where γ is the surface energy per unit area, ΔGv is the change of Gibbs free energy, C is the concentration of the solute, C0 is the equilibrium concentration or solubility, Ω is the atomic volume. It can be seen that the critical radius of the metal nucleus mainly depends on the surface energy and the concentration of the metal ions. Given the small size of the voids between the LLC rods and the low diffusion rate of Pt ions in the voids, it is reasonable to assume that the formation of new nuclei becomes difficult during the Pt deposition. In this situation, the oriented growth of existing grains could be thermodynamically favourable in comparison with the nucleation of new grains. We believe that the confinement of the narrow nanovoids in the LLC loaded AAO template and the low growth rate at low temperature are the main factors behind the formation of the single crystalline platinum nanowires. When the deposition reaches the LLC rods, these ultrathin LLC rods can be embedded without changing the structural continuity of the matrix, resulting in the single crystalline structure of the mesoporous Pt nanowires.
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