HAADF STEM observation of the Au/CeO2 nanostructures

Gold nanoparticles supported on oxide substrates are widely utilized as heterogeneous catalysts. Here, we apply a facile surfactant- and template-free hydrothermal method to fabricate Au/CeO2 nanostructures, and show a successful preparation of well-defined CeO2 nano-octahedrons with Au nanoparticles on their surface. The high-angle annular dark field scanning transmission microscopy imaging technique is applied to investigate microstructure of the Au/CeO2 nanostructure. We find that the Au clusters with a diameter of less than 2 nm cannot form the FCC Au lattice, and that twins emerge in the Au nanoparticles with a diameter of larger than 2 nm. Moreover, we identify preferential orientation relationships {111}(Au) parallel to {111}(CeO2) and < 110 >(Au) parallel to < 110 >(CeO2) between the Au nanoparticles and CeO2 nano-octahedrons. (C) 2014 Elsevier B.V. All rights reserved.