In this study, Co–N–C supported on silica spheres is prepared through heat-treatment of supported metalloporphyrin in an N₂ atmosphere. The catalytic performance of the catalysts for ethylbenzene oxidation is investigated and these catalysts are characterized by techniques such as BET, FT-IR, UV-vis, TEM and XPS. In comparison with other catalysts such as supported cobalt porphyrin and unsupported cobalt porphyrin, Co–N–C supported on silica spheres shows much higher catalytic activity for ethylbenzene oxidation (15.7%) and selectivity to acetophenone (76.5%). In addition, the catalyst can retain its high catalytic activity after several reuses. The results show that the high catalytic performance of the catalyst may be attributed to the formation of Co–N₄–C sites during the heat-treatment and supported Co–N–C catalysts may be beneficial to yield more Co–N₄–C sites.