Heteroatom-doped carbon-based materials are considered to be efficient metal-free catalysts for diverse organic synthetic reactions. However, compared with metal-based catalysts, there are still gaps in the catalytic performance of metal-free catalysts in the selective catalytic oxidation of C–H bonds. Herein, nitrogen-doped 3D hollow carbon spheres (N-HCSs) were prepared by the chemical vapor deposition (CVD) method. And the effects of deposition temperature, nitrogen content and pore structure on the catalytic performance are systematically investigated. For the model oxidation reaction of ethylbenzene, the obtained catalyst shows 98.4% conversion of ethylbenzene and 99.5% selectivity of acetophenone at 50 °C. The abundant mesopores and modest graphite nitrogen content are confirmed to be beneficial for improving their catalytic activity in the selective oxidation of C–H bonds.