Adsorption of Small Sulfur Compounds (H₂S and SO₂) on SiO₂ Supported Graphene–the Quest for a Metal-Free Catalyst–Experiment and Theory

Abstract

The adsorption of hydrogen sulfide (H 2 S) and sulfur dioxide (SO 2 ) was studied at ultrahigh vacuum conditions on silica (SiO 2 ) supported graphene, in order to characterize a potentially metal-free catalyst. However, kinetics experiments (using thermal desorption spectroscopy) and spectroscopy (Auger electron spectroscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy) revealed only molecular adsorption. Density functional theory (DFT) also obtained large activation energies for dissociation. The low reactivity contrasts with previously studied graphene on ruthenium [Stach, T. et al.