Electronic Structure Regulation of Fe sites by Coordinating Moieties in the Fenton-like Process Enables Tunable Water Decontamination

The electronic configuration modulation of active sites is critical to control the catalytic mechanism in the Fenton-like process as it offers a promising strategy for tunable water decontamination. Herein, electronic density-dependent catalysts based on FeOCl with externally coordinated moieties were fabricated to fulfill the switching of the catalytic oxidation mechanism in peroxymonosulfate (PMS)-based Fenton-like reactions. The experimental results indicate that the catalytic activity and reaction mechanism vary with the changes in electronic density around the Fe site, which determines the contributions of radical and nonradical mechanisms, thus achieving selective or nonselective oxidation. Theoretical simulations indicate that Fe sites with sufficient electronic density are inclined to adsorb the O sites of the O-O bond followed by subsequent electron transfer and radical generation. Conversely, Fe sites with a deficient electronic density tend to adsorb the terminal O of PMS, facilitating the oxidation of PMS to form sulfate radical anions, which then convert to singlet oxygen. The sustained activity of loaded catalysts during the 10 h continuous operation of the scaled-up experiment demonstrated their potential for practical application. This work brings an in-depth insight into the catalytic mechanism of the Fenton-like reaction and guides the electronic engineering of catalysts to meet the specific demands of various experimental scenarios.