Facile synthesis of Ti3+-TiO2 mesocrystals for efficient visible-light photocatalysis

Defect-rich TiO2 mesocrystals were successfully synthesized by facile vapor hydrolysis method for the first time. The as-prepared TiO2 mesocrystals showed typical mesoporous structure, and the specific surface area reached 124.88 m2 g−1. The as-prepared samples exhibited amazing visible light absorption and highly enhanced visible light photocatalytic activity for hydrogen production in comparison to that of P25 TiO2, and the highest visible light photocatalytic activity of Ti3+ doped TiO2 mesocrystals for hydrogen production reached 301.1 μmol g-1 h-1, which was about 131 times as high as that of P25 TiO2 photocatalyst. It was the formation of Ti3+ species, the long carriers' lifetimes and effective conduction pathways that highly enhanced the visible light photocatalytic activity of Ti3+-TiO2 mesocrystals. Finally, the schematic illustration of possible photo-generated electrons and holes transfer mechanism and visible light photocatalytic mechanism of Ti3+-TiO2 mesocrystals for hydrogen production were also proposed in detail.