Atomic Fe‒P Pairs Eliminate H ₂ O ₂ Migration Barriers for Sustainable Electro‐Fenton Water Treatment

Abstract

Abstract The electro‐Fenton process, involving O 2 reduction to H 2 O 2 and its subsequent activation into •OH, is an eco‐friendly strategy for degrading organic pollutants in wastewater. Enhancing electro‐Fenton efficiency necessitates two distinct functional sites: one for H 2 O 2 generation to preserve the O‒O bond and the other for activation to cleave the O‒O bond. Despite extensive efforts to optimize these functions, the role of H 2 O 2 migration between sites has been largely overlooked. Excessive inter‐site distances can lead to sluggish H 2 O 2 migration, making it a potential rate‐limiting step in electro‐Fenton catalysis. To address this challenge, we have developed Fe‒P pairs at the atomic level, achieving the theoretical shortest site distance, with single‐atom Fe acting as the H 2 O 2 activation center and P in its first coordination shell facilitating H 2 O 2 generation. Experimental and theoretical analyses revealed that Fe‒P pairs significantly shortened the H 2 O 2 diffusion time to ∼1.5 ps, over 10 times faster than unpaired configurations, by reducing the migration distance, thereby improving the H 2 O 2 utilization efficiency by over 4 times and enhancing electro‐Fenton performance. Life cycle assessment further highlighted the low environmental impact of this approach, indicating its potential for large‐scale wastewater treatment. By exploiting the previously neglected role of H 2 O 2 migration, this study not only enhances our understanding of the electro‐Fenton process but also offers new insights into the rational design of advanced electro‐Fenton catalysts.