Oxygen reduction on zirconium-stabilized-PdO surfaces: a first-principles study

Abstract

The oxygen reduction reaction properties on PdO and Zr-doped PdO surfaces, and the relative stability of the concerned surfaces, have been studied by first-principles calculations. The results demonstrate that the doped Zr element plays an important role in the stabilization of the PdO surfaces and the enhancement of the oxygen reduction activities on these surfaces. The Zr atoms prefer to replace the cus-Pd atoms on the PdO (101) surface, which is more stable than the Zr doped PdO (001) surface. The interaction between Pd and Zr could strengthen the hybridization between the adsorbed O 2p and Pd 4d states, thus lower the adsorption energy, improving the O₂ adsorption performance. The adsorbed O₂ molecules tend to be dissociated on the PdO (101) surface. It is also discovered that the increase of Zr doping concentration can also enhance the O₂ adsorption properties and facilitate the subsequent dissociation.