Nanorattles or Yolk–Shell Nanoparticles—What Are They, How Are They Made, and What Are They Good For?

Abstract

The development of nanotechnology has led to the design of cutting-edge nanomaterials with increasing levels of complexity. Although "traditional" solid, uniform nanoparticles are still the most frequently reported structures, new generations of nanoparticles have been constantly emerging over the last several decades. The outcome of this nano-art extends beyond nanomaterials with alternative compositions and/or morphologies. The current state-of-the-art allows for the design of nanostructures composed of different building blocks that exhibit diverse properties. Furthermore, those properties can be a reflection of either individual features, which are characteristic of a particular building block alone, and/or synergistic effects resulting from interactions between building blocks. Therefore, the unique structures as well as the outstanding properties of nanorattles have attracted increasing attention for possible biomedical and industrial applications. Although these nanoparticles resemble core-shell particles, they have a distinctive feature, which is a presence of a void that provides a homogenous environment for the encapsulated core. In this Review, we give a comprehensive insight into the fabrication of nanorattles. A special emphasis is put on the choice of building blocks as well as the choice of preparation method, because those two aspects further influence properties and thus possible future applications, which will also be discussed.

Mixed surfactant controlled syntheses of solid Ni2P and yolk–shell Ni12P5 via a hydrothermal route and their photocatalytic properties

“…Among them, hard or soft template route is often employed to prepare yolk-shell structures [14,15]. In the hard-template method, the inner templates are selectively removed by making use of one certain solvent or calcination [16][17][18].…”

Metal/Semiconductor Hybrid Nanocrystals and Synergistic Photocatalysis Applications

“…During the process, no any nanostructure is used as template or core-shell nanocrystals forming during the process are taken as self-template [56,64,65]. For example, Pt-CeO 2 yolkshell nanoparticles can be synthesized by hydrothermal method, although the mechanism may involve several factors [64].…”

“…Using soft template for metal-semiconductor yolk-shell nanocrystals: By soft template protocol, several kinds of chemical are usually employed as soft template, such as biomolecular, polymers, surfactants, or microemulsions [56,70]. In most of case, the large molecular would form microemulsions in solution and precursors react on the boundary of microemulsions.…”

“…With a unique structure, metal-semiconductor yolk/shell nanocrystals play an important role in photocatalysis and other fields [56][57][58][59][60][61][62][63]. As photocatalysts, metal-semiconductor yolk/shell nanocrystals process some advantages, such as stronger absorption, higher catalysts selectivity, and higher quantum yield.…”

Synthesis of Ag@SiO2 nanorattles for controlled Ag+ release

“…These nanoparticles are characterized by a void between a silica shell and a Ag nanoparticle as cargo. 3 The silica shell protects the Ag cores from aggregation and prolongs the release of the antimicrobial active Ag + ions. Moreover it provides reactive sites to functionalize the nanocontainers in order to attach them covalently to implant surfaces or to incorporate them into polymer materials.…”