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 (H2O2) production and FeIII reduction seriously limited the reaction kinetics. Here, we develop a two‐electron water oxidative H2O2 production (WOR−H2O2) 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−H2O2 and reduction of FeIII to FeII, thereby enabling a rapid reaction kinetics towards subsequent Fenton reaction of H2O2/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.