A metal-bismuth-based semiconductor nanocomposite material and its preparation method and its application in detecting veterinary drugs

Abstract

The present invention provides a metal-bismuth-based semiconductor nanocomposite material and a preparation method thereof and its application in detecting veterinary drugs. The present invention is prepared by the following method: synthesizing AuNRs solution using gold seeds, centrifugation washing and purification, and then dispersing in an aqueous solution; depositing Ag elements on AuNRs to prepare Au@AgNRs; the preparation of Bi2WO6-OV is by a simple one-step ethylene glycol-assisted solvothermal method, wherein ethylene glycol is used as a reducing agent to selectively remove oxygen atoms through a redox reaction between Bi2WO6 and ethylene glycol; calcining Bi2WO6-OV to obtain the original Bi2WO6 without oxygen vacancy defects. The Au@AgNR film is prepared by interfacial self-assembly, and Raman active molecules or veterinary drugs to be detected, and Bi2WO6-OV and Bi2WO6 solutions are sequentially added for Raman synergistic effect research and quantitative detection.

Description

Technical Field

[0001] The invention belongs to the field of Raman detection, and in particular refers to a metal-bismuth-based semiconductor nanocomposite material and a preparation method thereof and application thereof in detecting veterinary drugs. Background Art

[0002] Surface enhanced Raman spectroscopy (SERS) is considered to be one of the most reliable, sensitive and selective techniques, which mainly amplifies SERs signals by amplifying electromagnetic fields and / or causing / generating charge transfer in charge transfer states between chemical analyte molecules and SERs. However, it lacks high sensitivity with good stability and reproducibility. The applicability of SERS is quite limited. Due to its high plasma effect, traditional SERs substrates widely rely on precious metals (Au, Ag, Cu, etc.). Although the use of metal nanoparticles in SERS is simple and cost-effective, metals with high SERS signals often have rough structures, which leads to structural instability and high cost. Semiconductors have stable chemical structures and easy to control morphology. In addition, semiconductors have a high specific surface area, which is conducive to the adsorption of target molecules, and can also detect targets through their pore size specificity. Therefore, metal-semiconductor hybrid structures have great prospects in the field of SERS detection. Summary of the invention

[0003] To solve the above technical problems, the present invention proposes to introduce oxygen vacancy (OV) defects on the semiconductor surface. Bi2WO6-OV and Bi2WO6-OV are synthesized to study the role of oxygen vacancies. After the introduction of oxygen vacancies, the charge carrier density on the semiconductor surface will be greatly amplified, which may lead to the LSPR effect. The oxygen vacancies in Bi2WO6-OV lead to defect state energy levels, which are beneficial to the CT and LSPR effects, thereby enhancing the SERS signal. The Au@Ag NR film is homogeneous and the SERS signal is stable. The Au@Ag NR-Bi2WO6-OV film combines electromagnetic field enhancement and chemical enhancement mechanisms at the same time, greatly amplifying the SERS signal of the target.

[0004] The first object of the present invention is to provide a method for preparing a metal-bismuth-based semiconductor nanocomposite material, comprising the following steps:

[0005] S1: Disperse Bi(NO3)3 and Na2WO4 in ethylene glycol to obtain Bi(NO3)3 ethylene glycol solution and Na2WO4 ethylene glycol solution respectively, then drop the Na2WO4 ethylene glycol solution into the Bi(NO3)3 ethylene glycol solution, mix and stir to react, then transfer to a reaction vessel and react at 120-180°C for 20h to obtain Bi2WO6-OV;

[0006] S2: In air atmosphere, the Bi2WO6-OV obtained in S1 was calcined at 400 °C for 2-8 h to obtain the original Bi2WO6 without oxygen vacancy defects;

[0007] S3: Au@AgNRs is dissolved in a mixed solvent of water and hexane, and ethanol is added dropwise to form an Au@AgNRs monolayer film, the AuNBPs@AgNRs monolayer film is transferred to a carrier, and a Raman active molecule solution is added dropwise, followed by an aqueous solution of Bi2WO6-OV obtained in step S1 or an aqueous solution of Bi2WO6 in step S2 to obtain a metal-bismuth-based semiconductor nanocomposite material.

[0008] In one embodiment of the present invention, in step S1, the molar ratio of Bi(NO3)3 in the ethylene glycol solution of Bi(NO3)3 to Na2WO4 in the ethylene glycol solution of Na2WO4 is 2:1.

[0009] In one embodiment of the present invention, in step S1, the mixing and stirring is carried out for 1-24 hours.

