ZnO/Sepiolite Catalysts – Characterization and Photoactivity Measurements

Abstract

Sepiolite-supported ZnO catalysts (ZnO-SEP) were prepared and characterized using Xray diffraction (XRD), surface area (BET) measurements, scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra (UV-vis DRS) techniques. XRD analysis supplied information about the generation of ZnO nanoparticles. SEM images and elemental mapping scans revealed variations in the surface morphology of the SEP after ZnO loading. Supported catalysts possessed higher surface areas and pore volumes in comparison to unsupported catalyst (0.25 M ZnO). They also revealed suitable band-gap energies in the UV-A region. XPS analysis confirmed the build-up of ZnO nanoparticles on the SEP matrix with the form of Zn 2+ oxidation state. Photocatalytic performances were evaluated in terms of methyl orange (MO) decolorization process following pseudo-first-order kinetics. The repeatability of photocatalytic activity was also tested.