Photo-Fenton reaction of supported cationic cyclopentadienyl iron complexes of arene and application as heterogeneous catalysts in photodegradation of dyes under visible light

Cationic cyclopentadienyl iron complexes of arene ([CpFeAr](+)) were successfully loaded on silica gel (SiO) by physical absorption. The supported [CpFeAr](+) ([CpFeAr](+)/SiO) catalysts were characterized by SEM-EDX, FT-IR and UV-Vis spectra. The catalysts show strong and broad absorptions from 200 to 550 nm. [CpFeAr](+)/SiO carries out an effective photo-Fenton reaction with H2O2 under visible light for the photodegradations of organic dyes. Nearly total decolorations of rhodamine B (RhB) and crystal violet (CV) dyes were achieved by using [CpFeAr](+)/SiO as the heterogeneous catalyst. Hydroxyl radicals (center dot OH) were found in the photodegradation system of [CpFeAr](+)/SiO, H2O2 and dyes under visible light. The negative Delta G(el) values of CV/[CpFeAr](+) and RhB/[CpFeAr](+) systems indicate that the electron transfer processes for the dye/CpFe+ Ar systems are thermodynamically allowed. The possible mechanism for the degradation process of organic dyes in photo-Fenton reaction of [CpFeAr](+)/SiO with H2O2 is proposed. (C) 2013 Elsevier B.V. All rights reserved.