[0010] In one embodiment of the present invention, in step S3, the volume ratio of water to hexane is 5:1.

[0011] In one embodiment of the present invention, in step S3, the Raman active molecule in the Raman active molecule solution is ATP or NTP.

[0012] In one embodiment of the present invention, in step S3, the volume of the aqueous solution of Bi2WO6-OV is 5-40 μL.

[0013] In one embodiment of the present invention, in step S3, the volume of the aqueous solution of Bi2WO6 used is 5-40 μL.

[0014] The second object of the present invention is to provide a metal-bismuth-based semiconductor nanocomposite material obtained by the preparation method.

[0015] The third object of the present invention is to provide the use of the metal-bismuth-based semiconductor nanocomposite material in the qualitative or quantitative detection of agricultural and veterinary drugs.

[0016] In one embodiment of the present invention, the agricultural veterinary drug is diazepam, paraquat or chlorpyrifos.

[0017] The preparation methods of Au@AgNR-Bi2WO6-OV film in the present invention respectively adopt simple seed-mediated growth method and solvothermal method: 1. AuNRs solution is synthesized using gold seeds, purified by repeated centrifugation washing with deionized water, and then dispersed in aqueous solution. Ag element is deposited on AuNRs to prepare Au@AgNRs. 2. Bi2WO6-OV is prepared by a simple one-step ethylene glycol-assisted solvothermal method, in which ethylene glycol is used as a reducing agent to selectively remove oxygen atoms through the redox reaction between Bi2WO6 and ethylene glycol. Bi2WO6-OV is calcined at 400°C for 4h to generate a yellow solid. That is, the original Bi2WO6 without oxygen vacancy defects. 3. Au@Ag NR film is prepared by interfacial self-assembly, and Raman active molecules or veterinary drugs to be detected, and Bi2WO6-OV or Bi2WO6 solution are sequentially added for Raman synergistic effect research and quantitative detection.

[0018] The above technical scheme of the present invention has the following advantages over the prior art: Combining strong plasma and electrical properties, the metal-semiconductor heterostructure Au@Ag NR-Bi2WO6-OV film shows essential advantages compared with pure metal or semiconductor nanostructures: Enhanced capability: The metal-semiconductor heterostructure shows unprecedented improved Raman signals, which is attributed to the synergistic effect of plasmons and CT, allowing ultra-sensitive chemical and biological sensing; CT efficiency: The introduction of plasma metal can induce CT transition at the metal-semiconductor interface, thereby enhancing the contribution of CT to SERS. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0020] Figure 1 These are the Raman properties of the Au@Ag NR-Bi2WO6-OV and Au@Ag NP-Bi2WO6-OV / Bi2WO6 films in Example 1 of the present invention.

[0021] Figure 2 The Au@AgNR-Bi2WO6-OV film in the application example of the present invention is used to detect paraquat.

[0022] Figure 3 The Au@AgNR-Bi2WO6-OV film in the application example of the present invention is used to detect diazepam, paraquat and chlorpyrifos. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0024] Example 1

[0025] 1. Bi2WO6-OV: First, 4mM Bi(NO3)3·5H2O and 2mM Na2WO4·2H2O were uniformly dispersed in 30mL and 70mL ethylene glycol, respectively. Under vigorous stirring, the ethylene glycol containing Na2WO4·2H2O was then slowly added dropwise to the ethylene glycol containing Bi(NO3)3·5H2O. The mixed solution was vigorously stirred at room temperature for 1h, and then transferred to a 125mL reactor and reacted at 180℃ for 20h. After the reaction was completed, the autoclave was cooled to room temperature, the resulting precipitate was collected and washed twice with ethanol and deionized water alternately to remove residual ions. The final product was dried at 60℃ overnight to obtain a gray solid.

[0026] 2. Bi2WO6: In an air-rich atmosphere, Bi2WO6-OV was calcined at 400°C for 4 hours to generate a yellow solid, which is the original Bi2WO6 without oxygen vacancy defects.

