Composite photoelectrode for glucose content detection and preparation method and application thereof

Abstract

The invention discloses a composite photoelectrode for glucose content detection and a preparation method and application of the composite photoelectrode, 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) through a nitric acid solution system; the bismuth vanadate photoelectrode is obtained by carrying out calcination conversion and alkali treatment on a matrix of a dimethyl sulfoxide solution dripped with vanadyl acetylacetonate. Utilizing acetonitrile electrolyte to photoelectrically deposit a poly (terthienyl) (pTTH) layer on the surface of the bismuth vanadate; a nickel oxide layer is deposited through a water-phase electrolyte, and a multi-stage composite structure is obtained through calcination treatment, so that the nickel oxide / poly (terthienyl) / bismuth vanadate composite photoelectrode is obtained. Therefore, the nickel oxide / polyterthienyl / bismuth vanadate composite photoelectrode prepared by the method has high carrier separation efficiency and excellent catalytic stability, and an analysis method with simple steps is provided for effective voltage detection of glucose.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoelectrochemical analysis, and in particular relates to a composite photoelectrode for glucose content detection, a preparation method thereof, and an application thereof. Background Art

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

[0003] Although there are many methods for glucose detection at present, each method has fatal shortcomings such as complex equipment, short service life, poor timeliness, and low sensitivity. Photoelectrochemical detection, as a new generation of detection technology, has attracted more and more attention due to its advantages such as low detection limit, low energy consumption, fast detection speed, and the ability to quantify the degree of organic matter degradation. Its detection performance is mainly determined by the performance of the photoelectrode, but existing photoelectrodes often have shortcomings such as being affected by the electrolysis reaction of water, low charge separation efficiency, and poor stability. Therefore, the design and preparation of high-performance composite photoelectrode materials is a key issue in 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 solve the above technical problems, the present invention proposes a composite photoelectrode for glucose content detection, a preparation method and an application thereof. The composite photoelectrode of the present invention can effectively detect voltage in glucose solutions of different concentrations and has high stability.

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

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

[0007] The present invention provides a composite photoelectrode for detecting glucose content. 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) adding potassium iodide and bismuth nitrate pentahydrate to a nitric acid solution to obtain solution A; adding p-benzoquinone to ethanol to obtain solution B; mixing the solution A and the solution B to obtain an electrolyte A; using the electrolyte A as the electrolyte, using an electrochemical deposition method to deposit a bismuth oxyiodine film on the surface of a conductive substrate;

[0011] (2) adding vanadyl acetylacetonate to a dimethyl sulfoxide solution to obtain a solution C; dripping the solution C onto the surface of the conductive substrate on which the bismuth iodine oxide film is deposited, prepared in step (1), and calcining the substrate; after the calcination, immersing the product in a sodium hydroxide solution, washing, and drying the solution to obtain a bismuth vanadate photoelectrode;

[0012] (3) adding lithium perchlorate and terthiophene to an acetonitrile solution to obtain an electrolyte B; using the electrolyte B as an electrolyte, performing photoelectric deposition on the surface of the bismuth vanadate photoelectrode by an electrochemical deposition method, and washing and drying after completion to obtain a bismuth vanadate / polyterthiophene composite photoelectrode;

[0013] (4) dissolving nickel chloride in water to obtain electrolyte C; using the electrolyte C as the electrolyte, adopting an electrochemical deposition method to deposit on the surface of the bismuth vanadate / polyterthiophene composite photoelectrode, and then calcining, washing and drying to obtain a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode, which is the composite photoelectrode for detecting glucose content.

[0014] The present invention first uses a constant potential deposition method to form a bismuth oxygen iodine precursor film on the pretreated FTO surface, and 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 a thermal oxidation process, ultimately forming a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode (NiO / pTTH / BiVO4 composite photoelectrode).

