Evidence of Double-Walled Al−Ge Imogolite-Like Nanotubes. A Cryo-TEM and SAXS Investigation

Maillet, Perrine; Levard, Clément; Larquet, Éric; Mariet, Clarisse; Spalla, Olivier; Menguy, Nicolas; Armand, Michel; Dœlsch, Emmanuel; Rose, Jérôme; Thill, Antoine

doi:10.1021/ja908707a

Cited by 60 publications

(86 citation statements)

References 8 publications

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“…11 This leads to the synthesis of concentrated (molar) suspensions of single-or double-walled (DW) aluminogermanate nanotubes with larger external diameters, typically ~ 4 nm. 9,12 More recently, Fe-doped INT have also been explored by isomorphic substitution of Al…”

Section: Introductionmentioning

confidence: 99%

Effect of Ionic Strength on the Bundling of Metal Oxide Imogolite Nanotubes

et al. 2017

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Significant developments have been proposed over the past decade in the synthesis of aluminosilicate and aluminogermanate imogolite-like nanotubes. But, while liquid phase synthesis is well-controlled, it is not the case for the nanotube arrangement in the dry state. In particular, nanotubes are found to self-assemble in bundles of various sizes, which may impact the properties of the final product. Here, we investigate the effect of ionic strength on bundling of aluminogermanate single-walled imogolite nanotubes (Ge-SWINT) in aqueous suspensions and in the resulting powders after solvent evaporation. The nanotube arrangement as a function of salt concentration was studied by X-ray scattering experiments and simulations. In aqueous suspension, nanotubes bundling occurs only at high ionic strength (IS > 8 × 10–2 mol·L–1), while beyond this threshold, the increase of electrostatic repulsions induces a complete stabilization of individual nanotubes. After solvent evaporation, nanotube arrangement is shown to be dictated principally by the initial concentration of salt. Beyond an ionic strength of ∼10–3 mol·L–1 in the starting suspension, all Ge-SWINT samples tend to form large bundles in powder, whose lattice parameters are independent of the initial salt concentrations. These experimental results clearly show that the positive surface charge of imogolite can be used to control nanotubes bundling by anion condensation.

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Section: Introductionmentioning

confidence: 99%

Effect of Ionic Strength on the Bundling of Metal Oxide Imogolite Nanotubes

et al. 2017

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“…The growth mechanisms of these nanotubes were investigated using several complementary techniques, including transmission electronic microscopy (TEM) and dynamic light scattering (DLS) (Yang et al, 2008). Moreover, improved protocols and synthesis of aluminogermanate analogues (Al 2 GeO 7 H 4 ) with higher electronic density has facilitated characterization of mechanisms involved in the formation of imogolite type structures (Levard et al, 2008;Levard et al, 2011;Maillet et al, 2010;Maillet et al, 2011;Mukherjee et al, 2005;Mukherjee et al, 2007;Wada and Wada, 1982). For the first time, models of Ge-imogolite precursors (commonly referred to as proto-imogolites) were thus proposed that consist of roof tile shaped nanoparticles, up to 5 nm in size, with Ge vacancies and varying curvatures .…”

Section: Introductionmentioning

confidence: 99%

Structure and distribution of allophanes, imogolite and proto-imogolite in volcanic soils

Levard¹,

Dœlsch²,

Basile‐Doelsch³

et al. 2012

Geoderma

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“…Because of the unique physicochemical characteristics of this IONt, various synthetic processes have been developed [9,[11][12][13][14][15], reinforcing its industrial applications. It is used mainly as an adsorbent and catalytic support, with projected nanotechnological applications that increase its range of use at the industrial level [16][17][18][19][20]. The synthesis of imogolite involves a first step in which basic hydrolysis of the Si and Al precursors takes place, followed by polymerization at 95°C for a period of approximately five days during which the tubular structure is formed and the superficial active sites are modified [13,21].…”

Section: Introductionmentioning

confidence: 99%

Use of isoelectric point and pH to evaluate the synthesis of a nanotubular aluminosilicate

Arancibia‐Miranda

Escudey

Molina

et al. 2011

Journal of Non-Crystalline Solids

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To follow the synthesis of imogolite, transmission electron microscopy is needed. In this paper, the isoelectric point (IEP) and the aging pH are proposed as alternative methods. Two synthetic procedures were used (S-I and S-II), both involving a co-precipitation followed by an aging treatment where the aluminosilicate evolves from proto-imogolite (detected after the co-precipitation step), to imogolite; its formation is reached after 120 h (S-I) or 168 h (S-II) of aging, depending on the co-precipitation method used. In S-I the isoelectric point increases from 7.1 to 10.5, while in S-II it increases from 6.6 to 9.2 during the aging treatment. Additionally, a linear relationship between the IEP and the pH at different aging steps was found. That relationship may be used to follow the process of synthesis by simply measuring the pH, becoming an alternative to more complex methods.

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Evidence of Double-Walled Al−Ge Imogolite-Like Nanotubes. A Cryo-TEM and SAXS Investigation

Cited by 60 publications

References 8 publications

Effect of Ionic Strength on the Bundling of Metal Oxide Imogolite Nanotubes

Effect of Ionic Strength on the Bundling of Metal Oxide Imogolite Nanotubes

Structure and distribution of allophanes, imogolite and proto-imogolite in volcanic soils

Use of isoelectric point and pH to evaluate the synthesis of a nanotubular aluminosilicate

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