Photocatalytic activity of silver-modified titanium dioxide at solid–liquid and solid–gas interfaces

Silver-modified titania samples (Ag–TiO2) with varying silver content (0.1–1.0 wt%) were prepared. Silver-modification of titanium dioxide was examined by TEM, XRD, XPS and DR-UV–vis spectroscopy. Ag or AgOx particles on TiO2 surface could not be observed by XRD and TEM investigation, however the color of the Ag–TiO2 samples varied between light rose and purple-brown. XPS measurements revealed that silver exists mainly in oxide form. The photocatalytic activity of pure and Ag–TiO2 samples were compared both in solid–liquid and in solid–gas interfaces. In the liquid phase the 2,2′-thiodiethanol was used as test molecule. Ethanol photodegradation was examined in gas phase at dry initial condition. It was shown that the rate of photooxidation of organic compounds significantly enhanced by silver-modification of titania.