[0015] Compared with patent CN 117169305 A: The present invention focuses more on regulating the surface hydrophobicity (changing the thickness of the heterojunction pTTH layer and increasing the NiO hydrophobic layer to make it more hydrophobic) to make the surface of the modified BiVO4 photoanode more hydrophobic, improve its selectivity for glucose oxidation reaction, and reduce the impact of water decomposition reaction on the detection results. In addition, when the NiO / pTTH / BiVO4 composite photoelectrode prepared by the present invention is used as a photoanode, the detection signal of different glucose concentrations is much higher than that of patent CN 117169305 A (for example, at the same 0.1M concentration of glucose, the detection signal of the NiO / pTTH / BiVO4 composite photoelectrode in 0.8vs.RHE is 1.11mA·cm -2The detection signal of the photoelectrode in patent CN 117169305 A is only 0.6 mA·cm -2 About), and the NiO / pTTH / BiVO4 composite photoelectrode of the present invention can detect higher concentrations (1M glucose) and more evenly distributed glucose concentration gradients. The characteristic electrical signal generated by the NiO / pTTH / BiVO4 composite photoelectrode when oxidizing glucose of different concentrations realizes the quantitative detection of glucose, so the present invention can effectively detect voltage in glucose solutions of different concentrations. The bismuth vanadate photoanode itself is suitable for water decomposition reaction, and the organic oxidation reaction in glucose dissolution can easily destroy its structure and reduce its performance. The present invention improves its detection performance and stability in glucose content by constructing a heterojunction (pTTH) and adding a co-catalyst layer (NiO), so the NiO / pTTH / BiVO4 composite photoelectrode of the present invention has high stability.

[0016] Furthermore, 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 amount ratio of the prepared solution is less than the above ratio, the electrodeposited BiOI film will be too thin, and the detection performance will be reduced; when the amount ratio of the prepared solution is higher than the above ratio, the electrodeposited BiOI film will be too thick, and the detection performance will be reduced;

[0018] And / or, the electrochemical deposition method is a time-current curve method; during the electrochemical deposition process, the conductive substrate 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.

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

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

[0021] Furthermore, in step (2), the calcination temperature is 440-460°C, the time is 2h, and the heating rate is 2°C·min -1 When the calcination temperature is lower than 440℃, BiVO4 will be incompletely crystallized and the sample preparation will fail; when the calcination temperature is higher than 460℃, BiVO4 will be burned black and the sample preparation will fail;

[0022] And / or, the dripping amount of the solution C is 35 to 50 μL·cm -2 , preferably 40 μL·cm -2 , among which, when the dripping volume is less than 35μL·cm -2 When the drop volume is less than 50 μL·cm -2 When BiVO4 is burned black, the sample preparation fails.

[0023] And / or, the concentration of the sodium hydroxide solution is 1M, and the immersion time is 15 to 25 minutes. The present invention removes excess V2O5 by immersion in the sodium hydroxide solution. When the immersion time is less than 15 minutes, the V2O5 removal will be incomplete, and the performance will be reduced; when the immersion time is more than 25 minutes, the BiVO4 will be alkaline and turn yellow, and the performance will be reduced.

[0024] Illustratively, in step (2), the preparation method of solution C is as follows: 0.2 M vanadyl acetylacetonate is mixed with 5 mL of dimethyl sulfoxide, and the mixture is stirred 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, the platinum mesh is used as the counter electrode, the Ag / AgCl electrode is used as the reference electrode, and the light intensity is 100 mW·cm -2 .

[0027] Furthermore, in step (3), the process parameters of electrochemical deposition are: initial potential of 0V, upper limit potential of 0.85-0.95V, lower limit potential of 0V, termination voltage of 0.85-0.95V, initial scanning direction of positive, scanning speed of 0.05V·s -1 , the scanning circle number is 3 to 5 circles, the sampling interval is 0.001V, the static time is 2s, and the sensitivity is 1×10 -3 A, wherein, when the electrodeposition parameters are lower than the above parameters, the polyterthiophene (pTTH) loading amount will be too low and the performance will be reduced; when the electrodeposition parameters are higher than the above parameters, the pTTH loading amount will be too high and the performance will be reduced.

