A Facile Electrochemical Method for Graphene Nanoplatelets Preparation Using Multi‐walled Carbon Nanotubes

Fomanyuk²,

et al. 2020

ECS Trans.

A method for producing graphene quantum dots (GQDs) by ultrasonic grinding of e1lectrochemically obtained partially unzipped multi-walled carbon nanotubes is proposed. As a result, photoluminescent GQDs with a blue glow have been obtained from partially unzipped multi-walled carbon nanotubes processed two hours by ultrasonic grinding (UZ-CNTs). Various physicochemical methods including photoluminescence spectroscopy have been used to study the electrochemically synthesized UZ-CNTs GQD. After ultrasonic grinding of electrochemically synthesized UZ-CNTs the GQDs were obtained as a result of the exfoliation from the stress-bent MWCNTs walls one- or two-layer cup-shaped graphene nanoparticles 1.5-3 nm in size. The obtained GQDs are promising materials as a new type of catalyst carriers for oxygen electrodes of fuel cells.

Section: Introductionmentioning

confidence: 99%

Simple Method of Graphene Quantum Dots Preparation from Partially Unzipped Multi-Walled Carbon Nanotubes

Fomanyuk²,

et al. 2020

ECS Trans.

“…The literature describes various methods of unzipping nanotubes, which differ only in the method of the acting on multi-walled carbon nanotubes leading to a partial unzipping of nanotubes or the creation of a defective hybrid structure in nanotubes. They can be classified as chemical (7), mechanical (8), physical (9), electrochemical (10), and physicochemical methods (11). The resulting structures of carbon nanotubes can be called as etched (b), partially unzipped (c) and completely unzipped (d) nanotubes; upon further exposure, agglomerated nanocomposite fragments of graphene nanoplates can be obtained.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical Synthesis Partially Unzipped Multi-Walled Carbon Nanotubes as Electrode Materials for Fuel Cells

Rusetskii²,

et al. 2019

ECS Trans.

Results of electrochemical anodic oxidation of multi-walled carbon nanotubes in 80% sulfuric acid are presented. Using X-ray diffraction analysis, electron microscopy, and Raman spectra, it has been proven that, as a result of anodic oxidation, partially unzipped multi-walled carbon nanotubes were obtained by anodic oxidation. It is shown that the degree of unzipping multi-walled carbon nanotubes depends on the time of electrochemical oxidation of these materials. Using the oxygen electrode as testing electrodes was shown the dependence of the electrochemical characteristics of these materials of the degree of unzipping the multi-walled carbon nanotubes. It is suggested that the controlled synthesis of partially unzipping nanotubes is possible. It is also suggested that it is possible to estimate the degree of unzipping the nanotube based on the study of the electrochemical characteristics of oxygen electrodes. By the electrochemical method obtained partially unzipped multi-walled carbon nanotubes which are promising electrode materials.

“…In, 6 a method is reported for obtaining carbon nanocrystals emitting a strong blue luminescence after electrochemical treatment of MWCNTs. In our previous works, the possibility of controlled unzipping of MWCNTs was shown 7,8 The transformation of graphene sheets into graphene nanoribbons (1D), i.e. limiting them in one more dimension, leads not only to new effects, but also simplify their potential use in nanodevices, since usually graphene micron-sized (2D) sheets are too big.…”

mentioning

confidence: 99%

Graphene Quantum Dots from Partially Unzipped Multi-Walled Carbon Nanotubes: Promising Materials for Oxygen Electrodes

Fomanyuk²,

et al. 2021

J. Electrochem. Soc.

Self Cite

Photoluminescent graphene quantum dots (GQDs) the one- or two-layer graphene nanoparticles 1.5–3 nm in size with a blue emission have been obtained from electrochemically synthesized partially unzipped multi-walled carbon nanotubes ultrasonically treated for one hour. Various physicochemical methods including photoluminescence spectroscopy, XRD, TEM, and Raman spectroscopy, have been used to characterize the electrochemically synthesized partially unzipped multi-walled carbon nanotubes and GQDs. Two-layer oxygen electrodes were fabricated, where GQDs served as an active layer. The investigations of electrocatalytic characteristics of the oxygen electrodes fabricated of the obtained materials were carried out in a fuel half-cell with an alkaline electrolyte. The fabricated oxygen electrodes were stable for six months at a discharge current density of 200 mA cm−2. The obtained GQDs are promising materials as a new type of catalyst carriers for oxygen electrodes of fuel cells.