Nanowires and Nanotubes

Abstract

Nanowires and nanotubes are at the forefront of materials science and engineering. Owing to the unique structural one‐dimensionality and possible quantum confinement effects in two dimensions, nanowires and nanotubes exhibit many novel properties. They are considered to be critical building blocks for developing nanoscale devices. The synthesis and characterization of nanowires and nanotubes constitute an important part of the development of nanotechnology. Significant progress has been made in investigating their unique properties, especially mechanical, electronic, and optical properties. The general understanding of these materials serves as the foundation for advancing nanomanufacturing and nanodevices. This article introduces various types of nanowires and nanotubes, including their general synthesis, structure, characterization, physical and chemical properties, and their practical and potential applications.

Surface-Catalyzed Zinc Oxide Nanorods and Interconnected Tetrapods as Efficient Methane Gas Sensing Platforms

“…A thickness-dependence study on ZnO films under UV illumination conducted by Su et al demonstrated the highest sensitivity at ambient temperature and found that response to the target gas (NO 2 ) increased with increasing thickness to a maximum of 1500 nm, after which the response began decreasing [21,22]. While this study highlights the significance of UV for lowering operating temperature, the thicker films possessed higher porosity which had a larger penetration depth for the UV light to create more photogenerated carriers and efficient diffusion of gas molecules [17]. This study examines, at a fundamental level, the hierarchical morphology-promoted enhancement of methane sensing from vertically aligned nanorod and networked tetrapod ZnO films, surface catalysts, and thermal and UV excitation, providing a thorough physical and chemical understanding of sensing mechanism.…”

“…ZnO nanorod (ZnO-NR) thin films were prepared via the aqueous phase chemical solution growth method [16,17]. Briefly, a 25 mM zinc acetate in ethanol seed solution was prepared with 40 wt.% Au nanoparticles.…”

“…Different material catalysts studied include noble metals (i.e., Pd, Au, and Pt) to promote oxidative reactions with CH 4 at lower temperatures [12,13]. Palladium (Pd) has been effectively used as a catalyst for various ZnO thin film morphologies, such as interconnected nanoparticles, nanosheets, nanorods and nanoplates [14][15][16][17]. The operating temperature of the ZnO film plays a significant role in the adsorption/desorption of the methane (CH 4 ), as the adsorbed oxygen species at elevated temperatures (O − ) are more reactive than those generated at lower temperatures (O 2 − ) (T ≤ 100 • C) [18,19].…”