ZnO Nanofiber and Nanoparticle Synthesized Through Electrospinning and Their Photocatalytic Activity Under Visible Light

Abstract

In this paper, we fabricate ZnO nanofibers and nanoparticles through electrospinning precursor solution zinc acetate(ZnAc)/cellulose acetate(CA) in mixed‐solvent N,N‐dimethylformamide/acetone. Depending on the posttreatment of precursor ZnAc/CA composite nanofibers, both ZnO nanofibers and nanoparticles were synthesized after calcination of precursor nanofibers. The morphology and crystal structure of the ZnO nanofiber and nanoparticle were characterized by scanning electron microscopy, transmission electron microscopy, atomic force microscopy, and X‐ray diffraction. It was found that the mean diameter of the ZnO nanofiber and nanoparticle was ca. 78 and 30 nm, respectively. The photo‐degradation of dye molecules such as Rhodamine B and acid fuchsin catalyzed by the ZnO nanofiber and nanoparticle was evaluated under the irradiation of visible light. Both morphological ZnO species showed strong photocatalytic activity. However, the ZnO nanofiber in the form of nanofibrous mats showed much higher efficiency than the nanoparticle although the latter has a smaller size than the former. The porous structure of ZnO nanofibrous mats is believed to improve the contacting surface areas between the catalyst and the dye molecules, while the aggregation of ZnO nanoparticle in the solution lowers the photocatalytic efficiency.

Role of zinc interstitials and oxygen vacancies of ZnO in photocatalysis: a bottom-up approach to control defect density

“…25,26 Note that the controllability of the defect density depends on the type of defect and the semiconductor itself. 1,6,[8][9][10][11][12][13] In the context of ZnO, numerous studies deal with V O s, 4,8,10,11,13,21 which is not the case with Zn i s. It is also notable that the balance between the relative densities of Zn i s and V O s is still challenging. 15 The presence of Zn i s and V O s in ZnO can be easily identied by simple photoluminescence (PL) experiments, [15][16][17]27 indicated by blue and green emissions, respectively.…”

“…16,17,[28][29][30][31][32] In contrast, typically synthesized ZnO is predominant with V O s. 4,8,16,17,27,31,32 Consequently, photocatalysis studies involving V O s dominate the literature. 1,4,6,[8][9][10]13,21 In this context, it is very useful and important to study the effect of Zn i s in PCA and their efficiency against V O s. In addition to the fundamental interest, the results of such a study enable an efficient and cost effective design of novel photocatalysts. As shown earlier, 33 Zn i s are very unstable when compared to V O s, which are found to be stable even at 400 C. Aer nearly two years, theoretical support for this instability was provided by Janotti et al, 34 where the authors suggest that Zn i s diffuse faster through a migration barrier as low as 0.57 eV, cf.…”

Polymer–Inorganic Core–Shell Nanofibers by Electrospinning and Atomic Layer Deposition: Flexible Nylon–ZnO Core–Shell Nanofiber Mats and Their Photocatalytic Activity

“…It has been reported that ZnO nanoparticles and nanofibers have shown excellent photocatalytic properties because of their very high surface area and more porous nature. 48 Nevertheless, the metal oxide nanofibers are quite brittle and do not show any structural flexibility, and this cause significant problems during their handling and usage as a membrane material. For this reason, the development of flexible nanofibrous membranes or textiles having photocatalytic properties is still on demand for self-cleaning and water purification and waste treatment.…”

“…48−53 Fibrous membranes made of nanofibers show remarkable photocatalytic properties due to their unique morphological features including high surface area and nanoporosity. 48,49,52,53 ZnO is an important semiconductor material with a direct wide band gap (3.37 eV) and it is a wellknown nontoxic catalyst and therefore, the potential application of ZnO for water purification has been investigated. 48,49,51 Because the morphology of ZnO is quite crucial for photocatalytic efficiency, ZnO nanostructures in the form of nanoparticles and nanofibers have been examined in terms of their photocatalytic properties.…”

“…48,49,52,53 ZnO is an important semiconductor material with a direct wide band gap (3.37 eV) and it is a wellknown nontoxic catalyst and therefore, the potential application of ZnO for water purification has been investigated. 48,49,51 Because the morphology of ZnO is quite crucial for photocatalytic efficiency, ZnO nanostructures in the form of nanoparticles and nanofibers have been examined in terms of their photocatalytic properties. It has been reported that ZnO nanoparticles and nanofibers have shown excellent photocatalytic properties because of their very high surface area and more porous nature.…”