H2O2-assisted photocatalysis on flower-like rutile TiO2 nanostructures: Rapid dye degradation and inactivation of bacteria

•Hierarchically assembled rutile TiO2 was synthesized at room temperature.•Hydrothermal treatment enhanced the crystallinity, while morphology was maintained.•Hydrothermal treatment also led to larger crystallites and a lower surface area.•Effective K. pneumoniae killing and MO degradation were achieved with the use of H2O2.•Higher crystallinity enhanced the reaction rate in the presence of H2O2. Hierarchically assembled flower-like rutile TiO2 (FLH-R-TiO2) nanostructures were successfully synthesized from TiCl4 at room temperature without the use of surfactants or templates. An initial sol–gel synthesis at room temperature allowed long-term hydrolysis and condensation of the precursors. The resulting FLH-R-TiO2 possessed relatively high crystallinity (85wt%) and consisted of rod-shaped subunits assembling into cauliflower-like nanostructures. Hydrothermal evolution of FLH-R-TiO2 at different temperatures (150, 200 and 250°C) was followed by means of X-ray diffraction, transmission and scanning electron microscopy. These FLH-R-TiO2 nanostructures were tested as photocatalysts under simulated daylight (full-spectrum lighting) in the degradation of methyl orange and in the inactivation of a multiresistant bacterium, Klebsiella pneumoniae. The effects of hydrothermal treatment on the structure, photocatalytic behavior and antibacterial activity of FLH-R-TiO2 are discussed.