TiO2-Bi2S3 nano material, preparation method, photoelectrochemical sensor and application

Abstract

The invention discloses a TiO2-Bi2S3 nano material, a preparation method, a photoelectrochemical sensor and application, and belongs to the field of photoelectrochemical detection. The preparation method of the TiO2-Bi2S3 nano material comprises the following steps: preparing a TiO2 nanorod array by using a hydrothermal method, and then preparing the TiO2-Bi2S3 nano material on the basis of the TiO2 nanorod array by using a chemical bath deposition method, the photoelectrochemical sensor with high sensitivity and universality is constructed by taking the TiO2-Bi2S3 nano material as a photo-anode, a Pt sheet cathode and an Ag / AgCl reference electrode; the photoelectrochemical sensor shows an ultralow detection limit and a wide detection range (0.2 ng / mL to 10 [mu] g / mL) when detecting CAP, MB and MO, and has excellent universality and ultra-sensitive characteristics. The sensor can be popularized to efficient detection of various environmental and biological pollutants.

Description

Technical Field

[0001] The present invention belongs to the field of photoelectrochemical detection, and particularly relates to a TiO2-Bi2S3 nanomaterial, a preparation method, a photoelectrochemical sensor and an application thereof. Background Art

[0002] Food safety is directly related to public health and is a key area of global concern. Residues of toxins and pollutants in food not only threaten consumer health but also affect the sustainable development of the food industry. Therefore, the development of technologies capable of rapid, sensitive and universal detection is crucial for ensuring food safety. In the field of food safety, the detection of three chemical substances, namely CAP, MB and MO, has important practical significance. CAP is a broad-spectrum antibiotic. Due to its low cost and stability, there is still illegal use, and its residue may cause health problems such as bone marrow suppression and anemia. As a cationic dye, MB is widely used in the fields of food and water treatment, but its potential toxic reactions may cause damage to the liver and nervous system. As a food additive and anionic industrial dye, MO may affect the human digestive system and have an adverse impact on the environment when the residue exceeds the standard. Therefore, the development of efficient and sensitive detection technologies to ensure food safety has become an urgent problem to be solved.

[0003] Traditional detection methods such as chromatography and immunoassay have high sensitivity, but these methods usually rely on complex instruments, are cumbersome to operate and costly, and are difficult to meet the requirements of rapid and portable detection. In contrast, photoelectrochemical sensors have gradually become a highly potential detection technology due to their simple operation, low cost and excellent detection performance. However, current photoelectrochemical sensors are mostly designed for single target substances and often rely on bioreceptors or noble metal loading. This design not only increases the cost of the sensor but also limits its detection range and adaptability to multiple target substances, making it difficult to meet the detection requirements in practical applications. Therefore, the development of a universal photoelectrochemical sensor capable of simultaneously and efficiently detecting CAP, MB and MO has important research significance and application value. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a TiO2-Bi2S3 nanomaterial, a preparation method, a photoelectrochemical sensor and an application thereof, and solve the problems in the prior art.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A preparation method of a TiO2-Bi2S3 nanomaterial, comprising the following steps:

[0007] Mix deionized water, concentrated hydrochloric acid, and tetrabutyl titanate, stir well, and then add them to a reaction kettle; place the FTO glass in the reaction kettle for hydrothermal reaction. After cooling, rinsing, and drying, annealing is carried out to obtain a TiO2 nanorod array;

[0008] Prepare Bi(NO3)3 and Na2S solutions respectively; first immerse the TiO2 nanorod array in the Bi(NO3)3 solution and then wash it, and then immerse it in the Na2S solution and then wash it. As one cycle, after multiple cycles, dry it to obtain a TiO2-Bi2S3 nanomaterial.

[0009] Further, the solute of the Bi(NO3)3 solution is Bi(NO3)3·5H2O; the solute of the Na2S solution is Na2S·9H2O.

[0010] Further, the conductive surface of the FTO glass faces downward and is placed in the reaction kettle at an inclination of 30°.

[0011] Further, the temperature of the hydrothermal reaction is 150 °C and the time is 10 h.

