Fabrication of WO3/Cu2O composite films and their photocatalytic activity.

WO(3)/n-Cu(2)O and WO(3)/p-Cu(2)O composite films have been fabricated on titanium (Ti) substrates with a consecutive cathodic electrodeposition route. Those resulting films were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). Their photocatalytic activity under simulated natural light illumination was evaluated using Orange II (mainly) and Cr(VI) as model pollutants. The results indicate that WO(3)/p-Cu(2)O exhibits higher photocatalytic activity compared to both WO(3) and p-Cu(2)O alone, while the photocatalytic activity of WO(3)/n-Cu(2)O is higher than WO(3), but lower than n-Cu(2)O. Even in the absence of other reducing agents (hole scavengers), WO(3)/p-Cu(2)O also show certain photocatalytic activity towards reduction of Cr(VI). The photocatalytic activity of WO(3)/p-Cu(2)O is closely related to the deposition amount of p-Cu(2)O. Additionally, WO(3)/p-Cu(2)O composite film also possesses a relatively high stability during the reactions. The difference in photocatalytic activity between the two types of composite films is interpreted in terms of different mechanisms for transfer of charge carriers photogenerated within the heterojunctions.