One‐Dimensional Nanostructures: Synthesis, Characterization, and Applications

Abstract

This article provides a comprehensive review of current research activities that concentrate on one‐dimensional (1D) nanostructures—wires, rods, belts, and tubes—whose lateral dimensions fall anywhere in the range of 1 to 100 nm. We devote the most attention to 1D nanostructures that have been synthesized in relatively copious quantities using chemical methods. We begin this article with an overview of synthetic strategies that have been exploited to achieve 1D growth. We then elaborate on these approaches in the following four sections: i) anisotropic growth dictated by the crystallographic structure of a solid material; ii) anisotropic growth confined and directed by various templates; iii) anisotropic growth kinetically controlled by supersaturation or through the use of an appropriate capping reagent; and iv) new concepts not yet fully demonstrated, but with long‐term potential in generating 1D nanostructures. Following is a discussion of techniques for generating various types of important heterostructured nanowires. By the end of this article, we highlight a range of unique properties (e.g., thermal, mechanical, electronic, optoelectronic, optical, nonlinear optical, and field emission) associated with different types of 1D nanostructures. We also briefly discuss a number of methods potentially useful for assembling 1D nanostructures into functional devices based on crossbar junctions, and complex architectures such as 2D and 3D periodic lattices. We conclude this review with personal perspectives on the directions towards which future research on this new class of nanostructured materials might be directed.

Nanostructured Pt-alloy electrocatalysts for PEM fuel cell oxygen reduction reaction

“…119 The anisotropic morphology of preformed seeds could lead to the formation of branched Pt nanostructures through nonsymmetrical growth. 15 Using preformed nanostructures as seeds, well-defined core-shell structures, nanowires and nanotubes were synthesized. 16,96,98 Mahmoud et al 47 employed tetrahedral Pt as seeds to fabricate star-like Pt nanostructures with up to thirty arms, as shown in Fig.…”

“…51 Furthermore, some nanostructures enclosed within high-index facets could contain more unsaturated atomic steps, edges and kinks, which are believed to be more catalytically active than the commonly formed nanostructures within low-index facets. 15,37,52 Tian et al 53 reported Pt tetrahexahedra with exposed high-index planes (e.g. {730}, {210} and {520} facets), which exhibited 2-4 times more efficiency per unit surface area for ethanol oxidation compared to a commercially available Pt/C catalyst, that is usually enclosed with low-index planes such as {111} and {100}.…”

“…Some special nanoparticle shapes, such as cubic, truncated cubic and plate-like, can also be formed. 15,16,37,85 By extending the dimension of nanoparticles in a desired direction, some well-defined, so-called one-dimensional nanostructures such as nanotubes, nanowires, nanobelts, nanoneedles and nanorods have been synthesized, and these exhibit enhanced ORR catalytic activity and selectivity. 15,28 Apparently, we need systematic studies of controlling parameters in the synthetic routes of Pt nanostructures with different shapes-such as spheres, wires, rods, whiskers and tubes-for application in electrochemical energy devices.…”

“…[10][11][12] In each such approach, the effects of shape (zero-, one-, two-or three-dimensional nanostructures), morphology (exposed facets), and catalyst composition on electrocatalytic activity and stability should be considered. [13][14][15][16] In synthesis processes, optimizing catalyst shape, morphology and composition with respect to catalytic activity and stability is critical to achieve successful electrocatalysts.…”

n-Type Carbon Nanotubes/Silver Telluride Nanohybrid Buckypaper with a High-Thermoelectric Figure of Merit

“…Owning to these advanced properties as well as abundance of carbon on the earth, CNT is an important candidate to build flexible electronics. [25][26][27] However, it is seldom regarded as a TE material due to its poor Seebeck coefficient (< 60 μV/K) 28 and high thermal conductivity of a single tube (~ 250-10000 Wm -1 K -1 for single tube or aligned arrays) [29][30][31] . It has been reported that low thermal conductivities can be obtained in CNTs/conductive polymer composites and processed tubes.…”