title: Direct observation of the growth process of MgO nanoflowers by a simple chemical route.
abstract: Novel flowerlike nanostructures consisting of MgO nanofibers were successfully synthesized by a simple chemical route with H(2)O at 950 degrees C in an Ar atmosphere. Various durations of heating gave different growth stages that led to varied product morphologies. The synthesized products were systematically studied by X-ray powder diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis. The results show that the nucleation and growth process of the nanoflowers seems to be a vapor-solid mechanism, and that the total heating time during the reaction process is a critical factor for the development of MgO nanoflowers. Initially, Mg particles formed on the Si substrate, followed by the formation of MgO clusters as nucleation centers on the magnesium melt surface and the nucleation of short MgO nanofibers, then growth of the MgO nanofibers occurred, and finally MgO nanoflowers were formed. Besides nanoflowers, novel hierarchical MgO nanostructures were also observed. These nanostructures may be used as three-dimensional composite materials and as supports for other materials.
authors.affiliation: Key Laboratory of Materials Physics, Institute of Solid State Physics, Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, P.O. Box 1129, Hefei 230031, PR China. xshfang@yahoo.com.cn
authors.forename: Xiao-Sheng
authors.initials: XS
authors.lastname: Fang
authors.forename: Chang-Hui
authors.initials: CH
authors.lastname: Ye
authors.forename: Li-De
authors.initials: LD
authors.lastname: Zhang
authors.forename: Jun-Xi
authors.initials: JX
authors.lastname: Zhang
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Zhao
authors.forename: Peng
authors.initials: P
authors.lastname: Yan
mesh_terms: D002621:Chemistry / Q000379:methods; D003460:Crystallization; D008277:Magnesium Oxide / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008968:Molecular Conformation; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D010316:Particle Size; D012825:Silicon / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D008277:Magnesium Oxide; D010100:Oxygen; D012825:Silicon