Template-free synthesis of novel TiO2 microtube (MT) and N-doped MT and their photocatalytic properties decomposing organic compounds

Novel TiO2 microtubes (MTs) with a pore size of similar to 1.6 mu m, a wall thickness of similar to 200 nm, and lengths of 15-30 mu m were synthesized by solvothermal reaction without templates. TiO2 MTs, self-assembled with highly crystallized anatase particles, were obtained at the specific concentration ranges of titanium tetraisopropoxide (TTIP) and tetrabutyl ammonium hydroxide (TBAH) (0.32-0.45 M TTIP and 0.32-0.38 M TBAH). We also prepared nitrogen-doped TiO2 (N-TiO2) MTs by flowing gaseous ammonia to the bare TiO2 MTs at 550 degrees C and analyzed the photocatalytic properties of TiO2 MT and N-TiO2 MT in decomposing gaseous isopropanol (IPA) and aqueous salicylic acid (SA). Under UV-visible light illumination TiO2 MT showed slightly lower photocatalytic activities than commercial TiO2 NP (Aeroxide P25), but under visible light N-TiO2 MT demonstrated 2.2-3.4 times higher activities than N-TiO2 NP, presumably due to its effective structure for space-charge separation of the photo-generated electron/hole pairs.

Automated summary

TiO2 microtubes with a pore size of around 1.6 μm were synthesized using a solvothermal reaction without templates, showing slightly lower photocatalytic activities than commercial TiO2 NP under UV-visible light but significantly higher activities under visible light after nitrogen-doping treatment.