Journal Article

FZJ-2019-06514

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Nanoscopic Porous Iridium/Iridium Dioxide Superstructures (15 nm): Synthesis and Thermal Conversion by In Situ Transmission Electron Microscopy

Pappert, K.Extern* ; Loza, K. ; Shviro, M.FZJ* ; Hagemann, U. ; Heggen, M.FZJ* ; Dunin-Borkowski, R.FZJ* ; Schierholz, R.FZJ* ; Maeda, T. ; Kaneko, K. ; Epple, M. (Corresponding author)

2019
Wiley-VCH Weinheim

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Please use a persistent id in citations: http://hdl.handle.net/2128/23728  doi:10.1002/chem.201901623

Abstract: Porous particle superstructures of about 15 nm diameter,consisting of ultrasmall nanoparticles of iridium andiridium dioxide, are prepared through the reduction ofsodium hexachloridoiridate(+IV) with sodium citrate/sodiumborohydride in water. The water-dispersible porous particlescontain about 20 wt% poly(N-vinylpyrrolidone) (PVP), whichwas added for colloidal stabilization. High-resolution transmissionelectron microscopy confirms the presence of bothiridium and iridium dioxide primary particles (1–2 nm) ineach porous superstructure. The internal porosity(58 vol%) is demonstrated by electron tomography. In situtransmission electron microscopy up to 1000 8C underoxygen, nitrogen, argon/hydrogen (all at 1 bar), and vacuumshows that the porous particles undergo sintering and subsequentcompaction upon heating, a process that starts ataround 250 8C and is completed at around 8008C. Finally,well-crystalline iridium dioxide is obtained under all four environments.The catalytic activity of the as-prepared poroussuperstructures in electrochemical water splitting (oxygenevolution reaction; OER) is reduced considerably upon heatingowing to sintering of the pores and loss of internal surfacearea.

Keyword(s): Chemical Reactions and Advanced Materials (1st) ; Chemistry (2nd)

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Contributing Institute(s):

1. Physik Nanoskaliger Systeme (ER-C-1)
2. Grundlagen der Elektrochemie (IEK-9)
3. Elektrochemische Verfahrenstechnik (IEK-14)

Research Program(s):

1. 135 - Fuel Cells (POF3-135) (POF3-135)
2. 131 - Electrochemical Storage (POF3-131) (POF3-131)
3. 134 - Electrolysis and Hydrogen (POF3-134) (POF3-134)
4. DFG project 257727131 - Nanoskalige Pt Legierungselektrokatalysatoren mit definierter Morphologie: Synthese, Electrochemische Analyse, und ex-situ/in-situ Transmissionselektronenmikroskopische (TEM) Studien (257727131) (257727131)
5. 143 - Controlling Configuration-Based Phenomena (POF3-143) (POF3-143)

Appears in the scientific report 2019

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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