Tuning mixed-phase Nb-doped titania films for high-performance photocatalysts with enhanced whole-spectrum light absorption

Abstract

Recently, the use of TiO₂ under visible (vis) light to degrade pollutants has attracted increasing attention. In our previous study, conductive anatase Nb-doped titania (NTO) thin films were demonstrated as a novel strategy to achieve good photocatalytic performance under visible light. However, the photocatalytic properties of conductive rutile NTO films are not yet known. In this study, a simple, controllable and effective method with a high deposition rate was developed to form NTO thin films with tunerable phases. By introducing a seed layer combined with suitable sputtering conditions, e.g. sputtering power, small crystalline clusters with rutile phase could be well controlled in the as-grown films and become a key factor to form NTO thin films with different phases. Interestingly, the NTO thin film with mixed anatase and rutile phases shows excellent photocatalytic performance due to its better absorption, more effective separation of photo-generated holes and electrons and high charge transfer. This result could bring new insight and promising application of NTO thin films in both conductive films and photocatalytic applications, particularly self-cleaning windows.