WO2023024312A1

WO2023024312A1 - Galvanic replacement reaction-based sers enhanced substrate preparation method

Info

Publication number: WO2023024312A1
Application number: PCT/CN2021/135064
Authority: WO
Inventors: 柳鹏
Original assignee: 东莞理工学院
Priority date: 2021-08-24
Filing date: 2021-12-02
Publication date: 2023-03-02
Also published as: CN113720779A; CN113720779B

Abstract

A galvanic replacement reaction-based SERS enhanced substrate preparation method, wherein a metal salt, which has a good enhancement effect with respect to Raman spectroscopy, and a sacrificial template are used to perform a galvanic replacement reaction, and molecules to be researched or probe molecules are simultaneously added to the reaction solution. During the galvanic replacement reaction, a SERS signal of the system is detected in real time, so that a relational graph of the SERS signal and the galvanic replacement reaction time is obtained. According to the relational graph, an optimal experimental condition of a SERS substrate in an experimental program can be known.

Description

A preparation method of SERS-enhanced substrate based on electrodisplacement reaction

Cross-references to related applications.

This application claims the priority of the Chinese patent application submitted to the China Patent Office on August 24, 2021, with the application number "202110974441.1", and the title of the invention "A method for preparing a SERS-enhanced substrate based on an electrodisplacement reaction", all of which The contents are incorporated by reference in this application.

technical field

The invention relates to the technical field of surface-enhanced Raman spectroscopy, in particular to a method for preparing a SERS-enhanced substrate based on an electrical displacement reaction.

Background technique

Surface-enhanced Raman scattering (hereinafter referred to as "SERS") has the advantages of high sensitivity, fast detection speed, and non-destructive testing of samples. The preparation of SERS-enhanced substrate is the key to this technology, and the quality of the enhanced substrate directly affects important performance indicators such as detection sensitivity and reproducibility. The SERS signal is related to factors such as the material of the reinforcing substrate, the size of the reinforcing elements (such as particles) on the surface of the substrate, and the spacing between the reinforcing elements.

technical problem

The optimization of the preparation conditions in the SERS preparation methods reported in the literature has certain shortcomings, that is, when the material is fixed, the size of the reinforcing element is often optimized first, and then the spacing between the reinforcing elements is optimized, or both are optimized at the same time. . Regardless of the optimization method, on the one hand, the optimized parameters are relatively small, which may not be close to the "best state" under the current experimental conditions; on the other hand, this optimization method is time-consuming and laborious, and also increases costs.

technical solution

According to various embodiments of the present application, a method for preparing a SERS-enhanced substrate based on an electrodisplacement reaction is provided, and an optimal SERS substrate can be obtained with simple steps under low-cost and high-efficiency experimental conditions.

A method for preparing a SERS-enhanced substrate based on an electrodisplacement reaction, comprising the following steps.

a. Preparing a metal sacrificial template or a metal oxide sacrificial template.

b. Carrying out an electrodisplacement reaction between the sacrificial template in step a and a metal salt solution having a better SERS enhancement effect; at the same time, adding molecules to be studied or probe molecules into the reaction solution. During the electrodisplacement reaction process, the SERS signal of the system was detected in real time, so as to obtain the relationship diagram between the SERS signal and the electrodisplacement reaction time. According to this relationship diagram, the optimal preparation conditions of the SERS substrate in this experimental scheme can be known.

In one embodiment, in the step a, the selection condition of the sacrificial template is: the selected sacrificial template material can be replaced by the metal salt in step b.

In one of the embodiments, in the step b, the method of drawing the relationship graph between the SERS signal and the electrical displacement reaction time is as follows.

(1) Screening of SERS signal peaks: Select peaks with strong signals in a single SERS spectrum throughout the electrodisplacement reaction process.

(2) Measure the peak intensity of SERS signal: read the peak height or peak area of the peak selected in step (1) in each spectrum.

(3) Draw a graph of the relationship between the SERS signal and the electrical displacement reaction time: take the peak height or peak area measured in step (2) as the ordinate, and use the electrical displacement reaction time as the abscissa to plot the graph, that is, the SERS signal and the electrical displacement reaction time are obtained. Graph of reaction time.

