Support effects in catalytic wet oxidation of H2S to sulfur on supported iron oxide catalysts

Iron oxide catalysts supported on MgO, Al2O3, SiO2 and ZrO2 were prepared by an impregnation method. They were characterized by BET surface analysis, X-ray diffraction (XRD), temperature-programmed reduction (TPR) and Mössbauer spectroscopy. Fe/MgO catalyst shows the highest H2S removal capacity in wet oxidation at room temperature. Both the XRD and the TPR analyses of the catalysts indicate that H2S removal capacity correlates with the dispersion of iron oxide on supports. Mössbauer spectroscopy shows that four kinds of Fe3+ species are present in the supported iron oxide catalysts: two highly dispersed species, Fe3+ oxide clusters, and α-Fe2O3 particles. Two highly dispersed species, Fe3+ cation and MgFe2O4, are present in Fe/MgO. Fe3+ oxide clusters and α-Fe2O3 crystals are evident in both Fe/SiO2 and Fe/ZrO2. α-Fe2O3 crystals are only observed in Fe/Al2O3.