Alkali-promoted V2O5 catalysts for the partial oxidation of H2S to sulphur

Present paper describes the influence of the incorporation of alkali metal cations (AM = Li, Na, K, Cs; and an AM/V ratio of 0.04) and Na-content (Na/V ratio of 0.02–0.30) in alkali metal promoted V2O5 catalyst on both the catalyst structure and the catalytic performance in H2S partial oxidation reactions. The catalytic activity depends on the alkali metal and the amount of alkali metal added, although Na-containing catalysts seem to be the more active ones. However, selectivity to sulphur higher than 98% is achieved in the main of catalysts when working at reaction temperature lower than 220 °C. According to the characterization results of used catalysts, V4O9 is selectively formed during the catalytic tests on catalysts presenting V2O5 crystallites. In catalysts with Na/V ratios higher than 0.04, V4O9 and Na0.33V2O5 are observed, the presence of Na0.33V2O5 increasing when increasing the Na/V ratio. Accordingly, V4O9 and Na0.33V2O5 can be proposed as the active and selective crystalline phase in Na-containing catalysts. The role of the presence of V4+−O–V5+ pairs in partial oxidation of H2S is also discussed.

Figure optionsDownload high-quality image (231 K)Download as PowerPoint slideHighlights
► Partial oxidation of H2S to sulphur is selectively obtained over pure and Na-doped V2O5.
► V4O9 is selectively formed during the selective oxidation of H2S over V2O5.
► Na0.33V2O5 is mainly observed in Na-promoted catalysts with Na/V ratio higher than 0.1.
► Na0.33V2O5 bronze is also active and selective in partial oxidation of H2S.