Preparation method for ultrathin boron nitride nanosheets and dispersion liquid thereof

Abstract

The invention belongs to the technical field of nano materials and relates to a preparation method of ultrathin boron nitride nanosheets and dispersion liquid thereof. A one-step hydrothermal method is adopted for preparing the ultrathin boron nitride nanosheets in a laboratory; inexpensive boric acid and ammonia water as used as raw materials and subjected to a hydrothermal reaction for a certainperiod of time to prepare a boron nitride quantum dot solution which is simultaneously modified with amino groups and hydroxyl groups; the boron nitride quantum dot solution is cooled, placed under room temperature for one week, filtered and washed to obtain white transparent boron nitride crystals; the boron nitride crystals are added into ultrapure water, the mixture above is slowly heated to 60-80 DEG C, and the boron nitride crystals are gradually dissolved to obtain a colorless and transparent solution, namely the dispersion liquid of the ultrathin boron nitride nanosheets. Ultrathin boron nitride nanosheet powder can be obtained after the dispersion liquid is freeze-dried. The method has the advantages that the cost is low, the process is easy, and industrial production is facilitated; the obtained ultrathin boron nitride nanosheets are uniform in size distribution, high in crystallinity and good in dispersibility in an aqueous solution.

Description

technical field

[0001] The invention belongs to the technical field of nanometer materials, and relates to a preparation method of an ultrathin boron nitride nanosheet and a dispersion liquid thereof. Background technique

[0002] Hexagonal boron nitride is a graphene-like material. Because of its similar structure to graphene, hexagonal boron nitride nanosheets are also called white graphene. Hexagonal boron nitride has a wide band gap (about 5.7eV), good thermal conductivity, ultra-stable chemical properties, non-toxicity, high mechanical strength, and strong insulation. Hexagonal boron nitride nanosheets have been widely used Used in cosmetics, lubricating oil, ceramic additives and other fields. At present, there are two main methods for preparing hexagonal boron nitride nanosheets: top-down exfoliation method and bottom-up chemical synthesis method.

[0003] The top-down exfoliation method is to exfoliate the huge bulk compound into single-layer or several-layer two-d...

Examples

Embodiment 1

[0031] (1) Preparation of boron nitride quantum dots

[0032] Add 3g of boric acid powder into a polytetrafluoroethylene stainless steel autoclave, then add 60mL of concentrated ammonia water in a fume hood, after ultrasonication for 30min, put it in a blast drying oven and heat it to 200°C, and react for 24h to prepare a nitriding compound with simultaneous modification of amino and hydroxyl groups. Boron quantum dot (BNQD) solution;

[0033] (2) Preparation of boron nitride crystal

[0034] After the boron nitride quantum dot solution is cooled, pour it into a 100mL glass bottle and keep it sealed for a week. It can be observed that colorless and transparent crystals appear at the bottom of the vial. After ordinary filtration, wash with ultrapure water for 3 times, put Boron nitride crystals were prepared after drying in an oven at 70°C for 2.5 hours;

[0035] (3) Preparation of Ultrathin Boron Nitride Nanosheet Dispersion

[0036] Add boron nitride crystals into ultrapur...

Embodiment 2

[0040] (1) Preparation of boron nitride quantum dots

[0041] Add 5g of boric acid powder into a polytetrafluoroethylene stainless steel autoclave, then add 65mL of concentrated ammonia water in a fume hood, after ultrasonication for 30 minutes, put it in a blast drying oven and heat it to 180°C, and react for 24 hours to prepare a nitriding compound with simultaneous modification of amino and hydroxyl groups. Boron quantum dot (BNQD) solution;

[0042] (2) Preparation of boron nitride crystal

[0043] After the boron nitride quantum dot solution is cooled, pour it into a 100mL glass bottle and keep it sealed for a week. It can be observed that colorless and transparent crystals appear at the bottom of the vial. After ordinary filtration, wash with ultrapure water for 3 times, put Boron nitride crystals were prepared after being dried in an oven at 80°C for 3 hours;

[0044] (3) Preparation of Ultrathin Boron Nitride Nanosheet Dispersion

[0045] Add boron nitride crystals ...