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

[0029] Furthermore, in step (4), the electrochemical deposition method is a time-current curve method; during the electrochemical deposition process, a bismuth vanadate / polyterthiophene composite photoelectrode (BiVO4 / pTTH composite photoelectrode) 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.

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

[0031] Furthermore, 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 application of the composite photoelectrode in detecting glucose content.

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

[0035] The present 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, a constant potential deposition method is first used to form a bismuth oxygen iodine precursor film on the pretreated FTO surface, and a porous bismuth vanadate photoanode is obtained through high-temperature crystal phase transformation and alkali treatment; then, a pTTH modification layer is in situ generated in a terthiophene monomer solution through photoelectrochemical polymerization; finally, a NiO surface modification structure is constructed through 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 the present invention can be combined with photoelectric detection technology to effectively detect voltage in glucose solutions of different concentrations, 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 the present invention provides an analytical method with simple steps for the effective voltage detection of glucose. The present invention is simple and safe to operate, the materials are easily available, and large-scale production can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0038] Figure 1 This is a scanning electron microscope (SEM) image of the bismuth vanadate photoelectrode prepared in Example 1;

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

[0040] Figure 3 This is an SEM image of the polyterthiophene / bismuth vanadate composite photoelectrode prepared in Example 1;

[0041] Figure 4 TEM image of the polyterthiophene / bismuth vanadate composite photoelectrode prepared in Example 1;

[0042] Figure 5 This is a SEM image of the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode prepared in Example 1;

[0043] Figure 6 TEM image of the nickel oxide / polyterthiophene / 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 FT-IR spectra of the polyterthiophene / bismuth vanadate composite photoelectrode and the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode prepared in Example 1;

[0046] Figure 9 Linear sweep voltammograms of the polyterthiophene / bismuth vanadate photoelectrode deposited at different potentials in 0.1 M Na2SO4 solution according to Application Test Example 1;

[0047] Figure 10 Linear sweep voltammograms of the polyterthiophene / bismuth vanadate photoelectrode deposited at different potentials in 0.1M Na2SO4+0.1M glucose solution in Application Test Example 1;

[0048] Figure 11 Linear sweep voltammograms of the polyterthiophene / bismuth vanadate photoelectrode deposited at different potentials in 0.1M Na2SO4+0.1M hole trap solution in Application Test Example 1;

[0049] Figure 12 Linear sweep voltammograms of polyterthiophene / bismuth vanadate photoelectrodes with different deposition cycles in 0.1M Na2SO4 solution according to Test Example 2;

[0050] Figure 13 Linear sweep voltammograms of polyterthiophene / bismuth vanadate photoelectrodes with different deposition cycles in 0.1M Na2SO4+0.1M glucose solution in Test Example 2;

[0051] Figure 14 Linear sweep voltammograms of polyterthiophene / bismuth vanadate photoelectrodes with different deposition cycles in 0.1M Na2SO4+0.1M hole trap solution in Test Example 2;

[0052] Figure 15 This is a linear sweep voltammetry curve of the bismuth vanadate photoelectrode of Application Test Example 3;

[0053] Figure 16 This is a linear sweep voltammetry curve of the polyterthiophene / bismuth vanadate composite photoelectrode of Application Test Example 3;

[0054] Figure 17 This is a linear sweep voltammetry curve of the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode of Application Test Example 3;

[0055] Figure 18 This is a time-current curve of the bismuth vanadate photoelectrode in Test Example 4;

[0056] Figure 19 This is a time-current curve of the polyterthiophene / bismuth vanadate composite photoelectrode in application test example 4;

[0057] Figure 20 This is a time-current curve of the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode in Test Example 4;

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

[0059] Figure 22 This is a diagram showing the optical contact angle measurement of the polyterthiophene / bismuth vanadate composite photoelectrode in Example 1;

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

[0061] Figure 24These are the 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. DETAILED DESCRIPTION

[0062] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting 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 terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between any intermediate value within a stated value or stated range and any other stated value or intermediate value within the stated range is also encompassed by the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0064] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0065] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

