Photoinduced Electron Storage in WO3/TiO2 Nanohybrid Material in the Presence of Oxygen and Postirradiated Reduction of Heavy Metal Ions

A bulk-embedded TiO2-based nanohybrid material with WO3 clusters as the electron storage sites was designed and prepared. Conduction band electrons generated upon excitation of TiO2 were successfully stored in this nanohybrid material in the presence of O2, and the storage of electrons in WO3 clusters was further confirmed by the electron spin resonance (ESR) measurements. It is found that the reduction of oxygen on the surface of nanohybrid particles was much slower than that on pristine TiO2. Synthesis conditions were varied to optimize the storage behaviors of hybrid materials. The structure of the nanohybrid material was investigated using high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Raman, and X-ray diffraction. Potential environmental application of this nanohybrid material for the reduction treatment of poisonous heavy metal ions without in situ light irradiation was explored.