Probing Interfacial Electrochemistry on a Co3O4 Water Oxidation Catalyst Using Lab-Based Ambient Pressure X-ray Photoelectron Spectroscopy

2018 
The design and mechanistic understanding of efficient and low-cost catalysts for the oxygen evolution reaction (OER) are currently the focus of electrochemical water-splitting technology. Herein, we report the chemical transformations on the water-vapor/solid interface and catalytic performance of an OER catalyst consisting of Co3O4 nanoparticles on multiwalled carbon nanotubes (Co3O4–MWCNT). Using a specially constructed electrochemical cell incorporated to the lab-based ambient-pressure X-ray photoelectron spectroscopy (APXPS) to mimic operando conditions, we obtained experimental evidence for the formation of CoO(OH) as the catalytically active phase on a Co3O4–MWCNT OER catalyst. Under water and applied potential conditions, CoO(OH) is formed, enriching the surface of Co3O4 nanoparticles with subnanometer thickness, and oxidizing H2O into O2. However, immediately after the removal of the applied potential, the CoO(OH) phase is converted back to Co3O4. This back-conversion from CoO(OH) to Co3O4 is like...
    • Correction
    • Source
    • Cite
    • Save
    • Machine Reading By IdeaReader
    65
    References
    24
    Citations
    NaN
    KQI
    []