CN-121978076-A - Preparation method of SERS substrate based on gold-silver polyhedral alloy nano-frame

CN121978076ACN 121978076 ACN121978076 ACN 121978076ACN-121978076-A

Abstract

The application provides a preparation method of a gold-silver polyhedron alloy nano-frame SERS substrate, which comprises the steps of preparing gold polyhedrons with different sizes through a three-step seed growth method, sequentially adding chloroplatinic acid and chloroauric acid to react to form a hollowed platinum frame, further adding chloroplatinic acid, silver nitrate and ascorbic acid to prepare a hollowed gold@platinum polyhedron nano-material, treating with sodium iodide and chloroplatinic acid to obtain a platinum@gold@platinum alloyed nano-material, removing internal gold by using chloroauric acid to form a new platinum frame, selectively depositing gold or silver on the surface of the platinum@gold alloyed nano-material to obtain the platinum@gold or platinum@silver alloyed nano-material, mixing the platinum@gold alloyed nano-material and the platinum@silver alloyed nano-material in equal proportion, and preparing the gold-silver alloyed nano-frame material and applying the gold alloyed nano-frame material to detection of nitrophenol. The alloy nano-frame can obviously improve the sensitivity and stability of p-nitrophenol detection, and has good application prospect.

Inventors

ZHAO MIN
Yan Xuanhua
Gu Qingchen
WANG JUNYANG
MENG LINGYUE

Assignees

南通大学

Dates

Publication Date: 20260505
Application Date: 20260206

Claims (7)

