First-Principles Prediction of Oxygen Reduction Activity on Pd-Cu-Si Metallic Glasses

We carry out first-principles simulations to assess the potential of PdCuSi metallic glasses as catalysts for oxygen reduction reaction (ORR) using oxygen adsorption energy (E-O) as a descriptor. We find that the substitution of Cu on crystalline Pd(111) surface improves the ORR activity while the substitution of Si on the surface is in general detrimental to the ORR activity. Compressive strains are found to weaken oxygen binding on the surface and thus enhance the ORR activity. On the basis of the analysis of EO distribution on the Pd metallic glasses surfaces, we find that for Si-deficient adsorption sites, the local ORR activity could exceed that on pure Pd surface, while Si-rich sites exhibit a rather poor ORR activity. The Pd metallic glasses can sustain a much higher compression than the crystalline counterpart, thus their ORR activity can be improved substantially under a large compression. It is predicted that low-Si Pd metallic glasses could be excellent ORR catalysts under compression.