CN103286319A - One-pot method for preparing nitrogen doped mesoporous carbon/argentum nano particles and application thereof - Google Patents

Abstract

The invention discloses a one-pot method for preparing nitrogen-doped mesoporous carbon/silver nano particles, comprising the following steps: 1) mixing purified aniline with absolute ethanol and stirring, adding mesoporous molecular sieve (SBA-15 ) Stir at room temperature for 2 hours, then add 1.0M NH ₄ S ₂ O ₈ solution and 6ml of 1M silver nitrate solution, then stir at room temperature for 11-14 hours, dry the resulting solution at 70-80°C, and then heat it under hydrogen at 800°C Carbonization in the atmosphere for 2 hours; 2) Etching the solid obtained in step 1) with 20% HF for 24 hours, rinsing with a large amount of distilled water, and drying at room temperature to obtain nitrogen-doped mesoporous carbon/silver nanoparticles (NOMCs/Ag). The present invention uses a one-pot method to carbonize and shape mesoporous carbon, dope nitrogen and load silver nanoparticles. Therefore, compared with other methods, the preparation of nitrogen-doped mesoporous carbon/silver nanoparticle materials in the present invention is simple, rapid and economical efficient.

Description

One-pot preparation method and application of nitrogen-doped mesoporous carbon/silver nanoparticles

technical field

The invention relates to a method for preparing nitrogen-doped mesoporous carbon-loaded silver nanoparticles, a method for preparing an electrode modified by using nitrogen-doped mesoporous carbon-loaded silver nanoparticles, and an application in a sensor for detecting nitrobenzene. the

Background technique

Mesoporous materials refer to surfactants as templates, using physical and chemical processes such as sol-gel (sol-sel), emulsion (emulsion) or microemulsion (microemulsion), through the interface between organic matter and inorganic matter A class of inorganic porous solids with a pore size between 2.0 nm and 30.0 nm, a narrow pore distribution, and a regular pore structure generated by assembly. The structure and performance of mesoporous materials are between amorphous inorganic porous materials and inorganic porous materials with crystalline structure, and its pore size is far beyond the pore size range of conventional microporous molecular sieves and has good stability. The allure of mesoporous materials is that they have excellent properties that some other porous materials do not have: 

(1) It has a highly ordered pore structure, based on the high degree of pore order on the microscopic scale;

(2) The pore size has a single distribution, and the pore size can be adjusted in a wide range (2 - 30 nm);

(3) After optimizing the synthesis conditions or post-treatment, it can have good thermal stability and certain hydrothermal stability;

(4) The morphology is controllable, and can have different structures, skeleton compositions and properties, and the mesopores can have different shapes;

(5) High specific surface area (up to 2000 m ² /g);

(6) Diversity of inorganic components;

(7) Particles may have regular shapes, may have different shapes and appearances, and are controllable;

(8) In terms of microstructure, the pore walls of mesoporous materials are amorphous, which is very different from the ordered framework structure of microporous molecular sieves, but this does not mean that there must be no micropores in the pore walls.

Ordered mesoporous carbon has the characteristics of huge surface area, narrow pore size distribution, and regular pore arrangement. It has shown broad application prospects in the fields of chemical industry, biomedicine, and environmental protection, so it has received more and more attention. Nitrogen doping and carrying metal nanoparticles is an important method to modify carbon materials. However, the current preparation of this material requires nitrogen doping first, and then further loading of metal nanoparticles. The process is complicated, and the particle size of the metal nanoparticles in the obtained material is not uniform, and the quality needs to be improved. the

Nitroaromatic compounds such as nitrobenzene are important chemical raw materials and are widely used in national defense, printing and dyeing, plastics, pesticides and pharmaceutical industries. More than 10,000 tons of nitrobenzene are discharged into the environment every year around the world. With the development of the chemical industry, the demand for such chemicals has shown a clear upward trend, and the amount entering the environment has also increased. Due to the "three effects" of nitrobenzene compounds, they are highly toxic to humans and are listed as priority pollutants by various countries. Therefore, my country has higher requirements on the concentration of nitro compounds in wastewater, and strictly stipulates that the content of nitro compounds shall not exceed 5mg/L (GB 897821996). Because nitrobenzene is a highly toxic substance, its toxicity is generally 20-30 times that of other compounds, and it has weak mutagenicity. Long-term exposure is extremely harmful to humans, animals and plants. Since such substances are generally considered to be difficult to biodegrade or even non-biodegradable, it is particularly important to use appropriate pretreatment methods to improve their biodegradability. At present, the commonly used treatment method is to first destroy their nitro functional groups by physical and chemical methods, and then improve their biodegradable properties. In the current research, there are various treatment methods for this kind of compounds, and there are mainly three kinds in summary, namely: physical method, chemical method and biological method. In the chemical method, the electrochemical method is a method that can achieve rapid and highly sensitive detection, but because a more sensitive material has not been obtained for modifying the electrode, the detection signal of p-nitrobenzene is not large enough to be accurate. Detection of nitrobenzene. the