[0012] Further, the annealing temperature is 450 °C and the time is 1 h.

[0013] A TiO2-Bi2S3 nanomaterial is prepared using the above-mentioned TiO2-Bi2S3 nanomaterial.

[0014] The above-mentioned TiO2-Bi2S3 nanomaterial is used as a photoanode electrode in the preparation of a TiO2-Bi2S3 photoelectrochemical sensor.

[0015] A TiO2-Bi2S3 photoelectrochemical sensor uses the above-mentioned TiO2-Bi2S3 nanomaterial as a photoanode electrode, Pt as a cathode, and Ag / AgCl as a reference electrode.

[0016] The above-mentioned TiO2-Bi2S3 photoelectrochemical sensor is used in the detection of the concentrations of CAP, MB, and MO.

[0017] Further, the concentration detection range of CAP, MB, and MO is 0.2 ng / mL to 10 μg / mL.

[0018] The beneficial effects of the present invention:

[0019] 1. The TiO2-Bi2S3 photoelectrochemical sensor adopted by the present invention has excellent detection ability and can simultaneously detect various pollutants such as CAP, MB, and MO; the design of this sensor breaks through the limitation of traditional sensors for a single target and is applicable to the detection of a wide range of pollutants in complex environments, showing strong universality.

[0020] 2. The method of the present invention uses chemical bath deposition to prepare Bi2S3 nanoparticle - composite TiO2 nanorod arrays. The preparation route is simple, the preparation process is precisely controllable, and the cost is low.

[0021] 3. The present invention uses Bi2S3 nanoparticle - composite TiO2 nanorod arrays, which can expand the light absorption range, promote the separation of photo - generated carriers, and enable the photoelectrochemical sensor based on TiO2 - Bi2S3 to have excellent optoelectronic properties.

[0022] 4. The present invention uses the TiO2 - Bi2S3 nanorod array composite material, which can significantly enhance the photoelectric response performance and achieve ultrasensitive pollutant detection; the detection limit of the sensor is low, and it can work stably in a wide detection range, ensuring accurate detection of pollutants even at extremely low concentrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is the preparation flow chart of the TiO2 - Bi2S3 nanomaterial of the present invention;

[0025] Figure 2 It is the XRD patterns of TiO2, TiO2 - Bi2S3, and Bi2S3 of the present invention;

[0026] Figure 3 It is the SEM images of TiO2, TiO2 - Bi2S3 and the element mapping diagram of TiO2 - Bi2S3 of the present invention;

[0027] Figure 4 It is the TEM image of TiO2 - Bi2S3 of the present invention;

[0028] Figure 5 It is the XPS spectrum of the present invention;

[0029] Figure 6 It is the ultraviolet - visible absorption spectrum of the present invention;

[0030] Figure 7 It is the comparison diagram of the PEC performance of TiO2, Bi2S3, and TiO2 - Bi2S3 - 3 of the present invention;

[0031] Figure 8 It is the performance diagram of TiO2 - Bi2S3 - 3 for detecting CAP of the present invention;

[0032] Figure 9It is a fitting relationship diagram between the concentrations of MB and MO and the photocurrent density of the present invention. Specific Embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0034] The preparation method of the TiO2-Bi2S3 nanomaterial includes the following steps:

[0035] S1. Prepare TiO2 nanorod arrays using the hydrothermal method;

[0036] Mix deionized water and concentrated hydrochloric acid, then add tetrabutyl titanate, stir until the solution is clear, and then pour it into a reaction kettle; place the FTO glass conductive surface downward at 30° in the inner lining of the reaction kettle (Teflon inner lining) for hydrothermal reaction; after natural cooling, rinse with deionized water, then place it in an oven for drying; finally, anneal it in a muffle furnace to obtain TiO2 nanorod arrays;

[0037] S2. Prepare TiO2-Bi2S3 nanomaterials on the basis of TiO2 nanorod arrays using the chemical bath deposition method;

[0038] Prepare Bi(NO3)3 and Na2S solutions respectively. First, immerse the TiO2 nanorod arrays in the Bi(NO3)3 solution and then wash with deionized water, and then immerse them in the Na2S solution and then wash with deionized water again. As one cycle, after multiple cycles (the number of cycles is 1, 2, 3, or 4), dry them to obtain TiO2-Bi2S3 nanomaterials.

