Theoretical Study on the Structures and Stabilities of Cu n Zn 3 O 3 (n = 1–4) Clusters: Sequential Doping of Zn 3 O 3 Cluster with Cu Atoms.

Density functional theory (DFT) and coupled cluster theory (CCSD(T)) calculations are performed to investigate the geometric and electronic structures and chemical bonding of a series of Cu-doped zinc oxide clusters: Cu_nZn₃O₃ (n = 1–4). The structural evolution of Cu_nZn₃O₃ (n = 1–4) clusters may reveal the aggregation behavior of Cu atoms on the Zn₃O₃ cluster. The planar seven-membered ring of the CuZn₃O₃ cluster plays an important role in the structural evolution; that is, the Cu atom, Cu dimer (Cu₂) and Cu trimer (Cu₃) anchor on the CuZn₃O₃ cluster. Additionally, it is found that Cu_nZn₃O₃ clusters become more stable as the Cu content (n) increases. Bader charge analysis points out that with the doping of Cu atoms, the reducibility of Cu aggregation (Cu_n−1) on the CuZn₃O₃ cluster increases. Combined with the d-band centers and the surface electrostatic potential (ESP), the reactivity and the possible reaction sites of Cu_nZn₃O₃ (n = 1–4) clusters are also illustrated. [ABSTRACT FROM AUTHOR]