Gold nanoparticle self-assembled two-dimensional film with fano resonance characteristics and application thereof
The self-assembled two-dimensional thin films of gold nanoparticles prepared by mercapto-terminated polystyrene ligand exchange and interfacial self-assembly method have solved the problems of low photocatalytic efficiency and difficult catalyst recovery, and achieved highly efficient and stable photocatalytic performance and easy-to-recover catalyst.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SICHUAN UNIV
- Filing Date
- 2026-05-08
- Publication Date
- 2026-06-05
AI Technical Summary
Gold nanoparticles exhibit low photocatalytic efficiency in the photocatalytic conversion of organic pollutants, and the catalyst is difficult to recover and reuse.
Two-dimensional thin films with Fano resonance properties were prepared by thiol-terminated polystyrene ligand exchange and interfacial self-assembly. Stable Au-S bonds were formed between thiol groups and gold nanoparticles, and the polystyrene groups provided hydrophobicity, thus forming a stable two-dimensional nanofilm.
It improves photocatalytic efficiency, enhances the stability of photocatalysts, and makes the catalyst easier to recycle.
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Figure CN122141759A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of photocatalytic nanomaterials technology, and in particular to a two-dimensional thin film of gold nanoparticles with Fano resonance characteristics and its applications. Background Technology
[0002] Photocatalysis is a typical pathway for realizing solar energy utilization, effectively converting solar energy into chemical energy, and is of great significance for promoting the transformation of industrial chemistry. Among many photocatalytic nanomaterials, noble metal nanoparticles have attracted much attention due to their unique localized surface plasmon resonance characteristics. Noble metal nanoparticles can convert photon energy in the ultraviolet, visible, and near-infrared light regions, and have great potential in the field of efficient solar energy utilization.
[0003] Gold nanoparticles (AuNPs) can generate strong electromagnetic fields under visible light irradiation, thereby enhancing light absorption and photocatalytic activity, making them one of the commonly used photocatalysts. While gold nanoparticles exhibit unique advantages in the photocatalytic degradation of organic pollutants, several key challenges remain in practical applications. First, although the LSPR effect of AuNPs enhances visible light absorption, the rapid recombination of photogenerated electron-hole pairs remains a bottleneck for efficiency. Effective charge separation is required for photocatalytic reactions to generate reactive oxygen species (ROS), but AuNPs, as plasma materials, have limited carrier lifetimes. Studies also show that photocatalytic efficiency is limited by low quantum efficiency and restricted visible light activity, which is particularly evident in large-scale applications. Therefore, the photocatalytic efficiency of AuNPs still needs further improvement. Second, nanoscale AuNPs are dispersed and suspended in the reaction system, making effective recovery through simple filtration or sedimentation difficult, thus posing challenges for catalyst recovery and reuse. Summary of the Invention
[0004] To address the problems of low photocatalytic efficiency and difficulty in catalyst recycling and reuse in the current photocatalytic conversion of organic pollutants using gold nanoparticles, this invention provides a self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics.
[0005] The self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics provided by this invention is prepared by the following method: Step 1: Add tetrachloroauric acid and quaternary ammonium salt to sodium borohydride solution and stir at 30-40℃ for 2-4 hours to obtain solution A; add solution A to solution B containing ammonium salt, tetrachloroauric acid and ascorbic acid, stir and react at 30-40℃ for 10-15 hours, centrifuge to obtain gold nanoparticles with a particle size of 40-90 nm, and disperse them in deionized water to form a gold nanoparticle dispersion.
[0006] The quaternary ammonium salt is hexadecyltrimethylammonium chloride or hexadecyltrimethylammonium bromide.
[0007] Step 2: After centrifuging the gold nanoparticle dispersion, add it to a tetrahydrofuran solution of mercapto-terminated polystyrene and let it stand for 6-8 hours. Then, centrifuge to remove the supernatant, disperse the bottom precipitate in chloroform, and then drop the dispersion onto the surface of deionized water. The two-dimensional film is formed on the surface of deionized water by self-assembly.
[0008] The mercapto-terminated polystyrene has a molecular weight of 10,000-50,000 g / mol. Two-dimensional thin films with nano-intervals varying in the range of 10-15 nm were prepared by changing the molecular weight of the mercapto-terminated polystyrene.
[0009] In the tetrahydrofuran solution, the concentration of mercapto-terminated polystyrene is preferably 2-3 mg / mL.
[0010] The two-dimensional thin film prepared by the above method has Fano resonance optical properties in the visible light region.
