Size and Structure Matter: Enhanced CO2 Photoreduction Efficiency by Size-Resolved Ultrafine Pt Nanoparticles on TiO2 Single Crystals

A facile development of highly efficient Pt-TiO2 nanostructured films via versatile gas-phase deposition methods is described. The films have a unique one-dimensional (1D) structure of TiO2 single crystals coated with ultrafine Pt nanoparticles (NPs, 0.5–2 nm) and exhibit extremely high CO2 photoreduction efficiency with selective formation of methane (the maximum CH4 yield of 1361 μmol/g-cat/h). The fast electron-transfer rate in TiO2 single crystals and the efficient electron–hole separation by the Pt NPs were the main reasons attributable for the enhancement, where the size of the Pt NPs and the unique 1D structure of TiO2 single crystals played an important role.