阅读说明：本技术 一种Ag-MOF/AuNRs纳米复合材料及其制备与应用 (Ag-MOF/AuNRs nano composite material and preparation and application thereof ) 是由 李原婷 张蒙蒙 吴舟雅 韩生 李学剑 杨圆圆 于 2021-07-23 设计创作，主要内容包括：本发明涉及一种Ag-MOF/AuNRs纳米复合材料及其制备与应用,所述纳米复合材料包括作为基体的金纳米棒(AuNRs)以及自聚合在金纳米棒表面的金属有机框架(Ag-MOF),所述制备方法具体为：取AuNRs溶液和含有机配体的有机溶液均匀混合,再加入银源溶液,发生MOF在AuNRs表面自聚合的反应,反应结束后经后处理得到Ag-MOF/AuNRs纳米复合材料。与现有技术相比,本发明可达到良好的检测低浓度醛类物质的效果,另外本发明可满足实验室大批量快速分析需要,也可以选择性地检测环境中的醛类物质。(The invention relates to an Ag-MOF/AuNRs nano composite material and preparation and application thereof, wherein the nano composite material comprises gold nanorods (AuNRs) serving as a matrix and metal organic frameworks (Ag-MOF) self-polymerized on the surfaces of the gold nanorods, and the preparation method specifically comprises the following steps: and uniformly mixing the AuNRs solution and the organic solution containing the organic ligand, adding the silver source solution, carrying out self-polymerization reaction of the MOF on the surface of the AuNRs, and carrying out post-treatment after the reaction is finished to obtain the Ag-MOF/AuNRs nano composite material. Compared with the prior art, the method can achieve a good effect of detecting the low-concentration aldehyde substances, can meet the requirement of large-scale rapid analysis in a laboratory, and can also selectively detect the aldehyde substances in the environment.)

1. The Ag-MOF/AuNRs nanocomposite is characterized by comprising AuNRs serving as a matrix and Ag-MOF self-polymerized on the surface of the AuNRs, wherein the Ag-MOF takes one of 2-aminoterephthalic acid, terephthalic acid, 1,3, 5-benzenetricarboxylic acid or 3-phosphoryl benzoate as an organic ligand and takes silver ions as central metal ions.

2. A method for preparing a Ag-MOF/AuNRs nanocomposite material according to claim 1, wherein the method comprises: the preparation method comprises the steps of uniformly mixing an AuNRs solution and an organic solution, adding a silver source solution into the organic solution to generate one of 2-aminoterephthalic acid, terephthalic acid, 1,3, 5-benzenetricarboxylic acid and/or 3-phosphoryl benzoate, taking one of 2-aminoterephthalic acid, terephthalic acid, 1,3, 5-benzenetricarboxylic acid or 3-phosphoryl benzoate as an organic ligand source, taking silver ions in the silver source as a central metal ion source, carrying out self-polymerization reaction on the surface of AuNRs, and carrying out post-treatment after the reaction is finished to obtain the Ag-MOF/AuNRs nano composite material.

3. The method for preparing Ag-MOF/AuNRs nanocomposite as claimed in claim 2, wherein the AuNRs solution and the organic solution are mixed while stirring, the stirring speed is 50-150rpm, the stirring time is 60-120min, and the stirring temperature is 25-30 ℃.

4. The preparation method of the Ag-MOF/AuNRs nanocomposite material according to claim 3, wherein the stirring is continued after the silver source solution is added, the stirring speed is 50-150rpm, the stirring time is 30-60min, and the stirring temperature is 25-30 ℃.

5. The preparation method of the Ag-MOF/AuNRs nanocomposite material according to claim 4, wherein the standing is carried out at 25-30 ℃ for 18-24 h.

6. The preparation method of the Ag-MOF/AuNRs nanocomposite material according to claim 2, wherein the post-treatment process comprises the following steps in sequence: the mixed solution after the reaction is centrifuged at 7000-8000rpm for 20-30min, the solid is taken out and washed, and then vacuum drying is carried out at 55-65 ℃ for 8-12 h.

