Fig. 7. (a) Side view of the anatase TiO₂ (101) surface layer (in the 1 × 3 supercell). (b) Side and top views of adsorbed Cu_x (x = 1, 2, 3) atoms, (c) Cu₅ atoms in the chain-like structure, (d) Cu₅ 3D-like structure, (e) subsurface Cu atom, (f) one subsurface Cu atom in the Cu₅-chain structure, (g) Cu₅O₅ cluster and (h) Cu₁₀O₉ cluster adsorbed on the anatase TiO₂ (101) surface. (i) Adsorption energy (eV per atom) of Cu_xO_y clusters on the anatase TiO₂ (101) surface, with the cohesive energy of bulk CuO and Cu as references. (j) Bader charges versus Cu coordination number (selected according to Cu–O distances below 2.16 Å). Bader charges <0.4 correspond to Cu⁰, 0.4–0.7 to Cu⁺ and >0.7 to Cu²⁺. (k) Bader charges (e⁻) and (l) atomic magnetic moment (in μ_B) of Cu atoms in Cu₅O_y (y = 5, 4, 3, 2, 1, 0) clusters adsorbed on the anatase TiO₂ (101) surface.