Tailoring the Electronic Structure of Mesoporous Spinel γ-Al₂O₃ at Atomic Level: Cu-Doped Case

The well crystallized mesoporous spinel gamma alumina (γ-Al 2 O 3 ) has been widely studied as an important catalyst support. However, the tailoring of alumina catalyst is still an unresolved challenge when considered at the atomic level. On the basis of experimental characterization, it is found that the electronic structure of γ-Al 2 O 3 could be continuously tailored by metal doping via one-pot route. Combined with density functional theory (DFT) calculations, the nature of geometric and electronic structure evolution upon Cu doping in γ-Al 2 O 3 is investigated. The structure of γ-Al 2 O 3 and the influence of intrinsic defects are studied at first. Considering the nano effect and the charge compensation effects of these intrinsic defects, the doping mechanism of Cu inside γ-Al 2 O 3 lattice are in detail explored at the atomic level. At low doping level the excess electrons from V O or Al i would over compensate Cu dopants, leading to the formation of Cu + species. As the doping level increases, the preferred doping sites change from Oh sites to Td sites, while electrons from Al i correlate the Cu species, and an electronic phase transition is observed.