In situ spectroscopic analysis of nanocluster formation.
In situ spectroscopic analysis of nanocluster formation.
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DOI：
10.1002/cphc.200300859
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发表时间：
2004-01
期刊：
影响因子：
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通讯作者：
Jia Wang;H. Boelens;M. Thathagar;G. Rothenberg
中科院分区：
文献类型：
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作者：
Jia Wang;H. Boelens;M. Thathagar;G. Rothenberg
概述了小金属簇在催化中的重要性以及理解溶液中簇过程的问题。提出了一种新的紫外/可见光谱分析方法，并将其应用于原位监测离子还原和簇形成的动力学。该方法基于两种化学计量技术的组合，考虑了整个紫外/可见光谱，并提供比传统“谱带分配”方法更好的解释可能性。对于纳米团簇来说尤其如此，因为它们在通常与其相关的宽等离子体激元带之外也具有显着的光谱贡献。在两种不同的还原剂（硼氢化钠和乙酸四辛基铵）存在下监测钯、金和银离子的还原以及相应簇的形成。虽然发现 Pd2+ 直接还原和聚集，但 Au3+ 还原曲线的光谱分解显示了对应于 Au+ 中间体和 Au0 簇的两个物种。比较了 Pd、Au 和 Ag 的还原和团簇速率，并讨论了通过共还原合成这些金属的多金属团簇的可能性。
The importance of small metal clusters in catalysis and the problems in understanding the clustering process in solution are outlined. A new analysis method for UV/Vis spectra is presented and applied to monitor the kinetics of ion reduction and cluster formation in situ. This method, which is based on a combination of two chemometric techniques, takes into account the entire UV/Vis spectrum and offers better interpretation possibilities than the traditional "band-assignment" approach. This is particularly true for nanoclusters because these have significant spectral contributions also outside the broad plasmon band that is usually associated with them. The reduction of palladium, gold, and silver ions and the formation of the corresponding clusters is monitored in the presence of two different reducing agents, sodium borohydride and tetraoctylammonium acetate. While Pd2+ is found to reduce and cluster directly, the spectral decomposition of the Au3+ reduction profiles shows two species corresponding to the Au+ intermediate and the Au0 clusters. The rates of reduction and clustering for Pd, Au, and Ag are compared and the possibilities of synthesising multimetallic clusters of these metals by coreduction are discussed.