Quantum chemical study of the reactivity of boron-doped graphite layers towards water formation

Density functional calculations were used to study some fundamental features of boron-doped graphite layers (CxBy) and the boron influence on the mechanisms leading to the formation of water molecules on the CxBy graphite like layers. The Langmuir-Hinshelwood reactions leading to water formation on the graphite-like layers containing 12 at% boron take place with activation energies 3-5 times lower than on pure graphite ones. For the Eley-Rideal mechanism, the activation energies are always very low whether or not the graphite contains boron. Similar results were observed for 25 at% B doping. As a consequence, the oxygen and hydrogen can be more easily eliminated from the doped surfaces in the form of water molecules than from the corresponding pure ones. The CxBy layers with high boron content or having accumulations of boron, lose their planar structure. Two such parallel layers strongly interact through the boron atoms with the formation of a B-B bond and the displacement of the boron atoms into the inter-layer space. As a whole the system deviates from the graphite-like structure.