Nanoreactors with a delimited void space and a large number of mesoporous structures have attracted great attention as potential heterogeneous catalysts. In this work, a cobalt and nitrogen co-doped binary carbon@silica@carbon hydrophobic nanoreactor was synthesized by an in situ synthesis method. Cobalt porphyrin was used as an active component to construct Co-Nx sites, and the purpose of the double carbon layer coating was to enhance the hydrophobicity of the surface of the nanoreactor. The optimal nanoreactor could achieve 96.9% ethylbenzene conversion and 99.1% acetophenone selectivity and showed outstanding universality to many other aromatic alkanes. The superior performance was mainly due to the presence of double carbon layers and the high content of Co-Nx sites. The double hydrophobic carbon layer coating could not only promote the adsorption of organic molecules, but also implant Co-Nx active sites on both the inner and outer surfaces of the nanoreactor. This work proposed a meaningful strategy to obtain a highly efficient nanoreactor for C-H bond oxidation.