[0011] This invention also provides applications for the aforementioned self-assembled two-dimensional thin films of gold nanoparticles exhibiting Fano resonance properties. They are primarily used as photocatalysts, particularly in the photocatalytic conversion of organic pollutants.
[0012] The application method is as follows: First, the two-dimensional film is subjected to plasma cleaning treatment. The surface of the two-dimensional film is bombarded with plasma to remove the polystyrene ligands and expose the surface of the gold nanoparticles. Then, the two-dimensional film is added to an organic pollutant solution and photocatalytic reaction is carried out by irradiation with a xenon lamp.
[0013] Compared with the prior art, the advantages of the present invention are: (1) This invention employs a two-step method of thiol-terminated polystyrene ligand exchange and interfacial self-assembly to assemble two-dimensional thin films of gold nanoparticles, forming a gold nanoparticle self-assembled two-dimensional thin film exhibiting Fano resonance optical properties in the visible light region. In the thiol-terminated polystyrene used, the thiol groups form stable Au-S bonds with the gold nanoparticles, stabilizing the gold nanoparticles, while the polystyrene groups provide hydrophobicity, ensuring that the nanoparticles stably form a single-particle-thickness two-dimensional nanofilm at the water-air interface.
[0014] (2) By precisely designing the structural parameters such as the size and spacing of gold nanoparticles, the present invention can effectively control the spectrum of Fano resonance, forming a controllable two-dimensional thin film of gold nanoparticles with Fano resonance characteristics. (3) The self-assembled two-dimensional thin film with Fano resonance optical properties of the present invention has strong stability and high photocatalytic efficiency in the photocatalytic conversion reaction of organic pollutants in water system, and the catalyst is easy to recover and recycle.
[0015] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description
[0016] Figure 1 This is a scanning electron microscope image of the gold nanoparticles prepared in step (1) of Example 1.
[0017] Figure 2 This is a scanning electron microscope image of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2) of Example 1.
[0018] Figure 3 The image shows the extinction spectrum of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2) of Example 1.
[0019] Figure 4 This is a scanning electron microscope image of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2) of Comparative Example 1.
[0020] Figure 5 This is the extinction spectrum of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2) of Comparative Example 1.
[0021] Figure 6 This is a scanning electron microscope image of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2) of Example 2.
[0022] Figure 7 This is the extinction spectrum of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2) of Example 2.
[0023] Figure 8 This is a scanning electron microscope image of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2) of Comparative Example 2.
[0024] Figure 9 This is the extinction spectrum of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2) of Comparative Example 2. Detailed Implementation
[0025] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0026] Example 1 A two-dimensional thin film of gold nanoparticles with Fano resonance properties was prepared by the following steps: (1) 0.25 mL of 10 mM tetrachloroauric acid solution and 9.75 mL of 0.1 M hexadecyltrimethylammonium bromide solution were added to 0.60 mL of 10 mM sodium borohydride solution and stirred at 35 °C for 3 h to obtain solution A; solution A was added to solution B, which was prepared by 9.75 mL of 0.1 M hexadecyltrimethylammonium bromide solution, 4 mL of 10 mM tetrachloroauric acid solution and 15 mL of 0.1 M ascorbic acid solution and stirred at 35 °C for 12 h; gold nanoparticles with a particle size of 53 nm were obtained by centrifugation and dispersed in 10 mL of deionized water to obtain a gold nanoparticle dispersion.
[0027] (2) After centrifuging the gold nanoparticle dispersion, add 10 mg of 20000 g mol / L gold nanoparticle solution. 1 A solution of mercapto-terminated polystyrene and 5 mL of tetrahydrofuran was prepared and allowed to stand for 8 hours. After centrifugation, the supernatant was removed, and the bottom precipitate was dispersed in 10 μL of chloroform to form a dispersion. 20 μL of deionized water was added to an ITO glass, and then 1 μL of the dispersion was added to the surface of the deionized water. A two-dimensional film was formed by self-assembly on the surface of the deionized water. After the deionized water evaporated, a two-dimensional film was obtained deposited on the ITO glass.
[0028] Figure 1 This is a scanning electron microscope image of the gold nanoparticles prepared in step (1). It can be seen that the gold nanoparticles obtained in step (1) are spherical with an average diameter of 53 nm.
[0029] Figure 2 This is a scanning electron microscope image of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2). The image shows that the average nanometer gap of the self-assembled two-dimensional thin film is 10 nm.
