Coupling local oxygen enrichment with FeN5-mediated H2O2 activation for energy-efficient electro-Fenton oxidation of sulfamethoxazole

Synergistic microenvironment enables low-energy electro-Fenton SMZ degradation. • Amino-CNT site enhances oxygen utilization and FeN 5 boosts •OH generation. • Stable SMZ removal over 20 cycles and across pH 3–11 and real water matrices. The practical effectiveness of the electro-Fenton (EF) technology is severely constrained by sluggish oxygen mass transport and inefficient activation of hydrogen peroxide (H 2 O 2 ). Herein, a synergistic catalytic microenvironment was constructed by integrating a biomimetic FeN 5 single-atom nanozyme with an amino-functionalized carbon nanotube support (CNT−NH 2 ) to overcome these dual challenges. Experimental and theoretical results reveal that the −NH 2 groups on CNT−NH 2 induce a local oxygen-enriched interface, significantly enhancing oxygen (O 2 ) supply and promoting the 2e − oxygen reduction reaction (2e − ORR) for efficient in situ H 2 O 2 generation. Simultaneously, the FeN 5 sites facilitate hydroxyl radical (•OH) production by mimicking peroxidase activity, thereby lowering the activation energy for O−O bond cleavage in H 2 O 2 . The resultant FeN 5 −CNT−NH 2 EF system achieves complete degradation of sulfamethoxazole (100% in 45 min) with a remarkably low specific energy consumption (0.0235 kWh g −1 TOC), and demonstrates excellent stability and broad applicability in complex water matrices. This work provides a novel perspective for constructing high-performance EF process through synergistic microenvironment engineering. Download: Download high-res image (144KB) Download: Download full-size image