Synthesis of Ultralong, Monodispersed, and Surfactant-Free Gold Nanowire Catalysts: Growth Mechanism and Electrocatalytic Properties for Methanol Oxidation Reaction

Abstract

The understanding of factors influencing the growth of nanowires is critical for the precise control of the nanowire morphologies and the design of active nanowire catalysts for fuel cell reactions. While the formation of gold nanoparticles followed by self-assembly into short strings of nanowires is known, little is understood in terms of the control of the morphologies and surface properties toward enhanced electrocatalytic properties. This report describes novel findings of an investigation of the growth mechanism of ultralong, highly monodispersed, and surface surfactant-free gold nanowires (Au NWs) synthesized by a galvanic replacement reaction of Te NWs as an initial template. By manipulating reaction time and Au precursor concentration, an aggregative growth mechanism in terms of 1D and 3D growth pathways for the NW length and diameter, respectively, is revealed to be operative in the template-directed Au NW formation process, shinning some fresh insight into the controllability of the nanowire morphologies. In contrast to the use of various organic surfactants in most previous synthesis of Au NWs and catalysts, the surfactant-free Au NWs synthesized in this work have been demonstrated to exhibit enhanced electrocatalytic activities for methanol oxidation reaction, outperforming those for Au NWs with surface surfactants and Au NP counterparts.

Ultrathin Copper Nanowire Synthesis with Tunable Morphology Using Organic Amines for Transparent Conductors

“…One-dimensional (1D) metal nanostructures have drawn a great deal of interest because of their distinctive and superior optical, electrical, physical, catalytic, , and chemical properties compared to their bulk counterparts. They have great potential in fabricating nanoscale electronic, optoelectronic, and magnetic devices and provide an ideal test bed for investigating many basic physical phenomena .…”

Nanowire Genome: A Magic Toolbox for 1D Nanostructures

“…In 2009, Yu and co‐workers employed Te NWs to generate noble metal NWs for the first time, that is, Pt NTs, Pt NWs and Pd NWs with diameters of several nanometers and ultrahigh aspect ratios of ≈10 000 were prepared by adding H 2 PtCl 6 , PtCl 2 (NH 3 ) 2 and PdCl 2 to an ethylene glycol (EG) suspension of Te NWs . Afterward, a variety of single‐component and multicomponent noble metal NWs have been successfully synthesized via the galvanic replacement of Te NWs . When only one type of metal ion was added into the solution of Te NWs, Au, Pt or PdNWs were obtained (Figure (2)–(4)), respectively.…”

Surfactant-free synthesis of porous Au by a urea complex

“…Up to now, there are some studies on the surfactant-free synthesis of solid Au nanoparticles. [22][23][24] For example, Lai et al prepared homogeneous Au nanoparticles encapsulated by polythiophene analogues. 25 However, the growth of the porous and hollow Au nanoparticles is still rarely reported.…”