Room-Temperature Synthesis of Soluble Carbon Nanotubes by the Sonication of Graphene Oxide Nanosheets

Abstract

The transformation of two-dimensional graphene oxide (GO) nanosheets into carbon nanotubes was achieved by sonicating GO in 70% nitric acid. Through the use of mass spectrometry to track the evolution of molecular fragments during the acid ultrasonication, it was observed that GO can be readily decomposed into polyaromatic hydrocarbons (PAHs). The cavitation-induced condensation of these PAHs results in their molecular reconstruction to form folded carbon nanostructures. UV-emitting, water-soluble carbon nanoparticles as well as carbon nanotubes that exhibit magnetic properties were fabricated under catalyst-free conditions.

Production of large graphene sheets by exfoliation of graphite under high power ultrasound in the presence of tiopronin

“…TEM and HR-TEM micrographs of D-Tio reveal the presence of nanofibers. The formation of similar structures has been reported as being a result of the condensation of organic pieces of polyaromatics 14 or the radical polymerization of conjugated carbon polymers. 15 The nanofiber formation under sonication treatment indicates the occurrence of organic radical reactions close to the edges.…”

Direct Observation of Quantum‐Confined Graphene‐Like States and Novel Hybrid States in Graphene Oxide by Transient Spectroscopy

“…[24][25][26][27][28][29][30] In other experiments, owing to the photochemical activity of sp 3 domains, GO is treated as a precursor of a series of carbon nanomaterials: for example, carbon nanotubes, carbon nanoparticles, and graphene quantum dots (GQDs). [31][32][33] Among these new derivatives of GO are fl uorescent GQDs, which are tiny pieces of graphene decorated with functional groups fabricated by hydrothermally or electrochemically cutting GO and its reduction product; [ 34 ] these GQDs simplify the discussion on their photophysical properties to a considerable degree by abandoning the redundant sp 3 matrix, in return for which high photoluminescence (PL) emission appears. We have studied in detail the PL mechanism in green fl uorescence GQDs, in which bright molecule-like states and dark intrinsic states are responsible for the fl uorescence emission.…”

Preparation, characterization, and physical properties of graphene nanosheets and films obtained from low-temperature expandable graphite

“…The shear stress sliding exerted by the glass beads not only resulted in the folding of the outermost layers, but also activated the dislocation bands on the easy gliding (001) planes, from which the detachment of graphene nanosheets occurred in the subsequent ultrasonication process [53]. The formation of carbon nanotubes and nanoscrolls should be closely related to the shear-induced exfoliation and roll-up of graphene sheets, similar to the formation of carbon nanotubes from graphene oxide nanosheets and nanoscrolls from graphite nanoplatelets [54,55]. As the milling process proceeded, the graphite sheets became thinner, and the surface dislocation density increased to some extent.…”