# US 11,299,671 B2 · Preparation method for graphene quantum dots with different oxygen contents, graphene quantum dot, and fluorescent material

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- Number: US 11,299,671 B2
- Document ID: US11299671B2
- Status: Granted
- Kind: B2
- Application number: 15/744,852
- Filed: 2016-08-25
- Published: 2018-08-16
- Granted: 2022-04-12
- Earliest claimed: 2015-08-25
- Assignees: Linde Zhang
- Applicants: Linde Zhang
- Inventors: Linde Zhang; Mingdong Zhang
- Web page: https://patentgrep.com/patent/US11299671B2

## CPC

- C09K 11/65: containing carbon (in organic compounds C09K11/06)
- C01B 32/184: Preparation
- B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals
- B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites
- B82Y 40/00: Manufacture or treatment of nanostructures
- Y10S 977/734: Fullerenes, i.e. graphene-based structures, such as nanohorns, nanococoons, nanoscrolls or fullerene-like structures, e.g. WS2 or MoS2 chalcogenide nanotubes, planar C3N4, etc.
- Y10S 977/774: Exhibiting three-dimensional carrier confinement, e.g. quantum dots
- Y10S 977/842: for carbon nanotubes or fullerenes
- Y10S 977/95: Electromagnetic energy
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

The present invention provides a preparation method for graphene quantum dots with different oxygen contents, including the following steps: Step 1: dispersing a graphene oxide in a peroxide solution to obtain a graphene oxide dispersion; Step 2: mixing the graphene oxide dispersion with an alkali liquor, purifying to obtain a graphene quantum dot dry powder; Step 3: loading the graphene quantum dots dry powder on a carrier, performing a gradient elution to obtain a plurality of graphene quantum dots with different oxygen contents. The preparation method for graphene quantum dots can realize the control of oxygen content of the graphene quantum dots. Therefore, the control of the emission wavelength of the product is achieved, which provides a reliable premise for applications of the graphene quantum dots in the fields of LED, cell labeling, etc. In addition, the method provided by the present invention is also simple and easy to operate.

## Claims

### Claim 1

A preparation method for graphene quantum dots with different oxygen contents, comprising following steps:
step 1: dispersing a graphene oxide in a peroxide solution containing hydroxyl radicals to obtain a graphene oxide dispersion;
step 2: mixing the graphene oxide dispersion with an alkali liquor, purifying to obtain a graphenc quantum dot dry powder,
wherein a purifying step comprises reacting the purified product with a reducing agent in a solvent reduce an oxygen content of the graphene quantum dots, and purifying to obtain the graphene quantum dot dry powder, wherein the reducing agent is at least one of potassium borohydride, zinc-hydrochloric acid, iron-acetic acid, lithium aluminum hydride, sodium naphthalene, sodium amalgam, and Raney nickel, and
step 3: loading the graphene quantum dot dry powder on a carrier, performing a gradient elution to obtain a plurality of graphene quantum dots with different oxygen contents.

### Claim 2 (depends on 1)

The preparation method for graphene quantum dots with different oxygen contents according to claim 1, wherein a mass concentration of the graphene oxide in the graphene oxide dispersion is 0.1%-5%; and/or, a mass concentration of the peroxide solution is 3%-30%.

### Claim 3 (depends on 1)

The preparation method for graphene quantum dots with different oxygen contents according to claim 1, wherein the peroxide is at least one selected from the group consisting of hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium hydrogen persulfate, sodium perborate, dibenzoyl peroxide and dilauroyl peroxide.

### Claim 4 (depends on 1)

The preparation method for graphene quantum dots with different oxygen contents according to claim 1, wherein the gradient elution in step 3 includes performing the gradient elution using a vacuum liquid chromatography or a column chromatography.

### Claim 5 (depends on 4)

The preparation method for graphene quantum dots with different oxygen contents according to claim 4, wherein an eluent used for the gradient elution includes a first polar solvent and a second polar solvent, wherein a polarity of the first polar solvent is greater than that of the second polar solvent, wherein the first polar solvent is one or more selected from the group consisting of water, methanol, ethanol, ethylene glycol, hydrochloric acid-methanol solution, tetrahydrofuran, formic acid, acetic acid, acetonitrile, N, N-dimethylformamide, diethyl. ether, acetone and nitromethane, wherein the second polar solvent is one or more selected from the group consisting of cyclohexane, n-hexane, petroleum ether, ethyl acetate, dimethyl carbonate, dichloromethane, trichloromethane and carbon tetrachloride.

### Claim 6 (depends on 1)

The preparation method for graphene quantum dots with different oxvaen contents according to claim 1, wherein the dots produced have an emission wavelength is 550 nm-750 nm.

### Claim 7 (depends on 2)

The preparation method for graphene quantum dots with different oxygen contents according to claim 2, wherein the gradient elution in step 3 includes performing the gradient elution using a vacuum liquid chromatography or a column chromatography.

### Claim 8 (depends on 3)

The preparation method for graphene quantum dots with different oxygen contents according to claim 3, wherein the gradient elution in step 3 includes performing the gradient elution using a vacuum liquid chromatography or a column chromatography.

### Claim 9

A preparation method for graphene quantum dots with different oxygen contents, comprising:
a step of converting a graphene oxide to a graphene quantum dot powder and a step of purifying the graphene quantum dot powder,
wherein the step for converting a graphene oxide to a graphene quantum dot consists of:
step 1: dispersing a graphene oxide in a peroxide solution containing hydroxyl radicals to obtain a graphene oxide dispersion;
step 2: mixing the graphene oxide dispersion with an alkali liquor, purifying to obtain a graphene quantum dot dry powder,
wherein the step of purifying the graphene quantum dot powder comprises:
step 3: reacting the purified product with a reducing agent in a solvent reduce an oxygen content of the graphene quantum dots, and purifying to obtain the graphene quantum dot dry powder, wherein the reducing agent is at least one of: potassium borohydride, zinc-hydrochloric acid, iron-acetic acid, lithium aluminum hydride, sodium naphthalene, sodium amalgam, and Raney nickel, and
step 4: loading the graphene quantum dot dry powder on a carrier, performing a gradient elution to obtain a plurality of graphene quantum dots with different oxygen contents.