H₂S photocatalytic oxidation over WO₃/TiO₂ Hombikat UV100.

Hydrogen sulfide (H2S) is a toxic, corrosive and malodorous compound with damaging effects even when present at a low concentration in air. Consequently, the development of efficient and environmentally friendly remediation technologies as an alternative to conventional techniques is justified for environmental reasons and public concern over human health and well-being. In the context of indoor air quality control, the use of photocatalysis over semi-conductor oxides could be a valuable alternative purification technology due to its wide-ranging effect and its easy way of implementation. The superiority of the TiO2 Hombikat UV100 photocatalyst in comparison with the Aeroxide© TiO2 P25 standard was already apparent in the UV-A photocatalytic oxidation of H2S. We report here on the first use of WO3/TiO2 UV100 photocatalysts for this reaction. Associating WO3 to TiO2 UV100 was not beneficial in terms of semiconductor coupling and of charge transfer between both phases. Even if such coupled wide band-gap oxide semi-conductor photocatalysts suffered from on-flow deactivation due to the formation of poisoning sulfates as ultimate reaction products continuously stored at the surface, by contrast, their ability to strongly lower and delay the release of SO2 to the gas phase was very positive for maintaining a weak selectivity into the unwanted SO2 by-product.