Enhanced visible-light photocatalytic activity of N-doped C/Na2Ti6O13/TiO2 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/Na2Ti6O13/TiO2 hollow spheres (denoted as N-C/NTO/TiO2 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/TiO2 HS demonstrated improved photocatalytic efficiency (94%) and pseudo-first-order kinetic degradation rate (0.023 min-1). Moreover, after three cycles of testing, N-C/NTO/TiO2 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 TiO2 and Na2Ti6O13 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.