title: Toward a Quantitative Understanding of the Reduction Pathways of a Salt Precursor in the Synthesis of Metal Nanocrystals.
abstract: Despite the pivotal role played by the reduction of a salt precursor in the synthesis of metal nanocrystals, it is still unclear how the precursor is reduced. The precursor can be reduced to an atom in the solution phase, followed by its deposition onto the surface of a growing nanocrystal. Alternatively, the precursor can adsorb onto the surface of a growing nanocrystal, followed by reduction through an autocatalytic process. With Pd as an example, here we demonstrate that the pathway has a correlation with the reduction kinetics involved. Our quantitative analyses of the reduction kinetics of PdCl42-and PdBr42-by ascorbic acid at room temperature in the absence and presence of Pd nanocubes, respectively, suggest that PdCl42-was reduced in the solution phase while PdBr42-was reduced on the surface of a growing nanocrystal. Our results also demonstrate that the reduction pathway of PdBr42-by ascorbic acid could be switched from surface to solution by raising the reaction temperature.
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.|Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu, 30013, Taiwan.
authors.forename: Tung-Han
authors.identifier: 0000-0001-6161-4397
authors.initials: TH
authors.lastname: Yang
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors.forename: Hsin-Chieh
authors.initials: HC
authors.lastname: Peng
authors.affiliation: School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhou
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Chi-Ta
authors.initials: CT
authors.lastname: Lee
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.
authors.forename: Shixiong
authors.initials: S
authors.lastname: Bao
authors.affiliation: Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu, 30013, Taiwan.
authors.forename: Yi-Hsien
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, National Tsing Hua University , Hsinchu, 30013, Taiwan.
authors.forename: Jenn-Ming
authors.initials: JM
authors.lastname: Wu
authors.affiliation: The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University , Atlanta, Georgia 30332, United States.|School of Chemistry and Biochemistry, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.|School of Chemical and Biomolecular Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States.
authors.forename: Younan
authors.identifier: 0000-0003-2431-7048
authors.initials: Y
authors.lastname: Xia
keywords: Nanocrystal synthesis; kinetic model; precursor reduction; seed-mediated growth