In-situ structure and catalytic mechanism of NiFe and CoFe layered double hydroxides during oxygen evolution

NiFe and CoFe (MFe) layered double hydroxides (LDHs) are among the most active electrocatalysts for the alkaline oxygen evolution reaction (OER). Herein, we combine electrochemical measurements, operando X-ray scattering and absorption spectroscopy, and density functional theory (DFT) calculations to elucidate the catalytically active phase, reaction center and the OER mechanism. We provide the first direct atomic-scale evidence that, under applied anodic potentials, MFe LDHs oxidize from as-prepared α-phases to activated γ-phases. The OER-active γ-phases are characterized by about 8% contraction of the lattice spacing and switching of the intercalated ions. DFT calculations reveal that the OER proceeds via a…

• PU
  Purdue University
• DF
  Deutsche Forschungsgemeinschaft

  Awards: 390540038, 596/8-1, EXC 2008/1, 388390466, STR 596/12-1, EXC 2008/1 -390540038, STR 596/8-1, EXC 2008
• ES
  European Synchrotron Radiation Facility
• CA
  Chinese Academy of Sciences

  Award: QYZDJ-SSW-SLH054
• BF
  Bundesministerium für Wirtschaft und Energie

  Award: 03EIV041F
• UO
  University of Science and Technology of China
• IM
  International Max Planck Research School for Advanced Methods in Process and Systems Engineering
• OO
  Office of Science
• BE
  Basic Energy Sciences

  Award: DE-SC0010379