Structure manipulation of carbon aerogels by managing solution concentration of precursor and its application for CO₂ capture

A series of carbon aerogels were synthesized by polycondensation of resorcinol and formaldehyde, and their structure was adjusted by managing solution concentration of precursors. Carbon aerogels were characterized by X-ray diffraction (XRD), Raman, Fourier transform infrared spectroscopy (FTIR),N₂ adsorption/desorption and scanning electron microscope (SEM) technologies. It was found that the pore structure and morphology of carbon aerogels can be efficiently manipulated by managing solution concentration. The relative micropore volume of carbon aerogels, defined by V_micro/V_tol, first increased and then decreased with the increase of solution concentration, leading to the same trend of CO₂ adsorption capacity. Specifically, the CA-45 (the solution concentration of precursors is 45 wt%) sample had the highest CO₂ adsorption capacity (83.71 cm³/g) and the highest selectivity of CO₂/N₂ (53) at 1 bar and 0 °C.