A Nitrogen-Doped Carbon Dot-Sensitized TiO2 Inverse Opal Film: Preparation, Enhanced Photoelectrochemical and Photocatalytic Performance

In this study, a facile strategy for preparing nitrogen-doped carbon dots (N-CDs) was developed. A novel N-CD-sensitized, three-dimensionally ordered, porous TiO2 inverse opal structure (IOS) using a polystyrene (PS) opal as the template was constructed for the first time. The as-prepared N-CDs/TiO2 IOS shows enhanced photoelectrochemical performance and photocatalytic activity. The photo-response range of the composite film is expanded to the visible region due to the addition of N-CDs and the highly ordered void structure. The photocurrent density of the N-CDs/TiO2 IOS is approximately 6 times higher than that of TiO2 IOS and 18 times that of TiO2 nanoparticles (NPs). The photocurrent density is also enhanced 2-fold through sensitization of the N-CDs compared with that of CDs. In addition, the N-CDs/TiO2 IOS shows better photocatalytic activity in degrading organic dyes than CDs/TiO2 IOS, TiO2 IOS and TiO2 NPs. The good photoelectrochemical and photocatalytic performance makes N-CDs/TiO2 IOS a promising material in clean energy, water treatment and other applications.