Long-range electron transfer pathways at FeCu bimetallic interfaces: Bridging catalytic mechanisms and scalable applications for persistent pollutant degradation.

Abstract

Efficient and stable heterogeneous catalysts for peroxymonosulfate (PMS) activation are pivotal for advancing advanced oxidation processes in water treatment. However, the limited redox cycling capacity of single-metal sites often hinders their catalytic performance and durability. Here, dispersed Fe-Cu bimetallic clusters anchored on a nitrogen-sulfur codoped carbon matrix ((FeCu-SNC) were synthesized via a coordination-pyrolysis strategy. FeCu-SNC was engineered to activate peroxymonosulfate (PMS) for the degradation of bisphenol A (BPA) and structurally diverse pollutants. Combined experimental and density functional theory (DFT) analyses revealed that the Fe-Cu dual sites synergistically enhanced PMS adsorption and triggered a dominant electron transfer pathway (ETP), bypassing conventional radical-mediated mechanisms. The FeCu-SNC/PMS system achieved rapid BPA degradation (k_obs > 0.38 min^-1), with preferential oxidation of pollutants bearing electron-donating groups. A dynamic catalytic membrane system (DCMS) integrated with electrospinning technology enabled catalyst reuse, maintaining > 95 % BPA removal over 300 min of continuous operation. Furthermore, a scalable ETP device utilizing a salt bridge and ammeter effectively isolated sulfate ion leaching, attaining 96 % pollutant removal after 72 h while addressing secondary pollution. This work provides a dual strategy- catalyst design and process engineering-for sustainable water decontamination.