Preparation and photocatalytic activity of alkali titanate nano materials A2TinO2n+1 (A = Li, Na and K)

Photocatalysts nano A2TinO2n+1 (A = Li, Na, K) were prepared successfully by novel hydrothermal synthesis process. Powders were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible (UV–vis) absorption spectra and field-emission scanning electron microscope (FE-SEM) measurements. These results showed that the compositions of lithium, sodium and potassium titanates were Li2TiO3, Na2Ti3O7 and K2Ti8O17, respectively. The nano crystals of Li2TiO3 were self-assembled as snowflakes while that of Na2Ti3O7 and K2Ti8O17 were nanorods. Photocatalytic properties of alkali titanates were also investigated. The results indicated that alkali titanates as prepared have higher photocatalytic activities compared with P25 TiO2 in the degradation of chloroform under UV light irradiation. A combination of K2Ti8O17 and NiO produces a photocatalyst effective for the degradation of chloroform in aqueous solution. The framework of the tunnel structure was suitable for accommodating cocatalysts such as NiO to induce a strong interaction between the active species and cocatalysts. Na2Ti3O7 has high photocatalytic activity under visible-light irradiation due to its strong absorption in the visible light region. The photocatalytic properties of Li2TiO3 are inferior to that of Na2Ti3O7 and K2Ti8O17 due to its mono-perovskite structure.