Radiolytic control of the size of colloidal gold nanoparticles

Journal Article · Tue Dec 22 04:00:00 EST 1998 · Langmuir

DOI:https://doi.org/10.1021/la981278w· OSTI ID:316334

Henglein, A; Meisel, D ^[1]

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1. Univ. of Notre Dame, IN (United States)

Solutions containing KAu(CN){sub 2} ({approximately}5 {times} 10{sup {minus}4} M) methanol (0.3 M), and nitrous oxide (2.5 {times} 10{sup {minus}2} M) are {gamma}-irradiated in the presence of colloidal gold ({approximately}6 {times} 10{sup {minus}5} M; mean particle size, 15 nm). The hydroxymethyl radicals, {sup {sm_bullet}}CH{sub 2}OH, which are generated in these solutions, reduce Au(I) in Au(CN){sub 2}{sup {minus}}, and the reduced gold is completely deposited on the gold seeds to yield larger particles. The particle growth is followed spectrophotometrically and by electron microscopy. A mechanism is proposed in which the radicals transfer electrons to the gold particles and Au(CN){sub 2}{sup {minus}} is subsequently reduced by the stored electrons directly at the surface of the particles. In further steps of particle enlargement, Au(CN){sub 2}{sup {minus}} is reduced in solutions in which the gold particles synthesized in the preceding step serve as seeds, the result being larger and larger gold particles up to 120 nm. The reduction yield is discussed with respect to side reactions of the radicals, such as mutual deactivation and gold-catalyzed H{sub 2} formation. The radiation chemical method makes it possible to enlarge gold particles to any desired size. The reduction of Au(CN){sub 2}{sup {minus}} in the absence of seeds is also described.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• OSTI ID: 316334
• Journal Information: Langmuir, Journal Name: Langmuir Journal Issue: 26 Vol. 14; ISSN LANGD5; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
40 CHEMISTRY
CYANIDES
DEPOSITION
GAMMA RADIATION
GOLD
GOLD COMPOUNDS
METHANOL
NITROUS OXIDE
PARTICLE SIZE
POTASSIUM COMPOUNDS
RADIOLYSIS
REDUCTION