Visible light-responsive Fe-loaded TiO2 photocatalysts for total oxidation of acetaldehyde: Fundamental studies towards large-scale production and applications

[Display omitted] •Visible light responsive Fe-loaded TiO2 photocatalysts were prepared by TR-CVD method.•High photocatalytic performance can be achieved with controlled Fe loading.•Total oxidation of acetaldehyde was resulted.•Large scale production and great potential for real applications were shown. Various Fe loadings were applied onto P25 TiO2 using temperature-controlled vapour deposition and the resulting structures were subsequently annealed at 750 °C. As-received TiO2 was nearly photo-catalytically inactive for acetaldehyde decomposition under visible light, but when a very small amount of Fe below the threshold was loaded, the activity became maximized. Control of Fe loading is critical to prepare high-performing Fe-TiO2 photocatalysts since a larger amount of Fe forms larger iron oxide particles, which induces non-radiative recombination of the optically excited electron-hole pairs, thereby reducing the photocatalytic activity. Regarding the reaction mechanism, fast oxidation of acetaldehyde into CO2 and a slower path via acetic acid to CO2 were identified, where almost no evolution of secondary pollutant vapour was identified. A strategy towards large-scale production and stable fixation of photocatalyst powder on surfaces of construction materials for real air purification applications are discussed.