Preparation method of gold composite layered potassium titanate SERS substrate material for organic dye detection

Abstract

A method for preparing a gold-composite layered potassium titanate SERS substrate material for organic dye detection. This method solves the problems of high cost and poor stability of noble metal SERS substrates, low detection performance of non-metallic SERS substrates, and uneven distribution of AuNPs. Method 1: Layered K2Ti8O is prepared by hydrothermal mixing of TiO2 powder and KOH solution. 17 2. Sodium citrate reduces chloroauric acid to allow AuNPs to grow on layered K2Ti8O. 17 Part 3: Growing AuNPs on layered K2Ti8O 17 The composite substrate is placed on a silicon wafer, and AuNPs are then dropped onto it and allowed to air dry. In this invention, AuNPs are composited with layered K2Ti8O. 17 The SERS substrate material has a regular morphology, and AuNPs are present in K2Ti8O. 17 The surface is uniformly distributed, exhibiting excellent SERS detection performance. This invention avoids excessive energy consumption, is simple to operate, low in cost, and easily scalable for industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of preparation of surface-enhanced Raman scattering substrate materials, and particularly relates to a preparation method of a gold composite layered potassium titanate SERS substrate material for organic dye detection. BACKGROUND

[0002] Surface-enhanced Raman scattering (SERS) is an ultra-sensitive fingerprint spectroscopy technique. Its principle is to use the local surface plasmon resonance excitation (electromagnetic enhancement) of plasmonic nanostructures that generate high-intensity electromagnetic fields and different interactions (chemical enhancement) between target molecules and SERS substrate materials, including electron exchange, or by sharing or transferring with nanostructures, to significantly enhance the Raman signal of molecules adsorbed on the surface of the substrate material.

[0003] In recent years, with the rapid development of industrialization and urbanization, environmental pollution problems have become increasingly serious, especially organic dye pollution in water bodies such as crystal violet and methylene blue, which pose a great threat to the ecological system and human health due to their high stability and difficulty in degradation.

[0004] Surface-enhanced Raman scattering (SERS) technology has become a powerful tool for detecting environmental pollutants due to its ultra-high sensitivity and rapid detection capability. The design and preparation of SERS substrates are key to achieving efficient SERS detection. However, traditional SERS substrates (such as gold and silver) usually have some limitations, such as high cost, poor stability, etc. While non-noble metal SERS substrates have shown advantages such as low cost, easy mass production, high reproducibility and chemical inertness, their SERS efficiency is usually lower than that of noble metal SERS substrates. Therefore, the synergistic combination of noble metals and non-noble metal materials helps to overcome their limitations and improve detection performance. SUMMARY

[0005] The purpose of the present application is to solve the problems of high cost and poor stability of existing noble metal SERS substrates for detecting organic dye pollution, the lower detection performance of non-metal SERS substrates than noble metal SERS substrates, and the uneven distribution of AuNPs on the layered K2Ti8O 17 after compounding, and to provide a preparation method of a gold composite layered potassium titanate SERS substrate material for organic dye detection. 17

[0006] A preparation method of a gold composite layered potassium titanate SERS substrate material for organic dye detection, which is implemented in the following steps:

[0007] ​I. TiO2 is added to KOH aqueous solution, and after magnetic stirring, it is transferred to a reaction kettle, and reacted at 120-200℃ for 3-5 days. After the reaction is completed and the temperature is lowered to room temperature, the product is washed and dried to obtain layered K2Ti8O 17 SERS substrate material;

[0008] II. The above layered K2Ti8O 17 SERS substrate material is mixed with chloroauric acid solution by magnetic stirring. After stopping stirring, heating is started. After complete boiling, magnetic stirring is started again, and sodium citrate solution is added. Boiling is continued for 15 min. Stirring and heating are stopped, and the temperature is lowered to room temperature. The product is washed and dried to obtain a composite SERS substrate with AuNPs grown on the layered K2Ti8O 17 ;

[0009] III. The above composite SERS substrate with AuNPs grown on the layered K2Ti8O 17 is placed on a silicon wafer, and then AuNPs sol is added dropwise and naturally dried to obtain a SERS substrate material of AuNPs composite layered K2Ti8O 17 , i.e. a gold composite layered potassium titanate SERS substrate material for organic dye detection. The preparation method is completed.

