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6CCVD Research

Alternative Supports for Electrocatalysis of the Oxygen Evolution Reaction in Alkaline Media

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2025-06-25
JournalElectrochem
AuthorsGwénaëlle Kéranguéven, Ivan S. Filimonenkov, Thierry Dintzer, Matthieu Picher
InstitutionsInstitut de Chimie, Centre National de la Recherche Scientifique
AnalysisFull AI Review Included

This analysis is prepared for an engineering audience, focusing on the material science and electrochemical performance of alternative catalyst supports for the Oxygen Evolution Reaction (OER) in alkaline media.

Executive Summary

Section titled “Executive Summary”
  • Core Challenge: Conventional carbon supports (like Vulcan XC72) suffer severe degradation (Carbon Oxidation Reaction, COR) under the high anodic potentials required for the Oxygen Evolution Reaction (OER) in alkaline electrolyzers.
  • Alternative Supports Tested: Nanostructured Boron-Doped Diamond (BDD), Tungsten Carbide (WC), and Iron Oxide (Fe3O4) were investigated as high-stability alternatives to Vulcan XC72.
  • Stability Ranking: BDD proved to be the most stable support against anodic degradation, followed by Fe3O4 and WC, both demonstrating significantly lower degradation currents than Vulcan XC72.
  • OER Activity: Co3O4 composites supported on Vulcan, Fe3O4, and BDD showed high Faradaic efficiencies (90-98%) and competitive mass-normalized OER activity, with 29Co3O4ISACVulcan achieving the highest activity (55.7 A g-1oxide at 1.58 V RHE).
  • Durability Confirmation: Three-hour stability tests at 1.66 V vs. RHE confirmed that BDD- and Fe3O4-based composites maintain high stability, whereas Vulcan XC72 and WC composites suffer significant degradation.
  • Methodological Insight: The Rotating Ring-Disc Electrode (RRDE) method was critical for accurately separating the desired OER current from the unwanted support degradation currents, ensuring reliable performance metrics.
  • Synthesis Method: The In Situ Autocombustion (ISAC) method successfully produced highly dispersed Co3O4 nanoparticles (5-10 nm) on the support surfaces, enhancing the number of accessible active sites.

Technical Specifications

Section titled “Technical Specifications”
ParameterValueUnitContext
Electrolyte1 MNaOHAlkaline OER medium.
OER Activity (29Co3O4ISACVulcan)55.7 [54.6]A g-1oxideMass-normalized at 1.58 V RHE (uncorrected [corrected for support degradation]).
OER Activity (26Co3O4ISACFe3O4)24.8 [23.3]A g-1oxideMass-normalized at 1.58 V RHE (uncorrected [corrected]).
OER Activity (16Co3O4ISACBDD)14.2 [12.6]A g-1oxideMass-normalized at 1.58 V RHE (uncorrected [corrected]).
Tafel Slope (26Co3O4ISACFe3O4)48mV dec-1Lowest slope among ISAC composites, indicating favorable kinetics.
Tafel Slope (32Co3O4ISACWCcalc)134mV dec-1High slope, consistent with WC degradation and ohmic limitations.
Support Degradation (Vulcan XC72)500mA g-1Mass-normalized degradation current at 1.58 V RHE.
Support Degradation (BDD)5mA g-1Mass-normalized degradation current at 1.58 V RHE (lowest observed).
Co3O4 Nanoparticle Size (TEM)5-10nmObserved on BDD, WC, and Fe3O4 supports.
BDD BET Surface Area181m2 g-1High surface area mesoporous support.
Fe3O4 Electrical Resistivity0.3mΩ mLow resistivity (magnetite).
WC Electrical Resistivity0.2”Ω mComparable to some metals.
Critical Disc Current Density200”A cm-2Threshold above which O2 bubble formation compromises F.E. measurement.

Key Methodologies

Section titled “Key Methodologies”

  1. Catalyst Synthesis (ISAC): Co3O4-based composites were prepared using the In Situ Autocombustion (ISAC) method.

    • Precursors: Cobalt nitrate (Co(NO3)2) and glycine (NH2CH2COOH).
    • Support Material Addition: Appropriate amounts of BDD, WC, Fe3O4, or Vulcan XC72 were added during the synthesis process.
    • Thermal Treatment: Only the WC composite (32Co3O4ISACWCcalc) required calcination at 300 °C for 30 minutes to ensure the formation of the Co3O4 spinel phase.

  2. Material Characterization:

    • Structure and Phase Purity: X-ray Diffraction (XRD).
    • Morphology and Particle Size: Transmission Electron Microscopy (TEM) and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) mapping.
    • Surface Area and Porosity: N2-physisorption (BET and BJH methods).
    • Composition: Thermogravimetric Analysis (TGA) and X-ray Photoelectron Spectroscopy (XPS).

