Carbon nanotubes, nanochains and quantum dots synthesized through the chemical treatment of charcoal powder

Abstract

Here, carbon nanotubes (CNTs), carbon nanochains (CNCs) and carbon quantum dots (CQDs) were synthesized using charcoal powder in a mixture of concentrated H2SO4/HNO3 acidic solvent with the help of NaOH. It is demonstrated that the lower alkaline or basic environment is favourable to enhance the effectiveness for the formation of CNTs and CNCs whereas the higher alkaline or basic environment is effective for the formation of CQDs. The Raman measurements confirm the graphitic nature of the samples and also approve the structural changes in charcoal powder upon chemical treatment. The TEM measurement provides an evidence for the formation of CNTs, CNCs and CQDs from charcoal power as a result of varying pH of the reaction medium. The FTIR and XPS results further supports the chemical modification of charcoal powder by approving the appropriate bonding composition. The optical absorption behavior of the prepared samples was carried out with the help of UV–Vis. absorption spectra. The TG analysis shows the effect of chemical treatment on the thermal stability of the samples. Moreover, we have tried to provide an explanation to the experimental observations. This study not only provides insightful direction to synthesize CNTs, CNCs and CQDs in a facile way but also could lead to new developments in charcoal chemistries.