In situ assembly of well-dispersed Au nanoparticles on TiO2/ZnO nanofibers: A three-way synergistic heterostructure with enhanced photocatalytic activity

The TiO2/ZnO nanofibers embedded by Au nanoparticles (TiO2/ZnO/Au NFs) were fabricated by combining the electrospinning technique (for TiO2/ZnO nanofibers) and an in situ reduction approach (for Au nanoparticles). X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electronmicroscopy, X-ray photoelectron spectroscopy. UV-vis diffuse reflectance spectroscopy and photoluminescence spectroscopy, were used to characterize the as-synthesized nanofibers. The results showed that small Au nanoparticles (Au NPs) were well dispersed on the TiO2/ZnO nanofibers (TiO2/ZnO NFs). And, the TiO2/ZnO/Au nanofibers showed high charge separation efficiency under ultraviolet excitation, as evidenced by photoluminescence spectra. The photocatalytic studies revealed that the TiO2/ZnO/Au NFs exhibited enhanced photocatalytic efficiency of photodegradation of Methyl orange (MO) and 4-nitrophenol (4-NP) compared with the pure TiO2 nanofibers, ZnO nanofibers and TiO2/ZnO NFs under ultraviolet excitation, which might be attributed to the high separation efficiency of photogenerated electron-hole pairs based on the photosynergistic effect among the three components of TiO2, ZnO and Au. And, the TiO2/ZnO/Au NFs could be easily separated and recycled due to their one-dimensional nanostructural property. (C) 2012 Elsevier B.V. All rights reserved.