TEMPERATURE-PROGRAMMED FT-IR STUDY OF THE ADSORPTION OF CO AND COADSORPTION OF CO AND H-2 ON NI AL2O3/

The adsorption of CO and co-adsorption of CO and H-2, On Ni/Al2O3 cata lyst prepared by a distinct procedure were studied by means of FT-IR t echnique. The study shows that only one kind of CO adsorption site - t he linear CO adsorption site - exists on the Ni/Al2O3 catalyst used in present work. Temperature-programmed heating of CO adspecies in CO at mosphere reveals that the disproportionation of linearly adsorbed CO m ay occur at above 473 K. In H-2 + CO atmosphere, a new IR band centere d near 1910 cm(-1) emerges, the intensity of which increases and decre ases concomitantly with that of the band centered about 2050 cm(-1) wi th increasing temperature, indicating the occurrence of a new adspecie s in the dynamic process of CO hydrogenation under reaction conditions . This new adspecies is tentatively ascribed to nickel carbonyl hydrid e species. The methanation of CO on Ni/Al2O3 may occur via a mechanism involving the formation of nickel carbonyl hydride species.