Reactivity of H₂O and the Si-terminated surface of silicon carbide studied with ONIOM method

The reactivity of H₂O and the Si-terminated silicon carbide surface (001) was investigated on the triplet potential energy surface with the combined first principle and molecular mechanics ONIOM(CASSCF:AM1:UFF) method for the (SiC)₁₉₂·H₂O model. It was found that the H₂O molecule and the surface can form three physisorption complexes and follow five reaction paths to produce eight products, in which there are five main products having necessary energy barriers less than 300 kJ mol^-1. Compared with that on the C-terminated surface, the interaction with the Si-terminated surface has stronger physisorption energy, smaller lowest necessary energy barrier, more main and more stable products.