Catalytic oxidation of 1,2-dichlorobenzene over Ca-doped FeOx hollow microspheres

Abstract

Novel Ca-doped FeOx hollow microspheres were successfully prepared using carbon microspheres as templates. The as-prepared catalysts were characterized by FAAS, XRD, N2 adsorption/desorption, SEM, TEM, H2-TPR and XPS. The catalytic activities of the samples were evaluated by catalytic oxidation of 1,2-dichlorobenzene (o-DCB). The results showed that the molar ratios of Ca/(Ca+Fe) in the hollow microspheres and their morphologies significantly affected their catalytic performances. The low-temperature catalytic activity decreased in the order of FeCa10>FeCa20>Fe2O3>FeCa5, in well agreement with the sequence of their reducibility. The optimal FeCa10 catalyst exhibited not only excellent catalytic activity, water-resistant performance and stability but also lower apparent activation energy (21.6kJ/mol). In situ FTIR measurements revealed the acetate and formate species were the partial oxidation products, which could be subsequently oxidized to form CO2. It is concluded that the excellent catalytic performance of FeCa10 catalyst might be attributed to the combined effects of several factors such as small crystallite size, high surface active oxygen concentration, good low-temperature reducibility and the synergic effect between CaO and Fe3O4. It is reasonable for us to believe that such Ca-doped FeOx hollow microspheres are promising catalysts for the elimination of chlorinated volatile organic pollutants.