Template Synthesis of Nanotubes by Room-Temperature Coalescence of Metal Nanoparticles

Abstract

Metal nanoparticle nanotubes (NPNTs) have been introduced by us as a new class of template-synthesized, nanoparticle-based nanotubes possessing unique features such as room-temperature preparation, highly corrugated wall structure, electrical conductivity, mechanical stability, and defined optical absorbance. The nanotubes are prepared by passing a citrate-stabilized metal (Au, Ag) colloid solution through the pores of an aminosilane-modified nanoporous alumina membrane. The nanoparticles (NPs) aggregate, forming multilayers on the pore walls, and undergo spontaneous room-temperature coalescence to afford solid, porous, multiwall metallic nanotubes. Self-sustained NPNTs are obtained by membrane dissolution. It is shown that the nanotubes are formed in two stages, i.e., NP accumulation and initial coalescence in the wet stage, and final solidification upon drying, both crucial to their formation. The NPNT synthetic scheme is extended here to the construction of composite NPNTs, i.e., formation of bimetallic Au−Pd NPNTs using a mixed colloid solution. High-resolution transmission electron microscopy (HRTEM) of single-metal and composite NPNTs indicates actual coalescence and creation of metallic interfaces between individual NPs, with lattice continuation that extends into the NP bulk.

Au-Ag alloy nanoporous nanotubes

“…Template-based synthesis is one of the most widely used methods for the fabrication of one-dimensional (1-D) nanostructures [13 15]. For example, gold nanotubes [1,2] and nanoparticle nanotubes [16,17] can be fabricated by templating porous alumina membranes using different surface modifi cation techniques. Recently, based on a simple galvanic replacement reaction, Xia and co-workers have successfully synthesized a series of metallic hollow nanostructures with interesting properties, including nanoboxes, nanocages, and nanotubes [18 20].…”

Toward Greener Nanosynthesis

“…Solution phase assembly occurs primarily through crosslinking of soluble materials, which may be driven by hydrophobic or electrostatic interactions [258][259][260][261][262][263][264][265] or via covalent bond formation, 74,[266][267][268][269][270] and crystallization processes resulting from a controlled loss of solubility. 271,272 Typical crosslinking strategies include the use of bifunctional linker molecules capable of binding to the surface of a nanoparticle, coupling reactions that take advantage of existing pendant functional groups to bring particles together, electrostatic (ionic) interactions that create dynamic assemblies, and the exploitation of nonspecific (van der Waals, hydrophobic) interactions.…”

Study of Degradation Processes of Feni Nanostructures

“…Porous membranes based on alumina, polycarbonate or polyethylene terephthalate can be used as templates. An electrochemical deposition method is emphasized among the variety of methods [7][8][9][10] of obtaining nanostructures, its distinguishing features are simplicity, convenience, manufacture efficiency, as well as the ability to control the length and wall thickness, element and phase composition by changing the deposition conditions. In turn, one of the unique materials for practical use is an alloy of iron and nickel.…”