Mechanism Study of Photocatalytic Degradation of Gaseous Toluene on TiO2 with Weak-Bond Adsorption Analysis Using In Situ Far Infrared Spectroscopy

The development of far infrared spectroscopy offers a powerful method for comprehensive study in adsorption structure and photocatalytic degradation mechanism of photocatalysis. This study presented an improved in situ diffuse reflectance infrared Fourier transform spectroscopy technique in far infrared region for investigation of weak-bond adsorption and photocatalytic degradation of gaseous toluene on the surface of TiO2. It was found that toluene tends to be adsorbed on the hydroxyl group via three possible sites, the ortho-, meta-, and para-adsorption site, instead of ipso-structure. The methyl group of toluene is consumed first during the process of toluene photocatalytic degradation. Based on these, a reaction route for the photocatalytic degradation of gaseous toluene on TiO2 surface was proposed.