Isomorphous substitution of Cr by Fe in MIL-101 framework and its application as a novel heterogeneous photo-Fenton catalyst for reactive dye degradation

Abstract

Partial isomorphous substitution of Cr by Fe in the MIL-101 framework was achieved by direct synthesis using a hydrothermal method (conventionally, solvothermal method). The products were characterized by XRD, EDX, N₂ adsorption (BET), TEM, UV-vis, FTIR, XPS and testing the photo-Fenton activities in the degradation of the commercial reactive dye RR195. From FTIR and XPS results, it was revealed that Fe is really incorporated into the MIL-101 framework. From EDX results, an amount of ca. 25% of Cr atoms in the MIL-101 framework is substituted by Fe atoms. Fe substituted Cr-MIL-101 showed high adsorption capacity of reactive dye. Moreover, this material exhibited high photo-Fenton activity in reactive dye degradation, opening new applications of MOFs as novel heterogenous photo-Fenton catalysts.