[0039] Among them, the solute of the Bi(NO3)3 solution is Bi(NO3)3·5H2O. The solute of the Na2S solution is Na2S·9H2O.

[0040] In the above preparation method, a TiO2 nanorod array film with a high specific surface area is grown on the FTO substrate by the hydrothermal method, and the Bi2S3 nanomaterial is uniformly modified on the surface of TiO2 by the impregnation method, thereby constructing a heterojunction photoanode; the charge separation efficiency and photoelectric response performance of the photogenerated carriers are significantly enhanced by loading Bi2S3.

[0041] The TiO2-Bi2S3 nanomaterial is used as a photoanode electrode to prepare a TiO2-Bi2S3 photoelectrochemical sensor; the TiO2-Bi2S3 photoelectrochemical sensor uses the TiO2-Bi2S3 nanomaterial as the photoanode electrode, Pt as the cathode, and Ag / AgCl as the reference electrode, thereby forming a photoelectrochemical detection system;

[0042] The TiO2-Bi2S3 photoelectrochemical sensor is used to detect the concentrations of CAP, MB, and MO; the specific detection method includes the following steps:

[0043] Step 1, prepare a phosphate (PB) buffer salt solution (pH = 7.0, 0.1 mol / L) as the electrolyte;

[0044] Step 2, prepare solutions of CAP, MB, and MO with different concentrations;

[0045] Accurately weigh a certain amount of CAP, MB, and MO, and serially dilute them with PB to obtain a series of standard solutions with different concentrations, and the concentration range is 0.2 ng / mL to 10 μg / mL;

[0046] Step 3, draw the standard curve:

[0047] First, select a series of standard solutions of CAP, MB, and MO with known concentrations;

[0048] Using TiO2 / Bi2S3 as the photoanode for photoelectrochemical testing, Pt as the cathode, and Ag / AgCl reference electrode, form a photoelectrochemical detection system. Use the PB buffer salt solution containing CAP, MB, and MO with known concentrations as the electrolyte, and keep the light power density of the xenon lamp source at 100 mW / cm 2 , and measure the photocurrent density of this circuit with a three-electrode system to obtain a series of corresponding relationships between pollutant concentrations and photocurrent densities, thereby calculating and obtaining the standard curves for detecting CAP, MB, and MO, establishing a linear relationship between the photocurrent density value after adding pollutants and the logarithm of the concentration, and obtaining the corresponding linear regression equation.

[0049] The following specifically illustrates the preparation method and related applications of the TiO2-Bi2S3 nanomaterial through the following examples;

[0050] Example 1

[0051] In this example, a preparation method of the TiO2-Bi2S3 nanomaterial is proposed, as Figure 1 shown, including the following steps:

[0052] S1, use the hydrothermal method to prepare TiO2 nanorod arrays;

[0053] Mix 15 mL of deionized water with 15 mL of concentrated hydrochloric acid, then add 500 μL of tetrabutyl titanate, stir for ten minutes until the solution becomes clear, and place it in a Teflon liner. Place the FTO glass (5×2 cm 2 ) with the conductive side facing down, inclined at 30°, into the Teflon liner, and perform a hydrothermal reaction for 10 h at a temperature of 150 °C. After natural cooling, rinse with deionized water, and then place it in an oven to dry at 60 °C for 1 h. Finally, place it in a muffle furnace and anneal at 450 °C for 1 h (heating rate: 5 °C / min).

[0054] S2. Use the chemical bath deposition method to prepare TiO2-Bi2S3 nanomaterials on the basis of TiO2 nanorod arrays;

[0055] Dissolve 0.2425 g of Bi(NO3)3·5H2O in 50 mL of deionized water to obtain a Bi(NO3)3 solution, and dissolve 0.370 g of Na2S·9H2O in deionized water to obtain a Na2S solution. First, immerse the TiO2 nanorod arrays in the Bi(NO3)3 solution for 5 min, then wash with deionized water, and then immerse them in the Na2S solution for 5 min and wash with deionized water again, which is regarded as one chemical bath deposition cycle; in this example, 3 cycles are designed, and finally wash with deionized water and dry at 60 °C for 2 h. The sample is denoted as TiO2-Bi2S3-3.