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

[0067] The present invention uses a nitric acid solution system to electrochemically deposit a BiOI thin film on the surface of a conductive substrate (such as pretreated FTO conductive glass); a substrate dropwise coated with a dimethyl sulfoxide solution of acetylacetonato vanadium is calcined and converted, followed by alkali treatment to obtain a bismuth vanadate photoelectrode; an acetonitrile electrolyte is used to photoelectrode a polyterthiophene (pTTH) layer on the bismuth vanadate surface; a nickel oxide layer is deposited using an aqueous electrolyte and calcined to obtain a multi-level composite structure, thereby obtaining a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode. Thus, the nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode prepared by the present invention is a high-performance photoelectrode with both high carrier separation efficiency and excellent catalytic stability, providing a simple analytical method for the effective voltage detection of glucose.

[0068] "Grade 3 water" refers to a type of experimental water whose conductivity does not exceed 0.50mS / m (i.e. 5.0μS / cm) at 25°C and whose resistivity is not less than 0.2MΩ·cm.

[0069] During the electrodeposition process, the static time indicates the waiting time before deposition, and 0s means direct deposition without waiting.

[0070] Unless otherwise specified, the room temperature in the present invention is 25±2°C.

[0071] All raw materials used in the examples of the present invention are commercially available.

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

[0073] The technical solution of the present invention is further illustrated by the following examples.

[0074] Example 1

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

[0076] The preparation process of the nickel oxide / polyterthiophene / 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 and cut it into 2cm×3cm specifications using a glass cutting table. Then, ultrasonically wash it with acetone, ethanol, and third-grade 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, transfer it to a brown wide-mouth bottle and store it 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 translucent 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 solution A and solution B, and stir vigorously (at a speed of 450 rpm) to make them fully dissolve in each other to obtain electrolyte A.

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

[0081] After the electrodeposition is completed, the glass is rinsed with grade tertiary water and dried to obtain FTO conductive glass deposited with a bismuth oxide-iodine film, which is then cut into 2 cm × 1 cm specifications using a glass cutting table.

[0082] On a high-temperature resistant corundum sheet, a 2cm×1cm FTO conductive glass sheet with a bismuth iodine oxide film was placed, with a distance of 2mm between the sheets. 5mL of dimethyl sulfoxide (DMSO) was added with 0.2M vanadyl acetylacetonate and stirred vigorously (at 450rpm) until no obvious precipitation was observed to obtain solution C. A 100μL pipette was used to pipette 40μL·cm -2 As a standard, solution C was dripped onto the surface of the bismuth iodine oxide film, and then the corundum sheet was placed in a muffle furnace and heated at 2 °C·min -1 The temperature was raised to 450 °C at a heating rate of 1000 ℃ and calcined for 2 h.

[0083] After the muffle furnace is cooled to room temperature, the corundum sheet is taken out, and the fired FTO conductive glass is placed in a watch glass. 1M NaOH solution is added and soaked for 20 minutes. The mixture is rinsed with grade 3 water and dried to obtain a bismuth vanadate photoelectrode (BiVO4 photoelectrode).

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

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

[0086] Step 2: Preparation of polyterthiophene / bismuth vanadate composite photoelectrode:

[0087] 0.1 M lithium perchlorate and 0.01 M terthiophene were added to 50 mL of acetonitrile and ultrasonicated until the precipitate was completely dissolved to obtain electrolyte B. The obtained electrolyte B was used as the electrolyte for photoelectrodeposition of bismuth vanadate photoelectrode. The specific steps were as follows: the obtained electrolyte B was used as the electrolyte, the bismuth vanadate photoelectrode obtained above was used as the working electrode, the platinum mesh was used as the counter electrode, and the Ag / AgCl was used as the reference electrode. The light intensity was 100 mW·cm -2 Cyclic voltammetry was used for electrodeposition. The electrodeposition conditions were as follows: initial potential of 0 V, upper limit potential of 0.9 V, lower limit potential of 0 V, termination voltage of 0.9 V, initial scanning direction of positive, and scanning speed of 0.05 V s -1 , the number of scanning circles is 4, the sampling interval is 0.001V, the static time is 2s, and the sensitivity is 1×10 -3 A.

