The visible light induced photocatalytic activity of tungsten trioxide powders Original Research Article

The preparation, characterization and photoreactivity of tungsten trioxide powders are presented. Tungsten trioxide powders were prepared by air annealing of various W precursors. The effects of W precursor type and pretreatment conditions on the physical properties, and photocatalytic performance of the obtained WO3 powders were examined. The photooxidation of water to oxygen and protons in the presence of reducible additives Ce4+, using the luminous and near IR illumination was used as a test reaction to evaluate the activity of the powders. Increasing annealing temperatures gave materials with a high degree of crystallinity and red-shifted the onset of light absorption. The light absorption of the obtained powders in the long wavelength region versus the type of the W precursor increased in the order: H2WO4<(NH4)6W12O39<(NH4)10W12O41. The level of crystallinity of the obtained powders increased in the order: (NH4)10W12O41≈(NH4)6W12O39