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Nanoscopic Porous Iridium/Iridium Dioxide Superstructures (15 nm): Synthesis and Thermal Conversion by In Situ Transmission Electron Microscopy.
- Source :
- Chemistry - A European Journal; 8/22/2019, Vol. 25 Issue 47, p11048-11057, 10p
- Publication Year :
- 2019
-
Abstract
- Porous particle superstructures of about 15 nm diameter, consisting of ultrasmall nanoparticles of iridium and iridium dioxide, are prepared through the reduction of sodium hexachloridoiridate(+IV) with sodium citrate/sodium borohydride in water. The water‐dispersible porous particles contain about 20 wt % poly(N‐vinylpyrrolidone) (PVP), which was added for colloidal stabilization. High‐resolution transmission electron microscopy confirms the presence of both iridium and iridium dioxide primary particles (1–2 nm) in each porous superstructure. The internal porosity (≈58 vol%) is demonstrated by electron tomography. In situ transmission electron microscopy up to 1000 °C under oxygen, nitrogen, argon/hydrogen (all at 1 bar), and vacuum shows that the porous particles undergo sintering and subsequent compaction upon heating, a process that starts at around 250 °C and is completed at around 800 °C. Finally, well‐crystalline iridium dioxide is obtained under all four environments. The catalytic activity of the as‐prepared porous superstructures in electrochemical water splitting (oxygen evolution reaction; OER) is reduced considerably upon heating owing to sintering of the pores and loss of internal surface area. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09476539
- Volume :
- 25
- Issue :
- 47
- Database :
- Complementary Index
- Journal :
- Chemistry - A European Journal
- Publication Type :
- Academic Journal
- Accession number :
- 138204342
- Full Text :
- https://doi.org/10.1002/chem.201901623