Double-walled iron oxide nanotubes via selective chemical etching and Kirkendall process

Abstract

Double-walled oxide nanotube structures are interesting for a wide range of applications, from photocatalysis to drug delivery. In this work, a progressive oxidation method to fabricate double-walled nanotube structures is reported in detail. The approach is based on the electrodeposition of metallic iron nanowires, in porous alumina templates, followed by a selective chemical etching, nanoscale Kirkendall effect, a fast oxidation and out-diffusion of the metallic core structure during thermal annealing. To validate the formation mechanism of such core-shell structure, chemical composition and atomic structure were assessed. The resulting hematite nanotubes have a high degree of uniformity, along several microns, and a nanoscopic double-walled structure.

Shape Anisotropic Iron Oxide-Based Magnetic Nanoparticles: Synthesis and Biomedical Applications

“…Given their unique structural and magnetic properties, ferrite nanoparticles have been widely used for magnetic drug delivery [9][10][11], magnetic hyperthermia [12][13][14] and magnetic resonance imaging [15][16][17]. Research on preparation methods and characterization of different anisotropic shapes of these nanoparticles is important and it is recently increasing, since desired physicochemical properties and applications can be achieved by simply change structural parameters [18][19][20][21][22]. The magnetic behavior of ferrite nanoparticles is highly influenced by shape anisotropy.…”

Impact of Thermal Oxidation on Morphological, Structural and Magnetic Properties of Fe-Ni Wire-Like Nanochains

“…It is well known that various amorphous inorganic materials are frequently subjected to the thermal treatment in order to improve their crystallinity. [1,22,33,38,40] At the same time, the iron-containing materials suffer from the oxidation because iron as the element tends to be imminently bound with oxygen coming from the atmosphere even at room temperature. [7,[13][14][15][16]28,32] Thus, it is clear that the susceptibility to oxidation of the investigated Fe-Ni nanochains is linked with the amount of iron inside them and detailed analysis of the obtained XRD and RS data confirms this assumption.…”

“…To best of our knowledge, no paper describing the Kirkendall oxidation of the one-dimensional (1D) iron-nickel bimetallic nanostructures has been found, whereas only few papers about the impact of Kirkendall effect on thermally oxidized 1D Fe or Ni nanomaterials have been published so far. [18][19][20][21][22] This is mainly associated with the fact that it is difficult to control the final dimensions and morphologies of the more complexed nanostructures during their synthesis. [22] Nevertheless, some research group took an advantage of template-assisted methods and they investigated the influence of the nanoscale Kirkendall effect on the Fe and Ni wire-like nanostructures.…”

“…[18][19][20][21][22] This is mainly associated with the fact that it is difficult to control the final dimensions and morphologies of the more complexed nanostructures during their synthesis. [22] Nevertheless, some research group took an advantage of template-assisted methods and they investigated the influence of the nanoscale Kirkendall effect on the Fe and Ni wire-like nanostructures. The general conclusion coming from their works is that the total oxidation of metallic nanowires leads to the formation of metal oxide nanotubes.…”

Understanding the thermal conductivity variations in nanoporous anodic aluminum oxide

“…These AAO membranes are applied in very different ways such as the template-assisted synthesis of high-density arrays of 1D nanomaterials (such as nanowires, 1 nanotubes, 2,3 nanorods, 4,5 segmented nanowires, 6,7 etc. ), or 3D interconnected nanostructures, 8,9 as masks 10 for preparing nanodots or nanorod arrays or nanopatterned substrates, [11][12][13] and as substrates to deposit different materials on their surfaces and obtain nanohole or antidot arrays 14 or "holey" lms.…”