Emerging Noble Metal Aerogels: State of the Art and a Look Forward

Noble metal aerogels (NMAs), as the most important class of noble metal foams (NMFs), appear as emerging functional porous materials in the field of materials science. Combining the irreplaceable roles of noble metals in certain scenarios, as well as monolithic and porous features of aerogels, NMAs can potentially revolutionize diverse fields, such as catalysis, plasmonics, and biology. Despite profound progress, grand challenges remain in their fabrication process, including the efficient structure control, the comprehensive understanding of the formation mechanisms, and the generality of the fabrication strategies, thus inevitably retarding the material design and optimization. This Perspective focuses on the key progress, especially of the fabrication strategies for NMAs during the last two decades, while other NMFs are also succinctly introduced. Challenges and opportunities are summarized to highlight the unexploited space and future directions in expectation of stimulating the broad interest of interdisciplinary scientists. The advent of noble metal aerogels (NMAs), a type of functional porous materials belonging to the noble metal foams (NMFs), brings the hope of revolutionizing diverse fields such as catalysis, plasmonics, and biology. Combining features of noble metals and aerogels, NMAs display three-dimensional conductive backbones and interconnected hierarchical pores, which provide numerous active optical/catalytic sites and efficient electron/mass transfer pathways. Therefore, various NMAs have been fabricated and widely applied. Despite the impressive potential, their development is still at an infant stage and many challenges remain. This Perspective delivers a concise yet systematic overview of the development of NMAs during the last two decades, whereby other NMFs are also succinctly reviewed. Fabrication strategies are featured and properties/applications are briefly introduced. Finally, critical challenges and unexplored areas of NMAs are summarized, demonstrating tremendous opportunities and potential future research directions. Noble metal aerogels (NMAs) are a class of emerging porous materials that display enormous potential in diverse fields including catalysis, plasmonics, and biology. Despite profound progress, their development is still at an infant stage, and many challenges remain. This Perspective focuses on the key progress made for NMAs during the last two decades. Challenges and opportunities are also summarized, highlighting unexploited space and potential future research directions in this field.