Dissolution-recrystallization mechanism for the conversion of silver nanospheres to triangular nanoplates.
A solution chemistry method for transforming polycrystalline Ag spherical particles into single crystalline triangular Ag nanoplates has been developed. The synthesis consists of three consecutive steps: (1) the synthesis of Ag nanospheres by NaBH(4) reduction of AgNO(3) in the presence of sodium citrate; (2) the conversion of citrate-stabilized Ag nanospheres into SDS (sodium dodecyl sulfate)-stabilized Ag nanospheres, and (3) the aging of the SDS-stabilized Ag nanospheres in 0.01 M NaCl solution. Our study indicates that the shape evolved through a Ag nanoparticle dissolution- and re-deposition process; and demonstrated the critical role of SDS in the process: SDS regulates the dynamics in the dissolved O(2)/Cl(-) etching of the Ag nanospheres and the reduction of the released Ag(+) by citrate ions in the same solution. SDS also functions as a shape-directing agent to assimilate the Ag(0) atoms into single crystalline triangular Ag nanoplates. A model for the shape conversion is also proposed which provides the clue for the synthesis of anisotropic Ag nanoparticles with other shapes (rods, wires, cubes, etc.).
Yang
Jun
J
Department of Chemistry, Eugene F. Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA. yangjz@bc.edu
Zhang
Qingbo
Q
Lee
Jim Yang
JY
Too
Heng-Phon
HP
D001894:Borohydrides / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D010316:Particle Size; D012834:Silver / Q000737:chemistry*; D012835:Silver Nitrate / Q000737:chemistry*
D001894:Borohydrides; D012834:Silver; C025364:sodium borohydride; D012835:Silver Nitrate