CYANIDE INTERMEDIATES IN CATALYTIC REDUCTION OF NO BY C2H4 ON RHODIUM(111)

Temperature programmed reaction spectroscopy and secondary ion mass sp ectrometry (SIMS) have been applied to study reactions of NO and C2H4 coadsorbed on Rh(111). As expected, H2O, CO2, and N-2 are the main pro ducts at low C2H4 coverages, but at higher coverages H-2, HCN, CO, and NO, and even some C2N2 evolve as well. Static SIMS indicates the form ation of a large supply of adsorbed CN species, part of which desorbs as HCN, while the remainder decomposes and is responsible for delayed formation of N-2. For the highest C2H4 coverages, the majority of the nitrogen atoms in the initially adsorbed NO desorbs as HCN. (C) 1997 A merican Vacuum Society.