[0010] Further, in step I, the TiO2 is anatase type, with a mass of 2g and a particle size of 60nm.

[0011] Further, in step I, the volume of the KOH aqueous solution is 50mL, and the molar concentration is 1-20M.

[0012] Further, in step I, the magnetic stirring is at a speed of 100-1000rpm for 20-30min.

[0013] Further, in steps I and II, the washing and drying are performed 2-5 times with deionized water, and then drying is performed at 50-80℃ for 8-16h.

[0014] Further, in step II, the volume of the chloroauric acid solution is 50mL, and the mass fraction is 0.1%.

[0015] Further, in step II, the speed of the magnetic stirring is 100-1000rpm.

[0016] Further, in step II, the heating temperature is 160-180℃.

[0017] Further, in step II, the volume of the sodium citrate is 4mL, and the mass fraction is 1%.

[0018] Further, the AuNPs in step two grow on the layered K2Ti8O 17 , wherein the diameter of the AuNPs is 20-30 nm.

[0019] Further, in step three, the silicon wafer has a size of (0.5-1) cm x (0.5-1) cm, and the volume of the drop is 20-100 μL.

[0020] Further, in step three, the volume of the AuNPs sol is 40 μL, wherein the particle size of the AuNPs is 20-30 nm.

[0021] Further, in step three, the AuNPs sol is prepared by a sodium citrate reduction method, specifically, 4 mL of 1% sodium citrate is added to 50 mL of 0.1% chloroauric acid solution that is boiling.

[0022] The beneficial technical effects of the present application are as follows:

[0023] 1. The AuNPs composite layered K2Ti8O 17 SERS substrate material prepared by the present application has a regular morphology, and the AuNPs are uniformly distributed on the layered K2Ti8O 17 , and has excellent surface-enhanced Raman scattering performance. 17 The present application first uses a simple one-step hydrothermal alkaline etching method to prepare the layered K2Ti8O 17 , and the experimental raw materials used are TiO2 and KOH, and the hydrothermal temperature is about 180℃, which, compared with the existing synthesis method such as high-temperature calcination to prepare K2Ti8O 17 , avoids a large amount of energy consumption, is simple to operate, low in cost, and easy to realize industrial production.

[0024] 2. The AuNPs composite layered K2Ti8O 17 SERS substrate material prepared by the present application is used as inorganic nanomaterials and is used for organic dye detection.

[0025] The present application first uses sodium citrate to reduce chloroauric acid to make the AuNPs grow on the layered K2Ti8O 17 , and then drops AuNPs sol on the composite substrate, which solves the problems of high cost and poor stability of the noble metal SERS substrate for detecting organic dye pollution, the detection performance of the non-metal SERS substrate being lower than that of the noble metal SERS substrate, and the problem of uneven distribution of the AuNPs on the layered K2Ti8O 17 after the AuNPs are compounded with K2Ti8O 17 . The lowest detection limit of the organic dye crystal violet is 10 -12 M, and the lowest detection limit of methylene blue is 10-10 M. The detection method is simple and easy to operate, without other experimental operations, and easy to control.

[0026] The application is suitable for preparation of AuNPs composite layered K2Ti8O 17 SERS substrate material. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is an XRD graph of AuNPs composite layered K2Ti8O 17 SERS substrate material in the example;

[0028] Figure 2 is an SEM graph of layered K2Ti8O 17 SERS substrate material in the example;

[0029] Figure 3 is a local enlarged view of Figure 2 ;

[0030] Figure 4 is a TEM graph of AuNPs composite layered K2Ti8O 17 SERS substrate material in the example;

[0031] Figure 5 is a minimum detection limit graph of AuNPs composite layered K2Ti8O 17 SERS substrate material in the example;

[0032] Figure 6 is a minimum detection limit graph of AuNPs composite layered K2Ti8O 17 SERS substrate material in the example. DETAILED DESCRIPTION

[0033] The technical scheme of the application is not limited to the following specific embodiments, and any combination of the specific embodiments is also included.

