Vacancy engineering triggers Cu-O-Ti superexchange: Spatial charge separation and synchronous utilization for enhanced Fenton-like performance

Superexchange-mediated dual-acceptor sites enable spatial charge separation. • Synergistic single-atom and vacancy engineering creates multifunctional sites. • Cu SA -TO-O V delivered excellent corresponding turnover frequencies of 177.52 h −1 . • The photo-Fenton system exhibited wide pH adaptability and anti-interference. Synchronously and efficiently utilizing photogenerated electrons and holes remains a significant challenge in Fenton-like reaction. Herein, the Cu single-atom (Cu SA ) and oxygen vacancy (O V ) co-modified TiO 2 nanoflake-like catalyst is successfully synthesized. O V modulate the electronic coupling interaction, which is proposed to trigger superexchange -mediated electron transfer from Cu 3 d x 2 − y 2 to Ti 3 d xy via O 2 p y orbitals. Specifically, Cu SA serves as the hole-accepting site for 1 O 2 generation, while O V and Ti 3+ functions as the electron-accepting site for •OH production and contaminant adsorption. The substrate enrichment effect and the free radical/non-radical coupling interaction significantly enhances photo-Fenton catalytic performance, achieving superior sulfanilamide removal efficiency across a broad pH range (3–11) and a high turnover frequency of of 177.52 h −1 . This work not only highlights the potential of active site engineering in designing photo-Fenton catalysts but also advances the development of efficient and sustainable water purification solutions.