Large-scale solvothermal synthesis of fluorescent carbon nanoparticles

Abstract

The large-scale production of high-quality carbon nanomaterials is highly desirable for a variety of applications. We demonstrate a novel synthetic route to the production of fluorescent carbon nanoparticles (CNPs) in large quantities via a single-step reaction. The simple heating of a mixture of benzaldehyde, ethanol and graphite oxide (GO) with residual sulfuric acid in an autoclave produced 7 g of CNPs with a quantum yield of 20%. The CNPs can be dispersed in various organic solvents; hence, they are easily incorporated into polymer composites in forms such as nanofibers and thin films. Additionally, we observed that the GO present during the CNP synthesis was reduced. The reduced GO (RGO) was sufficiently conductive (σ ≈ 282 S m(-1)) such that it could be used as an electrode material in a supercapacitor; in addition, it can provide excellent capacitive behavior and high-rate capability. This work will contribute greatly to the development of efficient synthetic routes to diverse carbon nanomaterials, including CNPs and RGO, that are suitable for a wide range of applications.

Syntheses of N-Doped Carbon Quantum Dots (NCQDs) from Bioderived Precursors: A Timely Update

“…The bottom-up approaches involve the formation of CQDs from molecular precursors, and among them, the most common strategy relies on the hydrothermal/solvothermal method where the aqueous or nonaqueous solutions of precursors are heated at an elevated temperature in an autoclave under a sealed condition to carbonize the precursors into CQDs. − It is a relatively straightforward and inexpensive method and has the potential of producing various heteroatom-doped CQDs from a variety of molecular precursors. In addition, pyrolysis under an inert atmosphere utilizing various sources has also been considered for the preparation of CQDs. , Microwave (MW) heating as alternative source of energy has also been used for the preparation of CQDs, in which, depending on the MW power, reaction time, and the precursor type, heteroatom-doped CQDs can be obtained. , Moreover, sonochemical energy via the method of ultrasonication has been recently employed to synthesize metal-doped CQDs. ,, …”

Green Synthesis of Multifunctional Carbon Dots with Antibacterial Activities

“…There have been several efforts to apply fluorescent CDs into the field of sensors [7], optoelectronics [3], energy storage [8], light-emitting diode (LED) [9], drug delivery [10], antibacterial [11,12], bioimaging [13,14], catalysis [15], etc. To date, different synthetic routes have been identified to prepare CDs including hydrothermal [16,17], solvothermal [18,19], ultrasonication [20][21][22], simple heating [23,24], arc discharge [25], microwave-assisted pyrolysis [26,27], laser ablation [2,28], electrochemical [29,30], etc. Initially, carbonaceous materials were utilized for the preparation of CDs resulting in lower quantum yields (QY) and limited solubilities.…”

Carbon Quantum Dot-Induced MnO2 Nanowire Formation and Construction of a Binder-Free Flexible Membrane with Excellent Superhydrophilicity and Enhanced Supercapacitor Performance

“…Carbon quantum dots (CQDs), zero-dimensional carbon nanoparticles with size below 10 nm and containing diverse functional groups such as hydroxyl, carboxylate, and carbonyl, have generated huge interest in recent years due to their good dispersibility in solvent, excellent conductivity, large specific surface area, and easy preparation. They are widely used in various fields, such as photocatalysis, bioimaging, sensors, electrocatalysis, and supercapacitors. − Several recent studies into supercapacitors have revealed the bright prospect of CQDs and their composite materials as electrode materials, owing to their outstanding physical and chemical properties. Examples of these compounds are CQD/RuO 2 , CDs/NiCo 2 O 4 , , CQDs/Ni­(HCO 3 ) 2 –MnCO 3 , CQDs/PANI, CQDs/PPy, , CDs/Fe 3 O 4 , and CQD/graphene composites.…”