[0034] Specific embodiment one: a preparation method of gold composite layered potassium titanate SERS substrate material for organic dye detection, which is realized according to the following steps:

[0035] I. TiO2 is added into KOH aqueous solution, and after magnetic stirring, it is transferred into a reaction kettle, and reacted at 120-200℃ for 3-5 days. After the reaction is completed and the temperature is reduced to room temperature, the product is washed and dried to obtain layered K2Ti8O 17 SERS substrate material;

[0036] II. The layered K2Ti8O 17SERS substrate material and chloroauric acid solution are mixed by magnetic stirring, heating is started after stopping stirring, and then magnetic stirring is started again after complete boiling, and sodium citrate solution is added, boiling is continued for 15 min, stirring and heating are stopped, and the product is washed and dried to obtain AuNPs (gold nanoparticles) grown on the composite SERS substrate of layered K2Ti8O 17 ;

[0037] III. The composite SERS substrate of AuNPs grown on the layered K2Ti8O 17 is placed on a silicon wafer, then AuNPs sol is added dropwise and naturally dried to obtain the SERS substrate material of AuNPs composite layered K2Ti8O 17 , i.e. gold composite layered potassium titanate SERS substrate material for organic dye detection, and the preparation method is completed.

[0038] The SERS substrate material of AuNPs composite layered K2Ti8O 17 prepared in this embodiment is used as an inorganic nanomaterial for organic dye detection.

[0039] Specific embodiment two: different from specific embodiment one, the TiO2 type in step one is anatase type, the mass is 2 g, and the particle size is 60 nm. The other steps and parameters are the same as those in specific embodiment one.

[0040] Specific embodiment three: different from specific embodiment one, the volume of the KOH aqueous solution in step one is 50 mL, and the molar concentration is 1-20 M. The other steps and parameters are the same as those in specific embodiment one.

[0041] Specific embodiment four: different from specific embodiment one, the magnetic stirring in step one is at a speed of 100-1000 rpm for 20-30 min. The other steps and parameters are the same as those in specific embodiment one.

[0042] Specific embodiment five: different from specific embodiment one, the washing and drying in steps one and two are performed 2-5 times with deionized water and then at 50-80°C for 8-16 h. The other steps and parameters are the same as those in specific embodiment one.

[0043] Specific embodiment six: different from specific embodiment one, the volume of the chloroauric acid solution in step two is 50 mL, and the mass fraction is 0.1%. The other steps and parameters are the same as those in specific embodiment one.

[0044] Specific embodiment seven: different from the specific embodiment one, the rotating speed of the magnetic stirring in step two is 100-1000 rpm. Other steps and parameters are the same as the specific embodiment one.

[0045] Specific embodiment eight: different from the specific embodiment one, the heating temperature in step two is 160-180℃. Other steps and parameters are the same as the specific embodiment one.

[0046] Specific embodiment nine: different from the specific embodiment one, the volume of the sodium citrate in step two is 4 mL, and the mass fraction is 1%. Other steps and parameters are the same as the specific embodiment one.

[0047] Specific embodiment ten: different from the specific embodiment one, the AuNPs grow in the layered K2Ti8O 17 above in step two, and the diameter of the AuNPs is 20-30 nm. Other steps and parameters are the same as the specific embodiment one.

[0048] Specific embodiment eleven: different from the specific embodiment one, the silicon wafer in step three is (0.5 cm-1 cm) x (0.5 cm-1 cm), and the volume of the dropping is 20-100 μL. Other steps and parameters are the same as the specific embodiment one.

