Theoretical Study of Oxygen Chemisorption on Pd (111), Au (111) and Pd-Au (111) Alloy Surfaces

The chemisorption of an O atom on Pd (111), Au (111) and Pd-Au (111) alloy surfaces was systematically studied using the density functional theory generalized gradient approximation (DFT-GGA) method. The most favorable adsorption sites, binding energies and geometries during adsorption were obtained with a coverage of 0.25 ML. Results indicate that the preferred adsorption site is face centered cubic (fcc) site on pure or clean (111) surfaces and the order of the most stable adsorption energies for alloy (111) surfaces are Pd-3 (-4.83 eV) > Pd2Au (-4.16 eV) > PdAu2 (-3.57 eV) > Au-3 (-3.0 eV). In addition, when studying oxygen adsorption on a variety of alloy surfaces, we focused on the d-band center of the electronic properties to explain the relationship between binding strength and component of the alloy surfaces. The results indicate that the d-band center is further away from the Fermi level, the chemisorption bond of atomic oxygen on the surface is weaker.