Amorphization Strategy to Circumvent the Oxo Wall for Generating Active Co(IV)═O Species in Fenton‐Like Reactions

Abstract

Abstract High‐valent Co(IV)═O species have garnered significant attention as a promising non‐radical reactive species. However, their selective generation encounters substantial challenges due to the oxo wall rule that emphasizes intrinsic instability of the terminal metal–oxygen (M─O) bond. Here, we propose an amorphization strategy for TiO 2 support to circumvent the limitation of oxo wall, favoring the formation of high‐valent Co(IV)═O species. The advantages of Co(IV)═O species in terms of oxidative activity, durability, and environmental tolerance were investigated by Fenton‐like catalysis. Mechanistic studies revealed that amorphous TiO 2 endowed Co single atoms with a Co‐O 4 tetrahedral structure and a high‐spin state of 3 d electron, leading to strong Co 3 d ‐O 2 p interactions that promote peroxymonosulfate (PMS) activation. Notably, the produced Co(IV)═O species adopted a trigonal‐bipyramidal‐like configuration, which mitigated the electron occupation in the antibonding orbitals of terminal M─O bond, thus bypassing the oxo wall. This work enhances the understanding of the mechanism underlying heterogeneous Co(IV)═O formation and broadens strategies for preparing efficient catalysts for critical oxidation reactions.