Contributors: Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES); Université de Strasbourg (UNISTRA)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE); Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS); Paul Scherrer Institute (PSI); DLR Institute of Engineering Thermodynamics; German Aerospace Center (DLR); Helmholtz Institute Erlangen Nürnberg for Renewable Energy (IEK-11); Forschungszentrum Jülich GmbH; Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association; Max-Planck-Institut für Eisenforschung GmbH; Max-Planck-Gesellschaft; Electron Microscopy for Materials Science - EMAT (Antwerp, Belgium); Universiteit Antwerpen = University of Antwerpen Antwerpen; Laboratoire de Chimie Physique - Matière et Rayonnement (LCPMR); Institut de Chimie - CNRS Chimie (INC-CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS); Synchrotron SOLEIL (SSOLEIL); Centre National de la Recherche Scientifique (CNRS); Institut de chimie des milieux et matériaux de Poitiers UMR 7285 (IC2MP Poitiers ); Université de Poitiers = University of Poitiers (UP)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Centre National de la Recherche Scientifique (CNRS); Centre Procédés, Énergies Renouvelables, Systèmes Énergétiques (PERSEE); Mines Paris - PSL (École nationale supérieure des mines de Paris); Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL); FCH JU.; European Project: 621237,EC:FP7:SP1-JTI,FCH-JU-2013-1,INSIDE(2014); European Project: 779478,H2020-EU.3.3. - SOCIETAL CHALLENGES - Secure, clean and efficient energy / ,10.3030/779478,PRETZEL(2018)
نبذة مختصرة : International audience ; The use of high amounts of iridium in industrial proton exchange membrane water electrolyzers (PEMWE) could hinder their widespread use for the decarbonization of society with hydrogen. Nonthermally oxidized Ir nanoparticles supported on antimony-doped tin oxide (SnO2:Sb, ATO) aerogel allow decreasing the use of the precious metal by more than 70% while enhancing the electrocatalytic activity and stability. To date, the origin of these benefits remains unknown. Here, we present clear evidence of the mechanisms that lead to the enhancement of the electrochemical properties of the catalyst. Operando near-ambient pressure X-ray photoelectron spectroscopy on membrane electrode assemblies reveals a low degree of Ir oxidation, attributed to the oxygen spill-over from Ir to SnO2:Sb. Furthermore, the formation of highly unstable Ir(III) species is mitigated, while the decrease of Ir dissolution in Ir/SnO2:Sb is confirmed by inductively coupled plasma mass spectrometry. The mechanisms that lead to the high activity and stability of Ir catalysts supported on SnO2:Sb aerogel for PEMWE are thus unveiled.
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