[0088] After the electrodeposition, the electrodeposited material was rinsed with ethanol and grade 3 water respectively and dried to obtain a polyterthiophene / bismuth vanadate composite photoelectrode (pTTH / BiVO4 composite photoelectrode).

[0089] The scanning image of the polyterthiophene / bismuth vanadate composite photoelectrode under a scanning electron microscope (SEM) is shown in FIG. Figure 3 As shown; the scanning image of the polyterthiophene / bismuth vanadate composite photoelectrode under a transmission electron microscope (TEM) is shown Figure 4 As shown, it can be seen that the lattice spacing of bismuth vanadate is 0.274 nm, the corresponding crystal plane is -220 crystal plane, and the amorphous thin film polyterthiophene and bismuth vanadate are separated by white short dashed lines, which confirms that polyterthiophene is successfully loaded.

[0090] Step 3: Preparation of nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode:

[0091] Take 0.001M nickel chloride, add 50mL of grade tertiary water, and sonicate until the precipitate is completely dissolved. The obtained solution is used as electrolyte C for photoelectrodeposition of polytertiary thiophene / bismuth vanadate composite photoelectrode. Specifically: the obtained electrolyte C is used as the electrolyte, the polytertiary thiophene / bismuth vanadate composite photoelectrode obtained above is used as the working electrode, the platinum mesh is used as the counter electrode, and Ag / AgCl is used as the reference electrode. The time-current curve method is used for electrodeposition. The electrodeposition conditions are: the initial voltage is the open circuit voltage, the sampling interval is 0.1s, the deposition time is 900s, the static time is 0s, and the sensitivity is 1×10 -3 A.

[0092] After the electrodeposition, rinse with grade 3 water and dry. Place a 2cm×1cm FTO conductive glass with nickel oxide / polyterthiophene / bismuth vanadate layer on a high-temperature resistant corundum sheet. The distance between the sheets is 2mm. Then place the corundum sheet in a muffle furnace and heat it at 2℃·min. -1 The temperature was raised to 300 °C at a heating rate of 100 °C and calcined for 1 h.

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

[0094] The scanning image of nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode under scanning electron microscope (SEM) is shown as follows: Figure 5 As shown; the scanning image of the composite photoelectrode of nickel oxide / polyterthiophene / bismuth vanadate under transmission electron microscope (TEM) is as follows Figure 6 As shown, it can be seen that the lattice spacing of bismuth vanadate is 0.323 nm, the corresponding crystal plane is 026 crystal plane, the amorphous film polyterthiophene and bismuth vanadate are separated by white short dashed lines, and the nickel oxide particles and polyterthiophene are separated by white long dashed lines, which confirms the successful loading of nickel oxide.

[0095] The 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 this embodiment are shown in FIG. Figure 7 As shown, it can be seen that the bismuth vanadate crystals were successfully prepared. Because there is no XRD peak in the polymer, there is no peak of polyterthiophene in the figure, and nickel oxide is an electrodeposition product, so there is no corresponding characteristic peak.

[0096] The infrared spectra (FT-IR) of the polyterthiophene / bismuth vanadate composite photoelectrode and nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode prepared in this example are shown in FIG. Figure 8 As shown, we can see that 688cm -1 , 790cm -1 、1031cm -1 、1120cm -1 is the characteristic peak of polyterthiophene crystal, 496cm -1 、1031cm -1 、1384cm -1 、3448cm -1 It is the characteristic peak of nickel oxide.