(4) According to the results obtained in step (3), the design of the corresponding material SERS substrate can be guided. That is, according to the size and spacing of the metal nanoparticles with strong SERS enhancement effect obtained under the optimal reaction conditions, as well as the ratio of the nanoparticles to the sacrificial template material, the influence of these parameters on the SERS signal is speculated, so as to provide a basis for the design of the corresponding SERS substrate. Provide an experimental basis.

In one embodiment, cuprous oxide is used as a sacrificial template, and gold is used as a metal with better SERS enhancement effect, and the preparation method of the SERS enhancement substrate includes the following steps.

(1) Cu ₂ O/Ti with Cu ₂ O cubic particles with a diameter of 400-500 nm electrodeposited on the surface was used as a sacrificial template. A 1 mmol/L crystal violet solution was used as the mother solution of probe molecules. 1 mmol/L HAuCl ₄ solution was used as the noble metal replacement solution.

(2) Install the Cu ₂ O/Ti sacrificial template in a sealed in-situ Raman spectroelectrochemical cell; quickly add 0.1 mL of crystal violet solution and 9.9 mL of HAuCl ₄ solution to the spectroelectrochemical cell, and mix well ; Start timing and detect the SERS signal at the same time, the SERS signal changes from weak to strong and then weak; until the SERS signal is always lower than one-third of its maximum value, the experiment ends.

(3) Extract the SERS spectrum in step (2), according to the drawing method of the relationship between the SERS signal and the electrical displacement reaction time, select 1~3 strong peaks, and read the peaks of these peaks in each SERS spectrum High, plot the electrodisplacement reaction time, and obtain the SERS signal intensity of these peaks and the electrodisplacement reaction time curve. The experimental condition corresponding to the maximum value of the ordinate of this curve is the optimal preparation condition of the SERS substrate under this experimental scheme.

(4) During the experimental implementation of step (2), the Au nanoparticles grow from nothing, from small to large, from less to more, and the ratio of Au nanoparticles to Cu also changes from less to more, all of which change with the reaction time There is continuous change. Therefore, according to the results obtained in step (3), the design of the Cu-Au SERS substrate can be guided, that is, the size, spacing, and ratio of gold particles to Cu2O obtained under the optimal reaction conditions, these parameters can be speculated The impact on the SERS signal, thus providing an experimental basis for the design of the corresponding SERS substrate.

In one of the embodiments, the sacrificial template includes cuprous oxide material.

In one of the embodiments, the metal with better SERS enhancement effect includes gold.

In one embodiment, the probe molecules include crystal violet.

Beneficial effect

In the process of electro-displacement reaction, on the one hand, the application optimizes the enhanced substrate of SERS on-site, and observes the impact of changes in the size of nanomaterials, particle spacing, and the coupling effect between different materials on the SERS signal in real time, which can be simple, convenient and low-cost , obtain the best SERS substrate with high efficiency; on the other hand, the preparation of SERS substrate through electro-displacement reaction can reduce the amount of precious metal materials, which is economical and environmentally friendly.

In addition, in step a, using sacrificial templates made of different materials, it is possible to investigate in real time whether there is a coupling effect between different materials that is conducive to SERS signal enhancement; if there is, the coupling effect varies with the size, shape, and spacing of different materials. What about the relationship. In step b, the plotted SERS signal intensity and electrical displacement reaction time curve not only provides the optimal preparation conditions for the SERS substrate under the current experimental scheme, but also provides information such as the optimal particle size, the most The relevant parameters such as optimal particle spacing provide an experimental basis for the preparation of SERS substrates with corresponding materials.

Description of drawings

In order to better describe and illustrate embodiments and/or examples of the inventions disclosed herein, reference may be made to one or more of the accompanying drawings. Additional details or examples used to describe the drawings should not be considered limitations on the scope of any of the disclosed inventions, the presently described embodiments and/or examples, and the best mode of these inventions currently understood.

Fig. 1 is the SEM image of Example 1, which shows the electrodisplacement of Cu ₂ O in the mixed solution of chloroauric acid solution and crystal violet for 500 s.

