EP-4735381-A1 - A THERMOCHEMICAL PROCESS FOR SYNTHESIZING A CARBON NANOMATERIAL

Abstract

A new process for synthesizing a carbon nanomaterial by thermochemically reducing an oxygenic carbon source under an ambient pressure, and an onset temperature in the range of 50 - 150 °C in the presence of a hydrogen abstractor, an ionic salt, and a solvent. Said carbon nanomaterial is selected from the group of a nanocrystalline carbon with a 1D, 2D, or 3D structure, a graphitic nanocarbon, an N-doped graphitic nanocarbon, an amorphous carbon, graphene quantum dots, N-doped graphene quantum dots, and a combination thereof. The reaction time for synthesizing the carbon nanomaterial is no longer than 10 minutes.

Inventors

• NGANGLUMPOON, Rungkiat

Assignees

• CrystalLyte Co., Ltd.

Dates

Publication Date

20260506

Application Date

20230629

Claims (20)

1. 1. A process for synthesizing a carbon nanomaterial by thermochemically reducing an oxygenic carbon source under an ambient pressure, and an onset temperature in the range of 50 - 150 °C in the presence of a hydrogen abstractor, an ionic salt, and a solvent, wherein the carbon nanomaterial is selected from the group of a nanocrystalline carbon with a ID, 2D, or 3D structure, a graphitic nanocarbon, an N-doped graphitic nanocarbon, an amorphous carbon, graphene quantum dots, N-doped graphene quantum dots, and a combination thereof, and wherein the reaction time for synthesizing the carbon nanomaterial is no longer than 10 minutes.
2. 2. The process of claim 1, wherein the yield of said carbon nanomaterial is in the range of 0.3 - 3 kg-L^-h’ 1 .
3. 3. The process of claim 1, wherein the hydrogen abstractor is selected from the group of a hydroxyl compound and a peroxide compound.
4. 4. The process of claim 3, wherein the concentration of the hydrogen abstractor is in the range of 1 - 10 M.
5. 5. The process of claim 3, wherein the hydroxyl compound is potassium hydroxide.
6. 6. The process of claim 3, wherein the peroxide compound is hydrogen peroxide.
7. 7. The process of claim 3, wherein the thermochemical reduction occurs in presence of the hydrogen abstractor, the ionic salt, the solvent, and an acid.
8. 8. The process of claim 7, wherein the acid is selected from the group of formic acid, acetic acid, and sulfuric acid.
9. 9. The process of claim 8, wherein the concentration of the acid is in the range of 0.1 - 1 M.
10. 10. The process of claim 1, wherein the oxygenic carbon source is selected from the group of an oxygenic organic compound, a carbonate salt, and a bicarbonate salt.
11. 11. The process of claim 10, wherein the concentration of the oxygenic carbon source is in the range of 0.001 - 10 M.
12. 12. The process of claim 10, wherein the oxygenic organic compound is selected from the group of an amino acid, a sugar, a polypeptide, a phenolic compound, an amine, a carboxylic acid, an alcohol, a ketone, and an aldehyde.
13. 13. The process of claim 12, wherein the amino acid is selected from the group of glycine, alanine, and aspartic acid.
14. 14. The process of claim 12, wherein the sugar is selected from the group of glucose and sucrose.
15. 15. The process of claim 12, wherein the polypeptide is gelatin.
16. 16. The process of claim 12, wherein the phenolic compound is tannic acid.
17. 17. The process of claim 12, wherein the amine is selected from the group of monoethanolamine and dimethylethanolamine.
18. 18. The process of claim 12, wherein the carboxylic acid is selected from the group of glycolic acid and citric acid.
19. 19. The process of claim 12, wherein the alcohol is glycerol.
20. 20. The process of claim 12, wherein the ketone is acetone.

