Tuning wall thickness of TiO2 microtubes for an enhanced photocatalytic activity with thickness-dependent charge separation efficiency.

ABSTRACT

TiO2 microtubes with tunable wall thickness have been synthesized by a one-step electrospinning method linked with a calcination process. The wall thickness of TiO2 microtubes can be easily tuned by altering the dosage of liquid paraffin. The influence of the thickness on the light-harvesting ability and separation efficiency of the photogenerated carriers was studied using ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, photoluminescence emission spectroscopy, and photocurrent density measurements. Results show that TiO2 microtubes with an appropriate thickness exhibit enhanced light scattering effect, UV-vis light-harvesting ability, charge separation efficiency, and photocatalytic performance. The degradation rates of rhodamine B and 2,4-dinitrophenol by using TiO2 microtubes synthesized at a dosage of 0.14 g/mL liquid paraffin are 99.9% within 60 min and 97.8% within 40 min, respectively, which are higher than most of the reported values. All these results suggest that our work provides an ideal strategy for adjusting the wall thickness of TiO2 microtubes and new approach to enhance the photocatalytic performance of TiO2.