Size-Dependent Adsorption of Styrene on Pd Clusters: A Density Functional Theory Study

Abstract

When the size of a reactant molecule is comparable to that of a nanometer catalyst (such as an aromatic compound and a nanometer or subnanometer metal catalyst), the adsorption configuration of the molecule on the catalyst becomes different from that on their larger counterparts. Consequently, distinct catalytic performances can be observed for catalysts of different sizes. Therefore, it is crucial to understand the adsorption behaviors of molecules on various metal nanocatalysts. Here, the size-dependent adsorption of a representative system (i.e., styrene on Pd clusters) was systematically explored using the density functional theory calculations. For large Pd nanoparticles (between 31 and 73 atoms), the adsorption becomes weaker as the particle size increases. For particles with fewer than 31 atoms, the adsorption weakens rapidly with a decrease in size, which was also observed for Cu-supported Pd clusters. The peaks of adsorption strength of middle-sized particles are caused by the combination of the ...