Morphology and Crystal‐Plane Effects of Nanoscale Ceria on the Activity of CuO/CeO₂ for NO Reduction by CO

Abstract

Abstract The present work elucidated the morphology and crystal‐plane effects of nanoscale ceria on the activity of CuO/CeO 2 catalysts toward NO reduction. CeO 2 Nanopolyhedra were enclosed by (111) and (100) planes; the nanorods predominantly exposed (110) and (100) surfaces, and the nanocubes only showed the polar (100) planes. Moreover, the strongest interaction was between CuO and CeO 2 rods, followed by CuO/CeO 2 polyhedra, and the CuO/CeO 2 cubes showed the least interaction. Importantly, Cu 2+ ions could be incorporated into the pore and surface lattices by occupying the vacant sites in the nanostructure CeO 2 rods. Partial copper oxide species were segregated on the surface of CeO 2 cubes with larger particle sizes. As a result, the site geometry and coordination environment of Cu 2+ ions were different on the (111), (110), and (100) surfaces of CeO 2 . This surface structure effect in turn led to a higher surface reducibility, activity and N 2 selectivity of CuO/CeO 2 nanorods for NO reduction at low temperatures (below 250 °C); the polyhedra and cubes were less active.