CN110726709A - Preparation method of secondary deep graphene oxide loaded nanogold composite SERS enhanced substrate - Google Patents

Abstract

The invention discloses a preparation method of a secondary deep graphene oxide loaded nano-gold composite SERS enhanced substrate. First, the graphene oxide GO solution, deionized water, and hydrogen peroxide oxidant are mixed and heated to form a transition solution; then hydrogen peroxide oxidant is added, and the ro-GO solution is prepared by heating and stirring; and sodium citrate aqueous solution is added to the obtained ro-GO solution. and chloroauric acid, continue to heat and stir to obtain ro‑GO/AuNPs composite SERS enhanced substrate; use 2,3,7,8‑TCDD as Raman probe molecule to conduct Raman signal on ro‑GO/AuNPs composite SERS enhanced substrate Test: By adjusting the dosage ratio of sodium citrate to chloroauric acid, composite SERS-enhanced substrates with different nanometer sizes and loading densities were prepared. This method can increase the number of AuNPs supported on the surface of graphene oxide, which is suitable for SERS analysis of 2, 3, 7, 8‑TCDD.

Description

Fabrication of a secondary deep graphene oxide-supported nano-gold composite SERS-enhanced substrate backup method

technical field

The invention relates to the technical field of surface-enhanced Raman spectroscopy, in particular to a preparation method of a secondary deep graphene oxide-supported nano-gold composite SERS enhanced substrate.

Background technique

Graphene (Gr) is a two-dimensional carbon nanomaterial composed of carbon atoms hybridized with SP ² . The Graphene-mediated Enhanced Raman scattering (GERS) effect brought by Gr has been discovered. Due to its superior physical structure, it has unique optical and mechanical properties, which is considered to be a revolutionary sexual material. In recent years, the "Gr-MNP" type composites of Gr-loaded nano-precious metals have attracted much attention. This type of composites also has the surface-enhanced Raman Spectroscopy (SERS) effect of metal nanoparticles (MNPs). As well as the GERS synergistic effect of Gr, it is beneficial to improve the analytical sensitivity and stability of the target.

However, in the preparation of this material, how to improve the loading efficiency of Gr and optimize the nano-morphology of MNP has a great impact on the SERS effect of the Gr-MNP composite, and there is no corresponding solution in the prior art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a preparation method of a secondary deep graphene oxide supported nano-gold composite SERS enhanced substrate, which can increase the loading density of AuNPs on the surface of graphene oxide, thereby increasing the number of active functional groups on the surface of graphene oxide.

The purpose of this invention is to realize through the following technical solutions:

A preparation method of a secondary deep graphene oxide-loaded nano-gold composite SERS enhanced substrate, the method comprising:

Step 1. Mix and heat a certain amount of graphene oxide GO solution, deionized water and hydrogen peroxide oxidant to prepare a transition solution;

Step 2, take part of the transition solution and add a certain amount of hydrogen peroxide oxidant, and continue to heat and stir to make a secondary deep graphene oxide PD-GO solution;

Step 3. Add a certain proportion of sodium citrate aqueous solution and chloroauric acid to the prepared PD-GO solution, and continue to heat and stir to obtain a secondary deep graphene oxide-supported nano-gold PD-GO/AuNPs composite SERS enhanced substrate;

Step 4. Use 2,3,7,8-TCDD as a Raman probe molecule to test the Raman signal of the prepared ro-GO/AuNPs composite SERS enhanced substrate, and obtain the corresponding Raman spectrum data;

Step 5. Further, by adjusting the dosage ratio of sodium citrate to chloroauric acid, composite SERS-enhanced substrates with different nanometer sizes and loading densities are prepared.

It can be seen from the technical solution provided by the present invention that the above method can increase the loading density of AuNPs on the surface of graphene oxide, thereby increasing the number of active functional groups on the surface of graphene oxide, thereby improving the performance of the SERS-enhanced substrate.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic flowchart of a preparation method of a secondary deep graphene oxide-supported nano-gold composite SERS enhanced substrate provided in an embodiment of the present invention;

2 is a schematic diagram of the SERS spectra of 2,3,7,8-TCDD with different concentrations provided in an embodiment of the present invention;

3 is a schematic diagram of the SERS analysis of 2, 3, 7, 8-TCDD by a composite substrate prepared with different proportions of sodium citrate and chloroauric acid according to the embodiment of the present invention;

4 is a trend diagram of the stability (0-180 days) of the composite substrate prepared by the dosage of sodium citrate and chloroauric acid in different proportions according to the embodiment of the present invention to 2,3,7,8-TCDD at I ₁₂₀₇ .

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. FIG. 1 is a schematic flowchart of a method for preparing a secondary deep graphene oxide-supported nano-gold composite SERS enhanced substrate provided by the embodiments of the present invention, and the method includes: :

Step 1. Mix and heat a certain amount of graphene oxide GO solution, deionized water and hydrogen peroxide oxidant to prepare a transition solution;

In this step, the specific consumption of each component can be:

8 mL of GO solution, 50 mL of deionized water, and 5-8 mL of hydrogen peroxide oxidant.