Fig. 2 is the SERS spectra collected at different time periods during the electrodisplacement reaction of Cu ₂ O in Example 2 in the mixed solution of chloroauric acid solution and crystal violet.

Fig. 3 is a graph showing the variation of the SERS peak intensity of crystal violet in Example 3 at ~1580 cm ^-1 with the time of the electrodisplacement reaction.

Embodiments of the present invention

In order to facilitate the understanding of the present invention, the following will describe the present invention more fully. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the understanding of the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention.

The present application provides a method for preparing a SERS-enhanced substrate based on an electrodisplacement reaction, including the following steps.

In one or more embodiments, in step a, the selection condition of the sacrificial template is: the selected sacrificial template material can be replaced by the metal salt in step b.

In one or more embodiments, in the step b, the method of drawing the relationship graph between the SERS signal and the electrical displacement reaction time is as follows.

In one or more embodiments, cuprous oxide is used as a sacrificial template, and gold is used as a metal with better SERS enhancement effect, and the preparation method of the SERS enhancement substrate thereof includes the following steps.

In one or more embodiments, the sacrificial template includes a cuprous oxide material.

In one or more embodiments, the metal with better SERS enhancement effect includes gold.

In one or more embodiments, the probe molecule comprises crystal violet.

The following is a description of each embodiment.

Example 1: This example is the preparation of electrodeposited cuprous oxide/titanium sheet (Cu ₂ O/Ti) sacrificial template. First, the polished and cleaned titanium sheet was used as the working electrode, the platinum sheet was used as the auxiliary electrode, and the saturated calomel electrode (SCE) was used as the reference electrode. The prepared aqueous solution of 10 mM copper trifluoroacetate and 0.2 M potassium trifluoroacetate was used as the reaction electrolyte according to v:v=1:1; the deposition potential was set to −0.06 V, and the deposition time was 3600 seconds; after the preparation was completed, use After repeated washing with deionized water until clean, a Cu ₂ O/Ti sacrificial template with cuprous oxide particles with a diameter of 400-500 nm on the surface was obtained. The shape and size of Cu ₂ O can be seen in FIG. 1 .

Example 2: In this example, the Cu ₂ O/Ti prepared in Example 1 was used as the sacrificial template, the 1 mmol/L crystal violet solution was used as the probe molecule mother solution, and the 1 mmol/L HAuCl ₄ solution was used Replacement solution for precious metals.

In the laboratory's own sealed in-situ Raman spectroelectrochemical cell, the step Cu ₂ O/Ti sacrificial template was installed. Quickly add 0.1 mL of 1 mmol/L crystal violet solution and 9.9 mL of 1 mmol/L HAuCl ₄ solution into the spectroelectrochemical cell, and mix well. Start timing and detect the SERS signal at the same time. The SERS signal changes from weak to strong and then weak. About 1000 s after the experiment, several strong SERS peaks have dropped to less than a quarter of the strongest (reaction about 500 s). To be on the safe side, in this example, the experiment was carried out for a total of 3200 s. Different reactions The time SERS diagram is shown in Fig. 2.

Embodiment 3: In this embodiment, first extract the SERS spectrum in embodiment 2, select the SERS peak at ~1580 cm ^- 1, read the peak height at ~1580 cm ^-1 in each SERS spectrum, Plot the reaction time of electrodisplacement. The curves of SERS signal intensity and electrodisplacement reaction time of these peaks are obtained, as shown in FIG. 3 .

It can be seen from Fig. 3 that in this example, Cu ₂ O/Ti was electrodisplaced with 1 mmol/L HAuCl ₄ solution for about 500 s, and the SERS signal of crystal violet on the generated Cu ₂ O-Au substrate. That is, if such Cu ₂ O-Au is selected as the substrate, the optimal preparation condition of the SERS substrate is the electrodisplacement reaction between Cu ₂ O/Ti and 1 mmol/L HAuCl ₄ solution for 500 s at room temperature. If this kind of Cu ₂ O-Au is not selected as the substrate, according to the SEM image (see Figure 1) or high-resolution TEM image of Cu ₂ O/Ti and 1 mmol/L HAuCl ₄ solution electrodisplacement reaction for 500 s, it can be known that this The size of the Au nanoparticles and the distance between the particles can provide guidance for the preparation of other SERS substrates.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it should not be understood as limiting the patent scope of the invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims

