Visible light photocatalytic degradation of organics on nanoparticles of bi-metallic oxides

Various bi-metallic oxides, Bi ₂WO ₆, AgVO ₃, AgTaO ₃, BiTaO ₄, Cd ₂Ta ₂O ₇, InTaO ₄, CoTa ₂O ₆, CeTaO ₄ and EuTaO ₄, were synthesized by a solution method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy, and Fourier transform infrared spectroscopy (FTIR). All the materials were tested for photocatalytic decomposition of VOCs such as aqueous methylene blue and gaseous toluene. Results indicated that tantalum based ternary compounds like Cd ₂Ta ₂O ₇, AgTaO ₃ and BiTaO ₄ could decompose gaseous toluene under visible light irradiation at a much faster rate than TiO ₂. These compounds also demonstrated very stable activity under UV light irradiation in a longer period of time. Tantalum based compounds could also decompose methylene blue under UV-vis light irradiation but they exhibited lower activity than Bi ₂WO ₆ and AgVO ₃.