A Facile and Mild Synthesis of 1-D ZnO, CuO, and α-Fe₂O₃ Nanostructures and Nanostructured Arrays

Abstract

ZnO nanowires, CuO nanowires, and alpha-Fe(2)O(3) nanotubes as well as their corresponding arrays have been successfully synthesized via a low cost, generalizable, and simplistic template method. Diameters of one-dimensional (1-D) metal oxide nanostructures ( approximately 60-260 nm), measuring micrometers in length, can be reliably and reproducibly controlled by the template pore channel dimensions. Associated vertically aligned arrays have been attached to the surfaces of a number of geometrically significant substrates, such as curved plastic and glass rod motifs. The methodology reported herein relies on the initial formation of an insoluble metal hydroxide precursor, initially resulting from the reaction of the corresponding metal solution and sodium hydroxide, and its subsequent transformation under mild conditions into the desired metal oxide nanostructures. Size- and shape-dependent optical, magnetic, and catalytic properties of as-prepared 1-D metal oxides were investigated and noted to be mainly comparable to or better than the associated properties of the corresponding bulk oxides. A plausible mechanism for as-observed wire and tube-like motifs is also discussed.

Electrochemical Synthesis of Mesoporous Pt Nanowires with Highly Electrocatalytic Activity toward Methanol Oxidation Reaction

“…This is due to the non-uniformity of the PC channels. Similar situation has been often observed when using a PC membrane as a hard template [18,33,34]. On the surface of the obtained NWs, a large number of well-distributed mesopores can be observed, thus exposing the active Pt surfaces to the reagents.…”

One-dimensional ZnO nanostructures: Solution growth and functional properties

“…The template is attached to the surface of a substrate, which can be flat or curved, flexible or rigid. [129], among which, the diameters of the ZnO nanowires could be tuned from 60 to 260 nm, with lengths in the ~μm range, by reliably and reproducibly controlling the template pore channel dimensions [129]. However, the key issue for semiconductor nanowires fabricated by this technique is the crystalline quality, which in most cases is not perfect.…”

“…However, the key issue for semiconductor nanowires fabricated by this technique is the crystalline quality, which in most cases is not perfect. The resulting Figure 7 SEM images of (a) isolated ZnO nanowires, (b) ZnO nanowires embedded in a polycarbonate template, (c) free standing ZnO nanowire arrays after removal of the template, and (d) representative energy-dispersive X-ray spectroscopy (EDS) plot of the as prepared ZnO nanowire arrays [129]. Reproduced with permission materials are either amorphous or polycrystalline consisting of small crystals with an abundance of defects, which might greatly limit their technical applications, particularly in optoelectronic devices.…”

Physical Confinement Promoting Formation of Cu2O–Au Heterostructures with Au Nanoparticles Entrapped within Crystalline Cu2O Nanorods

“…Originally explored as a synthesis template for electrochemical growth of nanotubes or nanorods of conducting polymers and metals, 18,19 track-etched membranes have been used for the crystallization of transition metal oxides 20 and as synthetic models for studying crystallization in confinement. [21][22][23][24][25][26][27][28][29] Key outcomes of these works have included the ability to form high aspect ratio nanorods, 23,26 and a route to interface semiconducting transition metal oxide nanowire arrays into macroscale structures with spatial control.…”

“…[21][22][23][24][25][26][27][28][29] Key outcomes of these works have included the ability to form high aspect ratio nanorods, 23,26 and a route to interface semiconducting transition metal oxide nanowire arrays into macroscale structures with spatial control. 20 Up to this point, reports on electrochemical and solution-based crystallization within the pores of track-etched membranes have involved the formation of single phase or multilayered nanowires. [30][31][32][33] However, these membranes also present a means to physically control the encapsulation of (metal) nanoparticles within the target (semiconducting) crystalline nanorods, forming a crystal-within-acrystal dual-(or multi-) phase material.…”