Selective synthesis and characterization of flower-like ZnO microstructures via a facile hydrothermal route

Large-scale synthesis of flowerlike ZnO nanostructure by a simple chemical solution route and its gas-sensing property

“…Recently, wet chemical process without any catalyst or template has been employed to synthesize ZnO nanoflowers with nanorods [18][19][20][21][22][23][24][25][26] and ZnO nanoflowers with nanosheets [27][28][29][30][31]. For example, a large-scale flowerlike ZnO nanostructure assembled by many hexagonal-structured ZnO nanosheets was achieved in a relatively pure ethanol circumstance through a very simple solvothermal method [27].…”

Synthesis of ZnO micro-flowers assisted by a plant-mediated strategy

“…Alias et al observed that as‐produced ZnO powders aggloromated in acidic and neutral medium while well‐defined powders were obtained at pH levels above 9 . In addition Yi et al also observed that the pH of the reaction medium had a great effect on the size and morphology of the flowerlike ZnO microstructures produced . Thus, a more alkaline medium was suitable for the synthesis of ZnOMFs.…”

“…First, Zn (II)– C. camphora complexes are formed from the interaction of biomolecules present in the C. camphora leaf extract (especially the polyols) and the zinc precursor in solution before the addition of NaOH . Second, after the introduction of NaOH, a milky solution is observed probably due to the formation of [Zn(OH) 4 ] 2− – C. camphora complexes, from the interaction between OH − and Zn(II) ions which would later form ZnO or both . The formed ZnO nuclei consist of two adjacent sides an electropositive Zn 2+ (0001) and electronegative O − (0001).…”

Facile template-free hydrothermal fabrication of ZnO hollow microspheres for gas sensing applications

“…Then these tiny spheres would grow along with the hydrothermal progress, and uniform solid spheres could be obtained in large quantities by limiting the reaction time to 2 h. At this stage, crystallites located in the exteriors of the spheres with larger size are packed much looser than those in the interiors, therefore the crystallites located in the inner cores of the spheres are with higher surface energy, less crystallized than the exteriors. The inner small crystallites of the spheres will be dissolved gradually, simultaneously, outer larger ones serving as new starting growth sites are growing along the [001] direction, because of the one-dimensional growth habit of the hexagonal ZnO crystal [28,29], which is coincident with the detailed structural analysis of the building units of ZnO-HMs using TEM and HRTEM. The result of the following process should be the nanorods growing at the expense of the cores inside the spheres.…”