Transition metal doping effect and high catalytic activity of CeO2–TiO2 for chlorinated VOCs degradation

Abstract

A series of transition metals (Fe, Co, Ni, Cu, Cr and Mn)-doped CeO2–TiO2 catalysts were prepared by the sol–gel method and applied for the catalytic removal of 1,2-dichloroethane (DCE) as a model for chlorinated VOCs (CVOCs). The various characterization methods including X-ray diffraction (XRD), N2 adsorption–desorption, UV-Raman, NH3 temperature-programmed desorption (NH3-TPD) and H2 temperature-programmed reduction (H2-TPR) were utilized to investigate the physicochemical properties of the catalysts. The results show that doping Fe, Co, Ni or Mn can obviously promote the activity of CeO2–TiO2 mixed oxides for DCE degradation, which is related to their improved texture properties, acid sites (especially for strong acidity) and low-temperature reducibility. Particularly, CeTi–Fe doped with moderate Fe exhibits excellent activity for 1,2-dichloroethane (DCE) degradation, giving a T90% value as low as 250 °C. More importantly, only trace chlorinated byproducts were produced during the low-temperature degradation of various CVOCs (dichloromethane (DCM), trichloroethylene (TCE) and chlorobenzene (CB)) over CeTi–Fe1/9 catalyst with high durability.