Controllable Synthesis of Ceria Nanoparticles with Uniform Reactive {100} Exposure Planes

We investigate, by a systematic first-principles calculation, the surface energies of ceria {100} crystal planes with adsorption of 13 kinds of nonmetallic elements and nine kinds of metallic elements. We predict theoretically that adsorption of nonmetallic B, C, F, Si, P, S, Cl, Br, OH, and I and metallic Sr, La, Mg, Na, K, Y, Ca, and Ba can stabilize the ceria {100} planes through lowering their surface energies. Experimentally, we purposely select KOH as a mineralizing agent by taking into account the calculated surface energies and the factors in hydrothermal synthesis, and demonstrate a successful production of cube-shaped ceria nanoparticles of high purity via carefully optimizing the synthesis parameters. Further comprehensive transmission electron microscopy study identifies all the exposure planes of the cube-shaped ceria nanoparticles as the uniform {100} crystal planes. As a result of this unique morphology, the nanoparticles are found to show markedly enhanced UV-absorption capability as compared to either octahedron-shaped ceria nanoparticles or bulk ceria.