The effect of N-2 treatment on the photocatalytic activity of Pt-0/TiO2 was investigated. The results showed that after treatment at 500 degrees C in N-2, 70% of the photocatalytic activity of 1.0 wt.% Pt-0/TiO2 was lost by the evaluation of photocatalytic oxidation reaction of C3H6. Transmission electron microscopy (TEM) and Ar+ ion sputtering tests revealed that in the course of high-temperature N-2 treatment, the size of Pt-0 particles on TiO2 increases and a strong interaction between metal and support, i.e. Pt-0 particles encapsulated by TixOy, happens, which are the reasons for the deactivation of Pt-0/TiO2 photocatalyst treated by high-temperature N-2. (c) 2008 Elsevier B.V. All rights reserved.