title: Facile Synthesis of Silver Nanocubes with Sharp Corners and Edges in an Aqueous Solution.
abstract: It remains a challenge to synthesize Ag nanocubes in an aqueous system, although the polyol process was successfully adopted more than one decade ago. Here, we report an aqueous method for the synthesis of Ag nanocubes with an average edge length of 35-95 nm. It involves the formation of AgCl octahedra by mixing CF3COOAg with cetyltrimethylammonium chloride, followed by the nucleation and growth of Ag nanocrystals in the presence of ascorbic acid (AA) and FeCl3. The Fe3+/Fe2+redox pair is responsible for the removal of multiply twinned seeds through oxidative etching. The Cl-ions play two critical roles in the nucleation and growth of Ag nanocubes with a single-crystal structure. First, the Cl-ions react with Ag+ions to generate nanometer-sized AgCl octahedra in the initial stage of a synthesis. In the presence of room light and a proper reducing agent such as AA, the AgCl can be reduced to generate Agnnuclei followed by their evolution into single-crystal seeds and then Ag nanocrystals. Second, the Cl-ions can act as a specific capping agent toward the Ag(100) surface, enabling the formation of Ag nanocubes with sharp corners and edges. Based on the results from a set of time-lapse studies and control experiments, we formulate a plausible mechanism to account for the formation of Ag nanocubes that resembles the formation and development of latent image centers in silver halide grains in the photographic process.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhou
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Li
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors.forename: Kyle D
authors.initials: KD
authors.lastname: Gilroy
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory , Upton, New York 11973, United States.
authors.forename: Jing
authors.initials: J
authors.lastname: Tao
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Zhu
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors.forename: Xuan
authors.initials: X
authors.lastname: Yang
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Sun
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors.forename: Younan
authors.initials: Y
authors.lastname: Xia
keywords: aqueous method; nanocube; one-pot synthesis; silver; silver chloride