5-hydroxymethylfurfural as a potential monomer for the preparation of carbon aerogel

To explore a potential of 5-hydroxymethylfurfural (HMF) in the preparation of carbon aerogels, phloroglucinol–HMF–furfural (PHF) and phloroglucinol–HMF (PH) alcogels were synthesized. It was found in PHF carbon aerogels that the addition of HMF led to a change in their surface chemical properties, i.e., the favorable formation of surface C–O and O=C–O groups. When phloroglucinol and HMF were used as a carbon monomer, PH alcogels were formed at room temperature within tens of minutes. The resulting PH carbon aerogels showed a surface area of 975–1290 m2 g−1, a pore size distribution centered at about 30 nm, and a pore volume of 1.35–1.86 cm3 g−1. As a result of varying several preparation variables, their surface chemical properties were different in accordance with PHF samples. Additionally, a cyclic voltammetry test was conducted, resulting in the fact that the gravimetric capacitance of PHF and PH carbon aerogels showed strong dependence on their chemical characteristics. It was consequently revealed that, due to the peculiar structure of HMF, the preferential formation of C–O linkages through intermolecular dehydration occurs along with unreacted phenolic hydroxyl species of phloroglucinol at the surface, thus yielding a higher gravimetric capacitance.