Effect of copper on the photocatalytic activity of semiconductor-based titanium dioxide (anatase) and hematite (α-Fe2O3)

The photocatalysts titanium and iron oxides doped with copper were characterized and evaluated using a methylene blue photocatalytic degradation. The X-ray photoelectron spectroscopy (XPS) results of doped titanium oxides indicated a copper oxidation state of (I) and copper species were not observed in doped iron oxides. The copper may narrow the band-gap energy of iron oxides and improve their light absorption ability but does not modify the band gap of titanium oxide. The oxides exhibited high performance in the model reaction. The doped oxide activity was related with the Cu+ and Cu2+ species that acted as center donors and electron acceptors, which may contribute to the efficiency of the process. The iron oxide doped with 0.4% copper (4CFPC) exhibited the best performance. Organic carbon analyses confirmed partial photocatalytic dye mineralization with the use of 4CFPC, indicating that the oxide has the potential for use as an alternative material in photocatalysis. (C) 2014 Elsevier B.V. All rights reserved.