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

Abstract

A method for preparing a composite photoelectrode for glucose content detection includes the following steps: adding potassium iodide and bismuth nitrate pentahydrate to a nitric acid solution, adding p-benzoquinone to ethanol, and mixing to obtain electrolyte A; depositing a BiOI thin film on FTO conductive glass using an electrochemical method; dripping a dimethyl sulfoxide solution of vanadium acetylacetonate onto the surface of the BiOI thin film, calcining it, immersing it in NaOH solution, rinsing it, and drying it to obtain a BVO photoelectrode; adding lithium perchlorate and terthiophene to acetonitrile to obtain electrolyte B, and performing photoelectrodeposition on the BVO photoelectrode using an electrochemical method to obtain the composite photoelectrode. The preparation method of this invention is simple and safe to operate, uses readily available materials, and can be mass-produced; the prepared composite photoelectrode, combined with photoelectric detection technology, can detect glucose content, exhibits high stability, simple steps, rapid response, and high sensitivity, providing a new analytical method for glucose content determination.

Description

Technical Field

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

[0002] Photoelectrochemistry is an electrochemical process induced by light, where electrons in a substance transition from their ground state to an excited state under illumination, leading to electron transfer. Therefore, photoelectrochemical reactions can convert light energy into chemical and electrical energy. Based on this characteristic, photoelectrochemical sensors for measuring analyte concentrations and photoelectrochemical cells for power generation can be constructed. Devices developed based on photoelectrochemical analysis methods naturally inherit the high efficiency and low power consumption of photocatalysis, as well as the sensitivity, speed, and miniaturization advantages of electrochemical technology, demonstrating excellent development potential in the detection field.

[0003] Glucose is the most abundant and important monosaccharide in nature, widely found in fruits, vegetables, and other plants, and widely used in confectionery manufacturing, food processing, and medicine. Therefore, finding a rapid and convenient method for quantitative analysis of glucose in various aspects of daily life is of significant practical importance for fruit quality control, the processing and manufacturing of fruit and vegetable beverages, and disease diagnosis.

[0004] Although numerous methods exist for glucose detection, each suffers from fatal drawbacks such as high technical barriers, complex equipment, short lifespan, poor timeliness, and low sensitivity. Furthermore, enzymes are susceptible to influences from temperature, toxic substances, and pH, leading to inaccurate results. Therefore, determining how to detect glucose using photoelectrochemical analysis techniques without the use of biological enzymes is a crucial research topic. Summary of the Invention

[0005] Based on this, the present invention provides a method for preparing a composite photoelectrode for glucose content detection, thereby solving the problem of how to avoid using biological enzymes for glucose detection. The present invention uses fluorine-doped tin oxide (FTO) conductive glass as a substrate, and sequentially modifies it with bismuth vanadate and polyterthiophene. This achieves the attachment of polyterthiophene on the relatively fragile bismuth vanadate surface, thus protecting the bismuth vanadate. This results in a bismuth vanadate-polyterthiophene composite photoelectrode with advantages such as high stability, high sensitivity, and high environmental adaptability.

[0006] To achieve the above objectives, the present invention provides a method for preparing a composite photoelectrode for glucose content detection, comprising the following steps:

[0007] 1) Potassium iodide and bismuth nitrate pentahydrate were 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; BiOI thin film was deposited on FTO conductive glass using electrolyte A by electrochemical method.

[0008] 2) Take the FTO conductive glass with BiOI film deposited in step 1), drop a solution of vanadium acetylacetonate dimethyl sulfoxide onto the surface of the BiOI film, place it in a muffle furnace and calcine at 450°C, then soak it in NaOH solution, rinse it, and dry it to obtain the BVO photoelectrode.

[0009] 3) Lithium perchlorate and terthiophene were added to acetonitrile to obtain electrolyte B; electrochemical method was used to perform photoelectrodeposition on the BVO photoelectrode prepared in step 2) with electrolyte B, and after the deposition was completed, the electrode was rinsed to obtain a composite photoelectrode of bismuth vanadate and polyterthiophene.

[0010] As a further preferred technical solution of the present invention, in step 1), the preparation method of electrolyte A specifically includes:

[0011] Take 25 ml of nitric acid solution with pH 1.65–1.75, add 0.4 M potassium iodide and 0.04 M bismuth nitrate pentahydrate to obtain solution A;

[0012] Take 10 ml of ethanol and add 0.23 M p-benzoquinone to obtain solution B;

[0013] Mix solution A and solution B and stir to obtain electrolyte A.

