Termination Effects in Aluminosilicate and Aluminogermanate Imogolite Nanotubes: A Density Functional Theory Study

Poli, Emiliano; Elliott, Joshua D.; Chai, Ziwei; Teobaldi, Gilberto

doi:10.3390/cryst10111051

Cited by 6 publications

(4 citation statements)

References 78 publications

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“…[ 78 , 84 ] Notably, recent simulations of highly idealized, thence inevitably approximated, structures for the tube ends [ 81 ] suggest the INTs can develop, in addition to a radial dipole density, also a longitudinal polarization and ensuing band bending due to physical truncation and ensuing structural relaxation. [ 85 ]…”

Section: Main Features and Physical‐chemical Propertiesmentioning

confidence: 99%

Imogolite Nanotubes and Their Permanently Polarized Bifunctional Surfaces for Photocatalytic Hydrogen Production

Paineau,

Teobaldi,

Jiménez‐Calvo

2023

Global Challenges

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To date, imogolite nanotubes (INTs) have been primarily used for environmental applications such as dye and pollutant degradation. However, imogolite's well‐defined porous structure and distinctive electro‐optical properties have prompted interest in the system's potential for energy‐relevant chemical reactions. The imogolite structure leads to a permanent intrawall polarization arising from the presence of bifunctional surfaces at the inner and outer tube walls. Density functional theory simulations suggest such bifunctionality to encompass also spatially separated band edges. Altogether, these elements make INTs appealing candidates for facilitating chemical conversion reactions. Despite their potential, the exploitation of imogolite's features for photocatalysis is at its infancy, thence relatively unexplored. This perspective overviews the basic physical‐chemical and optoelectronical properties of imogolite nanotubes, emphasizing their role as wide bandgap insulator. Imogolite nanotubes have multifaceted properties that could lead to beneficial outcomes in energy‐related applications. This work illustrates two case studies demonstrating a step‐forward on photocatalytic hydrogen production achieved through atomic doping or metal co‐catalyst. INTs exhibit potential in energy conversion and storage, due to their ability to accommodate functions such as enhancing charge separation and influencing the chemical potentials of interacting species. Yet, tapping into potential for energy‐relevant application needs further experimental research, computational, and theoretical analysis.

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Section: Main Features and Physical‐chemical Propertiesmentioning

confidence: 99%

Imogolite Nanotubes and Their Permanently Polarized Bifunctional Surfaces for Photocatalytic Hydrogen Production

Paineau,

Teobaldi,

Jiménez‐Calvo

2023

Global Challenges

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“…[19][20][21][22][23] INT offers similar characteristics to those of carbon nanotubes (CNTs) in terms of rigidity, sizes and aspect ratios while retaining transparency and self-organization in highly dilute conditions. 24,25 Although they display larger band gaps than CNTs, 26 they are cheaper to produce with monodisperse diameters without further sorting techniques. Consequently, imogolite nanotubes represent an interesting alternative of the carbon nanotubes in numerous applications including the fabrication of polymer/filler nanocomposites with multifunctional characteristics.…”

Section: Introductionmentioning

confidence: 99%

Effect of Polymer Length on the Adsorption onto Aluminogermanate Imogolite Nanotubes

et al. 2021

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This study evidences the adsorption of model non-ionic polymers onto aluminogermanate imogolite nanotubes, an attractive porous nanofiller with potential molecular loading and release applications. We resolve the underlying mechanisms between nanotubes and polyethylene glycols with different molecular weight by means of nano-isothermal titration calorimetry. The analysis of the results provides a direct thermodynamic characterization, allowing to propose a detailed description of the energetics involved in the formation of polymer/imogolite complexes. The affinity towards the nanotube surface is enthalpy-driven and strongly depends on the polymer chain length, which significantly affects the polymer configuration and the flow properties of the resulting complexes, probed by small-angle neutron scattering and rheology, respectively. These findings open new avenues for the rational design of these hybrid mixtures for advanced applications.

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“…A large set of point defects and end terminations at imogolite nanotubes of different chiralities has been characterized using the large‐scale calculations within several advanced density‐functional theory (DFT) methods, serving not only as a reference for future quantum‐chemical models, yet, concluding on the modification of the optical and photochemical properties of imogolite due to intrinsic defects. [ 19,20 ]…”

Section: Introductionmentioning

confidence: 99%

Imogolite: Curvature‐Induced Hospitality for Trivalent Dopants

Popov

Enyashin

2021

Physica Status Solidi (b)

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Imogolite—a congregation of aluminosilicate nanotubes—has shown a great promise for fabrication of advanced materials. Imogolite nanotubes hold the record narrow diameters distribution and demonstrate one of the highest curvatures among noncarbon nanotubes. Current experimental and theoretical prospects for their modification are related mostly to surface functionalization or to progressive Si substitution on Ge, whereas a doping of Al sublattice is steadily neglected. The empirical rules of Hume–Rothery disallow such doping due to a large size mismatch between Al3+ and the majority of metal cations. Using the quantum‐chemical calculations, herein, the difference in coordination environment is unveiled for 12 sorts of trivalent cations at octahedral Al sites in both a highly curved imogolite layer and the flat gibbsite layer. The curvature of natural imogolite acts provoking for violation of the Hume–Rothery rules, sterically promoting the doping of Al sublattice by cations with radii 1.0–1.2 Å typical for rare‐earth elements. Theoretically, the synthesis of a metal‐doped imogolite is restricted only by the overlap of the phase stability fields for precursor reactants or by kinetic factors. This study might be inciting for the synthesis of chemically modified imogolite and related Ge‐imogolites.

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Termination Effects in Aluminosilicate and Aluminogermanate Imogolite Nanotubes: A Density Functional Theory Study

Cited by 6 publications

References 78 publications

Imogolite Nanotubes and Their Permanently Polarized Bifunctional Surfaces for Photocatalytic Hydrogen Production

Imogolite Nanotubes and Their Permanently Polarized Bifunctional Surfaces for Photocatalytic Hydrogen Production

Effect of Polymer Length on the Adsorption onto Aluminogermanate Imogolite Nanotubes

Imogolite: Curvature‐Induced Hospitality for Trivalent Dopants

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