Preparation and enhanced photocatalytic activity of Co/F codoped tin oxide nanotubes/nanowires: a wall thickness-dependence study

Aligned Co/F codoped tin oxide (SnO₂) nanotubes/nanowires with high photocatalytic activity were successfully prepared via the liquid-phase deposition (LPD) process by immersing the anodic aluminum oxide template in a (NH₄)₂SnF₆ aqueous solution. The mechanism proposed for the formation of Co/F codoped SnO₂ nanotubes/nanowires was discussed. The results showed that the morphology can be controlled by the careful manipulation of process parameters. The Co/F codoped SnO₂ first nucleated on the alumina membrane walls and then grew inwards, filling the nanoholes until nanotubes were obtained. By prolonging the deposition period up to 240 min, nanowires were also obtained. The photocatalytic behavior of the products was evaluated based on the photodegradation of methylene blue (MB) as a model organic compound under visible-light irradiation. The Co/F codoped SnO₂ nanotubes fabricated at 25 °C for 240 min exhibited the highest photocatalytic activity. In addition, the degradation of MB with the Co/F codoped SnO₂ nanotubes/nanowires confirmed improved photocatalytic performance compared to that of commercial SnO₂ nanoparticles and SnO₂ nanotubes.