Titanium carbide / bismuth oxyiodide / bismuth phosphate-based photoelectrochemical sensor for dopamine detection and preparation method thereof

Abstract

The present invention discloses a titanium carbide / bismuth oxyiodide / bismuth phosphate-based photoelectrochemical sensor for dopamine detection and a preparation method thereof. The photoelectrochemical sensor is prepared by forming a titanium carbide / bismuth oxyiodide / bismuth phosphate (BT / BiPO4) composite material into a film on the surface of a glassy carbon electrode. The BT / BiPO4 composite material has good light response, and rapid electron transfer provides high sensitivity for dopamine detection. The photoelectrochemical sensor of the present invention is applied to dopamine detection, has high sensitivity, and has good linear response in the range of 0.01 to 10 mM.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoelectrochemical sensor materials and their preparation and application, and specifically relates to a titanium carbide / bismuth oxyiodide / bismuth phosphate (BT / BiPO4) based photoelectrochemical sensor for dopamine detection and a preparation method thereof. Background Art

[0002] Dopamine (DA) is an excitatory chemical neurotransmitter that regulates physiological activity in the cerebral cortex and plays a crucial role in many neurological diseases. DA in the human body controls physiological characteristics. Drastic fluctuations in DA levels can easily lead to neurological disorders such as Parkinson's disease, schizophrenia, and depression. However, current medical technology is unable to effectively treat these diseases. The occurrence of most psychiatric disorders is closely associated with abnormal dopamine levels. Therefore, monitoring dopamine levels in the human body is of great benefit to clinical treatment, and the development of a highly sensitive and selective dopamine sensor is crucial. Currently, methods for measuring dopamine concentration include high-performance liquid chromatography (HPLC), chemiluminescence, spectrophotometry, and electrochemical methods. These methods have drawbacks such as the need for expensive instrumentation, relatively high costs, and low sensitivity. Electrochemical methods are inexpensive, but are susceptible to interference from dopamine-like electroactive substances such as AA and UA, resulting in poor selectivity and relatively low sensitivity. Therefore, developing a rapid and sensitive method for detecting dopamine is crucial.

[0003] In recent years, photoelectrochemical (PEC) sensors have rapidly emerged and have become a highly anticipated new type of sensor due to their unique advantages. PEC sensors convert optical signals into electrical signals through biorecognition elements and signal converters, and use changes in photocurrent signals to achieve qualitative and quantitative analysis of the target. Compared with fluorescence, electrochemistry, and electroluminescence technologies, PEC detection technology has become an analytical technology with great application value because of its independent excitation light source and signal acquisition system, which gives it lower background signals and higher detection sensitivity. However, the preparation of photoelectrochemical sensing platforms requires photoactive nanomaterials with efficient visible light driving properties, so it is very important to find a photoactive nanomaterial for photoelectrochemical sensing of dopamine.

[0004] Titanium carbide (Ti3C2T x ) is one of the most widely used MXenes (transition metal carbides, nitrides or carbonitrides), which has many advantages, including conductivity, mechanical properties, huge surface area, and especially compatibility with other nanomaterials. The above advantages make Ti3C2T x It is widely used in electrocatalysis, energy storage batteries, electrochemical sensors and other fields, but so far, Ti3C2Tx The research on PEC sensing technology is still in its infancy. It is worth noting that the Schottky junction generated by the difference between the valence band and Fermi level (EF) of MXene makes MXene (especially -OH functionalized Ti3C2T x ) can effectively conduct electricity and can separate and transport Ti3C2T x / semiconductor heterostructures, and then the photogenerated carriers in Ti3C2T x A built-in electric field is generated between the Ti3C2T x The accordion-like multilayer structure itself has an inherent negatively charged surface and active OH-Ti sites, and the first-principles calculations show that Ti3C2T x The Schottky barrier is close to 0, and the Ti3C2Tx-based composite material can be used in photoelectrochemical sensors to achieve the detection of targets.

