Heterojunction of FeTiO₃ nanodisc and TiO₂ nanoparticle for a novel visible light photocatalyst

For the first time, a single crystalline FeTiO₃ nanodisc in the ilmenite phase has been synthesized by a hydrothermal reaction at 220 °C. The prepared FeTiO₃ was a hexagonal disk-like structure with an average diameter of ̃400 nm and a thickness of ̃70 nm, while its hexagonal face was oriented in (001) plane and grown to (110) direction. The heterojunction structure was formed between the as-prepared FeTiO₃ nanodisc and Degussa P25 with an average particle size of ̃25 nm by employing maleic acid as an organic linker. The prepared FeTiO ₃/TiO₂ coupled at a nanoscale demonstrated greatly enhanced photocatalytic activity in removing 2-propanol and evolving CO ₂ in gas phase under visible light irradiation (λ ≥ 420 nm). Its degradation constant (k) in removing 2-propanol was ̃25 times that of Degussa P25, which suggests that its catalytic efficiency is comparable to that of a typical N-doped TiO₂. The remarkable photocatalytic activity of FeTiO₃/ TiO₂ could be explained by the intersemiconductor hole-transfer mechanism caused by the unique relative band positions of these two semiconductors.