Recent progress in the syntheses and applications of multishelled hollow nanostructures

Multishelled hollow nanostructures have attracted considerable research interest owing to their unique structural features, promising properties, and fascinating performances in relevant applications. During the past few decades, considerable progress has been made in the synthesis of multishelled hollow nanostructures by accurately controlling their geometric morphology, chemical composition, thickness, number of shells, and their applications in various fields. In this review, we present a comprehensive overview on the recently used synthesis approaches for fabricating multishelled hollow nanostructures. For a comprehensive review, the synthesis approaches have been classified into four categories, namely, hard template, soft template, self-template, and template-free approaches based on the template/structure-directing agent used. The advantages and disadvantages of each approach are discussed by comparing with each other. Furthermore, the fascinating performances of multishelled hollow nanostructures, application in energy conversion and storage, environment remediation, chemical catalysis, and biomedicine are comprehensively summarized. Combining certain typical examples and related theoretical analysis, the relationship between the structure of multishelled hollow nanomaterials and their specific application performances in the related areas is highlighted. Finally, the emerging challenges and future prospects of multishelled hollow nanostructures in the research and development for the future are outlined.