Description

TITLE OF THE INVENTION A THERMOCHEMICAL PROCESS FOR SYNTHESIZING A CARBON NANOMATERIAL FIELD OF INVENTION The present disclosure relates to the synthesis of a carbon nanomaterial, said carbon nanomaterial including a nanocrystalline carbon with a ID, 2D, or 3D structure, a graphitic nanocarbon, an N-doped graphitic nanocarbon, an amorphous carbon, graphene quantum dots, N-doped graphene quantum dots, and a combination thereof. BACKGROUND OF THE INVENTION Because of their excellent physical and electrical properties, carbon nanomaterials, including a nanocrystalline carbon with a ID, 2D, or 3D structure, a graphitic nanocarbon, an N-doped graphitic nanocarbon, an amorphous carbon, graphene quantum dots (GQDs), N-doped graphene carbon dots (N-GQDs), and a combination thereof, are raw materials for a variety of specialized applications, especially in the electronic optoelectronic and electromagnetic industries. The demand for those carbon nanomaterials has been increasing and is unlikely to be satisfied by conventional production techniques. Most conventional processes for synthesizing a carbon nanomaterial, particularly thermochemical processes, require considerably high-temperature conditions. The high thermal energy demand adversely affects the cost of synthesized carbon nanomaterial and the safety of the process. On the contrary, the processes conducted under mild conditions consume long processing time, which is not practical for industrial production. US patent application No. US 2015/0284318 Al discloses a thermochemical process for preparing graphene quantum dots by pyrolyzing an organic starting material. This process requires a temperature within the range of 185 - 225 °C and thus consumes high energy. US patent application No. US 2017/011396 Al presents a process that requires extremely high thermal energy to achieve a reaction temperature that is in the range of 500 - 1500 °C for converting biomass into carbon nanomaterials comprising a graphene and carbon nanotubes. Additionally, Dong et al. (2014) reports the synthesis of N-doped carbon dots (N-CDs) by thermochemically reducing monoethanolamine at 250 °C, which requires high thermal energy. Although some other prior arts disclose processes for preparing carbon nanomaterials under mild conditions, the resulting synthesis of carbon nanomaterial may require as long as several days. Examples include Pang et al. (2018) which discloses a thermochemical reduction of citric acid for producing N-doped graphene quantum dots at 70 °C that takes 1,800 minutes to complete, and Dai et al. (2021) which provides a preparation of various nanocrystalline carbon allotropes at the room temperature, requiring the reaction time in the range of 7,200 - 20,160 minutes. As such, achieving low energy consumption and high synthesis rate has been conventionally perceived as conflicting pursuits. SUMMARY OF THE INVENTION An object of the present invention is to provide a new process for preparing a carbon nanomaterial that addresses the problem of energy consumption while achieving the practical reaction time. In the first aspect, the present invention provides a new process for synthesizing a carbon nanomaterial by thermochemically reducing an oxygenic carbon source. Said thermochemical reduction is carried out under an ambient pressure, and an onset temperature in the range of 50 - 150 °C, and in the presence of a hydrogen abstractor, an ionic salt, and a solvent. Said carbon nanomaterial is selected from the group of a nanocrystalline carbon with a ID, 2D, or 3D structure, a graphitic nanocarbon, an N-doped graphitic nanocarbon, an amorphous carbon, graphene quantum dots, N-doped graphene quantum dots, and a combination thereof. The reaction time for synthesizing the carbon nanomaterial is no longer than 10 minutes. Said range of the onset temperature and ambient pressure are effects that distinguishes a process in accordance with the present invention from the previously available thermochemical reduction processes. Unlike the previously available processes, however, an embodiment’s substantially less energy-intensive operating conditions achieve excellent reaction times and yields. In an embodiment, the yield of said carbon nanomaterial is in the range of 0.3 - 3 kg-L’ ^h . The hydrogen abstractor is preferably a strong base or a compound that otherwise exhibits high affinity to a hydrogen atom or ion when dissolved in the respective solvent. In an embodiment, said hydrogen abstractor is selected from the group of a hydroxyl compound and a peroxide compound. Preferably, the concentration of the hydrogen abstractor is in the range of 1 - 10 M. Preferably, the hydroxyl compound is potassium hydroxide. Also preferably, the peroxide compound is hydrogen peroxide. In some embodiments, the thermochemical reduction occurs in presence of the hydrogen abstractor, the ionic salt, the solvent, and an acid. In such embodiments, the acid may be selected from the group of formi