[0005] Among many semiconductor materials, bismuth-based materials are low-cost, non-toxic, and have narrow band gaps. In addition, the 6s orbital of bismuth and the 2p orbital of oxygen give them excellent optical and electrical properties. Bismuth-based materials have a wide range of applications in photocatalysis and the preparation of photoelectrochemical sensors. Bismuth oxyiodide (BiOI) is a typical narrow band gap material with good visible light capture ability. However, due to the poor conductivity of BiOI, the photogenerated electron-hole pairs are easy to recombine, and the carrier separation efficiency is poor, which limits its application in the field of PEC.

[0006] The titanium carbide / bismuth oxyiodide / bismuth phosphate material prepared in this invention uses titanium carbide / bismuth oxyiodide to create a Schottky junction, and then introduces bismuth phosphate to create a PN junction. This promotes the separation of photogenerated electron-hole pairs and inhibits their recombination, thereby increasing the photocurrent. The combination of bismuth oxyiodide with titanium carbide and bismuth phosphate significantly enhances PEC activity, improving PEC performance by accelerating the transfer of photogenerated electrons and enabling rapid and highly selective dopamine detection. Summary of the Invention

[0007] The present invention provides a BT / BiPO4 material and a preparation method thereof. The BT / BiPO4 material can be further prepared into a photoelectrochemical sensor for dopamine detection.

[0008] The technical solutions of the present invention are as follows:

[0009] A method for preparing BT / BiPO4 material comprises the following steps:

[0010] (1) Bi(NO3)3·5H2O solution was added dropwise to KI solution and stirred for 1 h. Then Ti3C2 powder was added and ultrasonicated (300 W) for 10 min to obtain a mixed solution.

[0011] The mass ratio of Bi(NO3)3·5H2O, KI, and Ti3C2 is 145.5:49.8:25;

[0012] The solvents of Bi(NO3)3·5H2O solution and KI solution are both ethylene glycol;

[0013] (2) The mixed solution obtained in step (1) was transferred to a high-pressure reactor, reacted at 120° C. for 24 h, then cooled to room temperature, centrifuged and washed, and the precipitate was vacuum-dried to obtain a BT material;

[0014] (3) The BT material obtained in step (2) was mixed with BiPO4 and deionized water, ultrasonicated (300W) for 15 min, centrifuged, and the precipitate was vacuum dried to obtain a BT / BiPO4 material;

[0015] The mass ratio of BT material to BiPO4 is 1:1.

[0016] The preparation method of the BT / BiPO4 material of the present invention combines various preparation conditions within a limited range, so that the BT / BiPO4 material has good performance. Specifically, the present invention synthesizes the BT / BiPO4 material by constructing a heterojunction.

[0017] The present invention relates to a BT / BiPO4 material prepared by the above preparation method. The material has a sensitive detection characteristic for dopamine and has broad application prospects in medicine.

[0018] Therefore, the present invention also relates to a photoelectrochemical sensor for dopamine detection, which is prepared by forming a film of BT / BiPO4 material on the surface of a glassy carbon electrode; the specific preparation method is as follows:

[0019] The aqueous solution of BT / BiPO4 material is dropped onto the glassy carbon electrode and dried naturally in the air to form a film;

[0020] The concentration of the aqueous solution of the BT / BiPO4 material is preferably 4 to 10 mg / ml;

[0021] The volume of the solution added to the glassy carbon electrode is determined by the size of the glassy carbon electrode, so that the solution can completely cover the surface of the glassy carbon electrode.

[0022] The photoelectrochemical sensor of the present invention can be directly combined with dopamine. In the presence of dopamine, it can act as an electron donor to consume the photogenerated holes generated by the BT / BiPO4 composite material, resulting in an enhanced photocurrent, thereby quantitatively detecting dopamine.

