Domino Effect: Gold Electrocatalyzing Lithium Reduction to Accelerate Nitrogen Fixation

Area of Science:

• Electrochemistry
• Materials Science
• Green Chemistry

Background:

• Ammonia (NH3) production via electrochemical nitrogen reduction reaction (NRR) is a key area of green chemistry research.
• The Li-mediated NRR in non-aqueous solutions shows promise but suffers from unclear reaction mechanisms, hindering optimization.
• Understanding the electrocatalytic process is crucial for advancing NRR technology.

Purpose of the Study:

• To elucidate the mechanism of Li-mediated electrochemical NRR using a model catalyst.
• To investigate the role of gold (Au) in enhancing electron transfer kinetics and lithium intermediate formation.
• To provide insights into electrocatalyst design for efficient Li reduction in NRR.

Main Methods:

• Utilized gold-coated carbon fibrous paper (Au/CP) as a model catalyst for electrochemical NRR.
• Employed in-situ X-ray Diffraction (XRD) to confirm the transformation of lithium intermediates during the reaction.
• Analyzed electron transfer kinetics and ammonia yield/Faradaic efficiency.

Main Results:

• In-situ XRD confirmed lithium intermediate transformations during NRR.
• Au significantly improved electron transfer, promoting metallic Li formation and accelerating NRR.
• Achieved a high Faradaic efficiency of 34.0% and NH3 yield of 50 μg h⁻¹ cm⁻² on Au/CP.

Conclusions:

• The primary step in Li-mediated non-aqueous NRR is electrocatalytic Li reduction.
• Gold catalysts enhance NRR performance by facilitating Li reduction and improving electron transfer.
• This study offers a new strategy for designing electrocatalysts focused on Li reduction for ammonia synthesis.