Mechanism of piezoelectric field-enhanced electron transfer during peroxymonosulfate activation with MoS2/PVDF-HFP films

Piezoelectric molybdenum disulfide (MoS 2 ) has emerged as a promising candidate for peroxymonosulfate (PMS) activation in advanced oxidation processes (AOPs), yet the mechanistic role of its piezoelectric field, particularly regarding the electron transfer process, is not fully understood. Herein, we construct a MoS 2 /PVDF-HFP (MP) piezoelectric composite film stimulated by ultrasound to elucidate the piezoelectric field's enhancement effect on PMS activation for singlet oxygen ( 1 O 2 ) generation. Notably, the ultrasound-induced piezoelectric field enhanced 1 O 2 production by 26-fold compared to the non-piezoelectric system, leading to significantly improved degradation efficiency (≈94 % within 60 min) of methylene blue (MB). Through a combination of experimental analysis and density functional theory (DFT) calculations, we demonstrate that the piezoelectric field enhances the adsorption of PMS onto the MoS 2 surface (evidenced by a change in adsorption energy from –0.33 eV to –0.42 eV) and facilitates interfacial electron transfer (with an increase of 0.04 e⁻ transferred per PMS molecule), thereby promoting the conversion of PMS to 1 O 2 . This work elucidates the enhancement mechanism of the electron transfer process in the MoS 2 -PMS system and provides a film-based strategy for designing efficient, ultrasound-driven piezoelectric AOPs targeting selective 1 O 2 generation.