Abstract
FexZr1-x-S mixed oxide catalysts were prepared by precipitation of FeSO4 and ZrOCl2, and used in catalytic oxidation of dichloromethane (DCM). Analyses by a series of characterization technologies reveal that Fe-O-Zr solid solution with tetragonal ZrO2 or α-Fe2O3 structure can be formed, dependent on Fe/Fe + Zr ratio. Residual SO42− species obtained from FeSO4 precursor exist in a form of bridged bidentate complex with Zr4+ or Fe3+ ion, which increases acidity significantly. FexZr1-x-S catalysts with Fe/Fe + Zr of 0.2–0.5 possess high contents of both SO42− and surface oxygen, and are highly active in catalytic combustion of DCM with T90 below 320 °C and TOFs at 200 °C of 0.98–1.89 μmol/(m2 min). Another test shows that the activity for the other CVOVs oxidation over Fe0.5Zr0.5-S is 1,2-dichloroethane > dichloromethane > trichloroethylene > 1,2-di chlorobenzene. Because the substitution of Cl species for surface oxygen is retarded, high stable activity maintains within reaction temperatures for at least 80 h. In situ FT-IR indicates that DCM is adsorbed and activated mainly through the formation of chloromethyl sulfate, which is oxidized quickly into formate ion. The synergism between SO42- complex anchoring on Zr-O-Fe solid solution and surface oxygen obtained from Fe2O3 cluster or nano-particles promotes the oxidation of formate.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call