Highly Efficient FeIII‐initiated Self‐cycled Fenton System in Piezo‐catalytic Process for Organic Pollutants Degradation

Piezo-catalytic self-Fenton (PSF) system has been emerging as a promising technique for wastewater treatment, while the competing O2 reductive hydrogen peroxide (H2 O2 ) production and FeIII reduction seriously limited the reaction kinetics. Here, we develop a two-electron water oxidative H2 O2 production (WOR-H2 O2 ) coupled with FeIII reduction over a FeIII /BiOIO3 piezo-catalyst for highly efficient PSF. It is found that the presence of FeIII can simultaneously initiate the WOR-H2 O2 and reduction of FeIII to FeII , thereby enabling a rapid reaction kinetics towards subsequent Fenton reaction of H2 O2 /FeII . The FeIII initiating PSF system offers exceptional self-recyclable degradation of pollutants with a degradation rate constant for sulfamethoxazole (SMZ) over 3.5 times as that of the classic FeII -PSF system. This study offers a new perspective for constructing efficient PSF systems and shatters the preconceived notion of FeIII in the Fenton reaction.