We have designed and fabricated efficient photocatalysts sensitive to visible light, Cu(II)-grafted TiO2 (Cu(II)/TiO2) and WO3 (Cu(II)/WO3), after the suggestions made in the literature as to the photo-induced interfacial charge transfer from a semiconductor to an adsorbed molecular species and the catalytic multi-electron reduction of oxygen by Cu(I) ions. In fact, Cu(II)/TiO2 and Cu(II)/WO3 photocatalysts decomposed 2-propanol to CO2 via acetone under visible light (> 400 nm) with quantum efficiencies of 8.8% and 17%, respectively. The turnover numbers of this reaction exceeded 4.1 for Cu(II)/TiO2 and 51 for Cu(II)/WO3, indicating that both function catalytically. (C) 2008 Elsevier B.V. All rights reserved.