We examine DFT calculations on Pt and Pt–Au nanoparticles with a diameter of 2 nm.

Thermodynamically stable oxide structures are clarified.

Edges and corners of the Pt nanoparticle are shown to be inactive and easily dissolving sites.

A substitutional introduction of Au atoms to Pt nano-particles is promising for suppressing Pt dissolutions without decreasing the number of active sites for ORR.