Elementary reaction processes involving atomic and molecular oxygen on ZrB2 (0001)surface

Abstract

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 threefold 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 O2 over both terminated surfaces produces mainly its dissociation through non-activated 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 and even more accessible in the case of the B-finished surface.