Adsorption of H2S and SO2 on SiO2 Supported Graphene- A Surface Science Study

The sulfur compounds H2S and SO2 are common air pollutants released in the extraction and burning of natural gas. The toxicity and long-term environmental impact of these gasses have made their selective removal from natural gas and industrial processes a common area of study. Previous experiments have shown that graphene grown on ruthenium readily dissociates both of the target molecules in ultra-high vacuum (UHV), and this study seeks to both compare a different substrates' effect on graphene's reactive capabilities and characterize a potentially metal-free catalyst. Thus, the adsorption of H2S and SO2 was studied at ultra-high vacuum conditions on silica (SiO2) supported graphene. Thermal desorption spectroscopy (TDS) was utilized to obtain kinetics information and search for potential products of dissociation, and the data obtained is consistent with molecular adsorption/desorption of both molecules. In addition, X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and Raman spectroscopy revealed no change to the sample's surface, which is consistent with a solely molecular adsorption/desorption pathway.