  3. Electrochemical Testing (RRDE):

    • Setup: Rotating Ring-Disc Electrode (RRDE) in a three-electrode cell (Glassy Carbon disc, Gold ring).
    • Electrolyte: 1 M NaOH, N2-saturated, 1600 rpm rotation rate.
    • Potential Range: Successive potential steps from 1.53 V to 2.03 V vs. RHE (50 or 100 mV increments) for 15 minutes per step.
    • O2 Detection: Ring potential fixed at 0.3 V vs. RHE to detect oxygen reduction reaction (ORR) current, which is proportional to O2 generated at the disc.
    • Loading Control: Oxide loading kept below 40 ”goxide cm-2 to ensure accurate activity measurement and minimize O2 bubble interference.

  4. Stability Assessment:

    • Long-Term Chronoamperometry: Applied constant potential of 1.66 V vs. RHE for 3 hours (for BDD, Fe3O4, and Vulcan composites).
    • Short-Term Chronoamperometry: Applied constant potential of 1.58 V vs. RHE for 30 minutes (for WC composite).

Commercial Applications

Section titled “Commercial Applications”

The research directly addresses the material limitations in electrochemical energy conversion devices operating in harsh alkaline environments.

  • Green Hydrogen Production: The primary application is improving the efficiency and lifespan of Anion Exchange Membrane (AEM) Electrolyzers by providing stable, non-noble metal catalyst supports for the OER anode.
  • High-Stability Electrocatalysis: BDD and Fe3O4 supports are critical for any electrochemical process requiring high anodic stability in alkaline media, such as industrial wastewater treatment or chemical synthesis.
  • BDD Electrode Technology: The superior stability of Boron-Doped Diamond confirms its value as a durable, high-performance electrode material, relevant for specialized electrochemical reactors and sensors.
  • Energy Storage Systems: Materials with high OER activity and stability are essential components in rechargeable metal-air batteries (e.g., zinc-air) and regenerative fuel cells.
  • Transition Metal Oxide Catalysts: The ISAC synthesis route provides a scalable method for producing highly dispersed, nano-sized transition metal oxide catalysts (like Co3O4) on various conductive supports.
View Original Abstract

The anodic stability of tungsten carbide (WC) and iron oxide with a spinel structure (Fe3O4) were compared against similar data for nanostructured, boron-doped diamond (BDD), and the benchmark Vulcan XC72 carbon, in view of their eventual application as alternative supports for the anion exchange membrane electrolyzer anode. To this end, metal oxide composites were prepared by the in situ autocombustion (ISAC) method, and the anodic behavior of materials (composites as well as supports alone) was investigated in 1 M NaOH electrolyte by the rotating ring-disc electrode method, which enables the separation oxygen evolution reaction and materials’ degradation currents. Among all supports, BDD has proven to be the most stable, while Vulcan XC72 is the least stable under the anodic polarization, with Fe3O4 and WC demonstrating intermediate behavior. The Co3O4-BDD, -Fe3O4, -WC, and -Vulcan composites prepared by the ISAC method were then tested as catalysts of the oxygen evolution reaction. The Co3O4-BDD and Co3O4-Fe3O4 composites appear to be competitive electrocatalysts for the OER in alkaline medium, showing activity comparable to the literature and higher support stability towards oxidation, either in cyclic voltammetry or chronoamperometry stability tests. On the contrary, WC- and Vulcan-based composites are prone to degradation.

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2023 - Highly mixed high-energy d-orbital states enhance oxygen evolution reactions in spinel catalysts [Crossref]
  2. 2020 - Boosting the electrochemical water splitting on Co3O4 through surface decoration of epitaxial S-doped CoO layers [Crossref]
  3. 2020 - Ultrafine Co3O4 nanolayer-shelled CoWP nanowire array: A bifunctional electrocatalyst for overall water splitting [Crossref]
  4. 2019 - Carbon materials as additives to the OER catalysts: RRDE study of carbon corrosion at high anodic potentials [Crossref]
  5. 2015 - Synthesis of efficient Vulcan-LaMnO3 perovskite nanocomposite for the oxygen reduction reaction [Crossref]
  6. 2020 - How key characteristics of carbon materials influence the ORR activity of LaMnO3- and Mn3O4-carbon composites prepared by in situ autocombustion method [Crossref]
  7. 2019 - Magnetic resonance study of lightly boron-doped diamond [Crossref]
  8. 2018 - Development of electrochemical applications of boron-doped diamond electrodes [Crossref]
  9. 2020 - Influence of temperature on the electrochemical window of boron doped diamond: A comparison of commercially available electrodes

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