according to Figures 9-11 It can be seen that the pTTH / BiVO4 composite photoelectrode exhibits different detection performances with increasing deposition potential. The pTTH / BiVO4 composite photoelectrode prepared with a deposition potential of 0.90V shows higher performance in glucose content detection. Its charge separation is slightly lower than that of the photoanode prepared with 0.85V, but its performance in pure water is even lower, and it is less affected by water splitting reactions. Therefore, 0.90V is the optimal deposition potential. When the deposition potential is below 0.85V, the pTTH loading thickness is insufficient, resulting in reduced detection performance; when the deposition potential is above 0.95V, the pTTH loading thickness is excessive, also reducing detection performance.

[0102] Application Test Example 2

[0103] Linear scanning voltammetry was selected. Under chopping light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1M Na2SO4. The initial potential was 0.3V vs. RHE, the termination potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A. The photocurrent of the pTTH / BiVO4 composite photoelectrode deposited at potentials of 2, 4, 6, 8, and 10 electroplating cycles in 0.1 M Na2SO4 solution changes with potential. This photocurrent change is used to evaluate the material's performance in pure water. The resulting linear sweep voltammetry curve is shown below. Figure 12 As shown.

[0104] Linear scanning voltammetry was selected. Under chopping light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1M Na2SO4 + 0.1M glucose. The initial potential was 0.3V vs. RHE, the termination potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3A. The photocurrent of pTTH / BiVO4 composite photoelectrodes deposited at potentials of 2, 4, 6, 8, and 10 electroplating cycles in 0.1 M Na2SO4 + 0.1 M glucose was tested as a function of potential. This photocurrent change was used to evaluate the material's performance in glucose content detection. Figure 13 Linear scan voltammetry curve.

[0105] Linear scanning voltammetry was selected. Under chopping light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1M Na2SO4 + 0.1M hole scavenger. The initial potential was 0.3V vs. RHE, the termination potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A. The photocurrent of pTTH / BiVO4 composite photoelectrodes deposited at potentials of 2, 4, 6, 8, and 10 electroplating cycles in 0.1 M Na2SO4 + 0.1 M hole scavenger was tested as a function of potential. This photocurrent change was used to evaluate the charge separation performance of the material. Figure 14 Linear scan voltammetry curve.

[0106] according to Figures 12-14 It can be seen that the pTTH / BiVO4 composite photoelectrode exhibits different detection performances as the number of deposition cycles increases. The pTTH / BiVO4 composite photoelectrode prepared with 4 deposition cycles demonstrates excellent performance in all detection methods, while the photoanode with 2 deposition cycles exhibits excessively high performance in pure water and is significantly affected by water splitting. Therefore, 4 deposition cycles is the optimal number of deposition cycles. When the number of deposition cycles is less than 4, the pTTH loading thickness is insufficient, resulting in reduced detection performance; conversely, when the number of deposition cycles is more than 4, the pTTH loading thickness is excessive, also reducing detection performance.

[0107] Application Test Example 3

[0108] Linear scanning voltammetry was selected. Under illumination, the BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1M Na2SO4. The initial potential was 0.3V vs. RHE, the termination potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A. The photocurrent of the pTTH / BiVO4 composite photoelectrode as a function of potential was tested in glucose solutions of 0 M, 0.1 mM, 1 mM, 10 mM, 100 mM, and 1 M concentrations. Figure 15Linear scan voltammetry curve.

[0109] Linear scanning voltammetry was selected. Under illumination, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1M Na2SO4. The initial potential was 0.3V vs. RHE, the termination potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A. The photocurrent of the pTTH / BiVO4 composite photoelectrode as a function of potential was tested in glucose solutions of 0 M, 0.1 mM, 1 mM, 10 mM, 100 mM, and 1 M concentrations. Figure 16 Linear scan voltammetry curve.

[0110] Linear scanning voltammetry was selected. Under illumination, the NiO / pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte was 0.1M Na2SO4. The initial potential was 0.3V vs. RHE, the termination potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A. The photocurrent of the pTTH / BiVO4 composite photoelectrode as a function of potential was tested in glucose solutions of 0 M, 0.1 mM, 1 mM, 10 mM, 100 mM, and 1 M concentrations. Figure 17 Linear scan voltammetry curve.

