Figure 1.

Structures of Pd₈ and CeO₂ supported Pd₈ and Pd₈O_x nanoparticles. (a–c) Optimized structure of Pd₈ as a free particle, and on the stoichiometric and defective ceria surfaces (optimized by GA-DFT). (d) Metastable structure of Pd₈ on the defective ceria. (e,f) Structures of Pd₈O_x/CeO₂ (x = 12 and 6) obtained by GCMC-DFT at 300 K with oxygen atmospheres of 1 atm and 10^–20 atm, respectively. Color coding: cyan, red, white, and small yellow spheres represent Pd, O, Ce⁴⁺, and Ce³⁺ atoms, respectively; the purple spheres in defective ceria represent O atoms adjacent to O vacancy sites. This notation is used throughout this paper.