Stability of Pt nanoparticles and enhanced photocatalytic performance in mesoporous Pt-(anatase/TiO₂(B)) nanoarchitecture

A novel metal-semiconductor nanocomposite with stable metal nanoparticles and efficient photocatalytic performance has been prepared. It consists of highly dispersed ∼2 nm platinum (Pt) nanoparticles loaded on mesoporous and bicrystalline TiO₂ fibers (Pt/mb-TiO₂). Due to the well organized porous Pt/TiO₂ nanoarchitecture, rate of photodegradation of CHCl₃ was nearly doubled compared to both P25 and Pt/P25. And in photocatalytic production of H₂ (with methanol as an electron donor), Pt/mb-TiO₂ presented much more stable activity than Pt/P25. In a 20 h H₂ production, Pt nanoparticles on P25 agglomerated and grew remarkably from 2.0 ± 0.5 nm to 4.5 ± 2.5 nm, while Pt nanoparticles on mb-TiO₂ changed slightly from 2.0 ± 0.5 nm to 2.2 ± 0.5 nm. Moreover, the loss ratio of Pt on P25 is 36%, which is much larger than that of 7% on mb-TiO₂. The efficient charge transfer in the interfaces of Pt/TiO₂(B) and TiO₂(B)/anatase was discussed. We concluded that the high photocatalytic performance of Pt/mb-TiO₂ can be attributed to stable Pt nanoparticles supported on the mesoporous masonry frameworks of TiO₂ and efficient charge transfer in the interfaces.