[0111] according to Figures 15-17 It can be seen that the current density of the NiO / pTTH / BiVO4 composite photoanode in 1.3 vs. RHE is 3.66 mA·cm. -2 It is significantly superior to pTTH / BiVO4 photoanode (3.05 mA·cm⁻¹). -2 ) and pure BiVO4 photoanode (2.49 mA·cm -2 It possesses excellent detection signal and better detection gradient.

[0112] Application Test Example 4

[0113] The time-current curve method was selected. Under illumination with a lamp on, the BiVO4 photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte consisted of 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M glucose solutions prepared on a 0.1M Na2SO4 base. The initial scan potential was 0.6V vs. RHE, the sampling interval was 0.1s, the running time was 25s, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A, light intensity is 100mW / cm² 2 The photocurrent of the iron oxide photoelectrode was tested over time at glucose concentrations of 0 M, 0.1 mM, 1 mM, 10 mM, 100 mM, and 1 M. The resulting time-current curves are shown in the figure below. Figure 18 As shown.

[0114] The time-current curve method was selected. Under illumination with a light source, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte consisted of 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M glucose solutions prepared on a 0.1M Na2SO4 base. The initial scan potential was 0.6V vs. RHE, the sampling interval was 0.1s, the running time was 25s, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A, light intensity is 100mW / cm² 2 The photocurrent of the iron oxide photoelectrode was tested over time at glucose concentrations of 0 M, 0.1 mM, 1 mM, 10 mM, 100 mM, and 1 M. The resulting time-current curves are shown in the figure below. Figure 19 As shown.

[0115] The time-current curve method was selected. Under illumination with a lamp on, the NiO / pTTH / BiVO4 composite photoelectrode prepared in Experimental Example 1 was used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The electrolyte consisted of 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M glucose solutions prepared on a 0.1M Na2SO4 base. The initial scan potential was 0.6V vs. RHE, the sampling interval was 0.1s, the running time was 25s, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A, light intensity is 100mW / cm² 2 The photocurrent of the iron oxide photoelectrode was tested over time at glucose concentrations of 0 M, 0.1 mM, 1 mM, 10 mM, 100 mM, and 1 M. The resulting time-current curves are shown in the figure below. Figure 20 As shown.

[0116] Depend on Figures 18-20It was observed that under dark conditions, the dark current for all glucose concentrations was approximately zero, confirming that glucose cannot be electrochemically oxidized by the NiO / pTTH / BiVO4 composite photoanode. Under illumination, however, the current increased rapidly, then decayed after reaching a peak, and subsequently reached a steady state. The NiO / pTTH / BiVO4 composite photoelectrode exhibited a more pronounced gradient and higher performance as a photoanode in glucose solution (0.41 mA for NiO / pTTH / BiVO4, 0.25 mA for pTTH / BiVO4, and 0.19 mA for BiVO4 in 1 M glucose), further confirming that this sample is more suitable for detecting high glucose concentrations.

[0117] Figure 21 The image shows the optical contact angle measuring instrument of the BiVO4 photoelectrode in Example 1, indicating that the contact angle of the BiVO4 photoelectrode is 14.0°.

[0118] Figure 22 The image shows the optical contact angle measurement instrument of the pTTH / BiVO4 composite photoelectrode in Example 1. It can be seen that the contact angle of the pTTH / BiVO4 composite photoelectrode is 73.0°.

[0119] Figure 23 The image shown is an optical contact angle measurement of the NiO / pTTH / BiVO4 composite photoelectrode in Example 1. It can be seen that the contact angle of the NiO / pTTH / BiVO4 composite photoelectrode is 98.6°. Comparison confirms that the NiO / pTTH / BiVO4 composite photoelectrode has better hydrophobicity than the BiVO4 photoelectrode, thus minimizing the influence of water splitting reaction on organic reactions.

[0120] Figure 24 The steady-state fluorescence spectra of the BiVO4 photoelectrode, pTTH / BiVO4 composite photoelectrode, and NiO / pTTH / BiVO4 composite photoelectrode in Example 1 show that the average lifetime of the NiO / pTTH / BiVO4 composite photoelectrode is higher than that of the BiVO4 photoelectrode. This means that the NiO / pTTH / BiVO4 composite photoelectrode suppresses more photogenerated hole recombination, thus improving charge separation efficiency.

