First-Principles Calculations of Palladium Nanostructures Formed on $\gamma $-Alumina*

Palladium clusters supported on the $\gamma $-alumina surface serve as a catalyst for a variety of important chemical reactions. We report results of our first-principles quantum mechanical calculations for the bonding configurations of palladium atoms and clusters that are supported on the $\gamma $-Al$_{2}$O$_{3}$(110) surface. In particular, our results show that while a single Pd atom prefers to be bonded on the bridge sites of two surface aluminum atoms, a chain nanostructure and a ring-like nanostructure may be formed when more Pd atoms are adsorbed on the surface.