Computer simulation of dealloying in Cu-Pt nanoparticles

Two basic alternative atomistic simulation methods (molecular dynamics and Monte-Carlo) have been used to reproduce the dealloying phenomenon in Cu-Pt nanoalloys. Using the Gupta (tight-binding) potential, we simulated nanoparticles consisting initially of 1500 Cu and 1500 Pt atoms. The involved programs propose search and following removing Cu atoms with the lowest specific binding energies. We have found that as a result of dealloying the particle surface layer is really enriched with Pt atoms. However the particle core keeps in general the structure of the initial nanoalloy. This effect is especially noticeable in molecular dynamics simulation. We have also established that dealloying results in formation of a defected particle structure (vacancies, first of all). Presumably, just such an effect yields the porous structure of bigger Cu-Pt particles in laboratory experiments on dealloying.