[0056] Example 2

[0057] In this example, provide experimental comparison to verify the TiO2-Bi2S3 nanomaterials prepared in Example 1; the experiments include:

[0058] 1) Use an X-ray powder diffractometer (XRD) to characterize the crystal structure of the product;

[0059] Figure 2 are the XRD patterns of TiO2, TiO2-Bi2S3, and Bi2S3. It can be seen from the figure that with the composite of Bi2S3, the diffraction peaks of TiO2 / Bi2S3 are significantly enhanced compared with pure TiO2, indicating that the introduction of Bi2S3 promotes the growth of TiO2 crystals and improves its crystallinity.

[0060] 2) Use a scanning electron microscope (SEM) to characterize the microscopic morphology of the product;

[0061] Figure 3 (a) and (b) in are the SEM images of TiO2 and TiO2-Bi2S3 respectively; it can be observed from the figure that TiO2 nanorods grow uniformly on the FTO glass substrate, showing a highly ordered rod-like structure. With the introduction of Bi2S3 nanoparticles, the structure of TiO2 nanorods has changed significantly. The composite nanorods become significantly thicker, and their surface becomes rougher.

[0062] Figure 3 In (c)-(f) are the elemental mapping images of TiO2-Bi2S3. It can be seen from Figure 3 (c)-(f) that the Ti, O, Bi, and S elements are marked in red, green, blue, and purple respectively, and are evenly distributed on the surface of the nanorods, further confirming the good composite effect of TiO2 and Bi2S3.

[0063] 3) High-resolution transmission electron microscopy (HRTEM) was used to characterize the ultra-fine structure of the product;

[0064] Figure 4 is the TEM image of TiO2-Bi2S3; Figure 4 It can be observed from (a) in Figure 4 that Bi2S3 crystals uniformly cover the surface of TiO2 nanorods. From Figure 4 two different lattice fringes are observed in figure (b), and their lattice spacings are 0.354 nm and 0.351 nm respectively. Through comparison and calculation, these lattice spacings are attributed to the (130) crystal plane of Bi2S3 and the (101) crystal plane of TiO2 respectively.

[0065] 4) X-ray photoelectron spectroscopy (XPS) was used to obtain the chemical composition of the product;

[0066] Figure 5 is in the XPS image of TiO2-Bi2S3. As Figure 5 shown in (a), the full spectrum of TiO2-Bi2S3 clearly shows that the material contains Bi, O, and Ti elements. However, due to the weak signal of the S element, its peak is not clearly shown in the full spectrum. Figure 5 In (b) shows the fine spectra of Bi 4f and S2p orbitals in TiO2 and TiO2-Bi2S3. The two peaks with binding energies of 161.18 eV and 162.31 eV are attributed to S2p 3 / 2 and S2p 1 / 2 , indicating that sulfur exists in the form of S 2- in Bi2S3; the peaks with binding energies of 158.66 eV and 163.90 eV are attributed to Bi 4f 7 / 2 and 4f 5 / 2 , corresponding to Bi 3+ , further confirming the existence of Bi2S3. Figure 5 In (c) shows the fine spectra of Ti 2p and Bi 4d orbitals of the TiO2 / Bi2S3 composite material, where the two peaks at 458.69 eV and 464.39 eV are respectively associated with Ti 2p 3 / 2 and Ti 2p 5 / 2 respectively. In addition, the peak observed at 465.67 eV is attributed to Bi 4d3 / 2 , which reflects the chemical environment of Bi element in the composite material. Figure 5 (d) in shows the fine spectrum of the O1s orbital, where the three peaks at 529.91 eV, 531.13 eV, and 532.19 eV are attributed to lattice oxygen (O L ), oxygen vacancy (O V ), and adsorbed oxygen (O C ), respectively. O L indicates that the TiO2-Bi2S3 composite material has good crystallinity; the increase in the intensity of O V indicates that there are more electron and hole trapping centers in the composite material, which helps to improve the carrier separation efficiency; O C shows that the surface of the composite material provides more active sites, which is conducive to the progress of the photoelectrochemical reaction.