[0049] Specific embodiment twelve: different from the specific embodiment one, the volume of the AuNPs sol in step three is 40 μL, and the particle size of the AuNPs is 20-30 nm. Other steps and parameters are the same as the specific embodiment one.

[0050] Specific embodiment thirteen: different from the specific embodiment one, the AuNPs sol in step three is prepared by the sodium citrate reduction method, and specifically, 4 mL of sodium citrate with a mass fraction of 1% is added into 50 mL of chloroauric acid solution with a mass fraction of 0.1% which is boiled to prepare. Other steps and parameters are the same as the specific embodiment one.

[0051] The beneficial effects of the present application are verified by the following examples:

[0052] Example:

[0053] A preparation method of a gold composite layered potassium titanate SERS substrate material for organic dye detection, which is realized by the following steps:

[0054] I. TiO2 is added to KOH aqueous solution, and after magnetic stirring, it is transferred to a reaction kettle, and reacted at 120-200℃ for 3 days. After the reaction is completed and the temperature is lowered to room temperature, the product is washed and dried to obtain layered K2Ti8O 17 SERS substrate material;

[0055] II. The above layered K2Ti8O 17 SERS substrate material is mixed with chloroauric acid solution by magnetic stirring. After stopping stirring, heating is started. After complete boiling, magnetic stirring is started again, and sodium citrate solution is added. Boiling is continued for 15 min. After stopping stirring and heating, the temperature is lowered to room temperature. The product is washed and dried to obtain AuNPs (gold nanoparticles) grown on the layered K2Ti8O 17 composite SERS substrate;

[0056] III. The above AuNPs grown on the layered K2Ti8O 17 composite SERS substrate is placed on a silicon wafer, and then AuNPs sol is added dropwise and naturally dried to obtain AuNPs composite layered K2Ti8O 17 SERS substrate material, i.e. gold composite layered potassium titanate SERS substrate material for organic dye detection, and the preparation method is completed.

[0057] In step I, the TiO2 type is anatase, the mass is 2g, and the particle size is 60nm.

[0058] In step I, the volume of the KOH aqueous solution is 50mL, and the molar concentration is 15M.

[0059] In step I, the magnetic stirring speed is 700rpm, and the stirring time is 30min.

[0060] In steps I and II, the washing and drying are performed 5 times with deionized water, and then dried at 60℃ for 10h.

[0061] In step II, the volume of the chloroauric acid solution is 50mL, and the mass fraction is 0.1%.

[0062] In step II, the magnetic stirring speed is 700rpm.

[0063] In step II, the heating temperature is 170℃.

[0064] In step II, the volume of the sodium citrate is 4mL, and the mass fraction is 1%.

[0065] In step II, the AuNPs are grown on the layered K2Ti8O 17 , wherein the diameter of the AuNPs is 30nm.

[0066] The silicon wafer in step three: the size is (0.5cm-1cm) x (0.5cm-1cm); the volume of the drop is 20-100μL;

[0067] The volume of the AuNPs sol in step three is 40μL, wherein the particle size of the AuNPs is 30nm;

[0068] The AuNPs sol in step three: prepared by sodium citrate reduction method; specifically, 4mL of 1% sodium citrate is added to 50mL of 0.1% chloroauric acid solution under boiling to prepare.

[0069] The AuNPs composite layered K2Ti8O 17 SERS substrate material prepared in this example can be used for organic dye detection, and laser Raman spectrum test is carried out thereon, the process being as follows:

[0070] 40μL of crystal violet aqueous solution and methylene blue aqueous solution is respectively added dropwise to the gold composite layered potassium titanate SERS substrate material for organic dye detection, and then naturally air-dried, and then laser Raman spectrum test is carried out under the conditions of laser wavelength of 633nm, exposure time of 10s and laser power of 5%.

