Defect‐Engineering‐Mediated Long‐Lived Charge‐Transfer Excited‐State in Fe–Gallate Complex Improves Iron Cycle and Enables Sustainable Fenton‐Like Reaction

Abstract

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 H2O2 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 H2O2 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

Coupling homogeneous and heterogeneous catalysis for the efficient and selective activation of H2O2

“…61 However, the rate of the reaction between H 2 O 2 and Fe 3+ is very slow (0.001–0.01 M −1 s −1 ). 17 Alternatively, H 2 O 2 can decompose into O 2 , and Fe 2+ can act as an electron donor to reduce O 2 to ˙O 2 − . 28 However, this route requires efficient Fe 2+ /Fe 3+ cycling.…”

“…The classic homogeneous Fe 2+ catalyst is highly efficient in the activation of H 2 O 2 , but it preferentially generates ˙OH, 16 requires an acidic working condition, and creates Fe-based sludge as waste. 17 In contrast, heterogeneous transition-metal-based catalysts ( e.g. , metals, metal sulfides, and metal oxides) can manipulate the O–O and O–H stretching of H 2 O 2 (ref.…”

A “Ferroptosis-Amplifier” Hydrogel for Eliminating Refractory Cancer Stem Cells Post-lumpectomy

“…GFP possesses more ferrous ions than FeOOH, and this higher Fe 2+ content is beneficial for enhancing the Fenton catalytic capability. Moreover, it has been documented that GA-Fe species can work as an excellent Fenton-like agent due to the strong metal–ligand exchange coupling between Fe 3+ and GA ligand, resulting in a strong electronic delocalization that makes the value of the Fe center with spin densities closer to the values of Fe 2+ , thus promoting • OH generation. − Collectively, a higher Fe 2+ level and GA–Fe coupling effect contribute to the enhanced Fenton activity of GFP.…”