Effects of Ag on the photocatalytic activity of multiple layer TiO₂ films

Abstract

This work reports effective activated multiple layers Ag-TiO₂ films and Ag-TiO₂/Ag films via a solgel and direct coating approach. Scanning electron microscopy and transmission electronic microscope are performed to characterize the morphology. The roles of metallic Ag on TiO₂ films for photodegradation stearic acid are explained by UV–vis spectroscopy and photoluminescence spectroscopy. The photocatalytic activity of Ag-TiO₂ films for stearic acid decomposition is 5 times higher than that of pure TiO₂ films. Different Ag-TiO₂/Ag films have almost the same activity of photodegradation stearic acid. The strong surface plasmon resonance effect of Ag makes TiO₂ absorb more visible light. The separation effect of photogenerated electron–hole pairs could be increased by doping a small amount of Ag. For more Ag amount in Ag film, there will likely be an equilibrium between the separation of electron–hole pairs and the recombination of them.

Keywords:

• Multiple Ag-TiO₂ films
• Ag films
• Photocatalysis
• SPR effect