On the Design of the Metal-Support Interface in Methanol Electrocatalytic Oxidation

In this work, we present a theoretical investigation of the SrTiO₃ perovskite-supported Pd catalyst in the methanol electro-oxidation reaction. In order to determine the metal-support interactions, we designed a system consisting of a Pd (100) double layer supported on one of the two possible terminations of the (100) perovskite surface. These terminations are characterized by different reducibilities of the layers directly interacting with the Pd bilayer and result in the difference in the stability of the surface-bound intermediates. Despite the fact that the Pd surface is identical in terms of geometry, we observed significant differences in the overpotential required for the reaction; in the case of TiO₂ termination, the overpotential has been determined to be 0.68 V, while in the case of SrO termination, it amounts to as much as 1.35 V. We further investigate the charge transfers within the components of the system and the geometries of the intermediates to unravel the role of the electron structure on the overall efficiency of the process.