[0027] 3. Au@Ag (4) NRs: First, gold rod AuNRs were synthesized by seed-mediated method. The first step was to synthesize gold seed solution. CTAB solution (10mL, 0.1M) was prepared, and HAuCl4 (100μL, 25mM) aqueous solution and freshly prepared NaBH4 (0.6mL, 0.01M) were added in sequence under vigorous stirring, and the color of the solution changed from yellow to brown. The mixed solution was stirred for 2min and allowed to stand for 2 hours at 27°C. The second step was to synthesize AuNRs. CTAB (40mL, 0.1M) solution was prepared, and HAuCl4 (2mL, 10mM) aqueous solution, silver nitrate AgNO3 aqueous solution (0.4mL, 10mM), HCl (0.8mL, 1M) were added in sequence. After gently shaking the solution to mix evenly, ascorbic acid AA (0.32mL, 0.1M) was added to change the growth solution from dark yellow to colorless. 0.15mL of gold seed solution was added, and the solution was gently shaken to mix evenly, and then allowed to stand overnight. The synthesized AuNRs solution was centrifuged three times at 8500 rpm to remove excess CTAB and redispersed in 8 mL of ultrapure water. (4)NRs: The CTAB on the surface of AuNR was completely replaced with hexadecyltrimethylammonium chloride (CTAC) to enable rapid nucleation and growth of silver metal on the surface of AuNR and improve the uniformity of the silver shell. 1 mL of the gold rod solution was dispersed in the CTAC solution (20 mL, 0.08 M). AgNO3 aqueous solution (2.4 mL, 10 mM) and AA (1.2 mL, 0.1 M) were added in sequence. The mixture was reacted in a water bath at 60 ° C for 3 h under vigorous stirring.

[0028] 4. Au@Ag (4) Preparation of NRs films and study of their Raman properties: Au@Ag@N ... (4) Assembling Au@Ag between NRs aqueous solutions (4) NRs monolayer. The ratio of water to hexane is 5:1. Ethanol is added dropwise to the water-hexane layer. (4) NRs are captured at the interface to form a uniform monolayer. Since hexane is volatile, the assembled monolayer is transferred to a silicon wafer after the hexane is completely evaporated. 10 μL of ATP ethanol solution is dripped onto the silicon wafer of the monolayer. 5 mg / mL Bi2WO6-OV and Bi2WO6 aqueous solutions are prepared. They are dripped onto the Au@Ag (4) NRs film. After it is completely dried, its Raman signal is measured.

[0029] Example 2

[0030] 1. Au@Ag (1) NRs: First, gold rod AuNRs were synthesized by seed-mediated method. The first step was to synthesize gold seed solution. CTAB solution (10mL, 0.1M) was prepared, and HAuCl4 (100μL, 25mM) aqueous solution and freshly prepared NaBH4 (0.6mL, 0.01M) were added in sequence under vigorous stirring, and the color of the solution changed from yellow to brown. The mixed solution was stirred for 2min and allowed to stand at 27°C for 2 hours. The second step was to synthesize AuNRs. CTAB (40mL, 0.1M) solution was prepared, and HAuCl4 (2mL, 10mM) aqueous solution, silver nitrate AgNO3 aqueous solution (0.4mL, 10mM), HCl (0.8mL, 1M) were added in sequence. After gently shaking the solution to mix evenly, ascorbic acid AA (0.32mL, 0.1M) was added to change the growth solution from dark yellow to colorless. 0.15mL of gold seed solution was added, and the solution was gently shaken to mix evenly, and then allowed to stand overnight. The synthesized AuNRs solution was centrifuged three times at 8500 rpm to remove excess CTAB and redispersed in 8 mL of ultrapure water. (1)NRs: The CTAB on the surface of AuNR was completely replaced with hexadecyltrimethylammonium chloride (CTAC) to enable rapid nucleation and growth of silver metal on the surface of AuNR and improve the uniformity of the silver shell. 1 mL of the gold rod solution was dispersed in the CTAC solution (20 mL, 0.08 M). AgNO3 aqueous solution (0.4 mL, 10 mM) and AA (0.2 mL, 0.1 M) were added in sequence. The mixture was reacted in a water bath at 60 ° C for 3 h under vigorous stirring.

[0031] 2. Au@Ag (1) Preparation of NRs films and study of their Raman properties: Au@Ag@N ... (1) Assembling Au@Ag between NRs aqueous solutions (1) NRs monolayer. The ratio of water to hexane is 5:1. Ethanol is added dropwise to the water-hexane layer. (1) NRs are captured at the interface to form a uniform monolayer. Since hexane is volatile, the assembled monolayer is transferred to a silicon wafer after the hexane is completely evaporated. 10 μL of ATP ethanol solution is dripped onto the silicon wafer of the monolayer. 5 mg / mL Bi2WO6-OV aqueous solution is prepared. It is dripped onto the Au@Ag (1) NRs film. After it is completely dried, its Raman signal is measured.

