The Catalytic Activity Enhancement of Commercial TiO2 and Nb2O5 Catalysts by Iron for Elemental Sulfur Production from H2S

Abstract

Commercial TiO2 and Nb2O5 catalysts were used to determine catalytic activities for selective oxidation of H2S to elemental sulfur. Fe@TiO2 and Fe@Nb2O5 catalysts (containing 10% iron by weight) were also prepared by wet impregnation method to enhance the catalytic activity. TiO2 anatase phase and Nb2O5 were mainly observed in the crystalline structure of TiO2 and Nb2O5 based catalysts, respectively. Catalytic activity tests were performed in a fixed-bed flow reactor at 250 °C using stoichiometric feed ratio. 30% and 28% H2S conversions were obtained with commercial TiO2 and Nb2O5 catalysts. Complete conversion of H2S was reached with Fe@TiO2 and Fe@Nb2O5 catalysts at the same reaction conditions for 400 min. of reaction time. 100% of H2S conversion was obtained with iron-containing catalysts in the reaction tests carried out at 200 °C and 300 °C of reaction temperatures. Fe@TiO2 and Fe@Nb2O5 catalysts showed high sulfur selectivity (≥ 95%) under all reaction conditions. Iron addition enhanced the Lewis acidity and redox property of the commercial catalysts and this may be the reason for increase in catalytic activity.