[0014] As a further preferred technical solution of the present invention, in step 3), the preparation method of electrolyte B specifically includes:

[0015] Take 50 ml of acetonitrile, add 0.1 M lithium perchlorate and 0.01 M terthiophene, stir, and obtain electrolyte B.

[0016] As a further preferred technical solution of the present invention, in step 1), the electrochemical method is the time-current curve method, with FTO conductive glass as the working electrode, platinum mesh as the counter electrode, and Ag / AgCl electrode as the reference electrode.

[0017] As a further preferred embodiment of the present invention, in step 1), the process parameters for depositing a BiOI thin film on FTO conductive glass with electrolyte A are as follows: initial voltage -0.1V, sampling interval 0.1s, deposition time 180-250s, settling time 0s, and sensitivity 1×10⁻⁶. -3 A.

[0018] As a further preferred embodiment of the present invention, in step 3), the electrochemical method is cyclic voltammetry, with a BVO photoelectrode as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode, and the light intensity is 100 mW / cm². 2 .

[0019] As a further preferred technical solution of the present invention, in step 3), the process parameters for photoelectrodeposition of electrolyte B on the BVO photoelectrode are as follows: initial potential is 0V, upper limit potential is 0.8-1.0V, lower limit potential is 0V, termination voltage is 0.8-1.0V, initial scanning direction is positive, scanning speed is 0.05V / s, number of scanning segments is 2, sampling interval is 0.001V, settling time is 2s, and sensitivity is 1×10⁻⁶. -3 A.

[0020] As a further preferred technical solution of the present invention, in step 2), the concentration of the dimethyl sulfoxide solution of acetylacetonate vanadium oxide is 0.2M.

[0021] As another aspect of the present invention, the present invention also provides a composite photoelectrode, which is prepared by the above method.

[0022] As another aspect of the present invention, the present invention also provides an application of a composite photoelectrode in glucose content detection, so as to obtain the content of the electrolyzed organic compound through photocurrent signal.

[0023] The composite photoelectrode of this invention is a photoelectrode for glucose content detection based on the following principle:

[0024] Photoelectrochemical systems can mineralize organic compounds on the working electrode in a stoichiometric manner, which can be represented as:

[0025]

[0026] In this context, N and X represent one nitrogen atom and one halogen atom, respectively; the number of carbon, hydrogen, oxygen, nitrogen, and halogen atoms in an organic compound is represented by y, m, j, k, and q.

[0027] To minimize degradation time and maximize degradation efficiency, photoelectrocatalytic degradation of organic compounds was performed in a thin-layer photoelectrochemical cell. All analytes were electrolyzed, and Faraday's law, which measures the charge generated during the photoelectrochemical degradation of organic compounds, quantifies the concentration as follows:

[0028]

[0029] Q net Ci represents the net charge generated by the photoelectrocatalytic oxidation of organic compounds. phThe photocurrent generated by the photoelectrocatalytic oxidation of organic compounds is A; t is the time elapsed during illumination, s; C i and n i Let represent the molar concentration of type i, in mol / L, and the number of electrons transferred, respectively; F is the Faraday constant, in mol / C; and V is the sample volume, in L.

[0030] Based on the above principles, this invention prepares a composite photoelectrode of bismuth vanadate and polyterthiophene with good reproducibility, high stability and high efficiency. It can detect glucose content using photoelectric detection technology, with high stability, simple steps, rapid response and high sensitivity. It provides a new idea and method for glucose detection and has certain practical application value.

[0031] The composite photoelectrode for glucose content detection of the present invention, its preparation method, and its application, by adopting the above technical solution, can achieve the following beneficial effects:

[0032] 1) The preparation method of the present invention uses fluorine-doped tin oxide (FTO) conductive glass as a substrate, deposits BiOI thin film by electrochemical method, obtains BVO photoelectrode after calcination, and then deposits poly(terthiophene) (ptth) on the surface of BVO photoelectrode by photoelectrodeposition. The operation is simple and safe, the materials are readily available, and large-scale production can be realized.

[0033] 2) The composite photoelectrode of the present invention, combined with photoelectric detection technology, can detect glucose content, has high stability, simple steps, can obtain a rapid response, and has high sensitivity.

[0034] 3) The application of the composite photoelectrode of the present invention in glucose content detection provides a new analytical method for glucose content determination. Attached Figure Description

[0035] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0036] Figure 1 This is a scanning electron microscope (SEM) image of the BVO photoelectrode in Example 1.

[0037] Figure 2 The X-ray diffraction (XRD) patterns of the FTO conductive glass, BVO photoelectrode, and BVO+ptth composite photoelectrode in Example 1 are shown.

