“…To better understand the morphological evolution of Pd NCs, we employed a thermodynamic model for qualitative analysis (Scheme 2). [38] The total Gibbs free energies of Pd NCs are given by Equation (1), in which, U c , U s , U e , and U t are cohesive energy, surface energy, elastic strain energy, and twin-boundary energy respectively; V, S, and T are the volume, the total {111} surface area, and the twin-boundary area respectively; E c , g 111 , W, and g t are the cohesive energy per unit volume, the {111} surface energy per unit area, the elastic strain energy density, and the twin-boundary energy per unit area respectively.…”