Preparation of Y-H3PW12O40/TiO2 and La-H3PW12O40/TiO2 by hydrothermal method and its photocatalytic activity for dinitrotoluene decomposition

A series of mesoporous materials (H3PW12O40/TiO2, Y-H3PW12O40/TiO2 and La-H3PW12O40/TiO2) were prepared by a modified sol-gel-hydrothermal route, which realized the load and modification of H3PW12O40 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 H3PW12O40 remain intact. Nitrogen adsorption-desorption analysis suggested that suitable doping of rare earth elements could increase the specific surface area from 177.9 m2/g (H3PW12O40/TiO2) to 229.5 (1 wt.%Y-H3PW12O40/TiO2) or 236.1 m2/g (1 wt.%La-H3PW12O40/TiO2). Results of UV-Vis spectra showed that the band of the 1 wt.%Y-H3PW12O40/TiO2 and 1 wt.%La-H3PW12O40/TiO2 have an obvious redshift compared with the H3PW12O40/TiO2. 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.