Gas phase photocatalytic activity of ultrathin pt layer coated on α-Fe₂O₃ films under visible light illumination

In this paper, the α-Fe₂O₃ (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 α-Fe₂O₃ 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 α-Fe₂O₃ films coated with Pt ultrathin layer (Pt/Fe₂O₃) 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/Fe₂O ₃ films, and the Pt/Fe₂O₃ 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/Fe₂O ₃ was also discussed in detail.