Separate evolution of H2 and O2 from H2O on visible light-responsive TiO2 thin film photocatalysts prepared by an RF magnetron sputtering method: The effect of various calcination treatments on the photocatalytic reactivity
Visible light-responsive TiO2 thin film photocatalysts (Vis-TiO2) havebeen prepared on Ti metal foil (Vis-TiO2/Ti) or ITO glass (Vis-TiO2/ITO) substratesby a radio-frequency magnetron sputtering (RF-MS) method. The UV–Visspectra as well as photoelectrochemical performance of Vis-TiO2 were affected byvarious calcination treatments such as calcination in air or NH3. Calcinationtreatment in NH3 (1.0 9 104 Pa, 673 K) was particularly effective in increasing thevisible light absorption of Vis-TiO2 as well as in enhancing its photoelectrochemicalperformance and photocatalytic activity. A novel Vis-TiO2 thin film photocatalyst(Vis-TiO2/Ti/Pt) was prepared by an RF-MS method where Vis-TiO2 was depositedon one side of a Ti metal foil substrate and nanoparticles of Pt were deposited on theother side. The separate evolution of H2 and O2 from H2O could be successfullyachieved by using an H-type glass cell consisting of two aqueous phases separatedby Vis-TiO2/Ti/Pt and a proton-exchange membrane. It was found that the rate ofthe separate evolution of H2 and O2 was also dramatically enhanced by calcinationtreatment of Vis-TiO2 in NH3.