Title : Effects of doping aluminum and poly(vinyl alcohol) in nanosize ZnO on photocatalytic degradation of methyl orange under sunlight
Abstract:
Nanosize ZnO, Al-modified ZnO, ZnO/PVA, and Al-modified ZnO/PVA were synthesized using coprecipitation, and hydrothermal methods. As-synthesized nanomaterials were characterized by employing XRD, UV-visible spectroscopy, FTIR, and SEM techniques. The photocatalytic activities of prepared nanoparticles were determined by evaluating degradation of methyl orange (MO) dye in aqueous medium under sunlight. The doping Al in ZnO, and compositing the later with polyvinyl alcohol (PVA), both these processes improved the photocatalytic activity of ZnO under visible radiation owing to narrowing of semiconductor band gap, and the minimized recombination of charge carriers. The extent of MO degradation under visible light using different synthesized nanostructures were in the order: (Al-doped ZnO/PVA) > (Al-modified ZnO) > (ZnO/PVA) > (pure ZnO). The results show that Al doping, and compositing PVA with ZnO, both these processes cumulatively enhance the photocatalytic activity due to minimizing charge carriers’ recombination at the semiconductor. Using Al-modified ZnO/PVA as photocatalyst, maximum degradation (83.7 %) of MO could be achieved at 90 minutes.
