Metal-free honeycomb-like porous carbon as catalyst for direct oxidation of benzene to phenol

Benzene oxidation to phenol is an important chemical process in industry. We present here a honeycomb-like porous carbon (HPC) as metal-free catalyst for benzene direct oxidation to phenol in the presence of hydrogen peroxide under mild reaction conditions. Different from supported metal catalysts, carbon on HPC served as catalytically active sites for benzene direct oxidation to phenol as it was capable of decomposing H2O2 into active oxygen species. Characterizations by XPS and Raman spectra accompanied by H2O2 decomposition tests revealed that the catalytic activity was associated with structure defects of the HPC. The hydrogen-reduced HPC exhibited higher catalytic activity as compared to that of pristine HPC, which was attributed to the formation of more structure defects. With the hydrogen reduction, structure defects of the HPC were increased. Meanwhile, carbon active sites bonded by oxygen-containing species were released to attain more active sites, consequently accelerating the oxidation of benzene. (C) 2018 Elsevier Ltd. All rights reserved.