Synergistic piezoelectric effect and oxygen vacancies in MoS2/BiOIO3 heterojunctions boosting photocatalytic degradation of 17β-estradiol

Abstract

Insufficient separation of photogenerated charges significantly hinders the development of semiconductor-based photocatalytic technologies. Coupling piezoelectric Coupling piezoelectric effects with oxygen vacancies (OVs) effectively promotes bulk charge separation, enhancing photocatalytic removal of emerging contaminants. MoS₂/BiOIO₃ (MBI), a II-scheme heterojunction material with OVs, was synthesized via a simple hydrothermal method. Combining experimental investigations with density functional theory (DFT), we delved into the redox mechanisms of 17β-estradiol (17β-E2). The results demonstrated 91.4 % degradation of 17β-E2 by MBI-5 % within 15 min under photocatalysis. When applying piezo-photocatalysis, nearly 100 % degradation was achieved in the same duration. The reaction rate constant was 1.69 times that of the photocatalysis alone. The significant performance enhancement is attributed to the synergistic effects of the piezoelectric effect and OVs. Additionally, DFT analysis identified the vulnerable sites of 17β-E2 and revealed potential degradation pathways. Finally, the application experiments with distinct focuses further validated the superior performance of MBI nanomaterials. This study provides a reliable reference for applying piezoelectric photocatalysts with OVs to treat water environment contaminated by emerging pollutants.