Preparation of Y-H sub(3)PW sub(12)O sub(40)/TiO sub(2) and La-H sub(3)PW sub(12)O sub(40)/TiO sub(2) by hydrothermal method and its photocatalytic activity for dinitrotoluene decomposition

A series of mesoporous materials (H sub(3)PW sub(12)O sub(40)/TiO sub(2), Y-H sub(3)PW sub(12)O sub(40)/TiO sub(2) and La-H sub(3)PW sub(12)O sub(40)/TiO sub(2)) were prepared by a modified sol-gel-hydrothermal route, which realized the load and modification of H sub(3)PW sub(12)O sub(40) at the same time. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), nitrogen adsorption-desorption analysis, ultraviolet-visible absorption spectrum (UV-Vis) and scanning electron microscopy (SEM). The XRD and FT-IR results displayed that the catalysts had uniform anatase phase and the primary Keggin structure of H sub(3)PW sub(12)O sub(40) remain intact. Nitrogen adsorption-desorption analysis suggested that suitable doping of rare earth elements could increase the specific surface area from 177.9 m super(2)/g (H sub(3)PW sub(12)O sub(40)/TiO sub(2)) to 229.5 (1 wt.%Y-H sub(3)PW sub(12)O sub(40)/TiO sub(2)) or 236.1 m super(2)/g (1 wt.%La-H sub(3)PW sub(12)O sub(40)/TiO sub(2)). Results of UV-Vis spectra showed that the band of the 1 wt.%Y-H sub(3)PW sub(12)O sub(40)/TiO sub(2) and 1 wt.%La-H sub(3)PW sub(12)O sub(40)/TiO sub(2) have an obvious redshift compared with the H sub(3)PW sub(12)O sub(40)/TiO sub(2). Additionally, the composites were used as heterogeneous photocatalysts to the degradation of dinitrotoluene (DNT). It is the first time that polyoxometalate (POM) is applied in the degradation of explosive wastewater.