Catalyst-free fabrication of graphene nanosheets without substrates using multiwalled carbon nanotubes and a spark plasma sintering process

Abstract

Catalyst-free graphene nanosheets without substrates were synthesized using pure solid carbon sources of multiwalled carbon nanotubes (MWCNTs) and a spark plasma sintering (SPS) process. Single and few-hundred-nanometer graphene nanosheets were formed from gas-phase carbon atoms which were directly evaporated from MWCNTs at a local high temperature.

Simple route for gram synthesis of less defective few layered graphene and its electrochemical performance

“…S5a and S5b †). 28 This indicates the insertion of fewer oxygen functional groups during the exfoliation process, which is also consistent with FTIR and Raman spectroscopy.…”

Synthesis of graphene nano-sheet without catalysts and substrates using fullerene and spark plasma sintering process

“…Contacts were placed between two graphite rams in a cylindrical graphite (ISO-63) die with an inner diameter of 20 mm with 2 g fullerene. The pellets were heated to 600 o C at a heating rate of 10 o C/min with a pressure of 100 MP a between the rams, and the applied direct current was about 1500 A (voltage < 5 V) with a pulse duration of 12 ms and pulse interval of 2 ms during 10 min [16]. The thickness of compact sintered samples was about 2 mm.…”

Multiple-layered nonwoven nanosheets consisting of multiwalled carbon nanotubes

“…The applied direct current was in the range of 1500–2500 A (voltage <5 V) and the pulse duration and interval were 12 and 2 ms, respectively. As revealed in our previous paper , the pulse current flows through the MWCNTs during the SPS process, generating heat and thus providing energy to the MWCNTs.…”