[0067] 5) The optical absorption characteristics of TiO2-Bi2S3 were obtained using a UV-Vis spectrophotometer.

[0068] Figure 6 are the UV-Vis absorption spectra of pure TiO2, Bi2S3, and composite samples with several different CBD cycle numbers. It can be observed that the absorption edge of pure TiO2 is approximately located at 420 nm. With the composite of Bi2S3 nanoparticles, the absorption edge gradually extends beyond 800 nm, indicating that the absorption ability of the composite material in the visible light region has been significantly enhanced. The color changes of different samples in the upper right corner also reflect this rule. As the number of CBD cycles increases, the color of the samples gradually deepens.

[0069] 6) An electrochemical workstation was used to test the photoelectrochemical (PEC) and trace detection performance.

[0070] As Figure 7 shows, the PEC performance of the TiO2-Bi2S3-3 sample with the 3rd CBD cycle was compared with that of pure TiO2 and Bi2S3. As Figure 7 (a) in shows, in the electrochemical impedance spectroscopy diagram, TiO2-Bi2S3-3 has the smallest transfer resistance; as Figure 7 (b) in shows, in the linear sweep voltammogram, the onset voltages of TiO2, Bi2S3, and TiO2-Bi2S3-3 are -0.38, -0.23, and -0.44 V, respectively, indicating that TiO2-Bi2S3-3 has a lower onset voltage, which enhances the PEC reaction and reduces the voltage required for the reaction. Figure 7 (c) in shows that the photocurrent density of TiO2-Bi2S3-3 is 1.1 mA / cm 2It is 4.07 times higher than that of pure TiO2, indicating that the composite of Bi2S3 promotes the transfer of photo-generated carriers and enhances the PEC response. As Figure 7 shown in (d) of , during the open-circuit photovoltage test, the open-circuit photovoltage values of TiO2, Bi2S3, and TiO2-Bi2S3-3 under illumination are -0.09, -0.02, and -0.05 V respectively, indicating that the OCP value shifts towards a negative potential under illumination, which is in line with the characteristics of n-type semiconductors because photo-generated electrons cause a decrease in OCP. It can be seen from the figure that the open-circuit photovoltage difference of TiO2-Bi2S3-3 is significantly higher than that of TiO2. This increased photovoltage indicates that the composite of Bi2S3 promotes stronger band bending, which plays a positive role in the separation of photo-generated carriers and charge transport.

[0071] As Figure 8 shown in (a) of , the linear sweep voltammograms of TiO2-Bi2S3-3 before and after adding 100 ng / mL CAP (under the condition of 0.1 M PB, pH = 7.0) show a significant increase in photocurrent, and its photocurrent performance is better than that of pure TiO2 before and after adding CAP. In particular, at a bias voltage of 0 V (vs. Ag / AgCl), the photocurrent density of TiO2-Bi2S3-3 + 100 ng / mL is significantly higher than that of TiO2-Bi2S3-3 and pure TiO2, indicating that TiO2 / Bi2S3-3 has great potential for trace CAP detection without an external bias voltage.

[0072] Figure 8 The test results of the I-t curve under different concentrations of CAP are shown in (b) of . It can be seen that the photocurrent density of the TiO2-Bi2S3-3 photoelectrochemical sensor increases with the increase of CAP concentration, and finally a linear relationship between the photocurrent density and the CAP concentration is formed. In the range of CAP concentration from 0.2 ng / mL to 10 μg / mL, the fitting equation is: I (mA / cm 2 ) = 0.308 lg(CAP) (ng / mL) + 0.096, and the linear correlation coefficient reaches 0.99 (as shown in (c) of ). In addition, Figure 8 shown in (d) of , the PEC performance of TiO2 / Bi2S3-3 when different bias voltages are applied after adding 100 ng / mL CAP is further studied. The results show that with the increase of the bias voltage, the photocurrent density increases significantly, indicating that TiO2-Bi2S3-3 not only has good photo-generated carrier transfer ability, but also the carrier separation efficiency is significantly improved in the presence of CAP. Figure 8 shown in (d) of , the PEC performance of TiO2 / Bi2S3-3 when different bias voltages are applied after adding 100 ng / mL CAP is further studied. The results show that with the increase of the bias voltage, the photocurrent density increases significantly, indicating that TiO2-Bi2S3-3 not only has good photo-generated carrier transfer ability, but also the carrier separation efficiency is significantly improved in the presence of CAP.

