title: Controlling the morphology of rhodium nanocrystals by manipulating the growth kinetics with a syringe pump.
abstract: Noble-metal nanocrystals with well-defined and controllable morphologies are of great importance to applications in catalysis, plasmonics, and surface-enhanced spectroscopy. Many synthetic approaches have been demonstrated for controlling the growth habit and thus morphology of metal nanocrystals, but most of them are based on a thermodynamic approach, including the use of a capping agent. While thermodynamic control has shown its power in generating nanocrystals with a myriad of different morphologies, it is ultimately limited by the obligation to minimize the surface energy of a system. As a result, it is impractical to use thermodynamic control to generate nanocrystals having high-energy facets and/or a negative curvature. Using rhodium as an example, here we demonstrate a general method based on kinetic control with a syringe pump that can be potentially extended to other noble metals and even other solid materials. For the first time, we were able to produce concave nanocubes with a large fraction of {110} facets and octapods with a cubic symmetry in high yields by simply controlling the injection rate at which the precursor was added into the reaction solution. The concave nanocubes with {110} facets and a unique cavity structure on the surface are important for a variety of applications.
authors.affiliation: Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63130, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Weiyang
authors.initials: W
authors.lastname: Li
authors.forename: Mingshang
authors.initials: M
authors.lastname: Jin
authors.forename: Jie
authors.initials: J
authors.lastname: Zeng
authors.forename: Taekyung
authors.initials: T
authors.lastname: Yu
authors.forename: Deren
authors.initials: D
authors.lastname: Yang
authors.forename: Younan
authors.initials: Y
authors.lastname: Xia
mesh_terms: D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D012238:Rhodium / Q000737:chemistry*; D013499:Surface Properties; D013594:Syringes; D014025:Titanium / Q000737:chemistry*
chemical_list: D046911:Macromolecular Substances; C009495:titanium dioxide; D014025:Titanium; D012238:Rhodium