Surface morphology, metal dispersion, and pore texture of transition metal-doped monolithic carbon aerogels and steam-activated derivatives

Abstract

Fe, Co, Ni and Cu-doped organic aerogels were prepared by sol–gel method from resorcinol-formaldehyde mixtures containing the corresponding metal acetates. They were carbonized under nitrogen flow at 1000 °C, and some of them were further steam activated at 900 °C. A blank sample was also prepared. During carbonization, the shape of the CH 4 and CO 2 evolution profiles depended on the nature of the metal present in the aerogel. Samples were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction. Surface area and pore texture were characterized by N 2 and CO 2 adsorption at −196 and 0 °C, respectively, and by mercury porosimetry. Surface morphology of the monolithic organic aerogels was similar to that of their corresponding parent organic aerogels but with smaller particle size. Metals were dispersed at nanometric scale and some of them partially graphitized the carbon structure. The effects of carbonization and steam activation on the surface area and porosity varied according to the nature of the metal present.