Piezo-promoted regeneration of Fe2+ boosts peroxydisulfate activation by Bi2Fe4O9 nanosheets

The application of promising persulfate-based advanced oxidation processes (AOPs) for environment remediation is limited by the poor charge separation and the sluggish kinetic for active centers regeneration of the catalysts. Piezocatalytic activation has been proposed to solve the above concern recently, but little is known on its mechanism. Herein, novel piezocatalyst Bi2Fe4O9 nanosheets (BFO NSs) are demonstrated to significantly improve peroxydisulfate (PDS) activation efficiency via piezocatalysis, resulting SO4•− and •OH as the dominant active species for organic pollutants degradation. Further DFT calculations and experimental investigations confirm that the Fe2+ in BFO NSs as active sites donate electrons for PDS to generate SO4•−, and simultaneously that the piezo-electrons can accelerate the regeneration of Fe2+, thus leading to the superior catalytic activity. This work provides atomic-scale insights of catalytic sites and mechanisms of piezocatalytic PDS activation and may inspire the development of more efficient piezocatalysts and AOPs.