Unraveling Cathodic Defect-Electric Field Synergism in the Enhanced Electroactivation of Peroxydisulfate for Highly Efficient Removal of Emerging Contaminants

Herein, this study prepared a modified carbon felt cathode with defective D-MIL-88B(Fe) (D-MOF/CF) containing coordinatively unsaturated Fe sites (Fe CUS) and oxygen vacancies (O_V), which showed greatly enhanced effectiveness for the electroactivation of PDS to remove sulfamethoxazole.

Experimental characterization and theoretical calculations revealed that the electric field cooperated with O_V to induce local charge rearrangement, thereby modulating the local electronic structure and d-band center of Fe CUS, lowering the thermodynamic barrier for reactive species generation and simultaneously enhancing the Fe²⁺/Fe³⁺ cycling efficiency. This defect-electric field synergy substantially accelerated PDS activation kinetics, yielding high steady-state concentrations of ^·OH (5.96 × 10^–10 M) and SO₄^·– (3.55 × 10^–10 M) in the reaction process of the E-D-MOF/CF-PDS system and achieving 100% SMX removal with an electrical energy per order of 0.094 kWh m^–3 order^–1.