Efficient and stable noble-metal-free catalyst for acidic water oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient non-noble catalysts for the oxygen evolution reaction (OER) in acidic media is critical for advancing hydrogen production via water splitting.
• Current OER catalysts often suffer from insufficient activity and long-term stability, hindering practical applications.

Purpose of the Study:

• To develop a cost-effective and highly stable non-noble metal catalyst for the oxygen evolution reaction (OER) in acidic electrolytes.
• To investigate the catalytic mechanism and understand the factors contributing to the enhanced performance of the proposed catalyst.

Main Methods:

• Synthesis and characterization of manganese oxybromide (Mn7.5O10Br3).
• Electrochemical evaluation of OER activity and stability in acidic media.
• In situ spectroscopic techniques (Raman, XAS) and density functional theory (DFT) calculations to elucidate the catalytic mechanism.

Main Results:

• Mn7.5O10Br3 demonstrated excellent OER activity with a low overpotential of 295 ± 5 mV at 10 mA cm⁻².
• The catalyst exhibited remarkable stability, maintaining performance for over 500 hours under operating conditions.
• In situ studies and DFT calculations revealed the formation of a self-oxidized surface enhancing electronic transmission and catalytic performance.

Conclusions:

• Manganese oxybromide (Mn7.5O10Br3) is a promising non-noble catalyst for efficient and stable OER in acidic media.
• The self-oxidized surface plays a key role in the high activity and durability of the catalyst.
• This work offers valuable insights for designing advanced non-noble electrocatalysts for water oxidation.