The Claus Reaction: VI. The Reaction Mechanism over a Sn–Mo Oxide Catalyst

Based on the comparison of reactant conversions in pulses on the stationary surface of the catalyst, the Claus reaction is found to occur via a stepwise mechanism. The nature of interaction of the SO₂ and H₂S molecules with the catalyst surface was studied by FTIR and UV–VIS spectroscopy and the reactivity of the adsorbed species was studied in situ. The intermediate adsorbed reactant species are determined. A scheme of the reaction mechanism over the Sn–Mo oxide catalyst is discussed.