NO pairing and transformation to N2O on Cu(111) and Pt(111) from first principles

Density-functional calculations demonstrate an energetic preference for NO pairing on Cu(111) terraces and a new, kinetically preferred, pathway to NO formation through such intermediates. In contrast to the traditional NO + N route, this pathway does not require NO dissociation, which is shown to occur only at defects, Analogous calculations for Pt(111) show the inability of this surface to transform NO directly into either N-2 or N2O, which we trace to differences in both reaction energies and kinetic barriers on the two surfaces. (C) 2002 Published by Elsevier Science B.V.