CORRELATION BETWEEN THE SURFACE CONFIGURATIONS AND HYDROGENOLYSIS - ANILINE ON THE PT(111) SURFACE

A correlation has been developed between the structure of adsorbed rea ction intermediates and their hydrogenolysis reactivity for aniline in hydrogen pressures up to 0.001 Torr on the Pt(111) surface The compos ition and orientation of the species involved in aniline hydrogenolysi s were characterized using temperature programmed reaction (TPR) and n ear edge x-ray absorption fine structure (NEXAFS) measurements. The be nzene and ammonia formed by aniline hydrogenolysis during TPR on the P t(111) surface increase substantially in the presence of hydrogen atmo spheres. At reaction temperatures, the aromatic ring in aniline remain s parallel to the surface in the presence of coadsorbed hydrogen, whil e in the absence of hydrogen the aromatic ring is tilted relative to t he surface. This correlation between orientation and reactivity sugges ts that a parallel configuration may facilitate hydrogenolysis of the C-N bond in aniline. These in situ studies provide new insight into th e structure of surface intermediates which may play a critical role in the mechanisms of aniline hydrogenolysis on the Pt(111) surface in 0. 001 Torr of hydrogen.