Efficient Charge Separation from F^- Selective Etching and Doping of Anatase-TiO₂{001} for Enhanced Photocatalytic...

TiO₂ nanomaterials with coexposed {001} and {101} facets have aroused much interest owing to their outstanding photocatalytic performance. In this study, on the basis of its unique characteristics of photoinduced electron and hole transfer to different lattice planes, we synthesized F^- selective etching and doping on {001} facets of anatase TiO₂ nanosheets using TiO₂ nanosheets with coexposed {001} and {101} facets as a precursor. Through a series of measurements, such as photoluminescence, transient photocurrent response, electrochemical impedance spectra, and Mott-Schottky measurements, it is proved that F^- selective etching and doping on {001} facets of TiO₂ can extremely accelerate the separation of photogenerated carriers by shortening the transfer pathway of holes and introducing Ti³⁺ and oxygen vacancies in {001} facets. Therefore, the as-obtained sample shows excellent photocatalytic properties under the visible-light irradiation; the highest rate of photocatalytic H₂ evolution is up to 18270 μ mol h^-1 g^-1 and its quantum efficiency is up to 21.6% at λ = 420 nm. As an innovative exploration, this study provides a direct spatial charge separation strategy for developing highly efficient photocatalysts.