7. The method for preparing the Ag-MOF/AuNRs nanocomposite material according to claim 2, wherein the silver source is one or more selected from silver acetate and silver nitrate.

8. The preparation method of Ag-MOF/AuNRs nano composite material according to claim 2, wherein the molar ratio of AuNRs, silver ions and organic solute is (15-20) mM, (20-25) mM:5.5 mM.

9. Use of a Ag-MOF/AuNRs nanocomposite according to claim 1 as a surface enhanced raman enhancing substrate for selective SERS detection of aldehydes.

10. The use of the Ag-MOF/AuNRs nanocomposite of claim 9, wherein the SERS detection process is specifically: preparing a solution containing aldehyde substances, adding the Ag-MOF/AuNRs nano composite material into the solution containing the aldehyde substances, and performing SERS detection through pretreatment;

parameters for SERS detection were: the laser wavelength was 532nm, the power 10mW, and the integration time 3 s.

Technical Field

The invention belongs to the technical field of nano-material preparation and analytical chemistry detection, and particularly relates to an Ag-MOF/AuNRs nano-composite material and preparation and application thereof.

Background

The aldehydes are harmful to human health, uncomfortable symptoms such as headache, palpitation and insomnia can be caused after the aldehydes are exposed to the environment containing the aldehydes for a long time, even cancers such as leukemia and lymphoma can be caused, and at present, the detection of the aldehydes becomes one of important items for evaluating the indoor air quality, so that the detection of trace aldehydes in the environment is always a focus of people.

The novel portable surface enhanced Raman detection technology for rapidly detecting the trace aldehyde substances in the environment with high selectivity and high sensitivity can rapidly detect the trace aldehyde substances in the environment and reduce the occurrence probability of cancers. The Surface Enhanced Raman Spectroscopy (SERS) is an analysis technology for characterizing substances adsorbed on the surface of a rough precious metal on a molecular level, has the advantages of short detection time, high sensitivity, small water interference, direct in-situ analysis and the like, and needs a small amount of samples without a complex sample pretreatment process. However, the raman cross-sectional area of formaldehyde is very small and is not easy to be enriched on the surface of a noble metal substance, so that the application of SERS detection in the aspect of aldehyde substance detection is limited.

The high porosity and the ultra-large specific surface area provided by the Metal Organic Framework (MOF) material are utilized, not only can trace aldehyde substances in the environment be adsorbed and enriched, but also the substances to be detected can form a 'hot spot' of surface enhanced Raman around the gold nanorod to improve the SERS signal of trace analytes, and the MOF material is enriched around the gold nanorod to protect the gold nanorod from self agglomeration. At present, the study on the loading of gold nanoparticles on the surface of an MOF material can cause the blockage of a certain amount of pores on the surface of the MOF material, but the invention loads Ag-MOF on the periphery of a gold nanorod to avoid the problems.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an Ag-MOF/AuNRs nano composite material, and preparation and application thereof, which are used for meeting the requirement of rapid detection of environmental pollutants.

The purpose of the invention is realized by the following technical scheme:

the Ag-MOF/AuNRs nanocomposite comprises AuNRs serving as a matrix and Ag-MOF self-polymerized on the surface of the AuNRs, wherein the Ag-MOF takes one of 2-aminoterephthalic acid, terephthalic acid, 1,3, 5-benzenetricarboxylic acid or 3-phosphoryl benzoate as an organic ligand and takes silver ions as central metal ions.