[0032] 3. Preparation of Au@AgNPs film and study of its Raman properties: First, synthesize gold nanoparticles AuNPs of about 15nm, and then deposit an Ag layer on the surface. Through interfacial self-assembly, assemble the Au@AgNPs monolayer between n-hexane and plasma Au@AgNPs aqueous solution. The ratio of water to hexane is 5:1. Add ethanol dropwise to the water-hexane layer, and Au@AgNPs are captured at the interface to form a uniform monolayer. Since hexane is volatile. After the hexane is completely volatilized, transfer the assembled monolayer to a silicon wafer. Add 10μL of ATP ethanol solution to the silicon wafer of the monolayer. Prepare 5mg / mL of Bi2WO6-OV and Bi2WO6 aqueous solutions. Add them dropwise to the Au@AgNPs film respectively. Measure its Raman signal after it is completely dried.

[0033] Example 3

[0034] 1. Au@Ag (2)NRs: First, gold rod AuNRs were synthesized by seed-mediated method. The first step was to synthesize gold seed solution. CTAB solution (10mL, 0.1M) was prepared, and HAuCl4 (100μL, 25mM) aqueous solution and freshly prepared NaBH4 (0.6mL, 0.01M) were added in sequence under vigorous stirring, and the color of the solution changed from yellow to brown. The mixed solution was stirred for 2min and allowed to stand at 27°C for 2 hours. The second step was to synthesize AuNRs. CTAB (40mL, 0.1M) solution was prepared, and HAuCl4 (2mL, 10mM) aqueous solution, silver nitrate AgNO3 aqueous solution (0.4mL, 10mM), HCl (0.8mL, 1M) were added in sequence. After gently shaking the solution to mix evenly, ascorbic acid AA (0.32mL, 0.1M) was added to change the growth solution from dark yellow to colorless. 0.15mL of gold seed solution was added, and the solution was gently shaken to mix evenly, and then allowed to stand overnight. The synthesized AuNRs solution was centrifuged three times at 8500 rpm to remove excess CTAB and redispersed in 8 mL of ultrapure water. (2) NRs: Completely replace the CTAB on the surface of AuNR with hexadecyltrimethylammonium chloride (CTAC) to rapidly nucleate and grow silver metal on the surface of AuNR and improve the uniformity of the silver shell. Disperse 1mL of the gold rod solution into the CTAC solution (20 mL, 0.08M). Add AgNO3 aqueous solution (0.8mL, 10mM) and AA (0.4mL, 0.1M) in sequence. React in a water bath at 60℃ for 3h under vigorous stirring.

[0035] 2. Au@Ag (2) Preparation of NRs films and study of their Raman properties: Au@Ag@N ... (2) Assembling Au@Ag between NRs aqueous solutions (2) NRs monolayer. The ratio of water to hexane is 5:1. Ethanol is added dropwise to the water-hexane layer. (2) NRs are captured at the interface to form a uniform monolayer. Since hexane is volatile, the assembled monolayer is transferred to a silicon wafer after the hexane is completely evaporated. 10 μL of ATP ethanol solution is dripped onto the silicon wafer of the monolayer. 5 mg / mL Bi2WO6-OV aqueous solution is prepared. It is dripped onto the Au@Ag (2) NRs film. After it is completely dried, its Raman signal is measured.

[0036] Example 4

[0037] 1. Au@Ag (3)NRs: First, gold rod AuNRs were synthesized by seed-mediated method. The first step was to synthesize gold seed solution. CTAB solution (10mL, 0.1M) was prepared, and HAuCl4 (100μL, 25mM) aqueous solution and freshly prepared NaBH4 (0.6mL, 0.01M) were added in sequence under vigorous stirring, and the color of the solution changed from yellow to brown. The mixed solution was stirred for 2min and allowed to stand at 27°C for 2 hours. The second step was to synthesize AuNRs. CTAB (40mL, 0.1M) solution was prepared, and HAuCl4 (2mL, 10mM) aqueous solution, silver nitrate AgNO3 aqueous solution (0.4mL, 10mM), HCl (0.8mL, 1M) were added in sequence. After gently shaking the solution to mix evenly, ascorbic acid AA (0.32mL, 0.1M) was added to change the growth solution from dark yellow to colorless. 0.15mL of gold seed solution was added, and the solution was gently shaken to mix evenly, and then allowed to stand overnight. The synthesized AuNRs solution was centrifuged three times at 8500 rpm to remove excess CTAB and redispersed in 8 mL of ultrapure water. (3) NRs: The CTAB on the surface of AuNR was completely replaced with hexadecyltrimethylammonium chloride (CTAC) to enable rapid nucleation and growth of silver metal on the surface of AuNR and improve the uniformity of the silver shell. 1 mL of the gold rod solution was dispersed in the CTAC solution (20 mL, 0.08 M). AgNO3 aqueous solution (1.6 mL, 10 mM) and AA (0.2 mL, 0.1 M) were added in sequence. The mixture was reacted in a water bath at 60 ° C for 3 h under vigorous stirring.