1. The preparation method of the SERS substrate based on the gold-silver polyhedral alloy nano-frame is characterized by comprising the following steps of: s1, preparing gold polyhedrons with different sizes by a three-step seed growth method; s2, sequentially adding chloroplatinic acid and chloroauric acid into the Jin Duomian body to react to form a hollowed-out platinum frame; s3, adding chloroplatinic acid, silver nitrate and ascorbic acid into the hollowed-out platinum frame to prepare a hollowed-out gold@platinum polyhedral nano material; s4, based on the hollowed-out gold@platinum polyhedral nano material, treating by sodium iodide and chloroplatinic acid to obtain a platinum@gold@platinum alloying nano material; s5, selectively depositing gold/silver on the surface of the new platinum frame to obtain a platinum@gold alloyed nanomaterial and a platinum@silver alloyed nanomaterial; s6, mixing the platinum@gold alloyed nano material with the platinum@silver alloyed nano material in equal proportion to prepare the gold-silver alloyed nano frame material.
2. The method according to claim 1, characterized in that the method of step S1 comprises: s11, reducing chloroauric acid solution by using a mixture of sodium borohydride and cetyl trimethyl ammonium bromide prepared by ice fresh to obtain gold nanocube seeds, and then incubating for 4 hours in a 40 ℃ oven to prepare brown seed solution; S12, stirring the brown seed solution at the temperature of 30 ℃ for 2 to 5 hours, decomposing excessive sodium borohydride, and diluting the seed solution by ultrapure water for 1/100 to obtain diluted seed solution; S13, adding the diluted seed solution into a mixed solution of hexadecyl trimethyl ammonium bromide, chloroauric acid solution and ascorbic acid, wherein the brown seed solution is required to be added into a first mixed solution immediately after the ascorbic acid is added, and keeping the first mixed solution at 30 ℃ without disturbance overnight; s14, adding the gold polyhedron after the first growth into a second mixed solution of hexadecyl trimethyl ammonium bromide, chloroauric acid solution and ascorbic acid, and keeping the second mixed solution at 30 ℃ without disturbance overnight to obtain the gold polyhedron after the second growth; S15, adding the gold polyhedron after the second growth into a third mixed solution of hexadecyl trimethyl ammonium bromide, chloroauric acid solution and ascorbic acid, keeping the third mixed solution at 30 ℃ without disturbance overnight to obtain the gold polyhedron after the third growth, and then repeating the steps of centrifugation twice with 8000 revolutions per minute 10min, and re-diluting the solution to 15mL to obtain the Jin Duomian.
3. The method according to claim 2, characterized in that the method of step S2 comprises: s21, adding the Jin Duomian body solution into a mixed solution containing cetyltrimethylammonium bromide, sodium iodide, silver nitrate and ascorbic acid, and incubating for 1h in an oven; S22, adding a small amount of hydrochloric acid and chloroplatinic acid into the solution, and then incubating for 4 hours in an oven, wherein electrochemical reaction is promoted, platinum is caused to preferentially grow along the edge direction of the gold polyhedron, and reactants are removed by centrifugal washing with ultrapure water twice; S23, diluting the centrifuged solution to 15mL, mixing the diluted solution with the solution containing cetyltrimethylammonium bromide and chloroauric acid in the same volume, and keeping the temperature at 50 ℃ for 1h to etch gold in the gold@platinum alloy nanomaterial; s24, centrifugally washing the reaction product with ultrapure water twice after the reaction is finished, removing reactants, and diluting the solution to about 15mL to obtain the hollowed-out platinum frame.
4. A method according to claim 3, characterized in that the method of step S3 comprises: S31, mixing the hollowed-out platinum frame with cetyltrimethylammonium chloride, chloroauric acid, silver nitrate and ascorbic acid, and incubating for 30min in a 50 ℃ oven; s32, centrifugally washing with ultrapure water for 10min twice by 8000 rpm after incubation is completed, and obtaining the gold@platinum polyhedral nano material.
5. The method of claim 4, wherein the method of step S4 comprises: S41, adding cetyl trimethyl ammonium bromide, sodium iodide, silver nitrate and ascorbic acid into the gold@platinum nanomaterial solution, and incubating for 1h in a 70 ℃ oven; S42, adding hydrochloric acid and chloroplatinic acid after incubation is finished, maintaining for 3 hours at 70 ℃, then centrifugally washing twice, and diluting to 5mL by using ultrapure water; S43, adding hexadecyl trimethyl ammonium bromide and chloroauric acid into the diluted solution, incubating for 1h at 50 ℃, and centrifugally washing twice by using ultrapure water to obtain the novel platinum nano frame material.
6. The method of claim 5, wherein the method of step S5 comprises: s51, adding hexadecyl trimethyl ammonium chloride, silver nitrate, sodium hydroxide and ascorbic acid into the novel platinum nano frame material, and incubating for 30 minutes at the temperature of 30 ℃, wherein the volume of the silver nitrate is used for controlling the thickness of the edges and gaps of the silver nano frame material; S52, after silver is deposited on the platinum frame, centrifuging twice at 10000 rpm rotational speed, and diluting to 5mL by using ultrapure water to obtain a silver nano frame material; s53, adding hexadecyl trimethyl ammonium chloride, chloroauric acid, silver nitrate and ascorbic acid into the platinum nano frame material, and incubating for 30min at 30 ℃; S54, after gold is deposited on the platinum frame, centrifuging the gold twice at 10000rpm ℃ and diluting the gold to 5mL by using ultrapure water to obtain gold@platinum nano frame materials and silver@platinum nano frame colloid.
7. The method of claim 6, wherein the method of step S6 comprises: s61, sequentially mixing the gold@platinum nano frame material and the platinum@platinum nano frame colloid according to the proportion of 1:1,1:2 and 1:3, and washing with ultrapure water for 10min twice by using 9000 rpm; S62, placing a silicon wafer which is cleaned and subjected to hydrophilic treatment at the bottom of a funnel, closing a valve of the funnel, and pouring the prepared colloidal gold/silver@platinum nano frame material and n-hexane into the funnel in sequence according to the ratio of 1:1, so that a clear two-phase interface can be seen; s63, slowly dripping ethanol into the funnel, gradually capturing gold/silver@platinum nanoparticles to an interface along with the reduction of a barrier of a two-phase interface, and starting to form a nanoparticle film with random size; s64, opening the valve to enable the liquid level to slowly descend until scattered nano particle films are close to each other and form a layer of compact interface film, and closing the valve; s65, after the n-hexane is completely volatilized, fishing out the silicon wafer from the lower part of the funnel film interface by using a cleaned tweezers, and forming a gold/silver@platinum nano-frame monolayer film on the surface of the silicon wafer; S66, immersing the silicon wafer in ethanol for 3min to remove organic matters on the surface, drying at room temperature, sequentially dripping nitrophenol onto the silicon wafer according to different concentrations, and measuring by using a Raman spectrometer to obtain the gold-silver polyhedral alloy nano-frame SERS substrate.

