Simple preparation of floatable Nitrogen-doped TiO₂ films and their photocatalytic performance

In this study, polypropylene (PP) plates were used as the substrate for the fabrication of TiO₂ photocatalytic films, which were prepared by integrating the sol–gel method with a coupling agent approach. The resulting TiO₂ crystals exhibited a mixed phase of anatase and rutile crystals with irregular morphology at the micrometer scale. To enhance the photocatalytic activity under visible light, nitrogen doping was implemented using urea as the nitrogen source, yielding N-doped TiO₂ films. The results demonstrated that nitrogen doping not only improved the visible-light absorption but also facilitated the transfer and separation of photogenerated carriers while suppressing the recombination of photogenerated holes and electrons. Consequently, the photocatalytic activity across the full spectrum of light was significantly enhanced. Performance evaluation revealed that the N-doped TiO₂ films achieved up to 53% improvement in efficiency compared to their undoped counterparts. These floatable TiO₂ photocatalytic films hold great potential for applications in treating water surface pollution, such as marine oil spills.