Fenton-like degradation of methyl orange over CeO2 loaded on porous Al2O3: Catalyst preparation, efficiency and mechanism

Abstract

In this work, the CeO2/Al2O3 composites were prepared by in situ growth method and developed as the heterogeneous Fenton-like catalyst for efficiently catalytic degradation of methyl orange (MO). Porous Al2O3 was firstly prepared by an evaporation-sintering method, and then the CeO2/Al2O3 composites were constructed by the in situ growth of CeO2 onto porous Al2O3. The phases and morphologies of the porous Al2O3 and CeO2/Al2O3 composites were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and specific surface area and pore size analyzer. The results indicated that the higher amount of the porogenic agent (NH4Cl) could make the specific surface area of porous Al2O3 larger and the Fenton-like reaction efficiency of CeO2/Al2O3 better. Free radical trapping experiments showed that the singlet oxygen (1O2) was the main reactive oxygen species responsible for the MO degradation. Finally, the possible mechanism of the Fenton-like reaction catalyzed by CeO2/Al2O3 was proposed and discussed.