Catalytic properties of activated carbons I. Gas-phase oxidation of hydrogen sulphide

Gas-phase oxidation of hydrogen sulphide catalysed by the activated carbons of different origin and formation of SO_x in this process was studied. Using XPS, it was shown that H₂S adsorption from an inert atmosphere on activated carbons resulted in the formation of surface oxygen-containing complexes and elemental sulphur. It is suggested that carbon surface functional groups contribute significantly to the formation of SO_x in H₂S oxidation. Impregnation of the carbons with transition metals alters their catalytic activity and selectivity towards sulphur oxides and elemental sulphur. Varying the method of impregnation it is possible to synthesise materials with very different catalytic properties. A vanadium-grafted catalyst with high selectivity towards elemental sulphur was synthesised. It effectively works at the temperature exceeding the melting point of sulphur enabling to obtain high yield of elemental sulphur.