Size-Dependent Electrochemical Properties of Pure Metallic Nanoparticles

A generalized size-dependent thermodynamic model was derived to describe the electrochemical properties of nanoparticles, which takes into account the effects of size-dependent stress distributions in the surface shell and core of nanoparticles, based on the thermodynamic equilibrium theory. This model can be used to simultaneously analyze the nanoparticle size, stresses, electrochemical properties, and their coupling behaviors in thermodynamic equilibrium nanoparticles. Combined with the molecular dynamics simulations, the spherical nanoparticles of pure metals (Au, Pt, Ni, Cu, and Fe) were modeled as a core-shell structure. The thermodynamic analysis showed that the anodic current density decreased with decreasing nanoparticle radius, implying that the stability of nanoparticles was enhanced, which is qualitatively consistent with some experimental observations.