Influence of alkali additives on activity and toxicity of H 2S and thiophene over a Ni/SiO 2 catalyst

Abstract

The influence of alkali-doping of a Ni/SiO 2 catalysts on the deactivation by thiophene and H 2S during benzene hydrogenation at 200°C has been studied. an initial toxicity higher for thiophene than for H 2S has been found for all the catalyst tested. Furthermore, in comparison with the undoped catalyst, the thiophene/H 2S toxicity ratio decreases on alkali-doped catalyst. On the basis of benzene hydrogenation active sites, alkali-doping decreases both thiophene and H 2S initial toxicity. Temperature programmed surface reaction (TPSR) results suggest that the difference in toxicity may be explained by a layer of hydrocarbon species remaining on the nickel surface after thiophene adsorption at 200°C.