[0097] Application Test Example 1

[0098] Linear sweep voltammetry was selected, with a scan rate of 1 s / shot under AM 1.5G illumination. The pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh was used as the counter electrode, an Ag / AgCl electrode was used as the reference electrode, and the electrolyte was 0.1 M Na2SO4. The initial potential was 0.3 V vs. RHE, the end potential was 1.3 V vs. RHE, the scan rate was 0.025 V / s, the sampling interval was 0.001 V, the rest time was 0 s, and the sensitivity was 1×10 -3 A. The photocurrent of the pTTH / BiVO4 composite photoelectrode deposited at potentials of 0.80V, 0.85V, 0.90V, 0.95V, 1.00V, 1.05V, 1.10V, 1.15V, and 1.20V in 0.1MNa2SO4 solution was tested as a function of potential. The performance of the material in pure water was evaluated based on the change in photocurrent density. The obtained linear sweep voltammetry curve is shown in the figure below. Figure 9 shown.

[0099] Linear sweep voltammetry was selected. Under chopped light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh was used as the counter electrode, an Ag / AgCl electrode was used as the reference electrode, and 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 rest time was 0s, and the sensitivity was 1×10 -3 A. The photocurrent of the pTTH / BiVO4 composite photoelectrode 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+0.1M glucose was tested as a function of potential. The performance of the material in glucose content detection was evaluated based on the change in photocurrent density. The obtained linear sweep voltammetry curve is shown in the figure below. Figure 10 shown.

[0100] Linear sweep voltammetry was selected. Under chopped light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh was used as the counter electrode, an Ag / AgCl electrode was used as the reference electrode, and the electrolyte was 0.1M Na2SO4 + 0.1M hole trap. The initial potential was 0.3V vs. RHE, the end potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the rest time was 0s, and the sensitivity was 1×10 -3A. The photocurrent of the pTTH / BiVO4 composite photoelectrode 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+0.1M hole scavenger (Na2SO3, the same below) was tested as a function of potential. The charge separation performance of the material was evaluated by the change in the photocurrent density. The linear sweep voltammetry curve is shown in the figure. Figure 11 shown.

[0101] according to Figures 9 to 11 It can be seen that as the deposition potential increases, the pTTH / BiVO4 composite photoelectrode exhibits different detection performance. Among them, the pTTH / BiVO4 composite photoelectrode prepared at a deposition potential of 0.90V has higher performance in glucose content detection, and the charge separation is slightly lower than the photoanode prepared at 0.85V. However, its performance in pure water is lower and it is less affected by the water splitting reaction. Therefore, 0.90V is the optimal deposition potential. When the deposition potential is lower than 0.85V, the pTTH load thickness will be insufficient, and the detection performance will be reduced. When the deposition potential is higher than 0.95V, the pTTH load thickness will be too thick, and the detection performance will be reduced.

[0102] Application Test Example 2

[0103] Linear sweep voltammetry was used under chopped light, using the pTTH / BiVO4 composite photoelectrode prepared in Example 1 as the working electrode, a platinum mesh as the counter electrode, an Ag / AgCl electrode as the reference electrode, and 0.1 M Na2SO4 as the electrolyte. 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 rest time was 0 s, and the sensitivity was 1 × 10 -3 A. The photocurrent of the pTTH / BiVO4 composite photoelectrode deposited at 2, 4, 6, 8, and 10 electroplating cycles in 0.1M Na2SO4 solution was tested as a function of potential. The performance of the material in pure water was evaluated based on the photocurrent change. The obtained linear sweep voltammetry curve is shown in the figure below. Figure 12 shown.

[0104] Linear sweep voltammetry was selected. Under chopped light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh was used as the counter electrode, an Ag / AgCl electrode was used as the reference electrode, and 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 rest time was 0s, and the sensitivity was 1×10 -3A. Test the photocurrent variation of the pTTH / BiVO4 composite photoelectrode with the potential under the potential of 2, 4, 6, 8 and 10 electroplating cycles in 0.1M Na2SO4+0.1M glucose, and evaluate the performance of the material in glucose content detection based on the photocurrent variation. Figure 13 Linear sweep voltammetry curve.

