Defect Engineering-Mediated Long-Lived Charge Transfer Excited State in Fe-gallate Complex Improves Iron Cycle And Enables Sustainable Fenton-like Reaction.

Fenton reactions are inefficient because the Fe(II) catalyst cannot be recycled in time due to the lack of a rapid electron transport pathway. This result in huge H 2 O 2 wastage in industrial applications. Here, we show a sustainable heterogeneous Fenton system is attainable by enhancing ligand-to-metal charge transfer (LMCT) excited-state lifetime in Fe-gallate complex. By engineering oxygen defects in the complex, we improved the lifetime from 10 to 90 picoseconds. The lengthened lifetime ensured sufficient concentrations of excited states for efficient Fe cycle, realizing previously unattainable H 2 O 2 activation kinetics and hydroxyl radical ( • OH) productivity. Spectroscopic and electrochemical studies show the cyclic reaction mechanism involves in situ Fe(II) regeneration and synchronous supply of oxygen atoms from water to recover dissociated Fe-O bonds. Trace amounts of our catalyst effectively destroyed two drug-resistant bacteria even after 8 reaction cycles. Our work reveals the link between LMCT excited-state lifetime, Fe cycle, and catalytic activity and stability, with implications for de novo design of efficient and sustainable Fenton process. This article is protected by copyright. All rights reserved.