[0073] Figure 9(a) in it is the fitting relationship between the MB concentration and the photocurrent density of TiO2-Bi2S3-3, and the fitting equation is I (mA / cm 2 ) = 0.398lg(CAP) (ng / mL) + 0.071, and the linear correlation degree is 0.988. Figure 9 (b) in it is the fitting relationship between the MO concentration and the photocurrent density detected of TiO2 / Bi2S3-3, and the fitting equation is I (mA / cm 2 ) = 0.495lg(CAP) (ng / mL) + 0.078, and the linear correlation degree is 0.986.

[0074] It can be seen from Figure 9 that the TiO2-Bi2S3-3 photoelectrochemical sensor has excellent universality, can accurately respond to different concentrations of MB and MO, and is suitable for the detection of various pollutants. The good linear relationship between its photocurrent density and concentration (R 2 > 0.98), and the detection limit is 0.2 ng / mL, indicating that the sensor has ultra-sensitive detection ability and meets the high requirements in the fields of environmental monitoring and food safety, etc.

[0075] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0076] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art of this industry should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A preparation method of TiO2-Bi2S3 nanomaterials, characterized in that, It includes the following steps: Mix deionized water, concentrated hydrochloric acid, and tetrabutyl titanate and stir them, then add them to a reaction kettle; place the FTO glass in the reaction kettle for hydrothermal reaction, and after cooling, rinsing, and drying, perform annealing to obtain a TiO2 nanorod array; Prepare Bi(NO3)3 and Na2S solutions respectively; first immerse the TiO2 nanorod array in the Bi(NO3)3 solution and then wash it, and then immerse it in the Na2S solution and then wash it, as one cycle. After multiple cycles, dry it to obtain a TiO2-Bi2S3 nanomaterial.

2. The preparation method of a TiO2-Bi2S3 nanomaterial according to claim 1, characterized in that, The solute of the Bi(NO3)3 solution is Bi(NO3)3·5H2O; the solute of the Na2S solution is Na2S·9H2O.

3. The preparation method of a TiO2-Bi2S3 nanomaterial according to claim 1, characterized in that, Place the FTO glass with the conductive side facing down and inclined at 30° into the reaction kettle.

4. The preparation method of a TiO2-Bi2S3 nanomaterial according to claim 1, characterized in that, The temperature of the hydrothermal reaction is 150°C and the time is 10 h.

5. The preparation method of a TiO2-Bi2S3 nanomaterial according to claim 1, characterized in that, The annealing temperature is 450°C and the time is 1 h.

6. A TiO2-Bi2S3 nanomaterial, characterized in that, It is prepared by using a TiO2-Bi2S3 nanomaterial according to any one of claims 1-5.

7. Use of a TiO2-Bi2S3 nanomaterial according to claim 6 as a photoanode electrode in the preparation of a TiO2-Bi2S3 photoelectrochemical sensor.

8. A TiO2-Bi2S3 photoelectrochemical sensor, characterized in that, Using the TiO2-Bi2S3 nanomaterial according to claim 6 as the photoanode electrode, Pt as the cathode, and Ag / AgCl as the reference electrode.

9. Use of a TiO2-Bi2S3 photoelectrochemical sensor according to claim 8 in the detection of the concentrations of CAP, MB, and MO.

10. The application according to claim 9, characterized in that, The concentration detection range of CAP, MB, and MO is 0.2 ng / mL to 10 μg / mL.

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