Preparation of nanostructured carbon materials

Abstract

The low-density organic aerogels formed by the supercritical carbon dioxide drying of 5-methylresorcinol- formaldehyde gels are a good source material for the preparation of low-density carbon aerogels with a homogeneous structure. I n our research the supercritical drying process was optimized so that the resulting aerogels would not significantly shrink durin g the process. The density of the resulting 5-methylresorcinol-formaldehyde organic aerogel was as low as 0.1 g/cm 3 , its specific surface area being more than 350 m 2 /g. Also, the pyrolysis of the organic aerogel to get carbon material with a proper structure was optimized in relation to the low rate of the evolution of pyrolysis products during the process. The carbon material obtain ed had a uniform structure, consisting of sparsely packed particles with a narrow size distribution. The density of carbon aerogel s obtained was 0.2 g/cm 3 , their specific surface area being over 700 m 2 /g; the shrinkage was up to 30%. It was also found that the porosity of carbon aerogels could be varied by changing the cond itions of synthesis. The aerogels obtained were examined using scanning electron microscopy, infrared spectroscopy, and nitrogen adsorption-desorption analysis.