Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Nanoparticles I
CPP 8.2: Vortrag
Montag, 23. März 2009, 10:45–11:00, ZEU 114
Investigation of nucleation and growth processes of gold nanoparticles via coupled in situ SAXS/XANES — •Jörg Polte1, Friedmar Delißen1, Torsten T. Ahner2, Sergey Sokolov2, Ralph Kraehnert2, Martin Radtke1, Uwe Reinholz1, Heinrich Riesemeier1, Franziska Emmerling1, and Andreas F. Thünemann1 — 1BAM Federal Institute for Materials Research and Testing Richard-Willstätter-Str. 11, 12489 Berlin — 2LIKAT - Leibniz Institute for Catalysis, Richard-Willstätter-Str. 12, 12489 Berlin
Gold nanoparticles (AuNP) are among the most studied nanoscale material due to prospective applications in areas such as medicine, biotechnology and catalysis [1, 2]. To control the size and shape of metal nanoparticles, a detailed understanding of the mechanism and kinetics of precursor reduction and particle growth is essential. We report on a new method to determine in parallel the oxidation state of the reactants as well as the size, number and polydispersity of formed particles in-situ. The method relies on time-resolved XANES and SAXS measurements carried out on sample droplets exposed to synchrotron radiation. Supplemented by in-situ UV-Vis and SEM, the evolution of AuNP during reduction and particle formation was explored using different reducing agent. From the data, a mechanistic scheme is developed explaining the different phases of particle formation and growth, thus providing a basis for improved control over the synthesis process. [1] J. Park, J. Joo, S. G. Kwon, Y. Jang, T. Hyeon, Angewandte Chemie-International Edition 2007, 46, 4630. [2] M. C. Daniel, D. Astruc, Chemical Reviews 2004, 104, 293.