Carbon Nanorods Synthesized by Graphite Oxide Thermal Reduction with Microwaves

Recently, carbon nano-rods (CNRs) have been investigated for potential applications as support for catalytic metal nanoparticles, in gas storage, electrochemical energy storage, etc. [1]. The CNRs consist of stacked graphene sheets with aspect ratios ranging from 3 to 5 and their functional properties arise from quantum-confinement and surface effects [1]. These materials have been produced by different techniques, like for example arc discharge, plasma torch, CVD, nanocasting, etc. [1]. In this work, CNRs have been obtained as byproduct of the graphene synthesis made by thermal reduction of graphite oxide (GO), using microwave heating [2]. In particular, water solutions of GO have been synthetized according to the Hummers method and dried to give GO paper. This solid material has been dissolved in N-methyl-2-pyrrolydone (NMP) by a prolonged ultrasound treatment and the achieved GO/NMP solution has been heated to the solvent boiling point (202°C) in a microwave oven. In a few minutes the solution turned into a black graphene/NMP suspension and by a filtering procedure a graphite/NMP gel and a reddish CNRs/NMP solution have been obtained. The CNRs have been recovered by solvent removal and purified by washing with ethanol. The purified product has been morphologically characterized by transmission electron microscopy (TEM). According to the TEM micrographs shown in Figure 1, CNRs have length of several hundred nanometers (300-600 nm) and height less than 100 nm. The excitation-emission properties of these nanostructures were investigated by florescence spectroscopy.