Effect of N- and P-Type Doping on the Oxygen-Binding Energy and Oxygen Spillover of Supported Palladium Clusters*

The oxygen-binding energy is one of the primary factors determining catalytic activity in oxidation reactions. One strategy for controlling the binding of a reactant to a surface is to dope the surface to create complementary donor--acceptor pairs. As oxygen is an acceptor, we have investigated the effect of doping on the oxygen-binding energy on Pd atoms and clusters supported on a rutile TiO$_{\mathrm{2}}$(110) surface. We find that the P-type doping of the TiO$_{\mathrm{2}}$ surface dramatically reduces the O-binding energy to Pd. When extended to Pd$_{\mathrm{4}}$-supported clusters, we find that the P-type dopant decreases the energy for the oxygen to bind at spillover sites directly to the TiO$_{\mathrm{2}}$ surface. In Pd$_{\mathrm{4}}$O$_{\mathrm{2}}$, the oxygen-binding energy is reduced with P-type doping, suggesting that this strategy may be used to control the oxygen-binding energy to supported catalysts.