Chalcogen Elements in Regulating the Local Electron Density of Cu2X for an Efficient Heterogeneous Fenton-like Process

In this work, a novel strategy for Fenton activity improvement of Cu2X was reported, in which the local electron density of Cu sites was regulated via manipulation of simple chalcogen elements (O, S, and Se). Among them, Cu2Se catalysts show excellent catalytic activity to activate H2O2 for the complete removal of ofloxacin (10 mg/L) at an initial pH of 6.5 within 120 min. Radical scavenger experiments and electron spin resonance spectroscopy confirm that •OH radicals are the primary oxygen reactive species to drive ofloxacin degradation. In addition, density functional theory calculations further proved that electrons would migrate from X and accumulate on Cu active sites in the order Se > S > O. Compared with Cu2O and Cu2S, the highly concentrated electron density of Cu atoms in Cu2Se not only decreased the activation energy of the Fenton-like reaction but also boosted the Cu2+/Cu+ cycle with the generation of more •OH radicals (18-66 μm) and the maintenance of high stability of catalysts, leading to excellent catalytic activity and application potential. We believe this work will lay the foundation for designing excellent Fenton catalysts for practical applications since developing a heterogeneous Fenton system with the highest oxidation efficiency has always been the long-term goal in this field.