[0105] Linear sweep voltammetry was selected. Under chopped light, the pTTH / BiVO4 composite photoelectrode prepared in Example 1 was used as the working electrode, a platinum mesh was used as the counter electrode, an Ag / AgCl electrode was used as the reference electrode, and the electrolyte was 0.1M Na2SO4 + 0.1M hole trap. The initial potential was 0.3V vs. RHE, the end potential was 1.3V vs. RHE, the scan rate was 0.025V / s, the sampling interval was 0.001V, the rest time was 0s, and the sensitivity was 1×10 -3 A. Test the photocurrent variation of the pTTH / BiVO4 composite photoelectrode with 0.1M Na2SO4+0.1M hole scavenger at 2, 4, 6, 8, and 10 electroplating cycles. The charge separation performance of the material is evaluated by the photocurrent variation. Figure 14 Linear sweep voltammetry curve.

[0106] according to Figures 12 to 14 As can be seen, the pTTH / BiVO4 composite photoelectrode exhibits different detection performance as the number of deposition cycles increases. The pTTH / BiVO4 composite photoelectrode prepared with four deposition cycles exhibits excellent performance in all tests, while the photoanode prepared with two deposition cycles performs too well in pure water and is significantly affected by water splitting, making four deposition cycles the optimal number. Fewer than four deposition cycles results in insufficient pTTH loading, reducing detection performance; more than four deposition cycles results in excessive pTTH loading, reducing detection performance.

[0107] Application Test Example 3

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

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

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

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

[0112] Application Test Example 4

[0113] The time-current curve method was selected. Under light illumination, the BiVO4 photoelectrode prepared in Experimental Example 1 was used as the working electrode, a platinum mesh was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. The electrolyte was a 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M glucose solution prepared based on 0.1M Na2SO4. The initial scanning potential was 0.6V vs. RHE, the sampling interval was 0.1s, the running time was 25s, the rest time was 0s, and the sensitivity was 1×10 -3 A, light intensity is 100mW / cm 2 , the photocurrent of the iron oxide photoelectrode was tested at glucose concentrations of 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M, and the obtained time-current curve was as shown in the figure below. Figure 18 shown.

[0114] The time-current curve method was selected. Under light illumination, the pTTH / BiVO4 composite photoelectrode prepared in Experimental Example 1 was used as the working electrode, the platinum mesh was used as the counter electrode, the Ag / AgCl electrode was used as the reference electrode, and the electrolyte was a 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M glucose solution prepared based on 0.1M Na2SO4. The initial scanning potential was 0.6V vs. RHE, the sampling interval was 0.1s, the running time was 25s, the rest time was 0s, and the sensitivity was 1×10 -3 A, light intensity is 100mW / cm 2 , the photocurrent of the iron oxide photoelectrode was tested at glucose concentrations of 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M, and the obtained time-current curve was as shown in the figure below. Figure 19 shown.

[0115] The time-current curve method was selected. Under light illumination, the NiO / pTTH / BiVO4 composite photoelectrode prepared in Experimental Example 1 was used as the working electrode, a platinum mesh was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. The electrolyte was a 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M glucose solution prepared based on 0.1M Na2SO4. The initial scanning potential was 0.6V vs. RHE, the sampling interval was 0.1s, the running time was 25s, the rest time was 0s, and the sensitivity was 1×10 -3 A, light intensity is 100mW / cm 2 , the photocurrent of the iron oxide photoelectrode was tested at glucose concentrations of 0M, 0.1mM, 1mM, 10mM, 100mM, and 1M, and the obtained time-current curve was as shown in the figure below. Figure 20 shown.

[0116] Depend on Figures 18 to 20It can be seen that under dark conditions, the dark current of all glucose concentrations is approximately zero, which confirms that glucose cannot be electrochemically oxidized by the NiO / pTTH / BiVO4 composite photoanode. Under light conditions, the current increases rapidly, then decays after the current reaches a peak, and then reaches a stable state. The NiO / pTTH / BiVO4 composite photoelectrode as a photoanode has a more obvious gradient in glucose solution and higher performance (in 1M glucose, NiO / pTTH / BiVO4 is 0.41mA, pTTH / BiVO4 is 0.25mA, and BiVO4 is 0.19mA), which also confirms that this sample is more suitable for high glucose concentration detection.

