A template-free method was employed to synthesize cobalt catalysts embedded in N-doped carbon (Co-N-C) through heating cobalt(II) meso-tetraphenyl porphyrin (CoTPP) precursor at different temperature (600 degrees C, 700 degrees C, 800 degrees C). These catalysts were characterized by techniques such as BET, TG-DTA, TEM, STEM, XRD, Raman and XPS. The selective oxidation of ethylbenzene under solvent-free condition with molecular oxygen was carried out to explore the catalytic performance of Co-N-C. 13.4% conversion of ethylbenzene with 73.3% selectivity to acetophenone was achieved over Co-N-C and the catalytic performance of the catalyst was similar to the fresh even after six runs (i.e., 12.5% of ethylbenzene conversion and 72.2% of selectivity to acetophenone). The results show that the stable catalytic performance of the catalysts may be attributed to the stable N-doped graphitic carbon, the stability of carbon-encapsulated Co nanoparticles and the synergistic effect between N-C structure and cobalt oxide. (C) 2015 Elsevier B.V. All rights reserved.