An ONIOM study of H2O interacting with the C-terminated surface of silicon carbide

A combined first principle and molecular mechanics research on the adsorption and surface reactions of H2O molecule with the C-terminated silicon carbide surface was carried out. The three-layered ONIOM(B3PW91/6-31g(d):AM1:UFF) approach on the (SiC)192·H2O model was examined. Three distinct adsorption styles (molecular adsorption, molecular hydrogen dissociation adsorption and the H–OH bond dissociative adsorption) and eight possible reaction channels were found. The results show that there are three competitive reactions over the eight channels and the H2O molecule is in favor of dissociating the H–OH bond by the absorptions on the adjacent surface atoms.