In Situ Observation of Nucleation and Growth Process of Gold Nanoparticles by Quick XAFS Spectroscopy



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Right here, right now: In situ time-resolved quick X-ray absorption fine-structure spectroscopy was used to clarify the formation process of gold nanoparticles (AuNPs) from a toluene solution of HAuCl4 by NaBH4 reduction in the presence of dodecanethiol as a passivant. The spectral analysis revealed that AuNPs are formed by NaBH4 reduction of Au ions via small Au nuclei. A Au4 cluster is proposed as an example of their possible structure (see picture). The analysis also elucidates the time course of the growth of AuNPs.