[0023] Specifically, the method for using the photoelectrochemical sensor for dopamine detection is as follows:

[0024] Prepare dopamine standard solutions of different concentrations, measure the photocurrent response using a photoelectrochemical sensor, and establish a standard curve representing the logarithmic function of the photocurrent intensity and the concentration of the dopamine standard solution; measure the photocurrent response of the sample to be tested using the photoelectrochemical sensor, substitute the measured photocurrent intensity into the standard curve, and obtain the dopamine content in the sample to be tested;

[0025] The solvents of the dopamine standard solution and the sample to be tested are both 0.1 mol / L phosphate buffer solution with a pH of 7.0 to 7.4;

[0026] The photocurrent test conditions were: 0V applied potential, 300W xenon lamp light source; the photocurrent increased with increasing dopamine content, and had a good linear response in the dopamine content range of 0.01-10mM;

[0027] During the test, the volume of the solution added to the photoelectrochemical sensor is determined by the size of the photoelectrochemical sensor. The solution must completely cover the surface of the photoelectrochemical sensor, and the volume of the solution added must remain constant for solutions of different concentrations.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. BT / BiPO4 material was used as a photoanode for photoelectrochemical (PEC) bioanalysis.

[0030] 2. The BT / BiPO4 material prepared in the present invention has good light response, and the rapid electron transfer provides higher sensitivity for the detection of dopamine.

[0031] 3. The photoelectrochemical sensor prepared using BT / BiPO4 material in the present invention is applied to dopamine detection and has good sensitivity and good linear response in the range of 0.01 to 10 mM. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 : Photocurrent response curve of 4 mg / ml BT / BiPO4 material in Example 1.

[0033] Figure 2 : Photocurrent response curve of 8mg / ml BT / BiPO4 material in Example 2.

[0034] Figure 3 : Curve of the photocurrent response as the pH of the dopamine test system changes in Example 3.

[0035] Figure 4 : Photocurrent response curve of BT / BiPO4 material to different substances in Example 4.

[0036] Figure 5: The curve of photoelectric response changing with dopamine concentration and the linear correlation coefficient diagram in Example 5.

[0037] Figure 6 : Photocurrent response curve of 10 mg / ml BT / BiPO4 material in Example 6.

[0038] Figure 7 : SEM images of BT / BiPO4 materials; a: SEM image of BT / BiPO4, b: high magnification SEM image of BT / BiPO4. DETAILED DESCRIPTION

[0039] The present invention is further described below by means of specific examples, but the protection scope of the present invention is not limited thereto.

[0040] In the following examples,

[0041] The preparation method of Ti3C2 is:

