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SUMMARY:Performance and Durability of Iridium Oxide Catalysts to Enable La
 rge Scale Deployment of Proton Exchange Membrane Water Electrolyzers
DTSTART:20260828T161500
DTEND:20260828T171500
DTSTAMP:20261007T113421Z
UID:6b91b7b8db495456231c505ec5b92b99ee526c1accb696f6407ac2ff
CATEGORIES:Conferences - Seminars
DESCRIPTION:To meet cost targets for gigawatt-scale deployment of proton e
 xchange membrane water electrolyzers (PEMWEs)\, catalyst\, which is iridiu
 m (Ir) use needs to be reduced by about factor of ten to below 0.1 mg/cm2.
  However\, catalyst layer structure for low IrOx catalyst loadings can suf
 fer from poor in-plane electric conductivity and particle-to-particle conn
 ectivity. To study low catalyst loadings a rigorous methodology is needed\
 , where catalyst layer inhomogeneities can be identified before extensive 
 activity and durability studies. Here\, we present a framework for testing
  low loading IrOx catalysts within membrane electrode assembly (MEA)\, whe
 re loading study was conducted using two Ishifuku catalysts having differe
 nt structures: amorphous and crystalline. By varying catalyst loading\, el
 ectrochemical descriptors were obtained such as mass specific activity\, e
 xchange current density\, specific surface charge and others. The change i
 n voltage in kinetic region between various catalyst loadings corresponded
  to Tafel slope\, indicating that the catalyst surface area reduction was 
 the major reason for the activity loss at lower loadings. The amorphous ca
 talyst showed higher activity across all the loadings and current densitie
 s\, lower Tafel slope\, higher surface charge and about 5 times higher mas
 s activity and exchange current density compared to crystalline catalyst. 
 The physical characterization of the two catalysts through x-ray photoemis
 sion spectroscopy (XPS)\, Raman spectroscopy\, BET analysis\, x-ray diffra
 ction (XRD)\, electron imaging reveals the morphological and surface chara
 cteristics for each catalyst. Amorphous Ishifuku catalyst is confirmed to 
 have amorphous structure with high population of µ1 oxygen species on the
  surface that are believed to be responsible for high oxygen evolution rea
 ction (OER) rates. Overall\, here we show that loading study is a necessar
 y first step for catalyst layer characterization with low catalyst loading
 s. Furthermore\, we extend the study for 750 hours durability operation an
 d evaluate crystalline and amorphous catalysts at the end of life. Amorpho
 us catalyst structure shows transformation into crystalline\, where exact 
 mechanisms for such transformation are not yet well understood. This trans
 formation occurs continuously within these 750 hours of testing\, starting
  as soon as within first hours. The transformation is tracked with both cy
 clic voltammetry peaks shift and also periodic evaluation with XRD. This w
 ork highlights the importance of understanding structure to property to pe
 rformance relation of evaluated catalysts to enable durable operation of w
 ater electrolyzers.\n\nProf. Iryna Zenyuk\nProfessor and Chancellor’s Fe
 llow\,\nChemical and Biomolecular Engineering\, University of California I
 rvine\nDirector\, National Fuel Cell Research Center\, University of Calif
 ornia Irvine\nCo-Director\, Engineering + Sustainability Institute\, SPARC
 \, University of California Irvine\nProfessor Zenyuk holds a B.S. (2008) i
 n mechanical engineering from the New York University Tandon School of Eng
 ineering. She continued her studies at Carnegie Mellon University\, where 
 she earned M.S. (2011) and Ph.D. (2013) in mechanical engineering. Zenyuk 
 did her postdoctoral fellowship at Lawrence Berkeley National Laboratory i
 n Electrochemical Technologies Group.\nAt UC Irvine\, Zenyuk’s group wor
 ks on enabling clean energy solutions\, sustainable cement manufacturing a
 nd critical materials recovery by researching hydrogen fuel-cells\, and va
 rious types of electrolyzers. Zenyuk works on design strategy encompassing
  novel materials\, diagnostic tools and device-level testing to understand
  durability and feasibility of novel designs to be translated to industria
 l setting.\nShe is a recipient of the NSF CAREER award (2017)\, Interpore 
 society Fraunhofer Award for Young Researchers (2017)\, Research Corporati
 on for Science Advancement\, Scialog Fellow in Advanced Energy Storage (20
 17-2019)\, Electrochemical Society (ECS) Toyota Young Investigator Award (
 2018)\, UCI Samueli School of Engineering Early Career Faculty Excellence 
 in Research Award (2019) and ECS Energy Technology Division Srinivasan You
 ng Investigator Award (2021)\, UCI Beal Applied Innovations Early Career I
 nnovator of the Year (2021)\, UCI Samueli School of Engineering Mid-Career
  Faculty Excellence in Research Award (2022)\, Bessel Humboldt Research Aw
 ard (2026). Prof. Zenyuk published over 150 journal publications and deliv
 ered more than 150 invited presentations on topics of energy conversion an
 d storage.\nWebpage: https://faculty.sites.uci.edu/zenyuklab/\n\n 
LOCATION:MED 0 1418 https://plan.epfl.ch/?room==MED%200%201418
STATUS:CONFIRMED
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