The adsorption and reactions of aniline on Rh(111)

Abstract

The adsorption and reactions of aniline on a Rh(111) single-crystal surface have been investigated by temperature-programmed reaction and x-ray photoelectron spectroscopies under ultrahigh vacuum conditions. Aniline undergoes N-H bond cleavage to form C6H5NH and C6H5N on Rh(111) between 100 and 400 K. C6H5N decomposes at 475 K to form dihydrogen and surface atomic nitrogen and nitrogen-containing intermediates, which react to form gaseous HCN (75%) at 500-700 K and dinitrogen (25%) at 950 K. No hydrocarbon products were observed. Recombination of C6H5NH and C6H5N with surface deuterium yields N-deuterated aniline (C6H5NHD and C6H5ND2) at 230-260 K on a deuterium-precovered Rh(111) surface. The comparison of reactions of aniline on Rh(111) with those of phenol (C6H5OH) and benzenethiol (C6H5SH) suggests that the C-X (X = O,S,N) bond strength plays an important role in determining reaction kinetics and selectivity for the reactions of C6H5XH (X = O,S,NH) on Rh(111). PU - AMER INST PHYSICS PI - WOODBURY PA - CIRCULATION FULFILLMENT DIV, 500 SUNNYSIDE BLVD, WOODBURY, NY 11797-2999