TEM and STEM study of the Au nano-particles supported on cerium oxides

The structures of Au particles on CeO2 surfaces were observed by an analytical transmission electron microscopy (TEM) equipped with annular dark field scanning transmission electron microscopy (HAADF-STEM) systems. The Au/CeO2 model catalysts were prepared by using the poly-crystalline CeO2 substrates. The Au particles of 2-5 nm in diameter were deposited on the substrates. The preferential orientation relationship of (111)[1-10]Au//(111)[1-10]CeO2 was frequently observed in profile-view HRTEM images on CeO2 (111) surface. High resolution HAADF-STEM images were also obtained for Au-CeO2 interfaces. The position of atomic columns of Au and Ce at Au-CeO2 interface is directly investigated from HAADF-STEM images. The structure of the interfaces between Au particles and CeO2 (111), (100), (110) surfaces were discussed.