Controlling Allotropism in Ruthenium Nanoparticles: A Pulsed-Flow Supercritical Synthesis and in Situ Synchrotron X-ray Diffraction Study

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• 作者：Jian-Li Mi ; Yanbin Shen ; Jacob Becker ; Martin Bremholm ; Bo B. Iversen
• 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：11104-11110
• 全文大小：393K
• 年卷期：v.118,no.20(May 22, 2014)
• ISSN：1932-7455

文摘

Ruthenium nanoparticles have been synthesized by a novel pulsed-flow supercritical method using ethanol both as solvent and reducing agent. To improve the understanding of the formation and growth of Ru nanoparticles, the synthesis processes were also studied by in situ synchrotron radiation powder X-ray diffraction (SR-PXRD). Both the face-centered cubic (fcc) structure and the hexagonal close packed (hcp) structure of Ru can be synthesized in phase pure form by controlling the reaction conditions. When Ru(acac)₃ is used as the precursor, fcc Ru is formed at a reaction temperature of 200 掳C, while the hcp structure appears at higher temperatures. For syntheses with RuCl₃ as the precursor, pure hcp Ru forms at all temperatures investigated, but an intermediate, yet unidentified, compound is detected in the reaction process at 200 掳C. Both the pulsed-flow experiments and the in situ SR-PXRD experiments show that the reduction of the RuCl₃ precursor proceeds faster than the reduction of the Ru(acac)₃ precursor. Overall, the pulsed-flow supercritical approach provides a facile, green, and rapid synthesis of Ru nanoparticles with complete control of the allotropy.