Kinetic model of oxidation of metal nanoparticles: Cabrera-Mott and Kirkendall effects

The conventional Cabrera-Mott model for the formation of a thin (nm-sized) flat oxide film on the surface of a macroscopic metal crystal implies that the process is limited by the field-facilitated activated jumps of metal ions at the metal-oxide interface. Earlier, it was modified in order to describe oxidation of metal nanoparticles with the formation of the oxide shell around the close-packed metallic core. In reality, oxidation of metal nanoparticles is often accompanied by the appearance of a hollow in the metallic core (Kirkendall effect). Herein, the analytical treatment takes this effect into account. The numerical results obtained by integration of the corresponding equation show the specifics of the oxidation kinetics in this case.