Unique S-scheme structures in electrostatic self-assembled ReS2-TiO2 for high-efficiency perfluorooctanoic acid removal

Abstract

Perfluorinated compounds (PFCs), recognized as persistent organic pollutants, resist degradation in the environment due to the high bond energy of the C–F. Increasing carrier density via adopting electrostatic self-assembly strategy has been shown to effectively cleave C–F bonds. In this work, a unique S-scheme structure was fabricated by combining oppositely charged semiconductors, TiO2 and ReS2, through electrostatic self-assembly. The resulting 2 % ReS2-TiO2 composite achieved a photodegradation efficiency of 98 % for perfluorooctanoic acid (PFOA), considerably higher than the 62 % efficiency observed for pure TiO2. Additionally, the 2 % ReS2-TiO2 composite demonstrated broad applicability for the removal of other PFCs. The introduction of ReS2, with a lower work function than TiO2, could generate an internal electric field (IEF) to facilitate electron transfer from TiO2 to ReS2 under continuous irradiation and thereby enhance charge separation efficiency.