Wall by wall controllable unzipping of MWCNTs via intercalation with oxalic acid to produce multilayers graphene oxide ribbon

This article reports a modified recipe to produce multilayers graphene oxide nanoribbon, MLGOR, via lengthwise cutting and unraveling of multiwall carbon nanotube, MWCNT. The modified recipe depends on the intercalation of MWCNTs before unzipping by oxalic acid. The oxalic acid was selected owing to its ability to diffuse through the walls of the MWCNT because it has a molecular length equals the space between carbon walls. This step enables the oxidizing agent to smoothly cut the MWCNT along its longitudinal axis till reach to the interior tube and inhibit the destruction of the MWCNT during unzipping process. This step was confirmed by the TEM measurement. The mechanism of unzipping was investigated extensively by XRD, XPS and Raman spectroscopy. The results showed that each MWCNT is efficiently unzipped to MLGOR at 700 wt% oxidizing agent. The optical and electrochemical band gap of the produced intercalated MLGOR was about 1.5 eV.