Metal-free diatomaceous carbon-based catalyst for ultrafast and anti-interference Fenton-like oxidation

Herein, a diatomite biomorphic Si-O doped carbon-based catalyst (DB-SiOC) was prepared using natural mineral diatomite as the silicon source and porous template. The results showed that the metal-free DB-SiOC catalyst exhibited ultrafast oxidation towards chlorophenol (CP) via peroxymonosulfate (PMS) activation, which was almost one order of magnitudes than most of carbon-based catalysts. The DB-SiOC/PMS system also showed the high ability to resist the interference of environmental matrix. The radicals (•OH and SO4•‒) exhibited a very small contribution to the CP oxidation while the electron transfer processes (ETP) played the major role in the DB-SiOC/PMS system. The electron shuttles from the electron-donating CP molecules to the adjacent DB-SiOC/PMS* could be efficiently triggered via Si-O bonds as bridges, making it possible for ultrafast oxidation of CP. In addition, the hollow-disc shaped DB-SiOC provided the biomorphic DE structures with abundant pores for enriching the PMS and pollutants, thus further accelerating the oxidation reaction. This work provided a new routine for the fabrication of Si-O doped carbon-based catalysts with excellent Fenton-like catalytic activity, which would greatly promote their application prospects in Fenton-like systems.