Comparative studies of alkane activation by low-index surfaces of iridium and platinum

Abstract

The interaction of alkanes with low-index surfaces of iridium at low temperatures and pressures has been studied in our laboratory by thermal desorption mass spectrometry and low-energy electron diffraction. While the reconstructed (110)-(1 × 2) surface of iridium initiates dissociative chemisorption of ethane and all higher alkanes at 125 K in the low coverage limit, similar reactions with the close-packed (111) surface occur readily only at defect sites. Thus, surface geometry influences strongly the activation barriers to C-H bond scission in alkanes on iridium surfaces.