Synthesis of anatase TiO2 nanocrystals with {101}, {001} or {010} single facets of 90% level exposure and liquid-phase photocatalytic reduction and oxidation activity orders

Abstract

Anatase TiO2 nanocrystals with {101}, {001} or {010} single facets of 90% level exposure were controllably synthesized from potassium titanate (PT) without fluorine and organic capping surfactants, and characterized by X-ray diffraction patterns (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and fast Fourier transformation (FFT). The liquid-phase photocatalytic reduction (O2˙− generation) and oxidation (˙OH generation) activity orders of anatase TiO2 facets are {001} > {101} > {010} upon removing facet synergetic effect and surface fluorine effect. UV-vis diffuse reflectance spectra (DRS) and photoluminescence (PL) spectra showed that absorbance edge order, and separation efficiency order of photoexcited holes and electrons are {001} > {101} > {010}, which explains the photocatalytic activity order well together with the atomic arrangement of different facets.