Synthesis, Properties, and Applications of Hollow Micro-/Nanostructures

Abstract

In this Review, we aim to provide an updated summary of the research related to hollow micro- and nanostructures, covering both their synthesis and their applications. After a brief introduction to the definition and classification of the hollow micro-/nanostructures, we discuss various synthetic strategies that can be grouped into three major categories, including hard templating, soft templating, and self-templating synthesis. For both hard and soft templating strategies, we focus on how different types of templates are generated and then used for creating hollow structures. At the end of each section, the structural and morphological control over the product is discussed. For the self-templating strategy, we survey a number of unconventional synthetic methods, such as surface-protected etching, Ostwald ripening, the Kirkendall effect, and galvanic replacement. We then discuss the unique properties and niche applications of the hollow structures in diverse fields, including micro-/nanocontainers and reactors, optical properties and applications, magnetic properties, energy storage, catalysis, biomedical applications, environmental remediation, and sensors. Finally, we provide a perspective on future development in the research relevant to hollow micro-/nanostructures.

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

“…The most popular approach for the synthesis of hollow nanoparticles involves coating of the desired materials onto sacrificial templates [16]. These templating strategies, based on the coating of pre-fabricated (hard or soft) templates with a layer of a shell material, are conceptually the simplest one.…”

“…For a comprehensive and up-to-date review on templating approaches see Ref. [16]. Inspite of its simplicity and high versatility this conventional templating strategy presents some important limitations, associated with the difficulty of their fabrication in large quantities.…”

“…These challenging requirements can be achieved chemically, by the development of new and robust synthetic processes leading to the reproducible, scalable, and cost-effective production of hollow nanostructures with a high uniformity and well-controlled morphology, structure, and surface chemistry. In Section 2, we present a comprehensive summary on the synthesis of hollow nanostructures via templating approaches [16] and galvanic replacement reactions (GRRs) [17][18][19] with an emphasis on the latter technique.…”

Anisotropic Nanoscale Galvanic Replacement Reactions Studied by Liquid Cell Scanning Transmission Electron Microscopy

“…To tailor these physical/chemical properties and optimize device performance, different structural parameters and chemical composition of the metal nanostructures are tuned by controlling the nucleation and growth during synthesis process, or post treatment methods. Compared to the solid counterparts, hollow or porous anisotropic noble metal nanostructures possess lower mass density and larger specific surface area, which are favorable for reducing the usage of precious metals, increasing contact area with the surrounding reaction medium, accelerating mass and ion transportation, and accommodating local strain and stress in the working conditions [2]. It is therefore of great importance to understand the formation process and synthesize anisotropic noble metal nanostructures with hollow or porous morphology [2].…”

“…Compared to the solid counterparts, hollow or porous anisotropic noble metal nanostructures possess lower mass density and larger specific surface area, which are favorable for reducing the usage of precious metals, increasing contact area with the surrounding reaction medium, accelerating mass and ion transportation, and accommodating local strain and stress in the working conditions [2]. It is therefore of great importance to understand the formation process and synthesize anisotropic noble metal nanostructures with hollow or porous morphology [2].A galvanic replacement reaction (GRR) is a spontaneous process. One metal (A) is used as a sacrificial template and immersed in a solution containing ions of another metal (B) with higher reduction potential, then metal A will be continuously oxidized and dissolved into the solution, while metal B will be reduced and conformally coated onto the exposed surface of metal A.…”