Synthesis Approaches of Zinc Oxide Nanoparticles: The Dilemma of Ecotoxicity

Figure 1

Different structures of ZnO; one-dimensional ZnO: (a) nanosprings, (b) nanorings, (c) nanohelix, (d) nanocombs, (e) nanowires, and (f) nanorods (adopted from [89, 90]). Two-dimensional ZnO; (g) nanosheets, (h) nanopellets, and (i) nanoplates (adopted from [91–93]). Three-dimensional ZnO; (k) & (l) nanoflowers. (m) Nanomesosphere. (n) Nanourchins (adopted from [91, 94]).