[0030] Figure 3 The image shows the extinction spectrum of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2). It can be seen that the extinction spectrum curve shows two obvious peaks and one valley in the range of 550nm-800nm, indicating that it has Fano resonance characteristics.
[0031] Comparative Example 1 A self-assembled two-dimensional thin film of gold nanoparticles is prepared by the following steps: (1) Add 0.25 mL of 10 mM tetrachloroauric acid solution and 9.75 mL of 0.1 M hexadecyltrimethylammonium bromide solution to 0.60 mL of 10 mM sodium borohydride solution and stir at 35 °C for 3 h to obtain solution A; centrifuge solution A to obtain gold nanoparticles with a particle size of 30 nm, disperse them in 10 mL of deionized water to obtain gold nanoparticle dispersion.
[0032] (2) After centrifuging the gold nanoparticle dispersion, add 10 mg of 20000 g mol / L gold nanoparticle solution. 1 A solution of mercapto-terminated polystyrene and 5 mL of tetrahydrofuran was prepared and allowed to stand for 8 hours. After centrifugation, the supernatant was removed, and the bottom precipitate was dispersed in 10 μL of chloroform to form a dispersion. 20 μL of deionized water was added to an ITO glass, and then 1 μL of the dispersion was added to the surface of the deionized water. A two-dimensional film was formed by self-assembly on the surface of the deionized water. After the deionized water evaporated, a two-dimensional film was obtained deposited on the ITO glass.
[0033] Figure 4 This is a scanning electron microscope image of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2). The image shows that the average nanometer gap of the self-assembled two-dimensional thin film is 5 nm.
[0034] Figure 5 The image shows the extinction spectrum of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2). It can be seen that the extinction spectrum curve exhibits a distinct characteristic peak in the range of 550 nm to 800 nm, indicating that it does not possess Fano resonance characteristics. This demonstrates that when the particle size of the gold nanoparticles is small (less than 40 nm), it is impossible to prepare a two-dimensional thin film with Fano resonance characteristics.
[0035] Example 2 A two-dimensional thin film of gold nanoparticles with Fano resonance properties was prepared by the following steps: (1) Following the same method as step (1) of Example 1, a gold nanoparticle dispersion was obtained.
[0036] (2) After centrifuging the gold nanoparticle dispersion, add 10 mg of 50,000 g mol / L gold nanoparticle solution. 1 A solution of mercapto-terminated polystyrene and 5 mL of tetrahydrofuran was prepared and allowed to stand for 8 hours. After centrifugation, the supernatant was removed, and the bottom precipitate was dispersed in 10 μL of chloroform to form a dispersion. 20 μL of deionized water was added to an ITO glass, and then 1 μL of the dispersion was added to the surface of the deionized water. A two-dimensional film was formed by self-assembly on the surface of the deionized water. After the deionized water evaporated, a two-dimensional film was obtained deposited on the ITO glass.
[0037] Figure 6 This is a scanning electron microscope image of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2). The image shows that the average nanometer gap of the self-assembled two-dimensional thin film is 14 nm.
[0038] Figure 7The image shows the extinction spectrum of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2). It can be seen that the extinction spectrum curve exhibits a valley, a distinct peak, and a shoulder peak in the 550nm-800nm range, indicating that it possesses Fano resonance characteristics, but these characteristics are weaker than those of the two-dimensional thin film in Example 1. This demonstrates that by changing the molecular weight of mercapto-terminated polystyrene, the nano-gap in the two-dimensional thin film can be controlled, thereby effectively regulating the Fano resonance spectrum and obtaining a tunable self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics.
[0039] Comparative Example 2 A self-assembled two-dimensional thin film of gold nanoparticles is prepared by the following steps: (1) Following the same method as step (1) of Comparative Example 1, a gold nanoparticle dispersion was obtained.
[0040] (2) After centrifuging the gold nanoparticle dispersion, add 10 mg of 50,000 g mol / L gold nanoparticle solution. 1 A solution of mercapto-terminated polystyrene and 5 mL of tetrahydrofuran was prepared and allowed to stand for 8 hours. After centrifugation, the supernatant was removed, and the bottom precipitate was dispersed in 10 μL of chloroform to form a dispersion. 20 μL of deionized water was added to an ITO glass, and then 1 μL of the dispersion was added to the surface of the deionized water. A two-dimensional film was formed by self-assembly on the surface of the deionized water. After the deionized water evaporated, a two-dimensional film was obtained deposited on the ITO glass.
[0041] Figure 8 This is a scanning electron microscope image of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2). The image shows that the average nanometer gap of the self-assembled two-dimensional thin film is 9 nm.