Description

Preparation method of SERS substrate based on gold-silver polyhedral alloy nano-frame Technical Field The application belongs to the technical field of SERS substrate preparation, and particularly relates to a preparation method of a SERS substrate based on a gold-silver polyhedral alloy nano-frame. Background Nitrophenol is a high-toxicity organic pollutant widely existing in industrial wastewater and environmental water, has carcinogenic, teratogenic and mutagenic properties, and forms a serious threat to ecological environment and human health. Therefore, the high-sensitivity and rapid detection of nitrophenol in the water body is realized, and the method is an important research direction in the field of environmental monitoring. The existing detection method of nitrophenol compounds in water mainly comprises liquid chromatography, gas chromatography and mass spectrometry. Although the method has certain detection precision (the detection limit is about 0.8-8 nM), the method has the defects of long detection time, complex sample pretreatment and the like, and the actual requirements of real-time monitoring and on-site rapid detection are difficult to meet. The Raman spectrum technology is used as a nondestructive and high-sensitivity molecular spectrum analysis technology, and has remarkable advantages in substance structure identification and trace detection. The SERS technology can enhance the molecular Raman signal by several orders of magnitude by means of the local plasmon resonance effect of the noble metal surface, and trace detection of single-molecule level is realized. However, when the traditional single-component noble metal nano material (such as gold and silver nano particles) is used as a SERS substrate, the SERS enhancement effect of the gold nano material is limited, the detection limit is high, for example, the AuNPs@polyimide SERS heating chip prepared in Chinese patent CN202310006741.X has the detection limit of about 10-7M on 4-ATP, and the reliable detection of single molecules is difficult to realize. Patent CN202510159888.1 discloses a method for rapidly detecting BaP in edible oil by using a CTAB modified silver nano material based on LLE-SERS, wherein the material has high sensitivity but poor chemical stability, so that the detection performance is seriously attenuated along with the preservation time. Therefore, development of an alloyed nanomaterial with both high sensitivity and high stability is a key direction for research of SERS substrates. Noble metal nano-hollow frameworks generally refer to a class of hollow, framework-like nanostructures made from noble metals (e.g., gold Au, silver Ag, platinum Pt, etc.). The material has stronger localized plasmon effect, more excellent electromagnetic field localization effect, more efficient molecular capturing capability and higher research and application values in the fields of SERS, catalysis, sensing, biomedicine and the like. In the prior art, some of the alloy SERS substrates have been developed by researchers, and some alloy SERS substrates are developed, for example, china patent CN120268997A discloses a AuAgPt ternary alloy nano-frame, a preparation method thereof and application thereof in anti-tumor preparations, the method synthesizes the AuAgPt ternary alloy nano-frame through a four-step method and is used for researching anti-tumor effects, but the technology does not relate to a regulation method of substrate size and SERS performance, and is not applied to detection of organic pollutants. Disclosure of Invention The application provides a preparation method of a SERS substrate based on a gold-silver polyhedral alloy nano-frame, which aims to solve the technical problems. In order to solve the technical problems, the application adopts a technical scheme that the preparation method of the SERS substrate based on the gold-silver polyhedral alloy nano-frame comprises the following steps: s1, preparing gold polyhedrons with different sizes by a three-step seed growth method; S2, sequentially adding chloroplatinic acid and chloroauric acid into the gold polyhedron to react to form a hollowed-out platinum frame; S3, adding chloroplatinic acid, silver nitrate and ascorbic acid into the hollowed platinum frame to prepare a hollowed gold@platinum polyhedral nano material; S4, based on the hollowed-out gold@platinum polyhedral nano material, treating by sodium iodide and chloroplatinic acid to obtain a platinum@gold@platinum alloy nano material, and removing internal gold by using chloroauric acid to form a new platinum frame; S5, selectively depositing gold/silver on the surface of the new platinum frame to obtain a platinum@gold alloyed nanomaterial and a platinum@silver alloyed nanomaterial; s6, mixing the platinum@gold alloyed nano material with the platinum@silver alloyed nano material in equal proportion to prepare the gold-silver alloyed nano frame material. Further, the method of step S1 includes: s11, reducing c