Controllable solvothermal synthesis and photocatalytic properties of complex (oxy)fluorides K2TiOF4, K3TiOF5, K7Ti4O4F7 and K2TiF6

Complex (oxy)fluorides K2TiF6, K2TiOF4, K3TiOF5 and K7Ti4O4F7 have been successfully synthesized for the first time through a controllable solvothermal route involving different solvents, for example, methanol, methanol-H2O and methanol-H2O2. The as-prepared products were characterized by X-ray powder diffraction, N2 surface area adsorption, scanning electron microscope, Fourier transform infrared spectroscopy, UV-vis absorption spectra and X-ray fluorescence. The influences of reaction conditions such as the ratio of methanol to H2O2 or methanol to H2O, reaction temperature on the phase, crystallizability and purity of the (oxy)fluorides products were discussed in detail. Meanwhile, the photocatalytic behaviors of the as-prepared K2TiF6, K2TiOF4, K3TiOF5 and K7Ti4O4F7 were evaluated by degradation of rhodamine B molecules, and the results showed that all of the products possessed photocatalytic activities in the order of K2TiOF4 > K2TiF6 > K7Ti4O4F7 > K3TiOF5 at room temperature under the UV light.