Spatially Confined Formation and Transformation of Nanocrystals within Nanometer-Sized Reaction Media

• DOI: 10.1021/acs.accounts.8b00338
• Publication Date: 2018-10-16T12:39:15Z
• Authors: Amit Kumar; Ki-Wan Jeon; Nitee Kumari; In Su Lee
• Keywords: Nanometre

ConspectusThe extensive research performed in the past two decades has enabled production of a range colloidal nanocrystals, mostly through solution-based procedures that generate and transform nanostructures bulk-phase solutions containing precursors surfactants. However, understanding control each nanocrystal (trans)formation step during synthesis are still complicated because high complexity this process, which multiple diverse events such as nucleation, subsequent growth, attachment, ripening occur simultaneously bulk suspensions. Unlike well-established methods, solid-state reactions, had been at forefront traditional inorganic materials chemistry, quite rarely utilized realm nanomaterials temperatures required for most result clusters NCs prone to migrate reaction medium sinter together uncontrollably into large particles. We have pursuing "nanospace-confined approach" explore use variety solid hollow silica nanoparticles either or solution-phase media carry out syntheses transformations nanocrystals unique microenvironment, partitioning reactants, intermediates, transition states from rest medium. Such nanoconfined systems potential not only enable efficient selective conversion chemistries but also provide fundamental pertaining synthetic evolution transient mechanistic steps. The spaces with sizes few tens nanometers inside offer opportunity observe elucidate novel deconvoluted chemical phenomena impossible investigate systems, comprehensive chemistry can be implicated explaining controlling macroscopic behaviors. This Account describes our focused on developing spatially confined platforms transformations, highlighting diversity-oriented strategy, namely, "postdecoration approach", results new nanocatalytic sites preformed cavity diversifying their morphologies, number, density combinations. discuss key examples "nanoconfined involve reactions within thermally stable nanospheres synthesize complex hybrid increased functionality. In addition, an enlightening discussion conversions enclosed exposed cavities is included. Finally, important applications nanospace-confined various fields briefly discussed.