A Simple and Ligand‐Free Synthesis of Light and Durable Metal‐TiO₂ Polymer Films with Enhanced Photocatalytic Properties

Abstract The photocatalytic efficiency of TiO₂ can be increased by using co‐catalysts, such as metal nanoparticles, which act as electron sinks to suppress the recombination of photogenerated electron–hole pairs. The main challenge in preparing such systems is to create intimate contact between the metal and the TiO₂ surface while still maintaining control over the morphology and distribution of the metal nanoparticles in the TiO₂ matrix. Here lightweight TiO₂ films are prepared by assembling a layer of TiO₂ nanoparticles onto a thin polymer support, followed by physical vapor deposition of metal nanoparticles onto the TiO₂ surface. Importantly the fabrication does not involve any chemical modifications to the surface of NPs, which allows spontaneous formation of strong chemical bonds between deposited metal and TiO₂. Systematic optimization of this process gives materials 6× more catalytically active than the parent TiO₂ films and up to 18× more catalytically active than commercial photoactive TiO₂ glass. Moreover, the transparent, flexible, and robust polymer support enables the product films to be easily used for repeated photocatalytic reactions. Since the whole fabrication process is scalable and highly reproducible, this approach provides new opportunities for controlled synthesis of a new family of practical high‐performance metal‐ semiconductor hybrid photocatalysts.