[0038] Figure 3 This is a scanned image of the BVO+ptth composite photoelectrode in Example 1 under an electron microscope (SEM).

[0039] Figure 4 The image shows the FTIR spectrum of the BVO+ptth composite photoelectrode in Example 1.

[0040] Figure 5 Linear sweep voltammetry curves for application tests 1 and 2.

[0041] Figure 6 The time-current curve for application test 3.

[0042] Figure 7 The time-current curves of the BVO+ptth photoelectrode and the BVO photoelectrode in application test 4 are shown.

[0043] Figure 8 The UV-Vis absorption spectra of the BVO+ptth photoelectrode and the BVO photoelectrode in application test 4 are shown.

[0044] Figure 9 Linear sweep voltammetric curves of bismuth vanadate with different BiOI deposition times.

[0045] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0046] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0047] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0048] Example 1

[0049] Step 1, Preparation of BVO photoelectrode:

[0050] Take a 200×150mm piece of FTO conductive glass and cut it into 20×30mm pieces using a glass cutting table. Clean the glass sequentially with acetone, ethanol, and ultrapure water using ultrasonication for 15 minutes each. After cleaning, add ethanol and store for later use.

[0051] 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 prepared nitric acid solution and add 0.4 M potassium iodide (KI) and 0.04 M bismuth nitrate pentahydrate (Bi(NO3)3·5H2O), stirring vigorously until the solution is clear and transparent. Take 10 ml of ethanol and place it in a beaker, add 0.23 M p-benzoquinone, and stir vigorously until the precipitate is completely dissolved. Mix the two solutions and stir vigorously to ensure they are fully miscible. Use the resulting mixed solution as electrolyte A for electrodeposition on FTO conductive glass.

[0052] Specifically, the time-current curve method was selected, with FTO conductive glass as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The initial voltage was -0.1V, the sampling interval was 0.1s, the deposition time was 180s, the settling time was 0s, and the sensitivity was 1×10⁻⁶. -3 A, perform electrodeposition.

[0053] After electrodeposition, a thin film is formed on the surface of FTO conductive glass. After rinsing and drying, FTO conductive glass with BiOI film deposited is obtained. Then, it is cut into 20×10mm size using a glass cutting table.

[0054] FTO conductive glass sheets with a BiOI film deposited on them, each measuring 20×10 mm, are placed on a high-temperature resistant corundum sheet, with a distance of 3-5 mm between each sheet. 5 ml of dimethyl sulfoxide (DMSO) is added, and 0.2 M vanadium acetylacetonate is stirred vigorously until no obvious precipitate forms. 30 μL of the DMSO solution is pipetted and evenly dropped onto the BiOI film surface. The corundum sheet is then slowly placed in a muffle furnace and calcined at 450 °C for 2 hours, preferably with a temperature increase of 2 °C per minute.

[0055] After the muffle furnace cools to room temperature, slowly remove the corundum sheet and place the fired FTO conductive glass in a petri dish. Add an appropriate amount of 0.1M NaOH solution and soak for 20-30 minutes. The surface of the FTO conductive glass will be intact and uniform, and bright yellow. After rinsing and drying, the BVO photoelectrode (also known as the BiVO4 photoelectrode) is obtained.

[0056] The scanning image of the BVO photoelectrode under an electron microscope (SEM) is shown below. Figure 1 As shown.

[0057] Step 2, Fabrication of the BVO+ptth composite photoelectrode:

[0058] Take 50 ml of acetonitrile, add 0.1 M lithium perchlorate (LiClO4) and 0.01 M terthiophene, stir until the solution is clear and transparent, and use the resulting solution as electrolyte B for photoelectrodeposition of BVO photoelectrode.

[0059] Specifically, cyclic voltammetry was selected, with a BVO photoelectrode as the working electrode, a platinum mesh as the counter electrode, and an Ag / AgCl electrode as the reference electrode. The initial potential was 0V, the upper limit potential was 0.8V, the lower limit potential was 0V, and the termination voltage was 0.8V. The initial scan direction was positive, the scan rate was 0.05V / s, the number of scan segments was 2 (1 revolution), the sampling interval was 0.001V, the resting time was 2s, and the sensitivity was 1×10⁻⁶. -3 A, light intensity is 100mW / cm² 2 Photoelectrodeposition is then performed.

[0060] After deposition, the material was rinsed with ethanol and ultrapure water in sequence and then dried to obtain a composite photoelectrode of bismuth vanadate and poly(terthiophene) (also known as BVO+ptth composite photoelectrode).

