Capturing Electrochemically Evolved Nanobubbles by Electroless Deposition. A Facile Route to the Synthesis of Hollow Nanoparticles

Abstract

Gas evolution during electrochemical deposition has long been regarded as undesired and deliberately suppressed. Here, we show a new role of electrochemically evolved hydrogen bubbles, serving as both templates and reducing agent to form hollow Au nanoparticles via electroless deposition. Hollow gold nanoparticles with a complete nanocrystalline shell and a 50 nm hollow core were fabricated. By controlling the shell thickness, particle size can be varied from 100 to 150 nm. The process is very simple, scalable, and with a high throughput. Using this method, more complicated hollow nanostructures such as double nanoshells ("nanomatryoshka") can also be synthesized. These hollow nanoparticles possess desirable plasmonic properties and can potentially be used as nanocontainers to store and deliver gaseous materials. In addition, the process can be used for fundamental studies of nanobubble formation mechanism.

Hollow metal nanostructures for enhanced plasmonics: synthesis, local plasmonic properties and applications

“…In both of these approaches, the void size and the shape of the hollow structure are determined by the nature of the template while the morphology and composition of the shell (material, thickness and porosity) is mainly defined in the coating and removal processes. As a result, a wide variety of hollow NCs with different sizes, shapes, composition, and structures have been produced, using hard templates, such as polymers (polystyrene [54,55], formaldehyde resin [56,57], and poly(methyl)methacrylate [58], silica [59,60] and carbon particles [61]), or soft ones, such as emulsion block copolymer micelles [62], and even gas bubbles [63]. For a comprehensive and up-to-date review on templating approaches see Ref.…”

Thermodynamics of Surface Nanobubbles

“…Existence of surface nanobubbles was proposed as a reason for some surface phenomena such as the increase in attractive interactions between hydrophobic surfaces, 10 and thin liquid film rupture. 11,12 Moreover surface nanobubbles may potentially be used for: production of hollow nanomaterials by acting as soft nanotemplates, 13,14 separation of fine particles by air bubble floatation, 15,16 manipulation of adsorption on hydrophobic surfaces, 17,18 and enhancement of wall slip to achieve drag reduction in microfluidic devices, 19,20 among other proposed applications summarized in recent review papers. 1, [21][22][23] Among various methods for inducing surface nanobubbles summarized by Lohse and Zhang, 1 the most commonly used protocol is the solvent exchange process (commonly alcohol-water exchange).…”

Bottom-Up Synthesis of Gold Octahedra with Tailorable Hollow Features

“…(19) The preparation of these structures could be simplified if a materials removal step was not required and a bottom-up, rather than a top-down, approach is utilized. Recently, there have been reports of bottom-up syntheses for hollow nanostructures, which include one-pot galvanic replacement reactions, (20,21) electrochemical methods, (22,23) and reactions that utilize diffusion processes or Kirkendall effects. (24) However, it can be difficult to control all of the architectural parameters of the particles produced in these syntheses, especially when compared to the bottom-up seed-mediated syntheses of solid Au nanostructures, which can be used to generate a variety of different-shaped particles (e.g., cubes, (25) octahedra, (26) rods, (27,28) triangular nanoprisms, (29)(30)(31) and bipyramids (32) ) in a highly controllable manner.…”