Gas phase photocatalytic activity of ultrathin Pt layer coated on alpha-Fe2O3 films under visible light illumination.

In this paper, the alpha-Fe(2)O(3) (hematite) films were reactively prepared by dc facing targets sputtering method. The ultrathin Pt layer with thickness of around 2 nm was deposited on the surface of alpha-Fe(2)O(3) films by dc diode sputtering method. X-ray diffraction, spectrophotometer, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were used to study the structural, optical, surface morphological, and chemical composition properties of the as-deposited films. The gas phase photocatalytic activities of the alpha-Fe(2)O(3) films coated with Pt ultrathin layer (Pt/Fe(2)O(3)) were evaluated by decomposition of volatilized methanol under illumination of visible light. The variation of photocatalytic activity was depended on the sputtering conditions of Pt/Fe(2)O(3) films, and the Pt/Fe(2)O(3) deposited in low sputtering pressure showed the best photocatalytic performance, which was mainly attributed to the different size of grain boundary and carrier mobility. The mechanism of methanol decomposition on the surface of Pt/Fe(2)O(3) was also discussed in detail.