To Study Photocatalytic Effects of Nano Metal Oxides

Abstract

Industrial wastewater treatment has long been a huge global challenge which threatens to have adverse impact on ecology and environment. Wastewater specifically from printing, textile and tanning industries consists of many dissolved organic dyes which prove detrimental to flora and fauna. Currently, many techniques for removal of such toxic chemicals are in use like adsorption, membrane separation, ion exchange etc. Advanced Oxidation Processes (AOPs) like heterogeneous photocatalysis have proved to be a viable alternative to overcome the shortcomings of conventional treatment methods for the degradation of different water pollutants. Conventional photocatalysts like Titanium Dioxide (TiO2) have inherent limitations in the form of low visible light activity, large bandgap value etc. which makes them less efficient. Recently, numerous methods have been developed to subject pristine TiO2 to reducing conditions to produce reduced TiO2. This way, physicochemical properties of TiO2 could be altered to enhance the photocatalytic efficiency without the need of doping with foreign substances. However, most of these methods report requirement of sophisticated facilities and harsh conditions for reduction. In this research work, a simple and cost-effective method for the reduction of TiO2 nanoparticles has been developed where Aluminium foil is used along with Sodium Borohydride (NaBH4) for solid state reduction. This technique does not require inert environment and long reduction times as reported in other studies involving NaBH4 reduction. Changing reduction temperature and NaBH4/TiO2 molar ratio produced reduced TiO2 nanoparticles of varying color ranging from light grey to pitch black. Characterization of the reduced samples done using Electron Spin Resonance (ESR), X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), UV-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS), Photoluminescence Spectra (PL) and X-Ray Photoelectron Spectroscopy (XPS) reveal