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.