Regulating interfacial electronic structure in Fe2O3/g-C3N4 heterogeneous Fenton catalyst for efficient low-temperature flue gas denitrification

Fe 2 O 3 /g-C 3 N 4 accelerates Fe redox cycling for efficient H 2 O 2 activation. • g-C 3 N 4 pumps electrons to Fe sites, boosting interfacial charge transfer. • Alkaline microenvironment uniquely steers ROS pathway toward O 2 •− generation. • Process yields 93.2% NO x removal, converting NO into valuable N-resources. To overcome the challenges associated with low-temperature industrial flue gas denitrification, this study presents a highly efficient Fe 2 O 3 /g-C 3 N 4 heterogeneous Fenton catalyst synthesized via a facile impregnation approach. This composite effectively activates H 2 O 2 for deep NO x elimination. Under optimal alkaline conditions, the Fe 2 O 3 /g-C 3 N 4 system achieved a remarkable maximum NO x removal efficiency of 93.2%, while demonstrating exceptional durability by retaining over 80% efficiency across five consecutive reaction cycles. Comprehensive experimental characterization coupled with density functional theory (DFT) calculations reveal that g-C 3 N 4 serves as an electron-rich reservoir. This framework systematically accelerates the rate-limiting Fe 2+ /Fe 3+ redox cycling on the Fe 2 O 3 surface through enhanced interfacial charge transfer. Crucially, the alkaline environment uniquely steers the reactive oxygen species (ROS) evolution pathway toward the highly selective generation of superoxide radicals (O 2 •− ). These predominant O 2 •− species rapidly oxidized NO to form peroxynitrite intermediates, thereby promoting the deep conversion of NO into recoverable nitrate and nitrite products. This work provides a robust and scalable strategy for low-temperature NO ₓ purification and offers new mechanistic insights into how the reaction microenvironment regulates radical selectivity. Download: Download high-res image (294KB) Download: Download full-size image