Redox tuning the Weakley-type polyoxometalate archetype for the oxygen evolution reaction

Area of Science:

• Catalysis
• Renewable Energy
• Materials Science

Background:

• Water oxidation is crucial for converting solar energy to chemical fuels.
• Precious metal catalysts (Pt, Ir, Ru) are effective but costly.
• Earth-abundant metal catalysts are needed for sustainable energy systems.

Purpose of the Study:

• To develop and investigate a novel electrocatalyst for water oxidation using earth-abundant metals.
• To tune the catalytic activity by doping molybdenum into a tungsten-based framework.
• To assess the efficiency and stability of the modified catalyst for the oxygen evolution reaction.

Main Methods:

• Synthesis of a molybdenum-doped Weakley sandwich catalyst: [Co4(H2O)2(PW9O34)2]10-.
• Characterization using X-ray crystallography, electrospray ionization mass spectrometry, and inductively coupled plasma optical emission spectrometry.
• Electrochemical evaluation of the catalyst's performance in water oxidation.

Main Results:

• Successful doping of molybdenum into the Weakley sandwich framework was confirmed.
• The Mo-doped catalyst demonstrated water oxidation at a low onset potential.
• A significant reduction in the overpotential for the oxygen evolution reaction by 188 mV was achieved compared to the pure tungsten catalyst.
• The catalyst exhibited no degradation during the reaction, indicating high stability.

Conclusions:

• Molybdenum doping effectively tunes the redox properties of the Weakley sandwich catalyst.
• The developed earth-abundant catalyst offers a promising alternative to precious metals for efficient solar fuel production.
• This approach provides a pathway for designing advanced electrocatalysts for sustainable energy applications.