Synthesis, Photoluminescence and Photocatalytic Activity of Tetragonal SnO2 Prepared by Hydrothermal Sol-Gel Method

Luminescent SnO2 material was synthesized by a hydrothermal assisted sol-gel method. X-ray powder diffraction analysis indicates that the as-synthesized SnO2 is a tetragonal phase and the calculated lattice parameters a and c are 0.474 and 0.318 nm, respectively. Scanning electron microscopy shows that the prepared tetragonal SnO2 particles have regular rhombic shape and are polydisperse without any agglomeration. Ultraviolet-visible absorption spectroscopy was used to study the light-absorbing properties and bandgap of tetragonal SnO2, and the value of bandgap is obtained to be 2.894 eV. The emission spectrum detected at (ex) = 230 nm showed two peaks located at 375 and 415 nm, the first having the strongest luminescence intensity. The fluorescence emission spectra also show that an emission peak at 510 nm is observed when the (ex) is 400 nm. Photocatalytic experiments indicate that the tetragonal SnO2 exhibits a strongly enhanced photocatalytic activity than commercial nano-SnO2 in photocatalytic degradation of various dyes under visible light irradiation. The photocatalytic mechanism is discussed on the basis of X-ray photoelectron spectroscopy (XPS) data, Fourier transform infrared (FTIR) spectra, electrochemical measurements and photocatalytic experiments results.