Fe2O3 supported on hollow micro/mesospheres silica for the catalytic partial oxidation of H2S to sulfur

Abstract

A family of Fe-based catalysts supported hollow silica mesospheres has been synthesized and tested in the catalytic partial oxidation of HS to elemental sulfur at 170-180 °C, atmospheric pressure and under 300 min of time-on-stream. The characterization of the synthesized catalysts by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance UV–vis spectra (DRS), H-termoprogrammed reduction (H-TPR), N adsorption-desorption at −196 °C and X-ray photoelectron spectroscopy (XPS) reveals the formation of a catalytic system with high micro- and mesoporosity with high dispersion of the FeO species. The catalytic results reported high activity in the selective oxidation of HS, reaching a highest conversion value close to 94% with a selectivity towards elemental sulfur of 98% after 300 min of time on stream (TOS) at 180 °C for the HMS-10Fe catalyst. The comparison of Fe-containing HMS (10 wt% of iron loading) with other SiO-based supports, as a fumed silica (Cab-osil) or a mesoporous silica (SBA-15), presents different HS conversion values, following the next trend: HMS-10Fe > SBA-10Fe > Cab-10Fe. These results suggest that the use of a support with a narrow pore tend to facilitate the iron dispersion favoring higher conversion rates.