Interactions of SO2 and H2S with amorphous carbon films

There is significant interest in development of efficient catalyst-sorbents for the capture and conversion of sulfur-compounds such as H2S and SO2. In this work, ultra-high vacuum (UHV) techniques have been used to carefully prepare and thoroughly characterize amorphous carbon (a-C) thin films as models of activated carbon sorbents. Films with modified surface chemistries were prepared by oxidation of a sputter deposited carbon film (a-COx) and by sputter depositing carbon in the presence of N-2 (a-CNx) or methane (a-CHx). Temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) were used to study H2S and SO2 surface chemistry on these films and on a highly oriented pyrolytic graphite (HOPG) reference-surface. The modification of the carbons with different heteroatoms influences both the strength of their interactions with SO2 and H2S and their capacities for sulfur-compound adsorption. (C) 2009 Elsevier B.V. All rights reserved.