A preparation method of an Ag-MOF/AuNRs nano composite material comprises the following steps:

the method comprises the steps of uniformly mixing an AuNRs solution and an organic solution, adding a silver source solution into the organic solution to generate one of 2-aminoterephthalic acid, terephthalic acid, 1,3, 5-benzenetricarboxylic acid and/or 3-phosphoryl benzoate, taking one of 2-aminoterephthalic acid, terephthalic acid, 1,3, 5-benzenetricarboxylic acid or 3-phosphoryl benzoate as an organic ligand, taking silver ions in the silver source as a central metal ion source, carrying out self-polymerization reaction on the surface of AuNRs, and carrying out post-treatment after the reaction is finished to obtain the Ag-MOF/AuNRs nano composite material.

The AuNRs solution and the organic solution are mixed and stirred at the same time, the stirring speed is 50-150rpm, preferably 100rpm, the stirring time is 60-120min, and the stirring temperature is 25-30 ℃.

Adding the silver source solution, and stirring at 50-150rpm, preferably 100rpm, for 30-60min at 25-30 deg.C.

Then standing for 18-24h at 25-30 ℃.

The post-treatment process comprises the following steps: the mixed solution after the reaction is centrifuged at 7000-8000rpm for 20-30min, the solid is taken out and washed, and then vacuum drying is carried out at 55-65 ℃ for 8-12 h.

The silver source is selected from one or more of silver acetate or silver nitrate.

The molar ratio of AuNRs, silver ions and organic solute is (15-20) mM, (20-25) mM and 5.5 mM.

The Ag-MOF/AuNRs nano composite material is used as an enhanced substrate for surface enhanced Raman scattering and is used for selective SERS detection of aldehyde substances.

The SERS detection process specifically comprises the following steps: preparing a probe molecule crystal violet solution and an aldehyde substance-containing solution, adding the Ag-MOF/AuNRs nano composite material into the aldehyde substance-containing solution or the probe molecule crystal violet solution, and performing SERS detection through pretreatment. When the probe molecule crystal violet is used, the pretreatment is specifically as follows: adding the Ag-MOF/AuNRs nano composite material into a crystal violet solution, and sequentially performing centrifugation, ethanol washing and drying at room temperature; when the aldehyde substances are benzaldehyde, formaldehyde, phenylacetaldehyde and the like, the pretreatment specifically comprises the following steps: dissolving Ag-MOF/AuNRs nano composite material in deionized water, adding a certain amount of aldehyde solution, adding glycine-sodium hydroxide buffer solution to adjust the pH of the solution to be alkaline (preferably 9.58), finally diluting the solution, stirring and mixing at 50-60 ℃ for 15-30min, sequentially centrifuging, washing with ethanol, performing ultrasonic treatment on the reactant, and performing SERS detection.

Parameters for SERS detection were: the laser wavelength was 532nm, the power 10mW, and the integration time 3 s.

The aldehyde substances comprise benzaldehyde, formaldehyde, phenylacetaldehyde and the like.

The concentration of the glycine-sodium hydroxide buffer solution is 0.05M.

Metal Organic Frameworks (MOFs), also known as porous coordination polymers, are supramolecular materials with infinite lattice, highly ordered periodic networks. The unique structure of the MOF enables the MOF material to have special properties, such as ultra-large internal surface area and nano-scale porosity, rich metal active sites and high porosity. These unique physicochemical properties have led to the utilization of MOF materials in fields such as gas storage, adsorption and separation, and catalysis.

The gold nanorods and the silver-based metal organic framework are combined in a self-assembly mode to obtain the composite material, the composite material is used as an SERS substrate to detect the aldehyde substances on the basis of the characteristics that AuNRs have Raman activity and Ag-MOF has large specific surface area, can perform Schiff base reaction with the aldehyde substances, can perform reduction silver reaction, can also perform pi-pi interaction and the like, and the good SERS performance is shown through the double effects of chemical and electromagnetic enhancement in the detection process, so that the aldehyde substances in the environment can be detected through SERS. The invention can achieve the effect of well detecting the low-concentration aldehyde substances, can meet the requirement of large-scale and quick analysis in a laboratory, and can also selectively detect the aldehyde substances in the environment.

