Low-density organic and carbon aerogels from the sol–gel polymerization of phenol with formaldehyde

Abstract Low-density organic and carbon aerogels are prepared from the sol–gel polymerization of cheap phenol with formaldehyde using NaOH as the base catalyst, followed by ethanol supercritical drying. The effects of the preparation conditions, including the mole ratio of phenol to NaOH (P/C), the mole ratio of phenol to formaldehyde (P/F), phenol–formaldehyde (PF) concentration and gelation temperature, on the gelation time, the bulk density as well as the physical and chemical structures of the resultant organic and carbon aerogels were studied. The experimental results of TEM and nitrogen adsorption showed that the phenol derived organic and carbon aerogels have a three-dimensional network that consists of interconnected bead-like particles with diameters of approximately 10–15 nm, which define numerous mesopores less than 50 nm. The highest measured BET surface area and mesopore volume of the carbon aerogels obtained reached 714 m 2  g −1 and 1.84 cm 3  g −1 , respectively.