Continuous Production of Tailored Silver Nanoparticles by Polyol Synthesis and Reaction Yield Measured by X-ray Absorption Spectroscopy: Toward a Growth Mechanism

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• 作者：Jose Enrico Q. Quinsaat ; Andrea Testino ; Sonia Pin ; Thomas Huthwelker ; Frank A. N眉esch ; Paul Bowen ; Heinrich Hofmann ; Christian Ludwig ; Dorina M. Opris
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：May 22, 2014
• 年：2014
• 卷：118
• 期：20
• 页码：11093-11103
• 全文大小：654K
• 年卷期：v.118,no.20(May 22, 2014)
• ISSN：1932-7455

文摘

Two complementary topics are discussed: (i) the continuous production of silver nanoparticles (AgNPs) and (ii) the measurement of reaction yield by X-ray absorption near-edge spectroscopy (XANES). The continuous polyol synthesis of AgNPs in grams amount and in the size range of 7鈥?04 nm was carried out in the segmented flow tubular reactor (SFTR). Particle size was tailored by controlling the synthesis parameters such as temperature, reactant concentrations, and polyvinylpyrrolidone (PVP) molecular weight. The continuous production was tested for 4 h, and the product has shown constant particle size distribution over the whole production time. Reliable continuous production of 2.3 g h^鈥? of 100 nm AgNPs can be achieved with a lab-scale SFTR. The produced particles were fully characterized with respect to size, size distribution, and chemical purity. To better understand the growth mechanism, synchrotron-radiation high-resolution X-ray diffraction, and X-ray absorption spectroscopy data were collected directly on the AgNPs suspension. In particular, from XANES experiments, the conversion yield of Ag⁺ to Ag⁰ was measured. The results are consistent with a two-step process where PVP controls the particle nucleation while growth is ensured by thermally induced ethylene glycol oxidation.