A method for preparing a SERS-enhanced substrate based on an electric displacement reaction, comprising the steps of:

a. Preparing a metal sacrificial template or a metal oxide sacrificial template;

b. Carry out the electrodisplacement reaction through the sacrificial template in step a and the metal salt liquid solution with better SERS enhancement effect; at the same time, add the molecule to be studied or the probe molecule in the reaction solution; during the electrodisplacement reaction, real-time detection of the The SERS signal of the system can be obtained to obtain the relationship diagram between the SERS signal and the electrodisplacement reaction time; according to this relationship diagram, the optimal preparation conditions of the SERS substrate in the experimental scheme can be known.
The method according to claim 1, in the step a, the selection condition of the sacrificial template is: the selected sacrificial template material can be replaced by the metal salt in the step b.
According to the method claimed in claim 1, in said step b, the drawing method of the relationship diagram between SERS signal and electrical displacement reaction time is:

(1) Screening of SERS signal peaks: select peaks with strong signals in a single SERS spectrum during the entire electrodisplacement reaction process;

(2) Measure the peak intensity of the SERS signal: read the peak height or peak area of the peak selected in step (1) in each spectrum;

(3) Draw a graph of the relationship between the SERS signal and the electrical displacement reaction time: take the peak height or peak area measured in step (2) as the ordinate, and use the electrical displacement reaction time as the abscissa to plot the graph, that is, the SERS signal and the electrical displacement reaction time are obtained. Reaction time graph;

(4) According to the results obtained in step (3), the design of the corresponding material SERS substrate can be guided, that is, the size and spacing of the metal nanoparticles with strong SERS enhancement effect obtained according to the optimal reaction conditions, and the relationship between the nanoparticles and the sacrificial The ratio of the template material, speculate on the impact of these parameters on the SERS signal, thus providing an experimental basis for the design of the corresponding SERS substrate.
The method according to claim 3, using cuprous oxide as a sacrificial template, using gold as a metal with a better SERS enhancement effect, the preparation method of its SERS enhanced substrate comprises the steps:

(1) Cu 2 O/Ti with Cu 2 O cubic particles with a diameter of 400-500 nm electrodeposited on the surface was used as a sacrificial template, 1 mmol/L crystal violet solution was used as the probe molecular mother solution, and 1 mmol/L HAuCl 4 solution is noble metal replacement solution;

(2) Install the Cu 2 O/Ti sacrificial template in a sealed in-situ Raman spectroelectrochemical cell; quickly add 0.1 mL of crystal violet solution and 9.9 mL of HAuCl 4 solution to the spectroelectrochemical cell, and mix well ;Start timing and detect the SERS signal at the same time, the SERS signal changes from weak to strong and then weak; until the SERS signal is always lower than one-third of its maximum value, the experiment ends;

(3) Extract the SERS spectrum in step (2), according to the drawing method of the relationship between the SERS signal and the electrical displacement reaction time, select 1~3 strong peaks, and read the peaks of these peaks in each SERS spectrum High, plotting the electric displacement reaction time to obtain the SERS signal intensity of these peaks and the electric displacement reaction time curve; the experimental condition corresponding to the maximum value of the ordinate of this curve is the best preparation of the SERS substrate under this experimental scheme condition;

(4) During the experimental implementation of step (2), the Au nanoparticles grow from nothing, from small to large, from less to more, and the ratio of Au nanoparticles to Cu also changes from less to more, all of which change with the reaction time There is a continuous change; therefore, according to the results obtained in step (3), the design of the Cu-Au SERS substrate can be guided, that is, the size and spacing of the gold nanoparticles obtained according to the optimal reaction conditions, and the relationship between the gold particles and the Cu 2 O ratio, speculate on the influence of these parameters on the SERS signal, and provide an experimental basis for the design of the corresponding SERS substrate.
The method of claim 4, the sacrificial template comprising a cuprous oxide material.
The method according to claim 4, said metal having better SERS enhancement effect comprises gold.
The method of claim 4, said probe molecule comprising crystal violet.