Cyclic Performance and Photo-Induced Crystalline Growth of Nanostructured Agl/TiO2 Visible Light Photocatalyst

Nanostructured Agl/TiO2 visible light photocatalyst was prepared with AgNO3, KI, and Ti(OBu)(4) as precursors. The photocatalyst was used repeatedly to degrade methylene blue and methyl orange in water with visible light irradiation. Though a high photocatalytic efficiency was observed for the photocatalyst in the first cycle, the photocatalytic efficiency was found to decrease dramatically in subsequent cycles. X-ray diffraction and SEM analyses revealed an obvious crystalline growth of Agl in Agl/TiO2 nanocomposite after photocatalysis or visible light irradiation. It was proposed that photo-induced crystalline growth had occurred to Agl in the course of photocatalysis and resulted in dramatic decrease in the photocatalytic efficiency of the photocatalyst. Photo-induced crystalline growth may be a limiting factor for the lifetime of photocatalysts and should be examined as an important aspect of photostability when new photocatalysts are developed