Scott, Tyler Andrew (2017-12). PHOTOCATALYTIC DEGRADATION OF PHENOL IN WATER BY SILVER/TITANIUM DIOXIDE NANORODS COATED WITH AN ULTRATHIN MAGNESIUM OXIDE LAYER. Master's Thesis.
Phenol is one of the most widespread, toxic, and recalcitrant compounds commonly found in water sources. Due to its persistent nature, conventional wastewater treatment methods are not effective to remove or degrade phenol from water. In this work, a novel photocatalyst is developed to degrade phenol under simulated sunlight. The catalyst is composed of a 1D titanium dioxide (TiOv2) nanorod decorated with elemental silver (Ag) nanoparticles, coated in an ultrathin magnesium oxide (MgO) layer through an atomic layer deposition (ALD) method. The prepared catalyst was characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), and UV-vis diffuse reflectance spectroscopy (UV-Vis DRS). The solar light photocatalytic performance of the material was evaluated and correlated with the material properties. The Ag decoration promoted light absorption and transfer of photo-induced electron-hole pairs from within TiOv2 nanorods to the catalyst surface. The ultrathin MgO layer with a subnanometer thickness further increased the light absorption and inhibited surface charge recombination through a surface passivation effect, promoting phenol degradation. The photocatalytic reaction mechanism was investigated by the examination of hydroxyl and superoxide radical production in the photocatalytic system. The results from this work demonstrate a new strategy for fabricating efficient sunlight-driven photocatalysts for the degradation of persistent water contaminants.