Embodiment 3

[0048] (1) Preparation of boron nitride quantum dots

[0049] Add 4g of boric acid powder into a polytetrafluoroethylene stainless steel autoclave, then add 55mL of concentrated ammonia water in the fume hood, after ultrasonication for 30 minutes, put it in a blast drying oven and heat it to 160°C, and react for 24 hours to prepare a nitriding compound with simultaneous modification of amino and hydroxyl groups. Boron quantum dot (BNQD) solution;

[0050] (2) Preparation of boron nitride crystal

[0051] After the boron nitride quantum dot solution is cooled, pour it into a 100mL glass bottle and keep it sealed for a week. It can be observed that colorless and transparent crystals appear at the bottom of the vial. After ordinary filtration, wash with ultrapure water for 3 times, put Boron nitride crystals were prepared after drying in an oven at 65°C for 2.5 hours;

[0052] (3) Preparation of Ultrathin Boron Nitride Nanosheet Dispersion

[0053] Add boron nitride crystals i...

technical field

[0001] The invention belongs to the technical field of nanometer materials, and relates to a preparation method of an ultrathin boron nitride nanosheet and a dispersion liquid thereof. Background technique

[0002] Hexagonal boron nitride is a graphene-like material. Because of its similar structure to graphene, hexagonal boron nitride nanosheets are also called white graphene. Hexagonal boron nitride has a wide band gap (about 5.7eV), good thermal conductivity, ultra-stable chemical properties, non-toxicity, high mechanical strength, and strong insulation. Hexagonal boron nitride nanosheets have been widely used Used in cosmetics, lubricating oil, ceramic additives and other fields. At present, there are two main methods for preparing hexagonal boron nitride nanosheets: top-down exfoliation method and bottom-up chemical synthesis method.

[0003] The top-down exfoliation method is to exfoliate the huge bulk compound into single-layer or several-layer two-d...

Examples

Embodiment 1

[0031] (1) Preparation of boron nitride quantum dots

[0032] Add 3g of boric acid powder into a polytetrafluoroethylene stainless steel autoclave, then add 60mL of concentrated ammonia water in a fume hood, after ultrasonication for 30min, put it in a blast drying oven and heat it to 200°C, and react for 24h to prepare a nitriding compound with simultaneous modification of amino and hydroxyl groups. Boron quantum dot (BNQD) solution;

[0033] (2) Preparation of boron nitride crystal

[0034] After the boron nitride quantum dot solution is cooled, pour it into a 100mL glass bottle and keep it sealed for a week. It can be observed that colorless and transparent crystals appear at the bottom of the vial. After ordinary filtration, wash with ultrapure water for 3 times, put Boron nitride crystals were prepared after drying in an oven at 70°C for 2.5 hours;

[0035] (3) Preparation of Ultrathin Boron Nitride Nanosheet Dispersion

[0036] Add boron nitride crystals into ultrapur...

Embodiment 2

[0040] (1) Preparation of boron nitride quantum dots

[0041] Add 5g of boric acid powder into a polytetrafluoroethylene stainless steel autoclave, then add 65mL of concentrated ammonia water in a fume hood, after ultrasonication for 30 minutes, put it in a blast drying oven and heat it to 180°C, and react for 24 hours to prepare a nitriding compound with simultaneous modification of amino and hydroxyl groups. Boron quantum dot (BNQD) solution;

[0042] (2) Preparation of boron nitride crystal

[0043] After the boron nitride quantum dot solution is cooled, pour it into a 100mL glass bottle and keep it sealed for a week. It can be observed that colorless and transparent crystals appear at the bottom of the vial. After ordinary filtration, wash with ultrapure water for 3 times, put Boron nitride crystals were prepared after being dried in an oven at 80°C for 3 hours;

[0044] (3) Preparation of Ultrathin Boron Nitride Nanosheet Dispersion

[0045] Add boron nitride crystals ...

Embodiment 3

[0048] (1) Preparation of boron nitride quantum dots

[0049] Add 4g of boric acid powder into a polytetrafluoroethylene stainless steel autoclave, then add 55mL of concentrated ammonia water in the fume hood, after ultrasonication for 30 minutes, put it in a blast drying oven and heat it to 160°C, and react for 24 hours to prepare a nitriding compound with simultaneous modification of amino and hydroxyl groups. Boron quantum dot (BNQD) solution;

[0050] (2) Preparation of boron nitride crystal

[0051] After the boron nitride quantum dot solution is cooled, pour it into a 100mL glass bottle and keep it sealed for a week. It can be observed that colorless and transparent crystals appear at the bottom of the vial. After ordinary filtration, wash with ultrapure water for 3 times, put Boron nitride crystals were prepared after drying in an oven at 65°C for 2.5 hours;

[0052] (3) Preparation of Ultrathin Boron Nitride Nanosheet Dispersion

[0053] Add boron nitride crystals i...

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