Fabrication and application of macroscopic nanowire aerogels

Assembly of nanowires into three-dimensional macroscopic aerogels not only bridges a gap between nanowires and macroscopic bulk materials but also combines the benefits of two worlds: unique structural features of aerogels and unique physical and chemical properties of nanowires, which has triggered significant progress in the design and fabrication of nanowire-based aerogels for a diverse range of practical applications. This article reviews the methods developed for processing nanowires into three-dimensional monolithic aerogels and the applications of the resultant nanowire aerogels in many emerging fields. Detailed discussions are given on gelation mechanisms involved in every preparation method and the pros and cons of the different methods. Furthermore, we systematically scrutinize the application of nanowire-based aerogels in the fields of thermal management, energy storage and conversion, catalysis, adsorbents, sensors, and solar steam generation. The unique benefits offered by nanowire-based aerogels in every application field are clarified. We also discuss how to improve the performance of nanowire-based aerogels in those fields by engineering the compositions and structures of the aerogels. Finally, we provide our perspectives on future development of nanowire-based aerogels.