[0038] 2. Au@Ag (3) Preparation of NRs films and study of their Raman properties: Au@Ag@N ... (3) Assembling Au@Ag between NRs aqueous solutions (3) NRs monolayer. The ratio of water to hexane is 5:1. Ethanol is added dropwise to the water-hexane layer. (3) NRs are captured at the interface to form a uniform monolayer. Since hexane is volatile, the assembled monolayer is transferred to a silicon wafer after the hexane is completely evaporated. 10 μL of ATP ethanol solution is dripped onto the silicon wafer of the monolayer. 5 mg / mL Bi2WO6-OV aqueous solution is prepared. It is dripped onto the Au@Ag (3) NRs film. After it is completely dried, its Raman signal is measured.

[0039] Application Examples

[0040] In Example 1, the Au@AgNR-Bi2WO6-OV membrane was used to detect veterinary drugs: 10 μL paraquat solution (100 mg / L-10 ng / L) was used instead of ATP ethanol solution to detect the Raman signals of diazepam at different concentrations. In the concentration range of 100 mg / L-10 ng / L, the Raman signal showed a good linear relationship with the veterinary drug concentration (R 2 =0.997), the results are shown in Figure 3 At the same time, the characteristic Raman peaks of diazepam, paraquat and chlorpyrifos do not interfere with each other, which shows that the three veterinary drugs can be detected in multiple ways in a mixed matrix.

[0041] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. An application of a metal-bismuth-based semiconductor nanocomposite material in the qualitative or quantitative detection of agricultural and veterinary drugs, characterized in that: The preparation method of the metal-bismuth-based semiconductor nanocomposite material, The following steps are involved: S1: Disperse Bi(NO3)3 and Na2WO4 in ethylene glycol to obtain Bi(NO3)3 ethylene glycol solution and Na2WO4 ethylene glycol solution respectively, then drop the Na2WO4 ethylene glycol solution into the Bi(NO3)3 ethylene glycol solution, mix and stir to react, then transfer to a reaction vessel and heat to react, to obtain Bi2WO6-OV; S2: dissolving Au@AgNRs in a mixed solvent of water and hexane, and adding ethanol dropwise to form a Au@AgNRs monolayer film, transferring the Au@AgNRs monolayer film to a carrier, and dropping a Raman active molecule solution, and then dropping an aqueous solution of Bi2WO6-OV obtained in step S1 to obtain the metal-bismuth-based semiconductor nanocomposite material.

2. The use according to claim 1, characterized in that: In step S1, the reaction temperature is heated to 120-180°C.

3. The use according to claim 1, characterized in that: In step S1, the mixture is mixed and stirred for 1-24 h.

4. The use according to claim 1, characterized in that: In step S2, the volume ratio of water to hexane is 5:

1.

5. The use according to claim 1, characterized in that: In step S2, the Raman active molecule in the Raman active molecule solution is ATP or NTP.

6. The use according to claim 1, characterized in that: In step S2, the volume of the aqueous solution of Bi2WO6-OV is 5-40 μL.

7. The use according to claim 1, characterized in that: The agricultural and veterinary drugs are diazepam, paraquat or chlorpyrifos.

8. A metal-bismuth-based semiconductor nanocomposite material, characterized in that: Prepared by the following method: S1: Disperse Bi(NO3)3 and Na2WO4 in ethylene glycol to obtain Bi(NO3)3 ethylene glycol solution and Na2WO4 ethylene glycol solution respectively, then drop the Na2WO4 ethylene glycol solution into the Bi(NO3)3 ethylene glycol solution, mix and stir to react, then transfer to a reaction vessel and heat to react, to obtain Bi2WO6-OV; S2: dissolving Au@AgNRs in a mixed solvent of water and hexane, and adding ethanol dropwise to form a Au@AgNRs monolayer film, transferring the Au@AgNRs monolayer film to a carrier, and dropping a Raman active molecule solution, and then dropping an aqueous solution of Bi2WO6-OV obtained in step S1 to obtain the metal-bismuth-based semiconductor nanocomposite material.

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