Self-powered electron transfer on single-atom dual-reaction center: Achieving high-efficiency catalysis in...

Achieving efficient electron transfer from pollutants to a catalyst, without reliance on any exogenous oxidant, constitutes a key challenge in advanced oxidation processes. This study directly addresses this challenge by engineering a dual-reaction-center catalyst with atomically dispersed Fe-N₄ sites (DRC-FeN₄), designed to facilitate pollutant-driven self-powered electron activation. Through a combination of in-situ spectroscopic characterization, electrochemical analysis, and controlled mechanistic experiments, we provide evidence that organic contaminants serve as intrinsic electron donors. Electrons are directly transferred to the single-atom iron centers, initiating a self-powered catalytic cycle that operates independently of added oxidants or dissolved oxygen. A robust quantitative structure-activity relationship further confirmed that degradation kinetics were governed by the inherent electron-donating capacity of the pollutants (e.g., ΔE_gap shift, HOMO energy, and nucleophilicity index), decisively decoupling the catalytic electron-transfer pathway from non-catalytic adsorption. The practical viability and environmental sustainability of this oxidant-free (without additional oxidant) system were validated through its effective performance in continuous-flow reactors treating real water matrices and a complementary life cycle assessment. This work establishes a fundamental mechanistic framework and provides a clear design principle for developing efficient, predictable, and sustainable advanced oxidation technologies tailored for complex water purification scenarios.