[0042] In a fume hood, add 2.5 mL of ultrapure water and 7.5 mL of hydrochloric acid to a Teflon cup containing a rotor. Seal the cup and stir magnetically for 5 minutes. Weigh 0.5 g of LiF and add it to the Teflon cup, stirring continuously for 10 minutes. Weigh 0.5 g of Ti3AlC2 and slowly add it to the cup over 5 minutes. Seal the Teflon cup and place it in a beaker filled with a small amount of water. Place the beaker on a thermostatic magnetic stirrer and heat it in a water bath at 35°C and 500 rpm for 48 hours. Next, remove the sealing film from the Teflon cup in the fume hood, attach the outer rotor to the inner rotor, and pour the liquid into a centrifuge tube. Add 30 mL of ultrapure water, close the lid, shake well, and divide the mixture evenly among four centrifuge tubes. Add 25 mL of ultrapure water to each tube and centrifuge the tube at 3500 rpm for 5 minutes. Remove the tube, aspirate the upper layer of liquid, and repeat the above process. After centrifugation 8 times, collect the samples from the four tubes into one tube and add a small amount of ultrapure water. Pour the solution into a round-bottom flask and pass nitrogen for 30 minutes. Wrap the mouth of the flask with a nitrogen balloon and place it in an ultrasonic machine for 30 minutes. Remove the balloon, quickly transfer the solution into the centrifuge tube, and close the lid. Take an empty centrifuge tube and add water to balance it. Place it in a centrifuge with the previous centrifuge tube and centrifuge it (7500r / min) for 20 minutes. Take the precipitate in the centrifuge tube, vacuum dry it at 60℃ for 12 hours, and then grind the block solid into powder with a mortar. Take 120mg of powder. In a fume hood, add 2.5mL of ultrapure water and 7.5mL of hydrochloric acid to a polytetrafluoroethylene cup containing a rotor, seal it, and stir magnetically for 5 minutes. Weigh 350mg of LiF and add it to the polytetrafluoroethylene cup. Continue stirring for 5 minutes. Slowly add the powder to the above cup over 1 minute. Seal the Teflon cup and place it in a beaker filled with a small amount of water. Place the beaker on a thermostatic magnetic stirrer and heat in a waterbath at 35°C and 500 rpm for 24 hours. In a fume hood, remove the sealing film from the Teflon cup, place the outer rotor on top of the inner rotor, pour the liquid into a centrifuge tube, add 30 mL of ultrapure water, close the lid, and shake evenly. Divide the sample evenly between four centrifuge tubes. Add 25 mL of ultrapure water to each tube and place the tube in a centrifuge at 3500 rpm for 5 minutes. Remove the tube, aspirate the upper layer of liquid, and repeat the above process. After centrifugation eight times, combine the samples from the four tubes into one tube and add a small amount of ultrapure water. Pour the solution into a round-bottom flask and purge with nitrogen for 30 minutes. Wrap the flask with a nitrogen balloon and sonicate in an ultrasonic machine for 30 minutes. Remove the balloon, quickly transfer the solution into the centrifuge tube, and close the lid. Take an empty centrifuge tube, balance it with water, and place it in a centrifuge (7500 rpm) for 20 minutes. Remove the precipitate from the centrifuge tube and vacuum dry it at 60°C for 12 hours. Grind the solid block into a powder in a mortar. 40 mg of TiC2 is obtained.

[0043] The preparation method of BiPO4 is:

[0044] 145.5 mg of Bi(NO₃)₃·5H₂O was placed in a beaker with deionized water (2 ml) and glacial acetic acid (1 ml) and magnetically stirred at room temperature to form a homogeneous, transparent solution A. 107.4 mg of Na₂HPO₄·12H₂O was dissolved in 3 ml of deionized water to form solution B. Solution B was added dropwise to solution A to produce a white precipitate. After stirring for 1 hour, the slurry was transferred to a 15 mL autoclave, reacted at 160°C for 16 hours, and cooled to room temperature. The product was washed twice by centrifugation with deionized water and ethanol, respectively, and then dried at 60°C to yield 70 mg of BiPO₄.

[0045] The glassy carbon electrode was purchased from Tianjin Aida Hengsheng Technology Development Co., Ltd., with an inner core material of glassy carbon, an outer jacket material of polytetrafluoroethylene, a terminal length of 20 mm, an outer jacket length of 60 mm, and a glassy carbon core diameter of φ3.

[0046] Example 1:

[0047] Dissolve 145.5 mg of Bi(NO₃)₃·5H₂O and 49.8 mg of KI in a beaker containing 4 ml of ethylene glycol and stir using a magnetic stirrer until dissolved. While the KI solution is stirring, add the Bi(NO₃)₃·5H₂O solution dropwise to the KI solution and stir for one hour to obtain a yellow solution. Add 25 mg of Ti₃C₂ powder to the solution and sonicate at 300 W for 10 minutes to obtain a mixed solution. The mixed solution is transferred to a 15 ml Teflon-lined autoclave and reacted at 120°C for 24 hours. After the autoclave cools, wash the product by centrifugation at 5000 rpm twice with water and twice with alcohol. The precipitate is vacuum-dried at 60°C to yield 110 mg of BT material.

[0048] Weigh 10 mg of BT material and 10 mg of BiPO₄ into a 10 mL centrifuge tube. Add 4 mL of deionized water to the tube and sonicate at 300 W for 15 minutes. Centrifuge the tube once at 7000 rpm. Dry the precipitate under vacuum at 60°C to obtain 15 mg of BT / BiPO₄ material.

