Intermediates during the Nucleation of Platinum Nanoparticles by a Reaction with Ethylene Glycol: Operando X-ray Absorption Spectroscopy Studies with a Microfluidic Cell

Sylvia Britto; Christopher M A Parlett; Stuart Bartlett; Joshua D Elliott; Konstantin Ignatyev; Sven L M Schroeder

doi:10.1021/acs.jpcc.2c08749

Intermediates during the Nucleation of Platinum Nanoparticles by a Reaction with Ethylene Glycol: Operando X-ray Absorption Spectroscopy Studies with a Microfluidic Cell

J Phys Chem C Nanomater Interfaces. 2023 May 1;127(18):8631-8639. doi: 10.1021/acs.jpcc.2c08749. eCollection 2023 May 11.

Authors

Sylvia Britto¹, Christopher M A Parlett^{1

2

3

4}, Stuart Bartlett¹, Joshua D Elliott¹, Konstantin Ignatyev¹, Sven L M Schroeder^{1

5

6}

Affiliations

¹ Diamond Light Source Ltd, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K.
² Diamond Light Source, The University of Manchester at Harwell, Didcot, Oxfordshire OX11 0DE, U.K.
³ Department of Chemical Engineering and Analytical Science, The University of Manchester, Manchester M13 9PL, U.K.
⁴ Rutherford Appleton Laboratory, UK Catalysis Hub, Research Complex at Harwell, Harwell, Oxfordshire OX11 0FA, U.K.
⁵ School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, U.K.
⁶ Rutherford Appleton Laboratory, ESPRC Future Continuous Manufacturing and Advanced Crystallisation (CMAC) Hub, Research Complex at Harwell, Harwell, Oxfordshire OX11 0FA, U.K.

Abstract

Using operando X-ray absorption spectroscopy in a continuous-flow microfluidic cell, we have investigated the nucleation of platinum nanoparticles from aqueous hexachloroplatinate solution in the presence of the reducing agent ethylene glycol. By adjusting flow rates in the microfluidic channel, we resolved the temporal evolution of the reaction system in the first few seconds, generating the time profiles for speciation, ligand exchange, and reduction of Pt. Detailed analysis of the X-ray absorption near-edge structure and extended X-ray absorption fine structure spectra with multivariate data analysis shows that at least two reaction intermediates are involved in the transformation of the precursor H₂PtCl₆ to metallic platinum nanoparticles, including the formation of clusters with Pt-Pt bonding before complete reduction to Pt nanoparticles.