Self-cleaning semiconductor heterojunction substrate: ultrasensitive detection and photocatalytic degradation of organic pollutants for environmental remediation

Emerging technologies in the field of environmental remediation are becoming increasingly significant owing to the increasing demand for eliminating significant amounts of pollution in water, soil, and air. We designed and synthesized MoS₂/Fe₂O₃ heterojunction nanocomposites (NCs) as multifunctional materials that are easily separated and reused. The trace detection performance of the prepared sample was examined using bisphenol A (BPA) as the probe molecule, with limits of detection as low as 10^-9 M; this detection limit is the lowest among all reported semiconductor substrates. BPA was subjected to rapid photocatalytic degradation by MoS₂/Fe₂O₃ NCs under ultraviolet irradiation. The highly recyclable MoS₂/Fe₂O₃ NCs exhibited photo-Fenton catalytic activity for BPA and good detection ability when reused as a surface-enhanced Raman scattering (SERS) substrate after catalysis. The SERS and photocatalysis mechanisms were proposed while considering the effects of the Z-scheme charge-transfer paths, three-dimensional flower-like structures, and dipole-dipole coupling. Moreover, the prepared MoS₂/Fe₂O₃ NCs were successfully applied in the detection of BPA in real lake water and milk samples. Herein, we present insights into the development of MoS₂/Fe₂O₃ materials, which can be used as multifunctional materials in chemical sensors and in photocatalytic wastewater treatments for the removal of recalcitrant organic pollutants.