Supramolecular photocatalysts as electrons storage: Enhanced photocatalytic degradation activity via interfacial charge transfer effect with Fe (Ⅲ)

Abstract

Supramolecular photocatalysts based on organic π-conjugate semiconductors have attracted a lot of attention in the field of pollutants photodegradation. However, organic semiconductors also suffer from easy charge recombination which resulted in the low photocatalytic activity. In order to improve the separation of photogenerated charge, interfacial charge transfer (IFCT) on supramolecular photocatalysts of porphyrins (TCPP) and perylenediimide (PDINH) by Fe(III) ions was firstly employed to enhance the photocatalytic activity for degradation organic pollutants such as phenol. The photocatalytic activity of phenol degradation under visible light was significantly improved after introduction of Fe(III) in the system. The rate constant of degradation reaction using supramolecular photocatalysts TCPP/PDINH with Fe(III) can reach up to 42 times that of without Fe(III). The photo-induced electron transfer mechanism and the enhancement of charge separation via interfacial charge transfer interactions were studied and discussed. Supramolecular assemblies based on π-conjugated organic molecules could be used as electrons donors in electron transfer system under irradiation, the reducible metal ion Fe(III) as electron traps can effectively capture electrons and promote the electron-hole separation efficiency. This IFCT was proved to be an effective strategy to improve the photocatalytic oxidation activity of supramolecular photocatalysts.