[0117] Figure 21 This is a diagram of the optical contact angle measurement instrument of the BiVO4 photoelectrode in Example 1. It can be seen that the contact angle of the BiVO4 photoelectrode is 14.0°.

[0118] Figure 22 This is an optical contact angle measurement diagram 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 This is a graph showing the optical contact angle of the NiO / pTTH / BiVO4 composite photoelectrode in Example 1. The contact angle is 98.6°. This comparison confirms that the NiO / pTTH / BiVO4 composite photoelectrode is more hydrophobic than the BiVO4 photoelectrode, minimizing the effects of the water decomposition reaction on the organic matter reaction.

[0120] Figure 24 These are the steady-state fluorescence spectra of the BiVO4 photoelectrode, pTTH / BiVO4 composite photoelectrode and NiO / pTTH / BiVO4 composite photoelectrode in Example 1. It can be seen that the average lifespan of the NiO / pTTH / BiVO4 composite photoelectrode is higher than that of the BiVO4 photoelectrode, that is, the NiO / pTTH / BiVO4 composite photoelectrode suppresses more photogenerated hole recombination rates, thereby improving the 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 changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A composite photoelectrode for glucose content detection, characterized in that: The composite photoelectrode is a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode.

2. A method for preparing the composite photoelectrode for glucose content detection according to claim 1, characterized in that: The following steps are involved: (1) adding potassium iodide and bismuth nitrate pentahydrate to a nitric acid solution to obtain solution A; adding p-benzoquinone to ethanol to obtain solution B; mixing the solution A and the solution B to obtain electrolyte A; using electrolyte A as the electrolyte, using an electrochemical deposition method to deposit a bismuth oxyiodine film on the surface of a conductive substrate; (2) adding vanadyl acetylacetonate to a dimethyl sulfoxide solution to obtain solution C; The solution C is dripped onto the surface of the conductive substrate on which the bismuth iodine oxide film is deposited, prepared in step (1), and calcined. After the calcination, the product is immersed in a sodium hydroxide solution, washed, and dried to obtain a bismuth vanadate photoelectrode; (3) adding lithium perchlorate and terthiophene to an acetonitrile solution to obtain electrolyte B; Using the electrolyte B as the electrolyte, photoelectric deposition is performed on the surface of the bismuth vanadate photoelectrode by an electrochemical deposition method, and then washing and drying are performed to obtain a bismuth vanadate / polyterthiophene composite photoelectrode; (4) dissolving nickel chloride in water to obtain electrolyte C; using the electrolyte C as the electrolyte, adopting an electrochemical deposition method to deposit on the surface of the bismuth vanadate / polyterthiophene composite photoelectrode, and then calcining, washing and drying to obtain a nickel oxide / polyterthiophene / bismuth vanadate composite photoelectrode, which is the composite photoelectrode for glucose content detection.

3. The method for preparing a composite photoelectrode for glucose content detection according to claim 2, characterized in that: In step (1), the pH of the nitric acid solution is 1.65 to 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 a time-current curve method; during the electrochemical deposition process, the conductive substrate 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.

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

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

6. The method for preparing a composite photoelectrode for glucose content detection according to claim 2, 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, the platinum mesh is used as the counter electrode, the Ag / AgCl electrode is used as the reference electrode, and the light intensity is 100 mW·cm -2 .

7. The method for preparing a composite photoelectrode for glucose content detection according to claim 2, characterized in that: In step (4), the electrochemical deposition method is a time-current curve method; during the electrochemical deposition process, a bismuth vanadate / polyterthiophene composite photoelectrode is used as a working electrode, a platinum mesh is used as a counter electrode, and an Ag / AgCl electrode is used as a reference electrode.

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

9. The method for preparing a composite photoelectrode for glucose content detection according to claim 2, wherein: In step (4), the calcination temperature is 250-350° C. and the calcination time is 1 hour.

10. Use of the composite photoelectrode according to claim 1 in detecting glucose content.

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