A microwave-based method for the synthesis of carbon xerogel spheres

Carbon xerogel spheres with millimeter-scale diameters were synthesized by a simple process using microwave radiation as the heating source. Using this type of heating it is possible to establish the gelation point of different resorcinol–formaldehyde solutions and stop the gelation step of the material at the exact time of gelation. Organic gel spheres can then be directly obtained by stirring in a silicone bath at 80 °C. Finally, carbonization is performed to obtain carbon xerogels with a spherical shape. The size and porous texture of the spheres can be controlled by adjusting the synthesis conditions.