title: Tuning the size of gold nanoparticles in the citrate reduction by chloride ions.
abstract: A new approach was developed to control the size of gold nanoparticles in citrate reduction by altering the concentration of chloride ions. The size of the as-prepared gold nanoparticles could be tuned in the range 19-47 nm at a specific molar ratio of citrate and tetrachloroauric acid (5:1) by simply changing the concentration of chloride ions from 0 to 20 mM. UV-visible spectra and TEM observations showed that the increased size of the gold particles was primarily related to the promoted aggregation of the primary gold particles. The aggregation was attributed to their decreased surface charge as the chloride ion concentration in the reaction solutions increased. This approach could also be extended to other reaction systems, for example, the size of gold nanoparticles prepared by NaBH(4) reduction increased from 3 to 12 nm as the chloride ion concentration was increased from 0 to 20 mM.
authors: Contribution from the State Key Laboratory for Supramolecular Structures and Materials, College of Chemistry, Jilin University, Changchun 130012, PR China.
authors: Lili
authors: L
authors: Zhao
authors: Di
authors: D
authors: Jiang
authors: Yue
authors: Y
authors: Cai
authors: Xiaohui
authors: X
authors: Ji
authors: Renguo
authors: R
authors: Xie
authors: Wensheng
authors: W
authors: Yang
mesh_terms: D002712:Chlorides / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D019163:Reducing Agents / Q000737:chemistry
chemical_list: D002712:Chlorides; D007477:Ions; D019163:Reducing Agents; D019343:Citric Acid; D006046:Gold