Atom-Precision Engineering Chemistry of Noble Metal Nanoparticles

With nanoscience stepping into the new era of atom precision, reliable industrial applications of noble metal nanoparticles (NPs) require them to be engineerable at atom precision. The past two decades have witnessed remarkable achievements in precisely engineering the property-dictating attributes of metal NPs, including size, atomic packing structure, and spatial arrangement of individual NPs. More intriguingly, the accelerating rise of atomically precise metal nanoclusters (NCs) in the past two decades has provided unprecedented opportunities to understand the aforementioned processes at the atomic resolution. In this review, we systematically summarize recent progress on engineering the size, atomic packing structure, and hierarchical arrangement of both plasmonic metal nanocrystals and molecular-like metal NCs. The discussion is based on the methodological and mechanistic developments advancing the engineering chemistry to atomic precision. Specifically, the methodologies controlling the size and size monodispersity of metal NPs are first discussed, where the step-by-step reactions along the size growth route revealed at the molecular level are central in our discussion. Following the size engineering, the atomic packing structure engineering chemistry is concisely reviewed. The crystal phase engineering of plasmonic metal nanocrystals and the isomerism of molecular-like metal NCs are the cutting-edge topics in this aspect. Besides the size and atomic packing structure engineering at the intraparticle level, we also highlight recent advances in precisely arranging metal NPs in their hierarchical superstructures at the interparticle level. We subsequently conclude the discussion with our perspectives on the future development of engineering chemistry of noble metal NPs. The methodological and fundamental advances systemized in this Review may increase the acceptance of both plasmonic metal nanocrystals and molecular-like metal NCs in diverse industrial sectors such as catalysis, energy, and biomedicine.