Insight into electroreductive activation process of peroxydisulfate for eliminating organic pollution: Essential role of atomic hydrogen

Electrochemically activating peroxydisulfate (PDS) can eliminate organic pollution using electron as activator without the involvement of byproducts. Notwithstanding, process suffered from long hydraulic retention time, and activation regime remained unclear. Herein, Pd/Al2O3 catalyst particle electrode for initiating PDS oxidation in cathodic cell degrade various pollutants with varying kinetic constants 0.0256 min?1 to 0.0645 min?1, which were at least 5-fold higher than that previous studies. The reactive oxygen species determined be SO4•–/•OH. These radicals readily formed single-electron reduction by electro-induced atomic hydrogen (indirect mechanism), while direct two-electron transfer electro-generated H2 consumed its capacity yielding radical due energy barrier. Revealing mechanism electrochemically unleashing oxidative power into SO4•– rationalize design scalable PDS-based water purification.