Enhanced Interfacial Electron Transfer by Asymmetric Cu-Ov -In Sites on In2 O3 for Efficient Peroxymonosulfate Activation

Abstract

Enhancing the peroxymonosulfate (PMS) activation efficiency to generate more radicals is vital to promote the Fenton-like reaction activity, however, how to promote the PMS adsorption and accelerate the interfacial electron transfer to boost its activation kinetics remains a great challenge. Herein, we prepared Cu-doped defect-rich In₂ O₃ (Cu-In₂ O₃ /O_v ) catalysts containing asymmetric Cu-O_v -In sites for PMS activation in water purification. The intrinsic catalytic activity is that the side-on adsorption configuration of the O-O bond (Cu-O-O-In) at the Cu-O_v -In sites significantly stretches the O-O bond length. Meanwhile, the Cu-O_v -In sites increase the electron density near the Fermi energy level, promoting more and faster electron transfer to the O-O bond for generating more SO₄ ⋅^- and ⋅OH. The degradation rate constant of tetracycline achieved by Cu-In₂ O₃ /O_v is 31.8 times faster than In₂ O₃ /O_v , and it shows the possibility of membrane reactor for practical wastewater treatment.

Keywords: Asymmetric Cu-Ov-In sites; Electron Transfer; Fenton-Like Reaction; PMS Activation; Sulfate and Hydroxyl Radicals.