Laser Synthesis and Characterization of Nitrogen-Doped TiO₂ Vertically Aligned Columnar Array Photocatalysts

Nitrogen-doped TiO 2 vertically aligned columnar arrays were grown by reactive pulsed laser deposition using self-assembled polystyrene (PS) microsphere monolayers as templates and TiO 2 hemispherical arrays as buffers. The created columnar arrays showed significantly enhanced photocatalytic activity as compared with the reference thin films grown under identical experimental conditions but in the absence of the PS templates, both under visible- as well as UV-light irradiation. The photocatalytic activity decreased with the increase in the nitrogen doping level, suggesting the existence of a threshold value for the nitrogen incorporation in the TiO 2 crystal lattice.