Density Functional Theory Study of p-Chloroaniline Adsorption on Pd Surfaces and Clusters

The adsorption mode of aromatic molecules on transition metal surfaces plays a key role in their catalytic transformation. In this study, by means of density functional theory calculations, we systematically investigate the adsorption of p-chloroaniline on a series of Pd surfaces, including stepped surfaces, flat surfaces, and clusters. The adsorption energies of p-chloroaniline on these substrates [Pd(221), Pd(211), Pd(111), Pd(100), Pd-13-icosahedral, Pd-13-cubo-octahedron, Pd-55] are -1.90, -2.13, -1.70, -2.11, -2.53, -2.65, -2.23 eV, respectively. Benzene ring is adsorpted on catalyst rather than amine group in p-chloroaniline molecular. A very good linear relationship is further found between the adsorption energies of p-chloroaniline and the dband center of both Pd surfaces and clusters. The lower of d-band center of Pd models, the stronger adsorption of p-chloroaniline on catalysts. In addition, the frontier molecular orbital and density of states analysis explain the adsorption energy sequence: cluster Pd-13 > stepped Pd(221) surface > flat Pd(111) surface. (C) 2014 Wiley Periodicals, Inc.