Elementary Reaction Processes Involving Atomic and Molecular Oxygen on ZrB2 (0001) Surface

The interaction of atomic and molecular oxygen along with the atomic recombination on thin ZrB2(0001) Zr- and B-terminated surfaces were studied using density functional theory (GGA/PBE) calculations. The adsorption of atomic oxygen is predominantly produced on 3-fold hollow sites for the Zr-finished surface and on B B bridge sites for the B-finished surface. The experimental specular HREELS loss peaks and their shifts at high O exposures can be satisfactory explained by the present calculations. The interaction of O-2 over both terminated surfaces produces mainly its dissociation through nonactivated processes. This fact is in agreement with the observed open dissociation at room temperature. The atomic oxygen recombination over both ZrB2 surfaces shows that the Eley-Rideal reaction will be much more important than the Langmuir-Hinshelwood reaction at all temperatures accessible in the case of the B-finished surface.