Chemical Insights into the Formation of Colloidal Iridium Nanoparticles from In Situ X-ray Total Scattering: Influence of Precursors and Cations on the Reaction Pathway.

Mathiesen, Jette K; Quinson, Jonathan; Blaseio, Sonja; Kjær, Emil T S; Dworzak, Alexandra; Cooper, Susan R; Pedersen, Jack K; Wang, Baiyu; Bizzotto, Francesco; Schröder, Johanna; Kinnibrugh, Tiffany L; Simonsen, Søren B; Theil Kuhn, Luise; Kirkensgaard, Jacob J K; Rossmeisl, Jan; Oezaslan, Mehtap; Arenz, Matthias; Jensen, Kirsten M Ø (2023). Chemical Insights into the Formation of Colloidal Iridium Nanoparticles from In Situ X-ray Total Scattering: Influence of Precursors and Cations on the Reaction Pathway. Journal of the American Chemical Society, 145(3), pp. 1769-1782. American Chemical Society 10.1021/jacs.2c10814

[img] Text
jacs.2c10814.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (8MB) | Request a copy

Iridium nanoparticles are important catalysts for several chemical and energy conversion reactions. Studies of iridium nanoparticles have also been a key for the development of kinetic models of nanomaterial formation. However, compared to other metals such as gold or platinum, knowledge on the nature of prenucleation species and structural insights into the resultant nanoparticles are missing, especially for nanoparticles obtained from IrxCly precursors investigated here. We use in situ X-ray total scattering (TS) experiments with pair distribution function (PDF) analysis to study a simple, surfactant-free synthesis of colloidal iridium nanoparticles. The reaction is performed in methanol at 50 °C with only a base and an iridium salt as precursor. From different precursor salts─IrCl3, IrCl4, H2IrCl6, or Na2IrCl6─colloidal nanoparticles as small as Ir∼55 are obtained as the final product. The nanoparticles do not show the bulk iridium face-centered cubic (fcc) structure but show decahedral and icosahedral structures. The formation route is highly dependent on the precursor salt used. Using IrCl3 or IrCl4, metallic iridium nanoparticles form rapidly from IrxClyn- complexes, whereas using H2IrCl6 or Na2IrCl6, the iridium nanoparticle formation follows a sudden growth after an induction period and the brief appearance of a crystalline phase. With H2IrCl6, the formation of different Irn (n = 55, 55, 85, and 116) nanoparticles depends on the nature of the cation in the base (LiOH, NaOH, KOH, or CsOH, respectively) and larger particles are obtained with larger cations. As the particles grow, the nanoparticle structure changes from partly icosahedral to decahedral. The results show that the synthesis of iridium nanoparticles from IrxCly is a valuable iridium nanoparticle model system, which can provide new compositional and structural insights into iridium nanoparticle formation and growth.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Bizzotto, Francesco, Schröder, Johanna, Arenz, Matthias


500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry
000 Computer science, knowledge & systems




American Chemical Society




Pubmed Import

Date Deposited:

19 Jan 2023 08:19

Last Modified:

26 Jan 2023 00:16

Publisher DOI:


PubMed ID:





Actions (login required)

Edit item Edit item
Provide Feedback