LAUSR

Abstract The structural evolution of SF-soot (derived from the rapid pyrolysis of ShenFu bituminous coal) and a carbon black (Printex) was performed for air oxidation at 1273 and 1473 K. The morphology and nanostructure transformations were examined at conversion fractions ~0.2, 0.4, 0.6, and 0.8. Three modes of behavior were evident. The behavior of SF-soot followed an internal oxidation model (IOM) at 1273 K. The oxygen was able to fully permeate into the particle core, producing a sphere with variable removal of the interior structure with conversion. However, at the higher temperature, the SF-soot formed a concentric spherical structure with gradual consumption of the inner sphere due to restricted oxygen penetration. The fragmentation of hollow interior particles, on which the available literature is not extensive, was observed from HRTEM and SEM micrographs for the first time. During the oxidation of SF-soot, micropores were mainly generated during the 0–0.2 conversion, while the mesopore surface rapidly increased during the 0.6–0.8 conversion. The X-ray diffraction (XRD) patterns and Raman spectra both show that the oxidation of SF-soot is mainly a disordering process. The graphitic microcrystals were mainly consumed along the longitudinal orientation during the 0–0.2 conversion but were mainly consumed along the horizontal during the 0.4–0.8 conversion. The true densities of SF-soot and carbon black initially increase and then decrease monotonically during oxidation.