Interface manipulation of d-band center by single-atom iron cathodic electroactive membrane to boost molecular oxygen...

Electroactive membrane (EM) has garnered extensive attention for its remarkable efficacy in antibiotic removal from wastewater. Nevertheless, significant challenges remain in improving the stability and catalytic activity of EMs. To address this challenge, we prepared a phosphorus (P) and sulfur (S) co-doped single-atom iron (Fe) cathodic EM (Fe-SA@PSC₇₀₀/CM) and constructed the edge-type Fe-C₃P-S unsaturated coordination configuration with microscopic electron-rich regions on the membrane surface to remove amoxicillin (AMX) in pharmaceutical tailwater via electro-Fenton filtration. The coordination configuration of P, S, and Fe in first and second shell in the electroactive layer significantly enhanced atomic Fe dispersion and accelerated localized electrons enrichment at Fe active sites, thereby facilitating the sustained conversion of oxygen (O₂) to hydroxyl radicals (•OH) via effectively tunes the d-band center position. Remarkably, Fe-SA@PSC₇₀₀/CM demonstrated a kinetic rate constant 1-2 orders of magnitude higher than that of the iron nanoparticle electroactive membrane (Fe-NP@SC/CM), and possessed an efficient charge transfer rate of 10.69 × 10^-3 cm/s. Furthermore, Fe-SA@PSC₇₀₀/CM exhibited superior stability in long-term test and retained exceptional electrical conductivity under strongly acidic conditions. This work proposes a promising strategy to modulate the interfacial d-band center position of EMs, thereby enhancing the catalytic activity for wastewater remediation.