Oxygen Evolution Reaction Dynamics, Faradaic Charge Efficiency, and the Active Metal Redox States of Ni–Fe Oxide Water Splitting Electrocatalysts

Mixed Ni-Fe oxides are attractive anode catalysts for efficient water splitting in solar fuels reactors. Because of conflicting past reports, the catalytically active metal redox state of the catalyst has remained under debate. Here, we report an in operando quantitative deconvolution of the charge injected into the nanostructured Ni-Fe oxyhydroxide OER catalysts or into reaction product molecules. To achieve this, we explore the oxygen evolution reaction dynamics and the individual faradaic charge efficiencies using operando differential electrochemical mass spectrometry (DEMS). We further use X-ray absorption spectroscopy (XAS) under OER conditions at the Ni and Fe K-edges of the electrocatalysts to evaluate…

• DF
  Deutsche Forschungsgemeinschaft
• BF
  Bundesministerium für Bildung und Forschung

  Awards: 03SF0433A, 03SF0523A