Microporous carbon spheres derived from resorcinol-formaldehyde solutions. A new approach to coat supports

Abstract

Microporous carbon spheres of different morphology and porosity were synthesized from resorcinol-formaldehyde solutions by a simple and fast procedure. Polymeric spheres were shaped by means of microwave heating. Carbonization and activation with carbon dioxide were then applied to obtain the intended final carbon spheres. The influence of the pH, heating time and thermal treatments on the morphology and porosity of the carbon spheres was investigated. It was found that the size of the spheres, can be easily controlled during the synthesis process, specifically by modifying the pH of the precursor solution. An increase in the pH value from 3 to 5 led to carbon spheres with sizes of 4 μm and 3.5 μm, respectively, whereas time seemed to have no effect. These results have been attributed to the chemical mechanisms of the polymerization reaction. On the other hand, microporosity was tailored during the thermal treatments. Carbon spheres with surface areas of 630 m2/g and 1500 m2/g were obtained by applying carbonization and physical activation, respectively. Furthermore, the synthesis method proposed allows to obtained liquid polymerized inks that can be further used to coat ceramic supports by a simple spray-drying process, which enhances the potential of these materials for several applications.