The catalysts, namely noble-metal-free Co-N-C immobilized carbon nanotubes (CNTs), are synthesized via heating nitrogen-rich cobalt tetraphenyl porphyrin (CoTPP) supported on CNTs in N-2 atmosphere."The obtained catalysts have been characterized by BET, Raman, XRD, TEM, HRTEM and XPS. It is found that the synergistic effect between carrier and active sites plays an important role in the catalytic performance of Co-N-C/CNTs for ethylbenzene oxidation. When the mass ratio of CoTPP to CNTs is 0.15, the catalyst exhibits the highest catalytic performance for ethylbenzene oxidation (i.e. 19.9% for ethylbenzene conversion, 72.9% selectivity of acetophenone). It can be attributed to the well-dispersed Co-N-C species and the enhanced interaction chances between substrate and active sites with the introduction of CNTs. (c) 2016 Elsevier B.V. All rights reserved.