Persulfate activation at cathodic FeN4 single-atom sites in a sustainable FeNC electrocatalyst for fast degradation of antibiotics in water at near-neutral pH

Abstract

Cathodic persulfate (PS) activation mediated by solid-state Fe(II) produced in situ in a continuous manner has recently emerged as a powerful strategy to degrade organic pollutants. Conversely, the use of single-atom catalysts (SACs) that is now widespread in heterogeneous catalysis for water treatment has never been explored for the design of superior electrocatalysts for PS activation. In this work, the pyrolysis of abundant biopolymer chitosan mixed with an iron salt yielded abundant (15%) single-atom-metal sites (FeN4) coordinated with a graphitic matrix. For the first time, PS activation at cathodic FeII–N–C moieties (Eonset ∼0.65 V|RHE) is demonstrated to be highly effective for the fast degradation of a model antibiotic like piperacillin, being totally removed even in urban wastewater after 90 min at 20 mA cm−2.