Enhanced Photocatalytic Activity of Iron-Doped ZnO Nanowires for Water Purification

Abstract

Abstract:In order to improve the photocatalytic efficiency of ZnO nanowires, iron-doped ZnO nanowires (ZnO:Fe NWs) were successfully synthesized. The morphology, optical properties and photocatalytic performance of ZnO:Fe NWs were studied by scanning electron microscopy (SEM), UV-Visible spectrophotometry and photoluminescence spectroscopy (PL), respectively. The SEM observations showed that the morphology of the ZnO NWs was not modified by iron doping, but the band gap was reduced from 3.29 eV for ZnO NWs to 3.25 eV for ZnO:Fe NWs. This band gap reduction allows the semiconductor to harvest more photons to excite more electrons in the valence band; subsequently, resulting in an improvement of the degradability of the understudied organic dyes: methylene blue (MB), methyl orange (MO), and acid red 14 (AR14). The photocatalytic study showed that the photo-degradation rate of the MB, MO, and AR14 was improved 9%, 20%, and 5% respectively by 1% iron doping in the ZnO NWs.

Synthesis of ZnO doped high valence S element and study of photogenerated charges properties

“…In order to increase the photoresponse range of ZnO and improve the photocatalytic activity of ZnO, considerable efforts have been made such as controlling the morphology, 6,7 combining ZnO with other semiconductor materials, [8][9][10][11][12] loading noble metals, 13 and doping with other elements. 14,15 Among these, one efficient way involves doping with metals such as cobalt, iron or manganese. 14,15 However, doping with metals oen causes thermal instability, which is easy to become the carrier recombination center.…”

ZnO Nanostructure Based Photocatalysis for Water Purification

“…water and/or oxygen) to form hydroxyl radicals (OH•), which possess high oxidation power, and thus will react with the molecules to be degraded, if they are adsorbed on the surface of the photocatalyst. The detailed mechanism has been reported in our previous work [19]. The OH• radicals having a very strong oxidation power, they can lead to a partial or complete mineralization of the organic pollutants (i.e.…”

“…Furthermore, the magnetic stirring during the photocatalytic process can increase the oxygen supply in the aqueous solution, which can also improve the photocatalytic efficiency. In fact, as indicated in the photocatalysis mechanism presented in our previous work [19], the photo-generated holes of the VB can directly produce OH• radicals in the presence of H 2 O by an oxidation reaction; while the photo-generated electrons of the CB can also indirectly produce OH• radicals via a reduction reaction in the presence of O 2 , by producing the superoxide anions O 2…”

“…It is well known that such crystalline structure will give a better photocatalytic activity compared to other crystalline orientations [18]. In fact, the c-axis oriented ZnO NWs will favor the H 2 O 2 generation, then produce more OH• radicals, which improves the photocatalytic activity, according to the semiconductorbased photocatalysis mechanism [19].…”

Effect of Fe doping on Structural and Transport Properties of inverse spinel Zn2TiO4

“…Zinc titanate is the most extensively studied ternary system that used to overcome the shortcomings of TiO 2 owing to its different polymorphs. Inverse spinel cubic phase Zn 2 TiO 4 is particularly important for photocatalytic studies owing to its band gap and band structure (6)(7)(8)(9)(10). Fe doped TiO 2 was studied by many authors and their results revealed substitution of Fe 2+ or Fe 3+ with Ti 3+ or Ti 4+ in TiO 2 as their radii and energy levels are very close.…”