Characterization of coal before and after supercritical CO2 exposure via feature relocation using field-emission scanning electron microscopy

► We examine the effect of supercritical CO2 on coal structure and porosity. ► We investigate irreversible CO2 induced alterations of micro-, meso-, and macropores. ► Analyses indicate no changes observed in macropores after SCCO2 exposure. ► Meso- and micropore characteristics were slightly affected by SCCO2 exposure.