Structures and electronic properties of the TMn@W12O36 (TM = Cu, Ag and Au, n = 1–4) clusters

To determine the effect of the embedded Cu, Ag, and Au on the electronic properties of tungsten oxides, the structures, stability, and electronic properties of the TM_n@W₁₂O₃₆ (TM = Cu, Ag and Au, n = 1–4) clusters have been investigated by using density functional theory. The results reveal that the embedded TM_n clusters decrease the structural stability of the W₁₂O₃₆ cages. The Ag@W₁₂O₃₆ and Ag₃@W₁₂O₃₆ clusters exhibit higher structural stability than other TM@W₁₂O₃₆ and TM₃@W₁₂O₃₆ (TM = Cu and Au) clusters. The Cu₃ clusters prefer to be embedded into the W₁₂O₃₆ clusters. The embedded TM_n clusters increase obviously the chemical reactivity of the W₁₂O₃₆ cages. The chemical reactivity of the Ag₂@W₁₂O₃₆ and Ag₄@W₁₂O₃₆ clusters is similar to that of the Cu₂@W₁₂O₃₆ and Cu₄@W₁₂O₃₆ clusters. The Au@W₁₂O₃₆, Au₂@W₁₂O₃₆, Ag₃@W₁₂O₃₆ and Au₄@W₁₂O₃₆ clusters display more chemical stability. The charge transfer amounts between the Ag and O atoms of the TM_n@W₁₂O₃₆ clusters are larger than those between the Cu (Au) and O atoms of them.