Orientated reception-emission of electrons at Fe single atoms driving emerging contaminants decomposition via Fe-O/C...

The efficiency of heterogeneous catalysis in wastewater treatment is mainly constrained by the non-directional electron transfer at solid-liquid interfaces. To address this limitation and regulate interfacial electron directional transfer (EDT), we pioneered a dual-reaction-center (DRC) catalyst based on Fe single atoms anchored on nitrogen-doped carbon substrates (FeNC-SAs), which achieves self-sustained directional electron acceptance-emission cycles at interfaces without external energy input. DFT analyses reveal that Fe-N coordination induces robust interfacial d-pπ conjugation, redistributing π-electrons from graphitic layers to Fe sites and triggering localized surface electronic polarization to form electron-poor centers (EPCs) and electron-rich centers (ERCs). Strong hybridization between Fe 3d orbitals and the p orbitals of reactive oxygen species (O₂) or pollutant molecules (C-based) establishes efficient transfer channels for EDT. Remarkably, pollutants could be completely removed within 60 min in every cycle, while the removal efficiency could be retained only 30% after excluding dissolved oxygen (DO), unequivocally identifying DO as the terminal electron acceptor sustaining continuous EDT. This work establishes a mechanistic paradigm for steering interfacial EDT via atomic-level orbital hybridization, offering transformative insights for designing high-performance catalysts for environmental and catalytic applications.