Deep oxidation of 1,2-dichlorobenzene over Ti-doped iron oxide

Abstract

Ti-doped iron oxides with worm-like mesopores were successfully prepared using CTAB as the structure-directing agent. The as-prepared catalysts were characterized by XRD, Raman, H₂-TPR, XPS, TEM, and N₂ adsorption/desorption. The catalytic properties for oxidation of 1,2-dichlorobenzene (o-DCB) were investigated. The results showed that Fe₁₈Ti₂O_x with 10 mol% Ti-doping shows the best catalytic activity, and the total conversion of o-DCB can be obtained at 350 °C. Moreover, Fe₁₈Ti₂O_x exhibits higher stability, CO₂ selectivity and lower apparent activation energy. The high activity of Fe₁₈Ti₂O_x could be ascribed to the combined factors including a smaller crystallite size, excellent low-temperature reducibility, high surface active oxygen concentration and a synergic effect between TiO₂ and mixed iron oxide (γ-Fe₂O₃ and α-Fe₂O₃). Acetate and formate species as intermediates were detected by in situ FTIR spectroscopy. A two-step redox mechanism of o-DCB decomposition on the surface of Ti-doped iron oxides was proposed. These results demonstrated that Ti-doped iron oxides could be developed as environmentally friendly catalysts for the deep oxidation of chlorinated volatile organic pollutants.