Deciphering the work function induced local charge regulation towards activating an octamolybdate cluster-based solid...

Area of Science:

• Materials Science
• Electrochemistry
• Green Chemistry

Background:

• Developing robust electrocatalysts for the oxygen evolution reaction (OER) in acidic media is crucial for sustainable green hydrogen production.
• Non-iridium/ruthenium-based electrocatalysts face significant challenges in achieving high efficiency and stability at low pH.

Purpose of the Study:

• To investigate intrinsic electronic and structural modifications in an octamolybdate cluster-based solid activated with reduced graphene oxide (rGO).
• To enhance the conductivity, stability, and activity of the electrocatalyst for acidic OER without using precious metals like Ru or Ir.

Main Methods:

• Activation of [{Cu(pz)₄}₂Mo₈O₂₆]·2H₂O (an octamolybdate cluster-based solid) via room temperature grinding with rGO.
• Characterization of electronic structure, work function, and structural disorder of the composite material.
• Electrochemical testing of the catalyst for acidic OER performance and stability.

Main Results:

• The activated composite exhibited enhanced conductivity and stability compared to pristine polyoxometalates (POMs).
• A low overpotential of 185 mV was achieved at 10 mA cm^-2 for acidic OER.
• The catalyst demonstrated remarkable stability, operating for 24 hours at 100 mA cm^-2.

Conclusions:

• Precise activation of crystalline POMs with conductive non-metallic elements like rGO can yield highly efficient and stable electrocatalysts for water oxidation.
• This approach offers a promising pathway for advancing green hydrogen production by circumventing the reliance on expensive noble metals.