Interfacial structures and reactivities of CeO2/Cu(1 1 1) catalyst with strong interfacial interaction and charge transfer

In comparison to ceria thin film, CeO 2 /Cu inverse catalyst with different thickness of CeO 2 layers displays both good thermostability and excellent catalytic activity towards CO oxidation due to strong interfacial interaction and significant charge transfer • The strong interfacial interaction of CeO 2 /Cu(111) composites is attributed to the strong O-Cu bonds formed by the hybridization of O-2p orbital and Cu-3d orbital at the interface. • Significant charge transfer from Cu(111) substrate to CeO 2 (111) layer results in different charge accumulation on CeO 2 /Cu(111) surface as well as higher surface reactivity. • CeO 2 /Cu catalyst with different thickness of CeO 2 layers displays both good thermostability and excellent catalytic activity towards CO oxidation. Interfacial interactions have been recognized as a crucial factor affecting interfacial structures and catalytic performance. Herein, the interfacial structures, interactions, and catalytic properties of CeO 2 /Cu(111) composites including monolayer, bilayer and trilayer CeO 2 (111) on Cu(111) substrate were comparatively studied by DFT + U calculations. Our results showed that the interfacial interaction between CeO 2 (111) and Cu(111) substrate increased linearly with the increase of CeO 2 (111) thickness. This trend was well rationalized by analyzing the strong interfacial interactions, which were mainly due to the strong O-Cu chemical bonds formed by the hybridization of O-2p orbitals and Cu-3d orbitals at the interface. Significant charge transfer from Cu(111) substrate to CeO 2 (111) layer resulted in the charge accumulations of surface O-Ce-O layer in order of ML-CeO 2 /Cu(111) (-1.06 |e|) > BL-CeO 2 /Cu(111) (-0.40 |e|) > TL-CeO 2 /Cu(111) (+0.36 |e|). The intrinsic activity was further identified by employing CO oxidation as model reaction, and followed the order of BL-CeO 2 /Cu(111) > ML-CeO 2 /Cu(111) > TL-CeO 2 /Cu(111) > ML-CeO 2 (111) > TL-CeO 2 (111) > BL-CeO 2 (111). The results showed that the strong interfacial interaction and charge transfer were key factors for the good stability and excellent catalytic activity of CeO 2 /Cu catalyst. All these findings provided insights for the design and application of ceria-based catalysts.