[0049] 6 μL of 4 mg / ml BT / BiPO4 aqueous solution was dropped onto the glassy carbon electrode. After it was naturally dried in air to form a film, the photocurrent response was tested in a phosphate buffer solution with a pH of 7.4 (test conditions: external potential 0 V, 300 W xenon lamp light source). The results are as follows: Figure 1 As shown, the photocurrent is 0.2μA.

[0050] Example 2:

[0051] Dissolve 145.5 mg of Bi(NO₃)₃·5H₂O and 49.8 mg of KI in a beaker containing 4 ml of ethylene glycol and stir using a magnetic stirrer until dissolved. While the KI solution is stirring, add the Bi(NO₃)₃·5H₂O solution dropwise to the KI solution and stir for one hour to obtain a yellow solution. Add 25 mg of Ti₃C₂ powder to the solution and sonicate at 300 W for 10 minutes to obtain a mixed solution. The mixed solution is transferred to a 15 ml Teflon-lined autoclave and reacted at 120°C for 24 hours. After the autoclave cools, wash the product by centrifugation at 5000 rpm twice with water and twice with alcohol. The precipitate is vacuum-dried at 60°C to yield 110 mg of BT material.

[0052] Weigh 10 mg of BT material and 10 mg of BiPO₄ into a 10 mL centrifuge tube. Add 4 mL of deionized water to the tube and sonicate at 300 W for 15 minutes. Centrifuge the tube once at 7000 rpm. Dry the precipitate under vacuum at 60°C to obtain 15 mg of BT / BiPO₄ material.

[0053] 6 μL of 8 mg / ml BT / BiPO4 aqueous solution was dropped onto the glassy carbon electrode. After it dried naturally in the air to form a film, the photocurrent response was tested in a pH 7.4 phosphate buffer solution (test conditions: external potential 0 V, 300W xenon lamp light source). The results are as follows: Figure 2 As shown, the photocurrent is 0.39μA.

[0054] Example 3:

[0055] Dissolve 145.5 mg of Bi(NO₃)₃·5H₂O and 49.8 mg of KI in a beaker containing 4 ml of ethylene glycol and stir using a magnetic stirrer until dissolved. While the KI solution is stirring, add the Bi(NO₃)₃·5H₂O solution dropwise to the KI solution and stir for one hour to obtain a yellow solution. Add 25 mg of Ti₃C₂ powder to the solution and sonicate at 300 W for 10 minutes to obtain a mixed solution. The mixed solution is transferred to a 15 ml Teflon-lined autoclave and reacted at 120°C for 24 hours. After the autoclave cools, wash the product by centrifugation at 5000 rpm twice with water and twice with alcohol. The precipitate is vacuum-dried at 60°C to yield 110 mg of BT material.

[0056] Weigh 10 mg of BT material and 10 mg of BiPO₄ into a 10 mL centrifuge tube. Add 4 mL of deionized water to the tube and sonicate at 300 W for 15 minutes. Centrifuge the tube once at 7000 rpm. Dry the precipitate under vacuum at 60°C to obtain 15 mg of BT / BiPO₄ material.

[0057] 6 μL of 8 mg / ml BT / BiPO4 aqueous solution was dropped onto the glassy carbon electrode and dried in air to form a film. The photocurrent response was tested in phosphate buffer solutions with different pH values ​​(pH values ​​of 5, 6, 7, 7.4, 8, and 9, with an applied potential of 0 V and a 300W xenon lamp as the light source) with a DA concentration of 1 mM. The results are shown in Figure 2. Figure 3 As shown in the figure, the photocurrent increases with decreasing pH in the pH range of 5-8. In the pH range of 8-9, the photocurrent decreases with increasing pH. The photocurrent at pH 8 is the highest.

