In this paper, three kinds of noble metal nanoparticles (NMNs) were successfully loaded on hierarchical TiO₂ nanotube arrays (TiO₂ NTs) to improve photocatalytic (PC) activity of gas phase pollutants. The hierarchical TiO₂ NTs, with unique top-nanoporous and bottom-nanotubular structure, were prepared through a facile two-step anodization method, and then the noble metal nanoparticles were loaded on the TiO₂ NTs by means of a photo-reduction method. The gas phase photocatalytic activity of TiO₂ NTs and NMNs/TiO₂ NTs were estimated by decomposition of gaseous methanol. The formation of Schottky junctions between TiO₂ NTs and NMNs significantly improved the PC due to they could significantly accelerate the electron transfer and thus reduction of the recombination of photogenerated electrons and holes.