Facile preparation of Ti³⁺ self-doped TiO₂ nanosheets with dominant {0 0 1} facets using zinc powder as reductant

Highlights: • Ti³⁺-doped high-energy TiO₂ nanosheets was prepared using zinc powder as reductant. • Effects of Zn on morphology and BET surface areas of TiO₂ nanosheets is negligible. • Zn powder resulted in the formation of Ti³⁺ self-doped anatase TiO₂ nanosheets. • Ti³⁺ self-doped TiO₂ nanosheets showed enhanced visible-light photoactivity. - Abstract: Ti³⁺ self-doped TiO₂ nanosheets with dominant {0 0 1} facets for excellent visible-light photocatalytic activity were prepared by a facile one-pot hydrothermal reaction strategy using tetrabutyl titanate (TBT) as titanium source, hydrofluoric acid (HF) as structure-directing agent and zinc powder (Zn) as reductant. The synthesized catalysts were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectra (XPS), diffuse reflectance spectrum (DRS) and nitrogen adsorption–desorption isotherms. The photocatalytic activity of the photocatalyst was evaluated by measure the formation rate of photo-induced hydroxyl radicals (·OH) under visible-light irradiation (λ = 420 ± 10 nm) using coumarin as a probe. It was found that the presence of zinc shows little effect on the morphology, phase structure, BET surface areas and pore structure. However, the addition of Zn powder resulted in the formation of Ti³⁺ self-doped anatase TiO₂ nanosheets with dominant {0 0 1} facets, which is responsible for the enhanced visible-light photocatalytic activity. The sample prepared with zinc/TBT molar ratio of 0.3 showed the highest visible-light photocatalytic activity, which is 1.9 times higher than that of commercial P25 TiO₂