Interaction of NO with Pt-Rh alloy single crystal surfaces

The clean surfaces of Pt0.25-Rh0.75 alloy single crystals showed Pt surface enrichment that increased with increasing equilibration temp. The activity of the alloy for NO dissocn. is dependent on both the surface structure and the surface compn. (as varied by a proper choice of the equilibration temp.). The NO dissocn. activity was in the following order: Rh-rich (410) ³ Rh-rich (210) ³ Pt-rich (410) > Rh-rich (321) > Rh-rich (111) > Pt-rich (210) > Pt-rich (321) > Pt-rich (111