Effect of transition metal oxide doping on catalytic activity of titania for the oxidation of 1,2-dichloroethane

摘要

Transition metal oxides (MOx; M = Cr, Mn, Fe, Ni, Cu)-doped titania solid solution catalysts (10 wt% MOx-TiO2, denoted as 10MOx-TiO2) were prepared by the coprecipitation method. The techniques of XRD, TPR, TPD, XPS, TPSR, and in situ DRIFTS were used to characterize physicochemical properties of the materials, and their catalytic activities were evaluated for the oxidation of 1,2-dichloroethane (1,2-DCE). The introduction of MOx enhanced adsorption and activation of oxygen molecules, mobility of surface lattice oxygen, and lowtemperature reducibility. The 10MOx-TiO2 catalysts showed good performance, with 10CrOx-TiO2 exhibiting the highest catalytic activity (reaction rate = 2.35 x 10-7 mol/(gcat s) and apparent activation energy (Ea) =35 kJ/mol at space velocity = 40,000 mL/(g h)) and good resistance to chlorine poisoning, The mechanism of 1,2-DCE oxidation over 10CrOx-TiO2 was also discussed based on the results of TPSR and in situ DRIFTS characterization. It is concluded that strong acidity and redox ability, high adsorbed oxygen species concentration, and strong interaction between TiO2 and CrOx were accountable for the good performance of 10CrOx-TiO2.