Vanadium-ceria catalysts for H2S abatement from biogas to feed to MCFC

Vanadium-based catalysts supported on ceria were studied for the direct and selective oxidation of H₂S to sulphur and water at low temperature.Catalysts with two vanadium loading (20–50 wt% of V₂O₅) were prepared, characterized and tested at temperature of 150–200 °C in order to identify the best catalytic formulation. The most promising catalyst was the sample with the 20 wt% of V₂O₅ that showed 99% of sulphur selectivity and equilibrium H₂S conversion at 150 °C.The effect of the components of a typical biogas stream (CH₄, CO₂ and H₂O) was studied at 150 °C in order to investigate the possible formation of secondary products such COS, CS₂. No significant effect was observed in terms of H₂S conversion (99%) and selectivity to SO₂ (<1%) by adding CH₄ and CO₂ to the feed stream. Furthermore, the effect of the H₂S inlet concentration, temperature, contact time and molar feed ratio (O₂/H₂S) were also investigated at a reaction temperature of 80 °C.Finally, time on stream tests of 30 h were performed at 80 and 120 °C, in order to examine the catalyst stability.