Infrared-active nitrogen adsorbed on alumina, magnesia, or calcium oxide both with and without ruthenium

Abstract Infrared-active surface nitrogen species were formed at around 2200 and/or 2040 cm−1 on 2% RuAl2O3, 5% RuMgO, MgO, or CaO following NH3 decomposition at 200 or 350 °C. The 15N isotope wavenumber shifts (10 to 40 cm−1) were much smaller than those (ca. 70 cm−1) for weakly adsorbed dinitrogen on surfaces such as NiSiO2 (R. P. Eischens and J. Jacknow, in “Proceedings, 3rd International Congress on Catalysis, Amsterdam, 1964” (W. M. H. Sachtler et al., Eds.), p. 627, North-Holland, Amsterdam, 1965; R. V. Hardeveld and A. V. Montfoort, Surf. Sci. 4, 396 (1966), R. V. Hardeveld and A. V. Montfoort, Surf. Sci. 17, 90 (1969) ) or RhSiO2 ( Yu. G. Borodko and V. S. Lyutov, Kinet. Katal. 12, 238 (1971) ). NH3 had to be decomposed in order to obtain the surface nitrogen species. However, the condition for obtaining these species was not dependent on the degree of NH3 adsorption, the existence of surface carbonates, the extent of surface hydroxides, or the presence of Ru metal. It is suggested that these observed surface nitrogen species are dinitrogen strongly adsorbed on oxides (Al2O3, MgO, or CaO) even in the presence of Ru metal.