The photocatalytic degradation of 2-propanol was studied by using platinum, titania, and platinum loaded on titania as photocatalysts. In this study, the catalysts were prepared by microemulsion technique, which gives ultrafine particles in the range of 3-5 nm. Each synthesized photocatalyst was suspended in an aqueous solution of 2-propanol, and the solution was photoirradiated by an 11 W low pressure mercury lamp. The results showed a negligible activity of platinum and a relatively low activity of titania in the degradation of 2-propanol, but a significantly high activity of platinum loaded on titania was observed. The effects of the influencing factors, including initial concentration of 2-propanol, catalyst dosage, initial pH, and dissolved oxygen, were studied. The results revealed that the most efficient degradation of 2-propanol was achieved in a highly acidic region, and the degradation rate increased with both catalyst dosage and initial concentration of 2-propanol. The dissolved oxygen was found to have a significant influence affecting the photocatalytic degradation of 2-propanol since it acts as an electron scavenger and is responsible for producing hydroxyl radical. Acetone was detected as an intermediate during the photocatalytic reaction of 2-propanol. (C) 2007 Elsevier B.V. All rights reserved.