Synthesis of monodisperse carbon cryogel microspheres using membrane emulsification of a phenol–formaldehyde solution

Monodisperse carbon cryogel (MCC) microspheres were synthesized by membrane emulsification of a phenol–formaldehyde (PF) solution using a Shirasu porous glass membrane followed by freeze-drying and carbonization in an inert atmosphere. This approach made it possible to use inexpensive phenol as a carbon precursor in combination with formaldehyde. By adjusting the initial pH of the PF solution, it was possible to obtain PF-MCC microspheres with a high specific surface area and a large pore volume comparable to microspheres prepared by using the conventional and relatively expensive resorcinol as a carbon precursor in combination with formaldehyde.