Work

Spin‐Dependent Generation of Surface‐Bound Radicals Toward Selective and Long‐Lasting Water Purification

Year: 2026

Type: article

Abstract: ABSTRACT To address the self‐quenching and poor anti‐interference limitations of conventional free radical oxidation processes, this study develops an atomic engineering strategy to fine‐tune the spin state of α‐Fe 2 O 3 catalysts to modulate peroxymonosulfate (PMS) activation and selectively yield surface‐bound radicals. Specifically, Cu 2+ (3d 9 ) doping triggers Jahn‐Teller distortion, intensifying crystal field splitting and transitioning Fe spin state from high‐spin (e g = 2) to medium‐spin (e g = 1.38). The decreased electron density in the Fe‐e g orbital reduces σ* anti‐bonding interactions between Fe 3d and O 2p, thus strengthening adsorption and inducing moderate electron transfer to PMS. With electron co‐injection from Cu, the O‐O cleavage generates the surface‐bound SO 4 •− on Cu sites. While the 3d 10 of Zn 2+ has minimal impact on the crystal field, ensuring α‐Zn 0.1 Fe 1.9 O 3 in a relatively high‐spin (e g = 1.81), which promotes intense electron transfer to PMS to generate free SO 4 •− . Additionally, surface‐bound radicals endow the α‐Cu 0.1 Fe 1.9 O 3 /PMS 1.4‐fold higher aceclofenac removal k obs than α‐Zn 0.1 Fe 1.9 O 3 /PMS and superior anti‐interference capacity to water background factors, due to the extended lifespan, surface confined environment, and moderate oxidation potential of surface‐bound SO 4 •− . This study provides insights into the advanced design of spin‐regulated catalysts for surface‐bound radicals generation to secure both high oxidation and anti‐interference capacity in water purification processes.

Source: Advanced Functional Materials

DOI: 10.1002/adfm.202529316