Drawings

FIG. 1 is an infrared spectrum of the Ag-MOF/AuNRs nanocomposite prepared in example 1;

FIG. 2 shows the SERS data of crystal violet in example 4;

FIG. 3 shows the SERS data of benzaldehyde in example 5.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

The Ag-MOF/AuNRs nano composite material comprises AuNRs serving as a matrix and Ag-MOF self-polymerized on the surface of the AuNRs, wherein the Ag-MOF takes one of 2-amino terephthalic acid, 1,3, 5-benzene tricarboxylic acid or 3-phosphoryl benzoate as an organic ligand and silver ions as central metal ions.

A preparation method of a nano composite material such as Ag-MOF/AuNRs comprises the following steps:

the preparation method of the AuNRs solution (which is a method disclosed in the literature) specifically comprises the following steps: dissolving CTAB (cetyl trimethyl ammonium bromide) and NaOL (sodium oleate) in hot water, cooling, and sequentially adding AgNO₃(silver nitrate) solution and HAuCl₄Uniformly mixing (tetrachloroauric acid) solution, adding acid (hydrochloric acid) for regulation, sequentially adding ascorbic acid solution and seed solution, and standing to obtain AuNRs solution, wherein the seed solution contains HAuCl with the molar ratio of 2.5: 1: 6₄CTAB and NaBH₄，CTAB、NaOL、AgNO₃、HAuCl₄HAuCl in ascorbic acid solution or seed solution₄CTAB and NaBH in seed solution₄The addition ratio of (7.0-9.0) g, (1.3-1.6) g, (0.072-0.096) mM, (0.25 mM), (0.08 mM), (0.09-0.18) mM, (36.36-72.72) mM, (0.22-0.44) mM. The addition amount ratio is calculated based on the amount taken at the beginning, regardless of the reaction occurring between the compounds during the mixing.

Mixing AuNRs solution and organic solution uniformly, wherein the organic solute in the organic solution is one of 2-amino terephthalic acid, 1,3, 5-benzene tricarboxylic acid and/or 3-phosphoryl benzoate, stirring simultaneously at the speed of 50-150rpm for 60-120min at the stirring temperature of 25-30 ℃, adding silver source solution, continuing stirring at the speed of 50-150rpm for 30-60min at the stirring temperature of 25-30 ℃, allowing one of 2-amino terephthalic acid, 1,3, 5-benzene tricarboxylic acid or 3-phosphoryl benzoate to serve as an organic ligand and silver ions in the silver source to serve as a central metal ion source, carrying out self-polymerization reaction on the surface of the NRAus, standing at the standing temperature of 25-30 ℃, standing for 18-24h, after the reaction is finished, centrifuging the reacted mixed solution at 7000-8000rpm for 20-30min, taking out the solid for washing, and then vacuum-drying at 55-65 ℃ for 8-12h to obtain the Ag-MOF/AuNRs nanocomposite, wherein the molar ratio of AuNRs, a silver source and an organic ligand is (15-20) mM, (20-25) mM:5.5mM, the solvent of the organic solution is ethanol, the solvent of the silver source solution is water, and the silver source is selected from one or more of silver acetate or silver nitrate.

An application of Ag-MOF/AuNRs nano composite material, which takes the nano composite material as an enhanced substrate of surface enhanced Raman and is used for selective SERS detection of aldehyde substances. The SERS detection process comprises the following steps: dissolving the Ag-MOF/AuNRs nano composite material in deionized water, adding a certain amount of aldehyde solution, adding glycine-sodium hydroxide buffer solution to adjust the pH of the solution to be alkaline (preferably 9.58), finally diluting the solution to 10-15mL, stirring and mixing at 50-60 ℃ for 15-30min, sequentially centrifuging and washing reactants, and then carrying out SERS detection. The aldehyde substances include benzaldehyde, formaldehyde, phenylacetaldehyde and the like.

