Electrochemical Dissolution of Iridium and Iridium Oxide Particles in Acidic Media: Transmission Electron Microscopy, Electrochemical Flow Cell Coupled to Inductively Coupled Plasma Mass Spectrometry, and X-ray Absorption Spectroscopy Study

transmisijska elektronska mikroskopija info:eu-repo/classification/ddc/540 XAS Ir L3-edge XANES 02 engineering and technology 540 7. Clean energy 01 natural sciences 0104 chemical sciences EXAFS evolucija kisika 13. Climate action Iridium Oxide Par-ticles iridij Electrochemical Dissolution of Iridium ICP-MS elektrokataliza elektrolizer 0210 nano-technology
DOI: 10.1021/jacs.7b08071 Publication Date: 2017-08-15T22:09:05Z
ABSTRACT
Journal of the American Chemical Society 139(36), 12837 – 12846 (2017). doi:10.1021/jacs.7b08071<br/>Iridium based particles as the most promising proton exchange membrane electrolyser electrocatalysts were investigatedby transmission electron microscopy (TEM), and by coupling of electrochemical flow cell (EFC) with online inductivelycoupled plasma mass spectrometer (ICP-MS). Additionally, a thin-film rotating disc electrode (RDE), an identical location transmissionand scanning electron microscopy (IL-TEM and IL-SEM) as well as an X-ray absorption spectroscopy (XAS) studies havebeen performed. Extremely sensitive online time-and potential-resolved electrochemical dissolution profiles revealed that iridiumparticles dissolved already well below oxygen evolution reaction (OER) potentials, presumably induced by iridium surface oxidationand reduction processes, also referred to as transient dissolution. Overall, thermally prepared rutile type IrO2 particles (T-IrO2)are substantially more stable and less active in comparison to as prepared metallic (A-Ir) and electrochemically pretreated (E-Ir)analogues. Interestingly, under OER relevant conditions E-Ir particles exhibit superior stability and activity owing to the alteredcorrosion mechanism where the formation of unstable Ir(>IV) species is hindered. Due to the enhanced and lasting OER performance,electrochemically pre-oxidized E-Ir particles may be considered as the electrocatalyst of choice for an improved low temperatureelectrochemical hydrogen production device, namely a proton exchange membrane electrolyser.<br/>Published by American Chemical Society, Washington, DC<br/>
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