A kind of preparation method of nitrogen-doped carbon-based quantum dots

A carbon-based quantum dot, nitrogen-doped technology, applied in chemical instruments and methods, luminescent materials, etc., can solve the problems of less waste liquid discharge, environmental protection, influence on the purity of synthetic carbon-based quantum dots, and short reaction time, and easy to achieve. The effect of purification, improvement of fluorescence luminous efficiency, and short preparation period

Inactive Publication Date: 2018-02-23
CHENGDU SCI & TECH DEV CENT CHINA ACAD OF ENG PHYSICS
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Problems solved by technology

On the one hand, comparing the preparation methods of carbon-based quantum dots, it is found that the microwave-assisted method not only requires simple equipment and short reaction time, but also has less waste liquid discharge, which is beneficial to environmental protection. Therefore, the microwave-assisted reaction method is an effective preparation method. , but on this basis, it is necessary to solve the problem of the influence of external absorbing materials on the purity of synthesized carbon-based quantum dots

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  • A kind of preparation method of nitrogen-doped carbon-based quantum dots
  • A kind of preparation method of nitrogen-doped carbon-based quantum dots
  • A kind of preparation method of nitrogen-doped carbon-based quantum dots

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preparation example Construction

[0038] Further, the preparation method of nitrogen-doped carbon-based quantum dots comprises the following steps:

[0039] (1) Mix citric acid and imidazole compounds uniformly at a molar ratio of 1:0.5 to 1:12, wherein citric acid is a carbon source, and imidazole compounds are a nitrogen source.

[0040] (2) Heat the mixed material in step 1 with a microwave higher than 100W for 1-15 minutes to obtain a brown-black solid containing carbon-based quantum dots. According to the selection and adjustment of the reaction raw materials, the color of the carbon-based quantum dots obtained by microwave carbonization may be different, but this does not affect the realization of the purpose of the invention. Preferably, in order to facilitate the microwave treatment, the mixed material can be selected to be placed in a microwave oven for microwave treatment, and the microwave energy required for controlling the reaction material per unit volume (per liter) is not less than 1000KJ, and ...

Embodiment 1

[0047] Take 3g of citric acid and 0.9378g of imidazole solids (the molar ratio of citric acid and imidazole is 1:1) and put them in a beaker, stir them with a glass rod for physical mixing, put the mixed citric acid and imidazole directly in the microwave oven, set the microwave oven The power is 500W, and the reaction time is 3 minutes. After the reaction is completed, a brown-black solid is obtained, which contains the target nitrogen-doped carbon-based quantum dots.

[0048] Further, the product is purified. Add secondary water to the brown-black solid beaker, ultrasonically disperse for 30 minutes, vacuum filter the solution, and rinse with secondary water several times to remove unreacted citric acid and imidazole soluble in water, and obtain nitrogen-doped carbon-based Quantum dot filter cake. Finally, the filter cake was dried in a vacuum oven at 60°C for 1 hour to obtain pure nitrogen-doped carbon-based quantum dot solids.

Embodiment 2

[0050] Take 3g of citric acid and 2.8594g of imidazole solids (the molar ratio of citric acid and imidazole is 1:3) and put them in a beaker, stir them with a glass rod for physical mixing, put the mixed citric acid and imidazole directly in the microwave oven, set the microwave oven The power is 500W, and the reaction time is 3min. After the reaction is completed, a brown-black solid is obtained. Add secondary water to the beaker, ultrasonically disperse for 30 minutes, vacuum filter the solution, and rinse with secondary water several times to remove unreacted citric acid and imidazole soluble in water, and obtain nitrogen-doped carbon-based quantum dot filter cake. Finally, the filter cake was dried in a vacuum oven at 60°C for 1 hour to obtain pure nitrogen-doped carbon-based quantum dot solids. The UV absorption spectrum and fluorescence emission spectrum were tested as follows: figure 2 and image 3 , the results of specific nitrogen content and fluorescence luminous ...

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Abstract

The invention provides a preparation method of nitrogen-doped carbon-based quantum dots. In this method, nitrogen-doped carbon-based quantum dots are obtained by directly mixing cheap carbon sources and nitrogen sources through microwave carbonization. The chemical state of nitrogen in the nitrogen-doped carbon-based quantum dots prepared by the method of the present invention simultaneously exists on the surface of the carbon-based quantum dots and its skeleton in four structural forms: amino nitrogen, pyridine nitrogen, pyrrole nitrogen and four-membered ring nitrogen. In the structure, and the relative content of nitrogen chemical state and optical chemical properties are adjustable, the prepared nitrogen-doped carbon-based quantum dots have high fluorescence luminescence efficiency and good catalytic effect, and their performance can be further improved by surface modification for use in catalysis and other fields . In addition, the preparation process adopts the direct mixing and carbonization of nitrogen source and carbon source, without additional absorbing materials, the whole preparation process is simple and fast; and the prepared carbon-based quantum dots are insoluble in water, and the carbon-based quantum dots can be completed in a short time. The separation and purification of carbon-based quantum dots with high yield are of great significance to the production and application of carbon-based quantum dots.

Description

technical field [0001] The invention belongs to the field of nanometer material science, and specifically relates to a method for synthesizing nitrogen-doped carbon-based nanoparticles in one step by using a microwave-assisted method. Background technique [0002] In recent years, carbon nanomaterials composed of carbon elements have been continuously discovered, and its low toxicity or even non-toxicity makes it a hot material for technological innovation in the 21st century. Carbon-based nanoparticles (carbon-based quantum dots) were discovered by Sun in 2004 as a new type of carbon nanomaterial. It not only has the excellent luminescence performance of semiconductor quantum dots: it has a wide and continuous excitation spectrum, and can realize the characteristics of one-way excitation and multiple emission. ; The emission wavelength span is large, extending from the visible light region to the near-infrared light region; the fluorescence stability is high, and the biocom...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K11/65
Inventor 刘焕明黄家伟王群王聪唐昶宇赵云梅军
Owner CHENGDU SCI & TECH DEV CENT CHINA ACAD OF ENG PHYSICS
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