A high yield synthesis of ligand-free iridium oxide nanoparticles with high electrocatalytic activity

Yixin Zhao, Emil A. Hernandez-Pagan, Nella M. Vargas-Barbosa, Jennifer L. Dysart, Thomas E. Mallouk

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206 Scopus citations

Abstract

Stable blue suspensions of 2 nm diameter iridium oxide (IrO x·nH2O) nanoparticles were obtained by hydrolyzing IrCl62- in base at 90 °C to produce [Ir(OH) 6]2- and then treating with HNO3 at 0 °C. UV-visible spectra show that acid condensation of [Ir(OH)6] 2- results in quantitative conversion to stable, ligand-free IrO x·nH2O nanoparticles, which have an extinction coefficient of 630 ± 50 M-1cm-1 at 580 nm. In contrast, alkaline hydrolysis alone converts only 30% of the sample to IrO x·nH2O at 2 mM concentration. The acidified nanoparticles are stable for at least one month at 2 °C and can be used to make colloidal solutions between pH 1 and 13. At pH 7 and above, some hydrolysis to form [Ir(OH)6]2- occurs. Uniform IrOx ·nH2O electrode films were grown anodically from pH 1 solutions, and were found to be highly active for water oxidation between pH 1 and 13.

Original languageEnglish (US)
Pages (from-to)402-406
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume2
Issue number5
DOIs
StatePublished - Mar 3 2011

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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    Zhao, Y., Hernandez-Pagan, E. A., Vargas-Barbosa, N. M., Dysart, J. L., & Mallouk, T. E. (2011). A high yield synthesis of ligand-free iridium oxide nanoparticles with high electrocatalytic activity. Journal of Physical Chemistry Letters, 2(5), 402-406. https://doi.org/10.1021/jz200051c