Chemisorption and decomposition of C_1 and C_2 hydrocarbons on a Pd(111) surface: a periodic density functional study

摘要

The chemisorption of CH_x (x=0-3), C_2H_4 and H on a Pd(111) surface has been studied with Density Functional periodic calculations. For H the fcc hollow site is found to be the most stable. The carbon atom prefers a hollow site, the CH fragments is also in a hollow site, while the CH_2 is preferencially in a bridge and the CH_3 on top of a Pd atom, in simple agreemnt with the free valence. On the surfae the C-H bond cleavages are quasi thermoneutral, and the most stable species are CH and CH_3. The prefered binding mode for ethylene is di-sigma with a small binding energy, and the pi mode is only slightly less stable. The transformation of ethylene on the surface is discussed.