The structure and atomic ordering of Au-Ag nanoparticles grown in the gas phase are determined by a combination of HAADF-STEM, XPS and Refl-XAFS techniques as a function of composition. It is shown consistently from all the techniques that an inversion of chemical ordering takes place by going from Au-rich to Ag-rich compositions, with the minority element always occupying the nanoparticle core, and the majority element enriching the shell. With the aid of DFT calculations, this composition-tunable chemical arrangement is rationalized in terms of a four-step growth process in which the very first stage of cluster nucleation plays a crucial role. The four-step growth mechanism is based on mechanisms of a general character, likely to be applicable to a variety of binary systems besides Au-Ag.
Unravelling the nucleation mechanism of bimetallic nanoparticles with composition-tunable core-shell arrangement / T. Liao, A. Yadav, K. Hu, J. Van Der Tol, S. Cosentino, F. D'Acapito, R.E. Palmer, C. Lenardi, R. Ferrando, D. Grandjean, P. Lievens. - In: NANOSCALE. - ISSN 2040-3364. - 10:14(2018), pp. 6684-6694. [10.1039/c8nr01481g]
Unravelling the nucleation mechanism of bimetallic nanoparticles with composition-tunable core-shell arrangement
C. LenardiWriting – Original Draft Preparation
;
2018
Abstract
The structure and atomic ordering of Au-Ag nanoparticles grown in the gas phase are determined by a combination of HAADF-STEM, XPS and Refl-XAFS techniques as a function of composition. It is shown consistently from all the techniques that an inversion of chemical ordering takes place by going from Au-rich to Ag-rich compositions, with the minority element always occupying the nanoparticle core, and the majority element enriching the shell. With the aid of DFT calculations, this composition-tunable chemical arrangement is rationalized in terms of a four-step growth process in which the very first stage of cluster nucleation plays a crucial role. The four-step growth mechanism is based on mechanisms of a general character, likely to be applicable to a variety of binary systems besides Au-Ag.File | Dimensione | Formato | |
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