[0042] Figure 9 The image shows the extinction spectrum of the self-assembled two-dimensional thin film of gold nanoparticles obtained in step (2). It can be seen that the extinction spectrum curve shows a distinct peak in the 550nm-800nm range, indicating that it does not possess Fano resonance characteristics. This further demonstrates that when the particle size of the gold nanoparticles is small (less than 40nm), it is impossible to prepare a two-dimensional thin film with Fano resonance characteristics.
[0043] Application examples The two-dimensional films obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were used for the photocatalytic conversion of 4-nitrophenol. The specific experimental method was as follows: ITO glass slides with deposited two-dimensional films prepared in the examples or comparative examples were subjected to plasma cleaning for 1 min. The surface of the two-dimensional nanofilm was bombarded with plasma to remove the polystyrene ligands and expose the gold particle surface. Then, the ITO glass slides with the two-dimensional films were placed in a solution prepared by adding 60 μL of 5 mM 4-nitrophenol solution and 3 mL of 50 mM sodium borohydride aqueous solution. The solution was irradiated with a 300 W xenon lamp for 50 min, with the lamp 15 cm away from the sample. The UV-Vis absorption spectrum of the reaction solution was measured every 10 min, and the average photocatalytic conversion rate of 4-nitrophenol within 50 min was calculated. The results are shown in Table 1.
[0044] Table 1. Photocatalytic conversion effect of two-dimensional thin films prepared in the examples and comparative examples on 4-nitrophenol.
[0045] As shown in Table 1, the two-dimensional films prepared in Examples 1 and 2 both exhibit excellent 4-nitrophenol conversion performance, with the conversion product being 4-aminophenol. Although Comparative Examples 1 and 2 incorporated the same amount and molecular weight of mercapto-terminated polystyrene as Examples 1 and 2 during preparation, the small size of the gold nanoparticles prevented the formation of self-assembled two-dimensional films with Fano resonance characteristics, thus affecting the photocatalytic conversion performance of 4-nitrophenol.
[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A two-dimensional thin film of gold nanoparticles with Fano resonance characteristics, characterized in that, Made by the following method: Step 1: Add tetrachloroauric acid and quaternary ammonium salt to sodium borohydride solution and stir at 30-40℃ for 2-4 hours to obtain solution A; add solution A to solution B containing ammonium salt, tetrachloroauric acid and ascorbic acid, stir and react at 30-40℃ for 10-15 hours, centrifuge to obtain gold nanoparticles with a particle size of 40-90 nm, and disperse them in deionized water to form a gold nanoparticle dispersion. Step 2: After centrifuging the gold nanoparticle dispersion, add it to a tetrahydrofuran solution of mercapto-terminated polystyrene and let it stand for 6-8 hours. Then, centrifuge to remove the supernatant, disperse the bottom precipitate in chloroform, and then drop the dispersion onto the surface of deionized water. The two-dimensional film is formed by self-assembly on the surface of deionized water. The molecular weight of the mercapto-terminated polystyrene is 10,000-50,000 g / mol.
2. The self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics as described in claim 1, characterized in that, In step 2, a two-dimensional thin film with nano-gap varying in the range of 10-15 nm was prepared by changing the molecular weight of mercapto-terminated polystyrene.
3. The self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics as described in claim 1, characterized in that, In the tetrahydrofuran solution, the concentration of mercapto-terminated polystyrene is 2-3 mg / mL.
4. The self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics as described in claim 1, characterized in that, The quaternary ammonium salt is hexadecyltrimethylammonium chloride or hexadecyltrimethylammonium bromide.
5. The self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics as described in claim 1, characterized in that, It exhibits Fano resonance optical properties in the visible light region.
6. An application of a self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics as described in any one of claims 1-5, characterized in that, Used as a photocatalyst.
7. The application of the self-assembled two-dimensional thin film of gold nanoparticles with Fano resonance characteristics as described in claim 6, characterized in that, Used as a catalyst for the photocatalytic conversion of organic pollutants.
8. The application of the gold nanoparticle self-assembled two-dimensional thin film with Fano resonance characteristics as described in claim 7, characterized in that, First, the two-dimensional thin film is subjected to plasma cleaning treatment. The surface of the two-dimensional thin film is bombarded with plasma to remove the polystyrene ligands and expose the surface of the gold nanoparticles. Then, the two-dimensional thin film is added to an organic pollutant solution and photocatalytic reaction is carried out by irradiation with a xenon lamp.