Contents of the invention

The technical problem to be solved in the present invention is to overcome the existing defects and provide a method for preparing nitrogen-doped mesoporous carbon/silver nano-particles in one pot with simple operation and good product quality;

Another object of the present invention is to provide a method for preparing a modified electrode based on the above-mentioned nitrogen-doped mesoporous carbon/silver nanoparticles;

Another object of the present invention is to provide the application of the above electrodes.

The purpose of the present invention is specifically achieved through the following technical solutions:

A method for preparing nitrogen-doped mesoporous carbon/silver nano-particles in one pot, comprising the following steps,

1) Mix the purified aniline with absolute ethanol and stir, add porous mesoporous molecular sieve (SBA-15) and stir at room temperature for 2 hours, then add 1.0M NH ₄ S ₂ O ₈ solution and 6ml 1M silver nitrate solution, After stirring at room temperature for 11-14 hours, the resulting solution was dried at 60-80°C, and then carbonized in a hydrogen atmosphere at 650-1000°C for 1-3.5 hours.

Among them, aniline: absolute ethanol: SBA-15: 1.0M NH ₄ S ₂ O ₈ solution: 1M silver nitrate solution is 1ml: 1.5-3ml: 0.1-0.2g: 0.5-1.5ml: 4-8ml;

2) The solid obtained after carbonization in step 1) was etched with 20% HF for 24 hours, rinsed with a large amount of distilled water, and dried at room temperature to obtain nitrogen-doped mesoporous carbon/silver nanoparticles (NOMCs/Ag) .

Preferably, in the step 1), aniline: absolute ethanol: SBA-15: 1.0M NH ₄ S ₂ O ₈ solution: 1M silver nitrate solution is 1ml: 2ml: 0.15g: 1ml: 6ml.

Preferably, in the step 1), the drying temperature is 75°C, the carbonization temperature is 800°C, and the carbonization time is 3 hours. the

A preparation method of a nitrogen-doped mesoporous carbon/silver nanoparticle modified electrode, comprising the following steps,

1) The glassy carbon electrode is polished into a mirror surface with 0.3 μm and 0.05 μm aluminum oxide suspensions in turn, and then ultrasonicated by ethanol with a volume fraction of 95%-99.5%, 95%-99.5% acetone, and double distilled water. After cleaning, a cleaned glassy carbon electrode is obtained;

2) Add absolute ethanol and 0.1% Nafion to the nitrogen-doped mesoporous carbon/silver nanoparticles, disperse evenly by ultrasonic, measure 3ul primer to the surface of the electrode obtained in step 1), and let it dry naturally.

Wherein, the nitrogen-doped mesoporous carbon/silver nanoparticles: absolute ethanol: 0.1% Nafion is 2-4mg: 4-8ml: 20-40ul.

As a preferred solution of the above-mentioned nitrogen-doped mesoporous carbon/silver nanoparticle-modified electrode preparation method, nitrogen-doped mesoporous carbon/silver nanoparticles: absolute ethanol: 0.1% Nafion is 2mg: 4ml: 20ul. the

In the preparation method of the above-mentioned nitrogen-doped mesoporous carbon/silver nanoparticle modified electrode, the nitrogen-doped mesoporous carbon/silver nanoparticle is a method for preparing nitrogen-doped mesoporous carbon/silver nanoparticle according to a one-pot method Prepared. the

Application of nitrogen-doped mesoporous carbon/silver nanoparticles modified electrode in the preparation of sensors for the detection of nitrobenzene. the

Beneficial effects of the present invention:

1. The present invention uses a one-pot method to carbonize and form mesoporous carbon, nitrogen doping and loading silver nanoparticles, so compared with other methods, the present invention prepares nitrogen-doped mesoporous carbon/silver nanoparticle materials simply and quickly and cost-effective;

2. The method of the present invention can effectively solve the problem that the particle size of the metal nanoparticles in the prior art is not uniform and the quality needs to be improved. The reason is that the formation of nano-silver in the process of one-pot synthesis of nitrogen doping is actually SBA-15 Since it is a hard template, it will well control the size of nano-silver in a range (<30nm), and the size and dispersion of metal nanoparticles will affect its catalytic performance Therefore, it is necessary to synthesize silver nanoparticles in the range of <30nm to modify nitrogen-doped mesoporous carbon.

3. The present invention uses nitrogen-doped mesoporous carbon/silver nanoparticles to modify the electrode. The modified electrode prepared is simple, rapid, and highly sensitive, and is used to detect nitrobenzene sensors. The modified electrode is linear in the detection of nitrobenzene. The range is 6.6×10 ^-8 to 1.1×10 ^-6 mol/L.

Origin7.0 software was used for drawing, and the differential pulse method curve, XRD, XPS, and nitrogen adsorption isotherm obtained in the accompanying drawings were obtained. the

Select cyclic voltammetry and differential pulse technology in the technical options of the electrochemical workstation, the saturated calomel electrode is the reference electrode, the platinum wire is the counter electrode, and the glassy carbon electrode (3mm in diameter) is the working electrode;

It can be seen from Figure 1 that the reduction process of NOMCs/Ag material obtained in the present invention has electrocatalyzed nitrobenzene due to the synergistic effect of nitrogen-doped mesoporous carbon/silver nano-ions, so that the electrode and nitrogen-doped media Compared with porous carbon modified electrode, silver electrode and bare electrode, the reduction peak is enhanced (the peak current signal is enhanced).

By the electron microscope picture of Fig. 2, it is clear that the obtained NOMCs/Ag material of the present invention is doped with nitrogen and silver, the morphology of the mesoporous carbon does not change, and the silver nanoparticles are uniform in size and good in dispersion;

Through the XRD diagram of Fig. 3, it can be seen that the peaks of the NOMCs/Ag material prepared by the present invention at 2θ = 24.0° and 43.5° can be attributed to the (002) and (101) mirror peaks of mesoporous carbon, and the Ag The characteristic peaks of [111], [200], [220], and [311] can be observed at the same time as the peaks of mesoporous carbon and silver nanometers, indicating that this material makes our expected nitrogen-doped mesoporous carbon/silver nanometers particulate material;

By the XPS figure of Fig. 4, it can be known that the NOMCs/Ag material prepared by the present invention contains C-C bond, C-N bond Ag-N etc.; As evidence, this material contains C, N, Ag and other elements, that is to say, the mesoporous carbon we prepared is doped with nitrogen.

Through Fig. 5, the nitrogen adsorption isotherm of the NOMCs/Ag material prepared by the present invention gives a ₀ = 3.75380 nm, S _BET = 9324.2 m ² /g, V _total cm ³ /g = 0.468597 cm ³ /g, W _BJH = 3.75380 nm, nitrogen to carbon atomic ratio N/C = 3.37%. From this, a conclusion can be drawn: the nitrogen-doped mesoporous carbon/silver nanoparticle composite prepared by this method is in line with the characteristics of mesoporous materials, which can further explain that the material we prepared is NOMCs/Ag.

the

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

Fig. 1 is the differential pulse diagram of different modified electrodes (glassy carbon) of the present invention at 0.1M, containing 0.5M KCL, wherein, d--bare electrode, c-silver electrode, b--nitrogen-doped mesoporous carbon, a --NOMCs/Ag, scan rate: 20-50mv/s;

Fig. 2 is the electron micrograph of nitrogen-doped mesoporous carbon/silver nanoparticle modified electrode of the present invention;

Fig. 3 is the wide-angle XRD pattern of multi-nitrogen-doped mesoporous carbon/silver nanoparticles of the present invention;

Fig. 4 is the XPS full spectrum of nitrogen-doped mesoporous carbon/silver nanoparticles of the present invention;

