کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1523224 | 1511827 | 2012 | 6 صفحه PDF | دانلود رایگان |

MnNb2O6 nanogears have been generated by using mixed NbCl5 and MnCl2 at an optimized ratio of 1:1 in a cyclohexanol solvent in a simple solvothermal process. It has shown that the Mn:Nb ratio determines the shape of the products. Detailed characterization by electron microscopy has shown that increasing the Mn+2 concentration during the solvo-thermal synthesis promotes a morphological evolution from relatively long Nb2O5 nanorods to a mixture of short Nb2O5 nanorods and MnNb2O6 6-teeth nanogears, then to a mixture of short Nb2O5 nanorods and more MnNb2O6 6-teeth nanogears, then to more and more MnNb2O6 6-teeth nanogears that are occasionally accompanied with under-developed MnNb2O6 5-teeth nanogears, and eventually to fully developed pure 3-D nanogears. The driving force for such interesting geometry transformations is attributed to the inclusion of Mn2+ into the Nb2O5 template at low Mn2+ concentrations, which introduces internal stresses to the Nb2O5 nanorods. At high Mn2+ concentrations, close to the stoichiometric composition of MnNb2O6, the formation of the gears is triggered by the intrinsic sixfold symmetry of crystalline columbite, via a combination of initial nanorod nucleation and the competing self-assembly of neighboring parallel nanorods.
The geometry morphology of Nb-based nanomaterial evolved from long Nb2O5 nanorods to a mixture of short Nb2O5 nanorods and MnNb2O6 6-teeth nanogears, and eventually to fully developed pure 3-D nanogears.Figure optionsDownload as PowerPoint slideHighlights
► MnNb2O6 nanogears have been generated by a simple solvothermal process when the Mn: Nb ratio was 1:1.
► MnNb2O6 6-teeth nanogears accompanied with MnNb2O6 5-teeth nanogears are got when the Mn:Nb ratio reached 1:2.
► The nanomaterial consists of nanorods and 6-teeth nanogears at low Mn:Nb molar ratio(1:4).
► Pure long Nb2O5 nanorods are achieved by only using NbCl5
Journal: Materials Chemistry and Physics - Volume 133, Issues 2–3, 16 April 2012, Pages 599–604