[0071] The AuNPs composite layered K2Ti8O 17 SERS substrate material prepared in this example is subjected to X-ray diffraction phase analysis (XRD), and the characterization test result is shown in Figure 1 The XRD spectrum shows the characteristic peaks of K2Ti8O 17 and Au, corresponding to the K2Ti8O 17 phase of PDF#84-2057 and the Au phase of PDF#04-0784, which proves that the AuNPs composite layered K2Ti8O 17 composite SERS substrate contains gold and potassium titanate phases.

[0072] The AuNPs composite layered K2Ti8O 17 SERS substrate material prepared in this example is subjected to scanning (SEM) and transmission (TEM) electron microscope characterization. The results show that the layered K2Ti8O 17 is formed by a large number of fine nanowires intertwined to form a layered structure (see Figure 2 and Figure 3 , Figure 3 for Figure 2 local enlargement), the diameter of a single wire is 10-30nm, and the surface is free of impurities, and then 30nm AuNPs are uniformly distributed on the layered K2Ti8O 17 (see Figure 4 ).

[0073] The AuNPs composite layered K2Ti8O 17 SERS substrate material prepared in this example has a SERS lowest detection limit (LOD) for crystal violet as shown in Figure 5 a SERS LOD for methylene blue as shown in Figure 6 From the above, it can be seen that the AuNPs composite layered K2Ti8O 17 composite SERS substrate has a LOD for crystal violet of 10 -12 M and a LOD for methylene blue of 10 - 10 M.

[0074] The above-described embodiments are merely preferred modes of the present application and are not intended to limit the scope of the present application, and various modifications and improvements to the technical solutions of the present application made by those of ordinary skill in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1. A method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection, characterized in that... It is implemented in the following steps:

1. Add TiO2 to a KOH aqueous solution, stir magnetically, and then transfer to a reaction vessel. React at 120℃~200℃ for 3 to 5 days. After the reaction is complete, cool to room temperature, wash and dry the product to obtain layered K2Ti8O. 17 SERS substrate material; II. The above-mentioned layered K2Ti8O 17 The SERS substrate material was mixed with chloroauric acid solution using magnetic stirring. After stirring was stopped, heating was started until it reached a complete boil. Then, magnetic stirring was restarted, and sodium citrate solution was added. Boiling was continued for 15 minutes. Stirring and heating were stopped, and the mixture was cooled to room temperature. The product was washed and dried to obtain AuNPs grown on layered K2Ti8O. 17 Composite SERS substrate on; III. The above AuNPs were grown on layered K2Ti8O 17 The composite SERS substrate was placed on a silicon wafer, and then AuNPs sol was dropped on and allowed to air dry to obtain AuNPs composite layered K2Ti8O. 17 The SERS substrate material, namely the gold composite layered potassium titanate SERS substrate material used for organic dye detection, is prepared by the above method.

2. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The TiO2 mentioned in step one is anatase type, with a mass of 2g and a particle size of 60nm.

3. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The volume of the KOH aqueous solution in step one is 50 mL, and the molar concentration is 1–20 M.

4. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The magnetic stirring described in step one is performed at a speed of 100–1000 rpm for a duration of 20–30 min.

5. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The volume of the chloroauric acid solution in step two is 50 mL, and the mass fraction is 0.1%.

6. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The volume of sodium citrate mentioned in step two is 4 mL, and the mass fraction is 1%.

7. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The AuNPs described in step two are grown on layered K2Ti8O 17 The diameter of AuNPs is 20–30 nm.

8. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The silicon wafer mentioned in step three has a size of (0.5cm~1cm)×(0.5cm~1cm); the volume of the drop is 20~100μL.

9. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The volume of the AuNPs sol in step three is 40 μL, wherein the particle size of the AuNPs is 20–30 nm.

10. The method for preparing a gold composite layered potassium titanate SERS substrate material for organic dye detection according to claim 1, characterized in that... The AuNPs sol mentioned in step three is prepared by sodium citrate reduction method; specifically, 4 mL of sodium citrate with a mass fraction of 1% is added to 50 mL of boiling chloroauric acid solution with a mass fraction of 0.1%.

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