Step 2, take part of the transition solution and add a certain amount of hydrogen peroxide oxidant, and continue to heat and stir to make a secondary deep graphene oxide PD-GO solution;

In step 2, the amount of hydrogen peroxide oxidant used in the second oxidation is 5 mL.

Step 3. Add a certain proportion of sodium citrate aqueous solution and chloroauric acid to the prepared PD-GO solution, and continue to heat and stir to obtain a secondary deep graphene oxide-supported nano-gold PD-GO/AuNPs composite SERS enhanced substrate;

Step 4. Use 2,3,7,8-TCDD as a Raman probe molecule to test the Raman signal of the prepared ro-GO/AuNPs composite SERS enhanced substrate, and obtain the corresponding Raman spectrum data;

The process of step 4 is specifically:

To 10 μL of 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD), 600 μL of ro-GO/AuNPs composite SERS enhanced substrate was added;

Then add 80uL of nitric acid, and conduct Raman scanning after shaking for 60s. The specific parameters are: scanning time 10s, scanning times 2, smoothing parameter 1, and scanning power 100mw;

Then collect Raman spectral data in the range of 1000-2000 cm ^-1 , as shown in FIG. 2 , which is a schematic diagram of the SERS spectra of 2, 3, 7, 8-TCDD with different concentrations provided by the embodiment of the present invention. It can be seen from FIG. 2 that the two The sub-deep oxidation increases the number of AuNPs loaded on the surface of graphene oxide, and the Raman signal enhancement effect on 2,3,7,8-TCDD is also improved.

Step 5. Further, by adjusting the dosage ratio of sodium citrate to chloroauric acid, composite SERS-enhanced substrates with different nanometer sizes and loading densities are prepared.

Figure 3 is a schematic diagram showing the SERS analysis of 2,3,7,8-TCDD by a composite substrate prepared with different proportions of sodium citrate and chloroauric acid according to the embodiment of the present invention, and Figure 4 is a schematic diagram of the present invention The different proportions of sodium citrate and chloroauric acid described in the examples were prepared to obtain the stable (0-180 days) trend diagram of the composite substrate to 2,3,7,8-TCDD at I ₁₂₀₇ , combined with Figures 3 and 4:

Enhanced stability The characteristic peak intensity I ₁₂₀₇ decreased by 12.9% within 180 days. When the dosage ratio of sodium citrate and chloroauric acid was adjusted to 7:12, the prepared ro-GO/AuNPs composite SERS-enhancing substrate had the greatest SERS-enhancing effect on 2,3,7,8-TCDD.

It should be noted that the content not described in detail in the embodiments of the present invention belongs to the prior art known to those skilled in the art.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (5)

1. a preparation method of secondary deep graphene oxide loaded nano-gold composite SERS enhanced substrate, is characterized in that, described method comprises: Step 1. Mix and heat a certain amount of graphene oxide GO solution, deionized water and hydrogen peroxide oxidant to prepare a transition solution; Step 2, take part of the transition solution and add a certain amount of hydrogen peroxide oxidant, and continue to heat and stir to make a secondary deep graphene oxide PD-GO solution; Step 3. Add a certain proportion of sodium citrate aqueous solution and chloroauric acid to the prepared PD-GO solution, and continue to heat and stir to obtain a secondary deep graphene oxide-supported nano-gold PD-GO/AuNPs composite SERS enhanced substrate; Step 4. Use 2,3,7,8-TCDD as a Raman probe molecule to test the Raman signal of the prepared ro-GO/AuNPs composite SERS enhanced substrate, and obtain the corresponding Raman spectrum data; Step 5. Further, by adjusting the dosage ratio of sodium citrate to chloroauric acid, composite SERS-enhanced substrates with different nanometer sizes and loading densities are prepared. 2. preparation method according to claim 1 is characterized in that, in step 1, the concrete consumption of each component is: 8 mL of GO solution, 50 mL of deionized water, and 5-8 mL of hydrogen peroxide oxidant. 3. preparation method according to claim 1, is characterized in that, in step 2, the amount of hydrogen peroxide oxidant used in the second oxidation is 5mL. 4. preparation method according to claim 1, is characterized in that, the process of described step 4 is specifically: Add 600 μL of ro-GO/AuNPs composite SERS-enhanced substrate to 10 μL of 2,3,7,8-TCDD; Then add 80uL of nitric acid, oscillate for 60s, and perform Raman scanning. The specific parameters are: scanning time 10s, scanning times 2, smoothing parameter 1, and scanning power 100mw; Raman spectral data in the range of 1000-2000 cm ^-1 was then collected. 5. preparation method according to claim 1, is characterized in that, in step 5, When the dosage ratio of sodium citrate and chloroauric acid was adjusted to 7:12, the prepared ro-GO/AuNPs composite SERS-enhancing substrate had the greatest SERS-enhancing effect on 2,3,7,8-TCDD.

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