Photocatalytic Activity and Mechanical Performance of O and N Co-doped TiO₂ Thin Films

Amorphous TiO₂ films were deposited on non-alkali glass by reactive radio-frequency magnetron sputtering using a TiO₂ ceramic target. This study analyzed the effects of Ar/O₂/N₂ gas flow ratios, deposition time, and thermal annealing treatments on the morphological and structural phases and photocatalytic characteristics of the TiO₂ films. The XRD results showed a broad hump shape, indicating the existence of an amorphous phase characteristic of TiO₂ films. For O₂/N₂ co-doped TiO₂ films, as the O₂ and N₂ concentration increased, higher photocatalytic activity of TiO₂ materials was obtained, while the film growth rate and band gap energy (E_g) values tended to decrease. When increasing the TiO₂ film thickness, the amorphous phases remained unchanged, the E_g value narrowed, and higher photocatalytic activity was obtained. After thermal annealing treatments, the TiO₂ films showed ultra-hydrophilicity and outstanding photocatalytic efficiency. The TiO₂ film annealed at 450°C displayed higher photocatalytic performance and improved mechanical properties. It was seen that when using a higher nanoindentation load, higher hardness (H) and elastic modulus (E) were obtained, but the H/E, H³/E², and elastic recovery rate (%Re) did not change significantly. Graphical Abstract: [Figure not available: see fulltext.].