Acid-free and oxone oxidant-assisted solvothermal synthesis of graphene quantum dots using various natural carbon materials as resources

Abstract

To prepare carbon-based fluorescent materials such as graphene quantum dots (GQDs), new and effective methods are needed to convert one-dimensional (1D) or two-dimensional (2D) carbon materials to 0D GQDs. Here, we report a novel acid-free and oxone oxidant-assisted solvothermal synthesis of GQDs using various natural carbon resources including graphite (G), multiwall carbon nanotubes (M), carbon fibers (CF), and charcoal (C). This acid-free method, not requiring the neutralization process of strong acids, exhibits a simple and eco-friendly purification process and also represents a recycling production process, together with mass production and high yield. Newly synthesized GQDs exhibited a strong blue photoluminescence (PL) under 365 nm UV light illumination. The PL emission peaks of all the recycled GQDs did not change.

Highly transparent and flexible supercapacitors using graphene-graphene quantum dots chelate

“…A high-resolution transmission electron microscope (HR-TEM) image showed uniform GQDs with size less than 20 nm. The clear atomic lattice structure of GQDs exhibited a lattice spacing of 0.25 nm that crystal state of graphite [29][30][31], showing many crystalline domains highlighted white circle (Figure 2a and inset). Raman spectroscopy confirmed the synthesis and structural characterization of the GQDs (Figure 2b).…”

Green Synthesis of Graphene Quantum Dots from Cotton Cellulose

“…presented a solvothermal process to fabricate GQDs from carbon nanotubes (CNTs), in which H 2 O 2 was used as the oxidant and ethanol used as the solvent. Shin et al . reported a solvothermal synthesis of GQDs from carbon fibers (CFs) by utilizing oxone as the oxidant.…”

Selective Liquid‐Phase Extraction of Carboxylate‐Rich Graphene Quantum Dots from Graphene Oxide Dispersions

“…[10] In order to overcome this obstacle, alternative methods have been devoted using additional oxidation of GO to introduce more oxygen functionalities in GQDs, or the introduction of a cleavage effect through sono-chemical reactions. [11][12][13] However, these are inappropriate due to low carboxylation yield (< 5 wt.%) owing to the random reaction or inertness of the graphitic carbon contents. [9] Meanwhile, crucial issues to solve are effective purification and size separation of GQDs from the reactant, which is complicated and tedious.…”