Chang, SY, Gründer, Y, Booth, SG et al. (8 more authors) (2016) Detection and Characterisation of Sub-Critical Nuclei during Reactive Pd Metal Nucleation by X-ray Absorption Spectroscopy. CrystEngComm, 18 (5). pp. 674-682. ISSN 1466-8033
Abstract
The interfacial reduction of aqueous [PdCl4]2− at the interface with an organic solution of ferrocene has been characterised by X-ray absorption fine structure (XAFS) spectroscopy. Use of a liquid–liquid interface as a model for homogeneous nucleation permits control of the thermodynamic driving force for nucleation, through variation of the [PdCl4]2− and ferrocene concentrations in the bulk of the adjacent phases. We demonstrate that this approach permits characterisation of the system under conditions of (i) no particle nucleation, (ii) fast spontaneous nucleation of stable nanoparticles and (iii) an intermediate state, in which formation of metastable Pd sub-critical nuclei takes place. Analysis of the XAFS spectra in the metastable state revealed a stochastically fluctuating equilibrium in which Pd nuclei are constantly formed and re-dissolved, as evident from oxidation state fluctuations detected by the Pd XAFS. Supersaturation was evidently sufficient to induce nanoparticle formation but insufficient for nuclei to grow beyond the critical cluster size. We were able to maintain a system in this metastable state for several hours. Such sub-critical clusters are predicted by classical nucleation theory, but have not been detected except in liquid-cell TEM imaging and scanning electrochemical microscopy studies.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Royal Society of Chemistry 2015. This is an open access article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Chemical & Process Engineering (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 05 Jan 2016 11:09 |
Last Modified: | 23 Jun 2023 21:57 |
Published Version: | http://dx.doi.org/10.1039/C5CE01883H |
Status: | Published |
Publisher: | Royal Society of Chemistry |
Identification Number: | 10.1039/C5CE01883H |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:93046 |