Mechanism of Oxygen Evolution Catalyzed by Cobalt Oxyhydroxide: Cobalt Superoxide Species as a Key Intermediate and Dioxygen Release as a Rate-Determining Step

The oxygen evolution reaction (OER) is the performance-limiting half reaction of water splitting, which can be used to produce hydrogen fuel using renewable energies. Whereas a number of transition metal oxides and oxyhydroxides have been developed as promising OER catalysts in alkaline medium, the mechanisms of OER on these catalysts are not well understood. Here we combine electrochemical and in situ spectroscopic methods, particularly operando X-ray absorption and Raman spectroscopy, to study the mechanism of OER on cobalt oxyhydroxide (CoOOH), an archetypical unary OER catalyst. We find the dominating resting state of the catalyst as a Co(IV) species CoO2. Through oxygen isotope exchange experiments, we…

• MO
  Ministry of Science and Technology, Taiwan

  Award: MOST 108-2628-M-002-004-RSP
• HE
  H2020 European Research Council

  Award: 681292
• HM
  H2020 Marie Skłodowska-Curie Actions

  Award: 838367