[0058] Example 4:

[0059] Dissolve 145.5 mg of Bi(NO₃)₃·5H₂O and 49.8 mg of KI in a beaker containing 4 ml of ethylene glycol and stir using a magnetic stirrer until dissolved. While the KI solution continues to stir, add the Bi(NO₃)₃·5H₂O solution dropwise to the KI solution and stir for one hour to obtain a yellow solution. Add 25 mg of Ti₃C₂ powder to the solution and sonicate at 300 W for 10 minutes to obtain a mixed solution. The mixed solution is transferred to a 15 ml Teflon-lined autoclave and reacted at 120°C for 24 hours. After the autoclave cools, wash the product by centrifugation at 5000 rpm twice with water and twice with alcohol. The precipitate is vacuum-dried at 60°C to yield 110 mg of BT material.

[0060] Weigh 10 mg of BT material and 10 mg of BiPO₄ into a 10 mL centrifuge tube. Add 4 mL of deionized water to the tube and sonicate at 300 W for 15 minutes. Centrifuge the tube once at 7000 rpm. Dry the precipitate under vacuum at 60°C to obtain 15 mg of BT / BiPO₄ material.

[0061] 6 μL of an 8 mg / mL aqueous solution of BT / BiPO4 was dropped onto a glassy carbon electrode and allowed to air dry to form a film. The photocurrent response was then measured in 10 mL of phosphate buffer (pH 7.4) containing 10 μmol dopamine hydrochloride, 50 μmol lysine, 50 μmol arginine, 50 μmol urea, 50 μmol potassium chloride, 50 μmol sodium chloride, and 50 μmol magnesium chloride.

[0062] The results are as follows Figure 4As shown, the photocurrent in 10 ml phosphate buffer containing 10 μmol dopamine hydrochloride is -1.65 μA, the photocurrent in 10 ml phosphate buffer containing 50 μmol lysine is -0.3 μA, and the photocurrent in 10 ml phosphate buffer containing 50 μmol arginine, 50 μmol urea, 50 μmol potassium chloride, 50 μmol sodium chloride and 50 μmol magnesium chloride is close to 0 μA, indicating that the sensor has good selectivity and is resistant to interference from multiple ions and biological secretions.

[0063] Example 5:

[0064] Dissolve 145.5 mg of Bi(NO₃)₃·5H₂O and 49.8 mg of KI in a beaker containing 4 ml of ethylene glycol and stir using a magnetic stirrer until dissolved. While the KI solution continues to stir, add the Bi(NO₃)₃·5H₂O solution dropwise to the KI solution and stir for one hour to obtain a yellow solution. Add 25 mg of Ti₃C₂ powder to the solution and sonicate at 300 W for 10 minutes to obtain a mixed solution. The mixed solution is transferred to a 15 ml Teflon-lined autoclave and reacted at 120°C for 24 hours. After the autoclave cools, wash the product by centrifugation at 5000 rpm twice with water and twice with alcohol. The precipitate is vacuum-dried at 60°C to yield 110 mg of BT material.

[0065] Weigh 10 mg of BT material and 10 mg of BiPO₄ into a 10 mL centrifuge tube. Add 4 mL of deionized water to the tube and sonicate at 300 W for 15 minutes. Centrifuge the tube once at 7000 rpm. Dry the precipitate under vacuum at 60°C to obtain 15 mg of BT / BiPO₄ material.

[0066] 6 μL of an 8 mg / mL BT / BiPO₄ aqueous solution was dropped onto a glassy carbon electrode and allowed to air dry to form a film. The photocurrent response was then measured in various dopamine solutions (0 mM, 0.01 mM, 0.1 mM, 0.25 mM, 1 mM, 5 mM, and 10 mM, in phosphate buffer, pH 7.4) (applied potential 0 V, 300 W xenon lamp light source).

[0067] The results are as follows Figure 5 The results show that the sensor has good sensitivity, the photocurrent intensity increases with the increase of dopamine concentration, and has a good linear response in the dopamine concentration range of 0.01-10mM, and the linear correlation coefficient R 2 =0.996.