[0061] Figure 2 The X-ray diffraction (XRD) patterns of the FTO conductive glass, BVO photoelectrode, and BVO+ptth composite photoelectrode in Example 1 demonstrate the successful fabrication of the BVO photoelectrode and the BVO+ptth composite photoelectrode.

[0062] Figure 3 This is a scanned image of the BVO+ptth composite photoelectrode in Example 1 under a electron microscope (SEM), compared to... Figure 1 , Figure 3 The presence of a large area of ​​granules on the surface indicates that poly(terthiophene) (ptth) has been deposited on the BVO photoelectrode.

[0063] Figure 4 The image shows the FTIR image of the BVO+ptth composite photoelectrode in Example 1, which further confirms that ptth has been successfully deposited on the BVO photoelectrode.

[0064] Application Test 1

[0065] Application of BVO+ptth composite photoelectrode in glucose detection:

[0066] Linear scanning voltammetry was selected. Under conditions without illumination, the BVO+ptth 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 NaSO4. The initial potential was -0.2V, the termination potential was 0.8V, the scan rate was 0.1V / s, the sampling interval was 0.001V, the settling time was 2s, and the sensitivity was 1×10⁻⁶. - 3 A. The dark current of the BVO+ptth composite photoelectrode in 0M, 0.1mM, 0.5mM, 0.1M, and 0.5M glucose solutions as a function of potential was tested, and the results were obtained. Figure 5 Linear scan voltammetry curve.

[0067] Application Test 2

[0068] Application of BVO+ptth composite photoelectrode in glucose detection:

[0069] Linear scanning voltammetry was selected. Under illumination with a light source, the BVO+ptth 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 NaSO4. The initial potential was -0.2V, the termination potential was 0.8V, the scan rate was 0.1V / s, the sampling interval was 0.001V, the settling time was 2s, and the sensitivity was 1×10⁻⁶. -3 A, light intensity is 100mW / cm² 2 The photocurrent of the BVO+ptth composite photoelectrode in glucose solutions of 0 M, 0.1 mM, 0.5 mM, 0.1 M, and 0.5 M was tested as a function of potential, and the results were obtained. Figure 5 Linear scan voltammetry curve.

[0070] Application Test 3

[0071] Application of BVO+ptth composite photoelectrode in glucose detection:

[0072] The time-current curve method was selected. Under illumination with a light source, the BVO+ptth 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 NaSO4. The initial potential was -0.2V, the termination potential was 0.8V, the scan rate was 0.1V / s, the sampling interval was 0.1s, the settling time was 2s, and the sensitivity was 1×10⁻⁶. -3 A, light intensity is 100mW / cm² 2 The photocurrent of the BVO+ptth composite photoelectrode over time was tested in 0M and 0.5mM glucose solutions, and the results were obtained. Figure 6 The time-current curve.

[0073] from Figure 6 The photocurrent (i) observed in the blank solution blank The photocurrent (i) originates from water oxidation, while that observed in sample solutions containing organic matter (glucose) is derived from this oxidation. total ) is the total current of two different components, one originating from the photoelectrocatalytic oxidation of organic matter (i net One source is water oxidation, and both are related to blank photocurrent (i). blank The same. For a given time period, the photocurrent i blank and i total Q is obtained by integrating with time respectively. blank and Q total By Q total Subtract Q blank The net charge Q generated by the oxidation of organic compounds is obtained. net .

[0074] Application Testing 4

[0075] Using the time-current curve method, under illumination with a light source on, the BVO photoelectrode prepared in step 1 of Example 1 and the BVO+ptth composite photoelectrode prepared in step 2 were used as working electrodes, respectively. A platinum mesh was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. The electrolyte was 0.1M NaSO4. The initial potential was 0V, the sampling interval was 0.1s, the settling time was 2s, and the sensitivity was 1×10⁻⁶. -3 A, light intensity is 100mW / cm² 2 The photocurrent of BVO photoelectrode and BVO+ptth composite photoelectrode in 0M glucose was tested over time, and the results were obtained. Figure 7 The time-current curve.

[0076] The BVO photoelectrode exhibits poor stability in 0M glucose electrolyte and suffers severe photocorrosion under illumination, making it difficult to proceed with the experiment. Figure 7 Stability comparison test between BVO+ptth photoelectrode and BVO photoelectrode. From Figure 7 It is evident that with the introduction of ptth, the stability of the BVO+ptth photoelectrode is significantly improved, meaning it maintains a relatively stable current density under prolonged illumination. Furthermore, the combination of bismuth vanadate (BVO) and polyterthiophene (ptth), through their synergistic effect, expands the overall absorption range of the electrode, resulting in a significantly improved photoresponse capability compared to a single electrode. Consequently, a higher current density can be achieved under the same external bias voltage. In contrast, ordinary protective layers lead to performance degradation, resulting in a lower current density for the composite electrode compared to a single electrode; while the composite electrode of this invention exhibits a higher current density than the single electrode, due not only to the expanded absorption range but also to improved hole transport capability. Figure 8 As shown, the BVO+ptth photoelectrode exhibits significantly higher absorbance than the single BVO photoelectrode in the wavelength range of 300-800nm.

