The low temperature selective oxidation of H2S to elemental sulfur on TiO2 supported V2O5 catalysts

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The selective oxidation of H2S to elemental sulfur at low temperature (130 °C) was investigated on various TiO2-supported vanadium oxide catalysts. The TiO2 supports were commercially available pure anatase TiO2 (dXRD 21 and 43 nm with specific surface area 63 and 10 m2/g, respectively), solvothermal-synthesized pure anatase TiO2 (dXRD 15 nm, 69 m2/g), P-25 TiO2 (mixed anatase/rutile phase, 46 m2/g), and rutile TiO2 (dXRD 40 nm, 6 m2/g). In order to obtain high catalytic activity of the V2O5/TiO2 catalysts, a combination of highly dispersed vanadium oxides and a strong interaction of V-Ti species were found to be necessary. As revealed by the XPS, Raman, and O2-TPD results, the interaction between active V component and TiO2 support was shown by the presence of partially reduced V-Ti species. Due to the strong interaction between V and TiO2 support, the active V component, which was not fully oxidized, led to more oxygen vacancies being formed and facilitated a rapid catalyst regeneration from V4+ to V5+ (re-oxidation). Hence, the capability of the catalysts for H2S removal was greatly enhanced. Among them, the V2O5 supported on anatase TiO2 with dXRD 21 nm exhibited the best catalyst performances using the feed molar ratio (O2/H2S) of 0.5.