Fig. 5 is the nitrogen adsorption isotherm of the nitrogen-doped mesoporous carbon/silver nanoparticles of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention. the

The water used in the examples is double distilled water, and the reagents used in the experiments are all analytically pure. The experiments were carried out at corresponding temperatures. the

Apparatus and reagents used in the embodiment

CHI832 electrochemical analyzer (Shanghai Chenhua Instrument Co., Ltd.) for differential pulse experiments; saturated calomel reference electrode (Shanghai Ridao Scientific Instrument Co., Ltd.); quartz tube heating automatic double pure water distiller (1810B, Shanghai Asia Pacific) Technology Glass Company) for the preparation of double distilled water; electronic balance (Beijing Sartorius Instrument Co., Ltd.) for weighing drugs; JSM-6701F cold field emission scanning electron microscope (Japan Electronics Co., Ltd.) for nitrogen-doped mesoporous carbon / Morphological characterization of silver nanoparticles; ultrasonic cleaner (Kunshan Ultrasonic Instrument Co., Ltd.); aluminum oxide grinding powder (0.30 μm, 0.05 μm, Shanghai Chenhua Instrument Reagent Co., Ltd.) was used to treat glassy carbon electrodes; Potassium hydrogen, dipotassium hydrogen phosphate, potassium chloride (Tianjin Kaixin Chemical Industry Co., Ltd.), SBA-15 (Shenzhen Nanometer Harbor Co., Ltd.); high-purity nitrogen (purity 99.999% (O ₂ ≤0.001%) )wait.

Example 1:

One-pot method for preparing nitrogen-doped mesoporous carbon/silver nanoparticles

Redistill and purify aniline, mix 1ml with 2ml absolute ethanol and stir, add 0.15g SBA-15 and stir at room temperature for 2h, then add 1ml 1.0M NH ₄ S ₂ O ₈ solution and 6ml 1M silver nitrate solution. Then stir at room temperature for 12 hours, dry the above solution at 75°C, and then carbonize it in a hydrogen atmosphere at 800°C for 3 hours, etch the above solid with 20% HF for 24 hours, rinse with a large amount of distilled water, and dry it at room temperature. Dry.

Example 2:

One-pot method for preparing nitrogen-doped mesoporous carbon/silver nanoparticles

Redistill and purify aniline, mix 1ml with 1.5ml absolute ethanol and stir, then add 0.2g SBA-15 and stir at room temperature for 2h, then add 0.5ml 1.0M NH ₄ S ₂ O ₈ solution and 8ml 1M silver nitrate solution. Then stir at room temperature for 12 hours, dry the above solution at 60°C, and then carbonize it in a hydrogen atmosphere at 1000°C for 2 hours, etch the above solid with 20% HF for 24 hours, rinse with a large amount of distilled water, and dry it at room temperature. Dry.

Example 3:

One-pot method for preparing nitrogen-doped mesoporous carbon/silver nanoparticles

Re-distill and purify aniline, mix 1ml with 3ml absolute ethanol and stir, then add 0.1g SBA-15 and stir at room temperature for 2h, then add 1.5ml 1.0M NH ₄ S ₂ O ₈ solution and 4ml 1M silver nitrate solution . Then stir at room temperature for 12 hours, dry the above solution at 80°C, and then carbonize in a hydrogen atmosphere at 650°C for 3.5 hours, etch the above solid with 20% HF for 24 hours, rinse with a large amount of distilled water, and to dry.

Example 4:

A preparation method of nitrogen-doped mesoporous carbon/silver nanoparticles modified electrode

1) The glassy carbon electrode is polished into a mirror surface with 0.3 μm and 0.05 μm aluminum oxide suspensions in turn, and then ultrasonicated by ethanol with a volume fraction of 95%-99.5%, 95%-99.5% acetone, and double distilled water. After cleaning, a cleaned glassy carbon electrode is obtained;

2) Add absolute ethanol and 0.1% Nafion to the nitrogen-doped mesoporous carbon/silver nanoparticles, disperse evenly by ultrasonic, measure 3ul primer to the surface of the electrode obtained in step 1), and let it dry naturally.

Wherein, the nitrogen-doped mesoporous carbon/silver nanoparticles: absolute ethanol: 0.1% Nafion is 2mg: 4ml: 20ul.

