Dissociative Adsorption of Hydrogen on PdO(101) Studied by HRCLS and DFT

High-resolution core-level spectroscopy (HRCLS) and density functional theory (DFT) calculations have been used to investigate the adsorption and dissociation of hydrogen on a PdO(101) film grown on Pd(111). Energy-dependent measurements of the O 1s and Pd 3d 5/2 binding energies enable identification of surface components that correspond to undercoordinated Pd and O atoms. HRCLS data obtained at 110 K, after hydrogen exposure at the same temperature, reveal hydrogen adsorption and formation of Pd-H and O-H groups. Adsorption at room temperature results instead in complete reduction of the oxide. The experimental results are supported by the DFT calculations of core-level shifts and barriers for water formation.