Enhanced sulfur selectivity for H2S catalytic oxidation over Fe2O3@UiO-66 catalyst

Fe2O3 as a catalyst for H2S oxidation, has a high catalytic activity but a low sulfur selectivity. In this regard, a series of Fe2O3 supported on UiO-66 complex catalysts (xFe2O3@UiO-66, x represents the weight percentage of Fe2O3) with high sulfur selectivity were successfully synthesized, and their catalytic performance was investigated at varied reaction temperature (100–210 ℃). The experimental results indicate that 5Fe2O3@UiO-66 catalyst shows the best catalytic performance at 150 ℃, the H2S conversion keep at 100% and the sulfur selectivity reaches 93.06%, which is significantly higher than the bulk Fe2O3 (62%) and commercial Fe2O3 (80%). The superior catalytic performance is mainly attributed to the synergistic effect between Fe2O3 and UiO-66, the formed FeOZr bonds help the electrons transfer from Fe to Zr, which inhibits the formation of the intermediate of FeS2 during the catalytic process, a species that readily to be oxidized into SO2, thus promotes its sulfur selectivity. In addition, the high specific surface area, abundant pores and the high dispersion of Fe2O3 nanoparticles also contributed to its improved sulfur selectivity. The deposition of elemental sulfur and sulfates responsible for its deactivation.