Z-scheme charge transfer between a conjugated polymer and α-Fe2O3 for simultaneous photocatalytic H2 evolution and ofloxacin degradation

Abstract

The replacement of the oxygen evolution reaction with a higher valuable oxidation process can overcome the sluggish kinetics to promote renewable hydrogen production, simultaneously achieving energy storage and environmental protection. However, the effective integration of two redox half-reactions in one photocatalytic reaction system is still a challenge. Here the p-diethynylbenzene and dibenzothiophene sulfone copolymer (PEB-DBT) is well-designed to couple with α-Fe₂O₃via a palladium-catalyzed Sonogashira cross-linking reaction, forming a heterojunction with strong interfacial interaction. In particular, there is a different preferred charge transfer path of PEB-DBT/α-Fe₂O₃via modulating the work function difference in various solutions. The results suggest that the Z-scheme electron transfer pathway is predominant in triethanolamine (TEOA) and ofloxacin (OFL) solutions, instead of the type-II heterojunction that forms in H₂O or methylene blue (MB). The Z-scheme PEB-DBT/α-Fe₂O₃ heterojunction has excellent performance in the hydrogen evolution half-reaction and OFL degradation, which is about 2.7 times and 3.3 times higher than that of pure PEB-DBT, respectively. Finally, it successfully achieved simultaneous photocatalytic H₂ evolution and OFL degradation under visible light.