Example 5:

A preparation method of nitrogen-doped mesoporous carbon/silver nanoparticles modified electrode

The specific operation steps are the same as in Example 4, except that in step 2), nitrogen-doped mesoporous carbon/silver nanoparticles: absolute ethanol: 0.1% Nafion is 2mg: 8ml: 20ul.

Embodiment 6:

A preparation method of nitrogen-doped mesoporous carbon/silver nanoparticles modified electrode

The specific operation steps are the same as in Example 4, except that, in the step 2), nitrogen-doped mesoporous carbon/silver nanoparticles: absolute ethanol: 0.1% Nafion is 4mg: 4ml: 40ul.

Embodiment 7:

Application of nitrogen-doped mesoporous carbon/silver nanoparticles modified electrode in the preparation of sensors for the detection of nitrobenzene.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still understand the foregoing embodiments The recorded technical solutions are modified, or some of the technical features are equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention. the

Claims (7)

1. one kettle way prepares the method for the doped meso-porous carbon of nitrogen/silver-colored sodium rice corpuscles, it is characterized in that: comprise the steps,

1) aniline behind the purifying and the miscible back of absolute ethyl alcohol are stirred, add under the SBA-15 room temperature and stir 1-2h, then add 1.0M NH ₄S ₂O ₈The liquor argenti nitratis ophthalmicus of solution and 6ml 1M, stir 11-14h at normal temperatures then after, with gained solution 60-80 ℃ of down oven dry, carbonization 1-3.5h in 650-1000 ℃ of atmosphere of hydrogen again,

Wherein, aniline: absolute ethyl alcohol: SBA-15:1.0M NH ₄S ₂O ₈The liquor argenti nitratis ophthalmicus of solution: 1M is 1ml:1.5-3ml:0.1-0.2g:0.5-1.5ml:4-8ml;

2) with gained solid after the step 1) carbonization with 20% HF etching 20-24h, with a large amount of distilled water drip washing, at room temperature dry, namely get the doped meso-porous carbon of nitrogen/silver-colored sodium rice corpuscles.

2. prepare the method for the doped meso-porous carbon of nitrogen/silver-colored sodium rice corpuscles according to the described one kettle way of claim 1, it is characterized in that: in the described step 1), aniline: absolute ethyl alcohol: SBA-15:1.0M NH ₄S ₂O ₈The liquor argenti nitratis ophthalmicus of solution: 1M is 1ml:2ml:0.15g:1ml:6ml.

3. prepare the method for the doped meso-porous carbon of nitrogen/silver-colored sodium rice corpuscles according to the described one kettle way of claim 1, it is characterized in that: in the described step 1), bake out temperature is 75 ℃, and carburizing temperature is 800 ℃, and carbonization time is 3h.

4. the preparation method of the doped meso-porous carbon of nitrogen/Nano silver grain modified electrode is characterized in that: comprises the steps,

1) glass-carbon electrode is polished to minute surface with the alundum (Al suspension of 0.3 μ m, 0.05 μ m successively, again successively after volume fraction is the ethanol, 95%-99.5% acetone, redistilled water ultrasonic cleaning of 95%-99.5%, obtain handling the glass-carbon electrode after clean;

2) add absolute ethyl alcohol, 0.1% Nafion in the doped meso-porous carbon/Nano silver grain of nitrogen, ultrasonic being uniformly dispersed measures the 3ul primary coat to the electrode surface of step 1) gained, volatilizes naturally, get final product,

Wherein, the doped meso-porous carbon/Nano silver grain of described nitrogen: absolute ethyl alcohol: 0.1% Nafion is 2-4mg:4-8ml:20-40ul.

5. the preparation method of the doped meso-porous carbon of nitrogen according to claim 4/Nano silver grain modified electrode, it is characterized in that: the doped meso-porous carbon/Nano silver grain of described nitrogen: absolute ethyl alcohol: 0.1% Nafion is 2mg:4ml:20ul.

6. according to the preparation method of claim 4 or the doped meso-porous carbon of 5 described nitrogen/Nano silver grain modified electrode, it is characterized in that: the doped meso-porous carbon/Nano silver grain of described nitrogen is for to be prepared from according to each described method of claim 1 to 3.

7. the application of the doped meso-porous carbon of nitrogen according to claim 6/Nano silver grain modified electrode in the sensor of preparation detection nitrobenzene.

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