Title: TiO2 thin film for methanol preparation from photocatalytic reduction of carbon dioxide
Abstract: Holmium-TiO 2 thin films were fabricated by a sol-gel technique.Holmium-TiO 2 thin films were identified by many characterization techniques, such as UV-Vis, TEM, XPS, BET and XRD.The performance of the holmium-TiO 2 thin film photocatalyst was studied by studying methanol preparation from the photocatalytic reduction of carbon dioxide under visible light.The results showed that holmium-TiO 2 thin film photocatalytic properties can be adjusted by adjusting the holmium weight percent.XPS results revealed that holmium species were present as Ho 3+ ions due to the presence of a peak for Ho3d 5/2 at 163.1 eV.BET results reveal that the addition of holmium to TiO 2 led to an increase in the BET surface area of the TiO 2 thin film.Additionally, the addition of holmium species decreased the band gap and increased the e-h recombination rate of titanium dioxide thin films.The highest photocatalytic activity and lowest band gap of the holmium-TiO 2 thin film were achieved at 0.4 wt % holmium.The yield of methanol obtained using a 0.4 wt % Ho/TiO 2 thin film is approximately 32 times that of the TiO 2 thin film.The Holmium-TiO 2 thin film has stable photocatalytic activity until five times for methanol preparation from the photocatalytic reduction of carbon dioxide under visible light.