In Situ Exsolved FeRu Nanoparticles-Enhanced Biomimetic Electrode for Intermediate Temperature Ammonia Synthesis and...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Ammonia (NH3) is a crucial chemical feedstock and hydrogen carrier.
• The Haber-Bosch process for ammonia synthesis is energy-intensive and generates significant carbon emissions.
• There is a critical need for sustainable and efficient ammonia production methods operating under moderate conditions.

Purpose of the Study:

• To demonstrate and simulate the electrochemical synthesis of ammonia using a biomimetic electrode in a protonic ceramic electrochemical cell (PCEC).
• To design and implement advanced electrode materials inspired by nitrogenase for enhanced nitrogen (N2) activation and reduction.
• To investigate the performance and stability of the developed system for ammonia production.

Main Methods:

• Rational design of FeMo-based electrodes integrated with in situ exsolved FeRu nanoparticles, mimicking nitrogenase active centers.
• Electrochemical synthesis of ammonia within a protonic ceramic electrochemical cell (PCEC).
• Multiphysics simulations to understand reaction kinetics and identify limiting factors.

Main Results:

• The biomimetic electrode achieved a high ammonia synthesis rate of 4.06 × 10^-10 mol s^-1 cm^-2 at 500 °C and 0.2 V.
• The electrode demonstrated excellent stability, maintaining performance over 100 hours of operation.
• Simulations revealed that high temperatures and voltages, not hydrogen evolution reaction (HER), may inhibit ammonia synthesis.

Conclusions:

• The study presents a promising strategy for efficient and sustainable ammonia production via electrochemical synthesis.
• The developed biomimetic electrode and PCEC system offer a viable alternative to traditional ammonia synthesis methods.
• This work expands the catalytic applications of protonic ceramic electrochemical cells.