Obtained Carbon Nano-onions from Underwater Arc Discharge Without the Complex Purification Procedures

Salih Mohamed Osman,Fatma Osman Mahmoud,Andrea Scarcello,Francesca Alessandro,Lorenzo Caputi,Mohammed Bilal Sabahelkher,Asma Mohamed Elhussein

doi:10.11648/j.ajn.20210701.14

Salih Mohamed Osman, Fatma Osman Mahmoud + Show 5 more

Open Access

https://doi.org/10.11648/j.ajn.20210701.14

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Abstract

Carbon nano-onions (CNOs), which consist of concentric graphitic shells, currently attract much attention because of their unique structural and physical properties, which are different from the properties of the other carbon nanomaterials such as fullerenes, graphene, and carbon nanotubes (CNTs). Due to their small size, the large external surface area and high conductivity, CNOs are used for supercapacitor applications. The arc discharge underwater is an effective and simple method for the synthesis of larger CNOs in reasonable quantities. In this research, we have been obtained carbon nanomaterials using arc discharge in water between two high purity graphite electrodes. The main experimental techniques used to characterize carbon nanostructures have been Transmission Electron Microscopy (TEM) and Raman Spectroscopy. Among them, Raman spectroscopy is the most useful non-destructive technique capable of differentiating between these various structures. Our TEM images showed that the samples collected from the material floating on the water surface consist CNOs with other carbon nanomaterials such as CNTs. We observed for the first time the formation of solid agglomerate on the cathode surface. Raman and TEM results revealed that the agglomerate is made exclusively of CNOs. The defragmentation of such agglomerate allows to obtain CNOs free of other carbon nanomaterials without the complex purification procedures needed for floating nanomaterials.

Highlights

The arc discharge method offers an alternative to vacuum processes for the synthesis of larger Carbon nano-onions (CNOs) in reasonable quantities
They are the kind of nanomaterial obtained in several experimental methods of preparation of CNOs, as for example, the one based on a submerged arc discharge of graphite electrodes in water [2, 7], a technique used to obtain CNOs in the present work and a method frequently utilized for producing high-purity nanomaterials [7, 12]
The synthesis chamber presented carbon nanoparticle (CNP) clusters scattered on the bottom and on the surface of the reaction water

Summary

Introduction

The arc discharge method offers an alternative to vacuum processes for the synthesis of larger CNOs in reasonable quantities. The previous researches devoted to study CNOs by Raman data [7,8,9] showed that contrary to what can be thought, their spectra are very different with respect to other CNPs such as fullerenes They resemble the spectra of graphene and graphite. As a matter of fact, the importance of polyhedral CNOs has been increasing in the last years They are the kind of nanomaterial obtained in several experimental methods of preparation of CNOs, as for example, the one based on a submerged arc discharge of graphite electrodes in water [2, 7], a technique used to obtain CNOs in the present work and a method frequently utilized for producing high-purity nanomaterials [7, 12]. The TEM image in the inset shows the polyhedral shape of CNOs [13]

Experiment and Synthesis Procedure

Results and Discussions

Conclusions