In-situ hydrothermal synthesis of carbon nanorice using Nafion as a template

Carbon nanorice has been prepared by the hydrothermal carbonization of heparin in a Nafion solution at a mild temperature of approximately 100 degrees C. Through transmission electron microscopy, the individual grains of this nanorice were found to have a diameter in the range of 100 nm and a length of approximately 500 nm. The mechanism of formation for this nanoscale rice-like structure is suggested to be a self-assembling process; wherein charring of the heparin causes desulfation followed by carbonization, ultimately forming 5-hydroxylmethyl furfural in the presence of a Nafion membrane. This is confirmed through Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, with this method also shown to produce a much greater number of carbon structures than other synthesis methods. Moreover, this new method results in carbon nanorice that exhibits fluorescence, which is of great interest for potential biomedical or optoelectronic applications. (C) 2014 Elsevier Ltd. All rights reserved.