Example 1

A preparation method of an Ag-MOF/AuNRs nano composite material specifically comprises the following steps:

mixing 2mL of 18mM AuNRs solution with 2mL of 5.5mM 2-aminoterephthalic acid solution, stirring at the rotating speed of 100rpm at 30 ℃ for 60min, slowly adding 2mL of 22mM silver acetate solution into the solution, stirring at the rotating speed of 100rpm at 30 ℃ for 30min, standing at 30 ℃ for 24h, centrifuging at the rotating speed of 7000rpm for 30min, washing with ethanol, and vacuum drying at 60 ℃ for 8h to obtain the Ag-MOF/AuNRs nanocomposite.

The synthesized materials were subjected to infrared tests, each as shown in fig. 1. Shown in FIG. 1, 3445cm^-1The characteristic peak at (A) represents the elongation of O-H, 1610cm^-1The characteristic peak at (A) represents the elongation of N-H, 1416cm^-1The characteristic peak at (A) represents the elongation of C ═ O, 1375cm^-1The characteristic peak at (A) represents the elongation of C ═ C, 1251cm^-1The characteristic peak at (A) represents the symmetrical stretch of C-O-C, 1100cm^-1The characteristic peak at (A) represents C-O stretching, 832-760cm^-1The characteristic peaks in the range represent C-H stretches, indicating that the material produced is indeed a Ag-MOF/AuNRs nanocomposite.

Example 2

An Ag-MOF/AuNRs nanocomposite material prepared by the method disclosed by the embodiment 1 is the same as that of the embodiment 1 except that a silver source solution is a silver nitrate solution.

Example 3

An Ag-MOF/AuNRs nanocomposite was prepared as in example 1, except that the reaction temperature was 25 ℃.

Example 4

The embodiment provides an application of detecting Raman probe molecular crystal violet by using an Ag-MOF/AuNRs nano composite material for detecting SERS enhanced performance of the material, which comprises the following detection steps: the preparation concentration is 1 multiplied by 10 in sequence^-3、1×10^-4、1×10^-5、1×10^-6M, and each 5mL, then four 15mg portions of the Ag-MOF/AuNRs nanocomposite obtained in example 1 were immersed in the above-mentioned solutions of different concentrationsAnd stirring the crystal violet solution for 3h, centrifuging at 8000rpm, washing with ethanol, drying at room temperature, and placing the material on a silicon wafer for Raman detection. The wavelength of the Raman detection laser is 532nm, the power is 10mW, and the integration time is 3 s. As shown in FIG. 2, the SERS signal of crystal violet was clearly observed at 912cm^-1、1169cm^-1、1387cm^-1、1616cm^-1The area is a characteristic peak of crystal violet, which shows that the Ag-MOF/AuNRs nano composite material has better SERS performance.

Example 5

The Ag-MOF/AuNRs nano composite material prepared in the embodiment 1 is used for SERS detection of benzaldehyde solution, and the method comprises the following steps:

dissolving 20mg of Ag-MOF/AuNRs nano composite material in 1mL of deionized water, and then adding 1mL of 1 × 10^-3Adding 0.05M glycine-sodium hydroxide buffer solution into M benzaldehyde solution, adjusting the pH value of the solution to 9.58, finally diluting the solution to 10mL, stirring and mixing the solution at 50 ℃ for 30min, centrifuging the reactant at 8000rpm for 15min, washing the obtained solid ethanol, removing the redundant upper layer liquid, carrying out ultrasonic treatment on the rest for 1min, absorbing 10 mu L dispersion liquid on a silicon wafer, and carrying out Raman detection after the ethanol is volatilized. The wavelength of the Raman detection laser is 532nm, the power is 10mW, and the integration time is 3 s. As shown in FIG. 3, SERS signal of benzaldehyde is clearly observed, wherein the SERS signal is 998cm^-1、1596cm^-1The characteristic peak of benzaldehyde is shown.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.