[0077] To further investigate the effect of bismuth vanadate deposition amount on FTO conductive glass on the composite photoelectrode, the same preparation method as in Example 1 was used, except that the deposition amount of bismuth vanadate was controlled by adjusting the BiOI deposition time in step 1. When the deposition time was less than or greater than 180 seconds, the photoelectric performance of the composite photoelectrode gradually decreased. Based on a large amount of experimental data, the preferred deposition time was 180-250 seconds, with 180 seconds being the optimal value. The linear sweep voltammetry curves for deposition times of 90 seconds, 180 seconds, and 360 seconds are shown below. Figure 9 As shown in the figure.

[0078] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing a composite photoelectrode for glucose detection, characterized by, The method comprises the following steps: 1) adding potassium iodide and bismuth nitrate pentahydrate into nitric acid solution to obtain solution A; adding p-benzoquinone into ethanol to obtain solution B; mixing solution A and solution B to obtain electrolyte A; using an electrochemical method, depositing BiOI thin film on FTO conductive glass by using electrolyte A; 2) taking the FTO conductive glass with BiOI thin film prepared in step 1), dropping vanadyl acetylacetonate dimethyl sulfoxide solution on the surface of the BiOI thin film, and performing calcination treatment at 425-475 DEG C; after calcination, the FTO conductive glass is immersed in NaOH solution, washed, dried, and then BVO photoelectrode is obtained; 3) adding lithium perchlorate and terthiophene into acetonitrile to obtain electrolyte B; using an electrochemical method, performing photoelectrodeposition on the BVO photoelectrode prepared in step 2) by using electrolyte B to obtain a composite photoelectrode of bismuth vanadate and polyterthiophene.

2. The method for preparing a composite photoelectrode for glucose detection according to claim 1, characterized by, In step 1), the preparation of electrolyte A specifically comprises the following steps: taking 25ml of nitric acid solution with pH of 1.65-1.75, adding 0.4M potassium iodide and 0.04M bismuth nitrate pentahydrate to obtain solution A; taking 10ml of ethanol, adding 0.23M p-benzoquinone to obtain solution B; mixing solution A and solution B, stirring to obtain electrolyte A.

3. The method for preparing a composite photoelectrode for glucose detection according to claim 1, characterized by, In step 3), the preparation of electrolyte B specifically comprises the following steps: taking 50ml of acetonitrile, adding 0.1M lithium perchlorate and 0.01M terthiophene, and stirring to obtain electrolyte B.

4. The method for preparing a composite photoelectrode for glucose detection according to claim 1, characterized by, In step 1), the electrochemical method is time-current curve method, FTO conductive glass is used as working electrode, platinum mesh is used as counter electrode, and Ag / AgCl electrode is used as reference electrode.

5. The method for preparing a composite photoelectrode for glucose detection according to claim 4, characterized in that, The process parameters for depositing BiOI thin film on FTO conductive glass in step 1) of electrolyte A are as follows: initial voltage -0.1 V, sampling interval 0.1 s, deposition time 180-250 s, standing time 0 s, sensitivity 1 x 10 -3 A.

6. The method for preparing a composite photoelectrode for glucose detection according to claim 1, wherein, In step 3), the electrochemical method is cyclic voltammetry, the BVO photoelectrode is used as the working electrode, a platinum net is used as the counter electrode, an 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 detection according to claim 6, wherein, The process parameters for the photoelectrodeposition of electrolyte B on the BVO photoelectrode in step 3) are: initial potential 0 V, upper limit potential 0.8-1.0 V, lower limit potential 0 V, end voltage 0.8-1.0 V, initial scanning direction positive, scanning speed 0.05 V / s, scanning segment number 2, sampling interval 0.001 V, standing time 2 s, sensitivity 1 x 10 -3 A.

8. The method for preparing a composite photoelectrode for glucose detection according to claim 1, wherein, In step 2), the concentration of vanadyl acetylacetonate dimethyl sulfoxide solution is 0.2M.

9. A composite photoelectrode, characterized by, Prepared by the method of any one of claims 1-8.

10. Application of the composite photoelectrode of claim 9 in glucose content detection.

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