Evaluating the photocatalytic activity of Pt/TNT film catalyst

TiO2 nanotubes (TNT) were prepared by a hydrothermal method from the commercially available TiO2-P25. Five types of TNT were produced at different temperatures (120 °C, 130 °C, and 150 °C) and by using different reaction times (12 h, 24 h, and 30 h). The photocatalytic reactor that was used is a film catalytic reactor, in which the height of the catalyst is 1.0 mm. The BET and FESEM analysis results showed that TNT130-24 (130 °C, 24 h) and TNT150-12 (150 °C, 12 h) possessed well-formed tubular structures with a high specific surface area (282.9-316.7 m2 g−1) and large pore volumes (0.62-0.70 cm3 g−1). However, TNT120-30 (120 °C, 30 h) presented the best photocatalytic activity upon CO removal due to the synergistic effect of TiO2 nanotubes and TiO2 particles. After the TNT catalysts were modified with Pt particles, the removal efficiency was in the order of Pt/TNT120-30>Pt/TNT130-24>Pt/P25. Pt/TNT120-30 showed 99% removal efficiency in a continuous photoreactor with a high space velocity of 1.79×104 h−1. The results of the TEM and DRS analyses confirmed that the Pt particles enhanced the photocatalytic reaction, which was attributed to the well-dispersed nature of the 1 nm nanoscaled Pt particles on the surfaces of the TNT catalysts, and narrowed the band gap from 3.22 eV to 3.01 eV.