“…As a consequence of titania modification with copper, it can exist as copper oxides (Cu 2 O, CuO), 15,23,25,26,[28][29][30] copper metal deposited on the titania surface 17,19,20,22,[31][32][33] or as dispersed ions in the titania lattice. 29,34 There are also reports identifying copper in the form of the distorted CuO cluster in which the apical oxygen approaches the Cu(II), thereby forming a five-coordinate square pyramid.…”