Sintering of catalytically active porous iridium/iridium dioxide nanoparticles by in situ TEM heating

Kateryna Loza, Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, Germany
Kevin Pappert, Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, Germany
Marc Heggen, Ernst Ruska-Centre and Peter Gruenberg Institute, Forschungszentrum Juelich GmbH, Juelich, Germany
Matthias Epple, Inorganic Chemistry and Centre for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Essen, Germany

Ir-based heterogeneous catalysts are important for many industrial applications including the hydrogenation of alkenes, aldehydes and ketones (1, 2) and as anode and cathode electrocatalysts in fuel cells (3, 4). Thermal deactivation, i.e. sintering, is an important issue for the loss of catalytic activity (5). This mechanism is particularly important for high temperature processes, like combustion, steam reforming, or automotive exhaust treatment because the surface properties of nanoparticles are critical to the catalytic performance. Here, we report on the dynamic morphological evolution of dispersed porous iridium/iridium oxide nanoparticles (20 nm), prepared by a colloid-chemical route. High-resolution transmission electron microscopy (HRTEM) was performed to characterize the morphology, crystal structure and composition of the nanoparticles at elevated temperature (up to 1000 °C). Our results provide a detailed microscopic insight into the thermal behavior of porous iridium/iridium dioxide nanoparticles.

References
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