[0068] Example 6:

[0069] Dissolve 145.5 mg of Bi(NO₃)₃·5H₂O and 49.8 mg of KI in a beaker containing 4 ml of ethylene glycol and stir using a magnetic stirrer until dissolved. While the KI solution continues to stir, add the Bi(NO₃)₃·5H₂O solution dropwise to the KI solution and stir for one hour to obtain a yellow solution. Add 25 mg of Ti₃C₂ powder to the solution and sonicate at 300 W for 10 minutes to obtain a mixed solution. The mixed solution is transferred to a 15 ml Teflon-lined autoclave and reacted at 120°C for 24 hours. After the autoclave cools, wash the product by centrifugation at 5000 rpm twice with water and twice with alcohol. The precipitate is vacuum-dried at 60°C to yield 110 mg of BT material.

[0070] Weigh 10 mg of BT material and 10 mg of BiPO₄ into a 10 mL centrifuge tube. Add 4 mL of deionized water to the tube and sonicate at 200 W for 15 minutes. Centrifuge the tube once at 7000 rpm. Dry the precipitate under vacuum at 60°C to obtain 15 mg of BT / BiPO₄ material.

[0071] 6 μL of 10 mg / ml BT / BiPO4 aqueous solution was dropped onto the glassy carbon electrode. After it dried naturally in the air to form a film, the photocurrent response was tested in a pH 7.4 phosphate buffer solution (test conditions: external potential 0 V, 300 W xenon lamp light source). The results are as follows: Figure 6 As shown, the photocurrent is 0.3μA.

Claims

1. A method for preparing BT / BiPO4 material, characterized in that: The steps include: (1) Bi(NO3)3·5H2O solution was added dropwise to KI solution and stirred for 1 h. Then Ti3C2 powder was added and ultrasonicated for 10 min to obtain a mixed solution. (2) The mixed solution obtained in step (1) was transferred to a high-pressure reactor, reacted at 120° C. for 24 h, then cooled to room temperature, centrifuged and washed, and the precipitate was vacuum-dried to obtain a BT material; (3) The BT material obtained in step (2) was mixed with BiPO4 and deionized water, ultrasonicated for 15 min, centrifuged, and the precipitate was vacuum dried to obtain BT / BiPO4 material.

2. The method for preparing the BT / BiPO4 material according to claim 1, wherein: In step (1), the mass ratio of Bi(NO3)3·5H2O, KI, and Ti3C2 is 145.5:49.8:

25.

3. The method for preparing the BT / BiPO4 material according to claim 1, wherein: In step (1), the solvents of the Bi(NO3)3·5H2O solution and the KI solution are both ethylene glycol.

4. The method for preparing the BT / BiPO4 material according to claim 1, wherein: In step (3), the mass ratio of BT material to BiPO4 is 1:

1.

5. The method for preparing the BT / BiPO4 material according to claim 1, wherein: In step (1) or step (3), the power of ultrasound is 300W.

6. BT / BiPO4 material prepared by the preparation method according to any one of claims 1 to 5.

7. A photoelectrochemical sensor for dopamine detection, characterized in that: The BT / BiPO4 material according to claim 6 is formed into a film on the surface of a glassy carbon electrode.

8. The method for preparing the photoelectrochemical sensor according to claim 7, wherein: The preparation method is as follows: The aqueous solution of BT / BiPO4 material is dropped onto the glassy carbon electrode and dried naturally in the air to form a film; The concentration of the aqueous solution of BT / BiPO4 material is 4-10 mg / ml.

9. Use of the photoelectrochemical sensor in dopamine detection according to claim 7, characterized in that: The application method is as follows: Prepare dopamine standard solutions of different concentrations, measure the photocurrent response using a photoelectrochemical sensor, and establish a standard curve representing the logarithmic function of the photocurrent intensity and the concentration of the dopamine standard solution; measure the photocurrent response of the sample to be tested using the photoelectrochemical sensor, substitute the measured photocurrent intensity into the standard curve, and obtain the dopamine content in the sample to be tested; The solvents of the dopamine standard solution and the sample to be tested are both 0.1 mol / L phosphate buffer solution with a pH of 7.0 to 7.4; The photocurrent test conditions are: external potential 0V, 300W xenon lamp light source.

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