LAUSR

In reactions involving gas-solid interactions on nanostructured supports, the distinction between catalytically significant atomic structures and unreactive spectators is obscured by the variety of surface states that exist under reaction conditions. Studies of catalysts with well-defined support morphologies could assist in limiting the scope of structural configurations under consideration. Cerium dioxide (CeO2), a technologically important redox catalyst owing to its aliovalent behavior, can be synthesized into nanocrystalline cubes and rods; cubes surface-terminate with {100} planes, while rods surface-terminate with {110} and {100} planes [1]. Density functional theory (DFT) calculations indicate that CeO2 {100} surfaces are less stable than {110} surfaces, which suggests that cubes should be more reactive than rods [2]. However, for the CO oxidation reaction, rods are reported to be more active than cubes [1, 3]. No atomic-resolution, in situ information exists for the surface structures or metal-support interfaces that occur on CeO2 rod/cube-supported catalysts, so we may only speculate upon the origin of the rods’ superior activity. This study employs ex situ and in situ environmental transmission electron microscopy (ETEM) to probe the atomic processes that give CeO2 rod-supported catalysts enhanced catalytic activity.