Size effects and active state formation of cobalt oxide nanoparticles during the oxygen evolution reaction

Abstract Water electrolysis is a key technology to establish CO 2 -neutral hydrogen production. Nonetheless, the near-surface structure of electrocatalysts during the anodic oxygen evolution reaction (OER) is still largely unknown, which hampers knowledge-driven optimization. Here using operando X-ray absorption spectroscopy and density functional theory calculations, we provide quantitative near-surface structural insights into oxygen-evolving CoO x (OH) y nanoparticles by tracking their size-dependent catalytic activity down to 1 nm and their structural adaptation to OER conditions. We uncover a superior intrinsic OER activity of sub-5 nm nanoparticles and a size-dependent oxidation leading to a near-surface…

• DF
  Deutsche Forschungsgemeinschaft

  Awards: 390540038, 2008-390540038-UniSysCat, 388390466-TRR 247, 388390466, EXC 2008-390540038-UniSysCat, Germany's Excellence Strategy-EXC 2008-390540038, 406944504, 406944504-SPP 2080, SPP 2080, TRR 247, EXC 2008-390540038, EXC 2008
• M
  Max-Planck-Gesellschaft
• IM
  International Max Planck Research School for Advanced Methods in Process and Systems Engineering
• HB
  Helmholtz-Zentrum Berlin für Materialien und Energie
• DE
  Deutsches Elektronen-Synchrotron