[0121] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a composite photoelectrode for glucose content detection, characterized in that, Includes the following steps: (1) Potassium iodide and bismuth nitrate pentahydrate are added to nitric acid solution to obtain solution A; p-Benzoquinone was added to ethanol to obtain solution B; solution A and solution B were mixed to obtain electrolyte A; using electrolyte A as the electrolyte, an electrochemical deposition method was used to deposit a bismuth-oxyiodine thin film on the surface of a conductive substrate. (2) Add acetylacetone vanadium oxide to dimethyl sulfoxide solution to obtain solution C; Solution C is dropped onto the surface of the conductive substrate with bismuth-oxygen-iodine film deposited in step (1), and calcined. After the calcination is completed, the product is immersed in sodium hydroxide solution, washed and dried to obtain bismuth vanadate photoelectrode. (3) Lithium perchlorate and terthiophene were added to an acetonitrile solution to obtain electrolyte B; Using electrolyte B as the electrolyte, photoelectrochemical deposition was performed on the surface of the bismuth vanadate photoelectrode. After washing and drying, a bismuth vanadate / polyterthiophene composite photoelectrode was obtained. (4) Dissolve nickel chloride in water to obtain electrolyte C; using electrolyte C as electrolyte, electrochemical deposition is performed on the surface of the bismuth vanadate / polyterthiophene composite photoelectrode. After the deposition is completed, the photoelectrode is calcined, washed and dried to obtain nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode, which is the composite photoelectrode used for glucose content detection.

2. The method for preparing the composite photoelectrode for glucose content detection according to claim 1, characterized in that, In step (1), the pH of the nitric acid solution is 1.65~1.75; And / or, the molar ratio of potassium iodide, bismuth nitrate pentahydrate and p-benzoquinone is 4:0.4:2.3; And / or, the electrochemical deposition method is the time-current curve method; during the electrochemical deposition process, a conductive substrate is used as the working electrode, a platinum mesh is used as the counter electrode, and an Ag / AgCl electrode is used as the reference electrode.

3. The method for preparing the composite photoelectrode for glucose content detection according to claim 2, characterized in that, In step (1), the process parameters of the electrochemical deposition method are as follows: initial voltage of -0.10 ~ -0.15 V, sampling interval of 0.1 s, deposition time of 150 ~ 200 s, settling time of 0 s, and sensitivity of 1 × 10⁻⁶. -3 A.

4. The method for preparing the composite photoelectrode for glucose content detection according to claim 1, characterized in that, In step (2), the calcination temperature is 440~460 ℃, the time is 2 h, and the heating rate is 2 ℃·min. -1 ; And / or, the drop volume of solution C is 35~50 μL·cm. -2 ; And / or, the concentration of the sodium hydroxide solution is 1 M, and the soaking time is 15-25 min.

5. The method for preparing the composite photoelectrode for glucose content detection according to claim 1, characterized in that, In step (3), the molar ratio of lithium perchlorate to terthiophene is 1:0.1; And / or, the electrochemical deposition method is cyclic voltammetry; during the electrochemical deposition process, the bismuth vanadate photoelectrode is used as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode, with a light intensity of 100 mW·cm. -2 .

6. The method for preparing the composite photoelectrode for glucose content detection according to claim 1, characterized in that, In step (4), the electrochemical deposition method is the time-current curve method; during the electrochemical deposition process, the bismuth vanadate / polythiophene composite photoelectrode is used as the working electrode, the platinum grid is used as the counter electrode, and the Ag / AgCl electrode is used as the reference electrode.

7. The method for preparing the composite photoelectrode for glucose content detection according to claim 6, characterized in that, In step (4), the process parameters for electrochemical deposition using the time-current curve method are as follows: initial potential is the open-circuit voltage, sampling interval is 0.1 s, deposition time is 600~1200 s, settling time is 0 s, and sensitivity is 1×10⁻⁶. -3 A.

8. The method for preparing the composite photoelectrode for glucose content detection according to claim 1, characterized in that, In step (4), the calcination temperature is 250~350 ℃ and the time is 1 h.

9. A composite photoelectrode for glucose content detection, characterized in that, It is prepared according to any one of claims 1 to 8.

10. The application of the composite photoelectrode as described in claim 9 in the detection of glucose content.

Images