Enhanced visible-light photocatalytic activity of N-doped C/NaTiO/TiO hollow spheres for efficient dye degradation.

Doping and hybridization with other semiconductors are highly effective ways to address the limitations, including their weak response to visible light and significant recombination of photogenerated carriers. In addition, the assisted carbon on the catalyst surface and the structural design have the advantage of being catalytically active. Herein, visible-light-active N-doped C/NaTiO/TiO hollow spheres (denoted as N-C/NTO/TiO HS) were successfully prepared using a facile two-step method and evaluated for methylene blue (MB) aqueous solution degradation under visible-light irradiation. The as-obtained N-C/NTO/TiO HS demonstrated improved photocatalytic efficiency (94 %) and pseudo-first-order kinetic degradation rate (0.023 min). Moreover, after three cycles of testing, N-C/NTO/TiO HS showed a 91 % degradation rate in its photostability. The enhanced photocatalytic performance was attributed to the combined effects of N-doping, carbon species on the surface, and the coupling of TiO and NaTiO using morphology engineering. Finally, based on the experimental results, a possible photocatalytic mechanism was proposed. This study provides a rational approach toward the development of high-performance titanate-based photocatalysts for solar energy-assisted wastewater treatment.