Employed Silver Doping to Improved Photocatalytic Properties of ZnO Micro/Nanostructures
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Employed Silver Doping to Improved Photocatalytic Properties of ZnO Micro/Nanostructures Raad S. Sabry1 · Wisam J. Aziz1 · Muntadher I. Rahmah1 Received: 19 March 2020 / Accepted: 7 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract In this study, undoped zinc oxide (ZnO) and silver (Ag) doped ZnO micro/nanostructures were successfully synthesized for photodegradation of Methylene Blue (MB) dye under visible-light. X-ray diffraction (XRD) patterns confirm appeared of the Ag phase and polycrystalline structure of ZnO with a wurtzite hexagonal phase growth in 101 direction. The energy dispersive spectra (EDX) study confirms homogeneity and purity of specimens. Field emission scanning electron microscopy (FESEM) results exhibited agglomeration of irregularly shaped nanoparticles (NPs), decreasing with increasing Ag doped concentration. UV–visible spectra revealed that the Ag leads to shifting in ZnO spectra and increased absorptance in a visible-light region. The photocatalytic result showed significantly enhanced with photodegradation activity 92.2%, 93.1%, 95.08%, and 96.7% for doped specimens, respectively, as compared to 73.8% for an undoped specimen. The enhance of photocatalytic performance may be attributed to increasing the aspect ratio of specimens, improve separation of charge carriers, surface Plasmon resonance (SPR) and high electron photogenerated efficiency Keywords ZnO · Ag · Photocatalyst · Methylene blue · Micro · Nanostructures
1 Introduction A photocatalysis process is a special case of self-cleaning technology involves breaks down of organic dirt on surfaces using ultraviolet light or visible-light [1–4]. The semiconductor materials have the best heterogeneous photocatalysis property because of the electronic transitions that occur after the surfaces exposed to UV or visible light, therefore any photons with energy greater than band-gap energy of photocatalyst are absorbed by electrons in the valence band then jump to conduction band to producing electrons-holes pair in lattices of materials and these pair participate in a surface redox reaction, which increases the hydrophilicity of surface and decomposes the contamination [5, 6]. Various semiconductors materials have been used as photocatalyst such as * Muntadher I. Rahmah [email protected] Raad S. Sabry [email protected] Wisam J. Aziz [email protected] 1
Physics Department, College of Science, Mustansiriyah University, Baghdad, Iraq
TiO2, ZnS, ZnO, W O3, and CdS [7–11]. In contrast, ZnO define as an II-VI semiconductor compound with a wide direct band-gap (3.37 eV) at room temperature and used in much self-cleaning application due to its possession physical–chemical stability, low cost, easy availability, high oxidative capacity, and better degradation to organic molecules [12]. Many efforts have been made to well of fabricating ZnO with different morphologies such as hierarchical ZnO [13], Nano-rods [14], Nanoporous [15], Nano-wires [16], hollow-sph
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