Effect of particle size on the photocatalytic activity of BiNbO4 under visible light irradiation

Numerous attempts have focused on developing more efficient visible-light active photocatalysts. Bismuth niobate (BiNbO4) was reported as a potential candidate for photocatalytic water splitting and for the degradation of organic molecule under visible-light irradiation because of its small band gap and appropriate band positions. Here, three BiNbO4 samples with different, uniform particle sizes were synthesized. The effect of BiNbO4 particle size on its photocatalytic activity was studied by using the reduction of 4-nitroaniline as model reaction. Results show that the photocatalytic degradation of 4-nitroaniline varies systematically with the change in particle size and surface areas. To better understand the correlation between structure, composition, morphology, and optical properties, the catalysts were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), Powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller (BET) surface area, UV-vis diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL).