Reverse the Impact of Le Chatelier's Principle in Two-Electron Air Electroreduction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• High-purity oxygen electrofixation for hydrogen peroxide (H2O2) production is costly due to pre-treatment.
• Direct air electrofixation is challenging because nitrogen (N2) dilutes oxygen (O2) and hinders reaction rates.

Purpose of the Study:

• To develop a catalyst system for efficient direct air electrofixation of H2O2.
• To investigate the mechanism by which nitrogen enhances the catalytic activity.

Main Methods:

• Combined theoretical and experimental analyses.
• Development of a catalyst system based on iron oxide (FeOx) and nickel-metal organic frameworks (Ni-MOF).
• Electrochemical testing for H2O2 yield rate and Faradaic efficiency.

Main Results:

• The FeOx-Ni-MOF catalyst system demonstrated exceptional H2O2 yield rate (262.6 mg h⁻¹ cm⁻²) and Faradaic efficiency (95.61%) using atmospheric air.
• The presence of N2 was found to be beneficial for catalytic activity, contrary to conventional understanding.
• Performance surpassed that of systems using high-purity O2 (184.32 mg h⁻¹ cm⁻², 67.06% efficiency).

Conclusions:

• A synergistic catalyst system utilizing FeOx and Ni-MOF enables efficient direct air electrofixation of H2O2.
• Nitrogen's role in the electrocatalytic process was redefined, showing a positive impact on O2 activation.
• This finding offers a new paradigm for leveraging atmospheric air in electrocatalytic applications, reducing production costs.