In this paper, cobaltporphyrin is used as a precursor to synthesize carbon nitrides with metal active sites supported on silica spheres by heat treatment (i.e. M-N-C/SiO2). The catalytic performance of M-N-C/SiO2 for ethylbenzene oxidation has been investigated and techniques such as N2 adsorption/desorption isotherm, NH3-TPD, HRTEM, STEM mapping and X-ray photoelectron spectroscopy (XPS) are e...