Non-Noble FeCrO Bimetallic Nanoparticles for Efficient NH₃ Decomposition

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Ammonia is a promising hydrogen carrier due to its high hydrogen content and ease of storage.
• Efficient ammonia decomposition catalysts are crucial for releasing hydrogen without CO2 emissions.
• Developing robust and active catalysts for ammonia decomposition remains a significant challenge.

Purpose of the Study:

• To synthesize and characterize FeCr bimetallic oxide nanocatalysts for high-performance ammonia decomposition.
• To investigate the effect of FeCr metal ratios on catalyst properties and catalytic activity.
• To identify the active species and understand the structure-activity relationship in ammonia decomposition.

Main Methods:

• Synthesis of FeCr bimetallic oxide nanocatalysts using the urea two-step hydrolysis method.
• Characterization using X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and X-ray Absorption Fine Structure (XAFS).
• Evaluation of catalytic activity through ammonia decomposition experiments at various temperatures.

Main Results:

• FeCr bimetallic oxide nanocatalysts with uniform morphology and controlled composition were successfully synthesized.
• The Fe$_{0.75}$Cr$_{0.25}$ catalyst demonstrated superior performance, achieving nearly 100% ammonia conversion at 650 °C.
• XAFS analysis identified Fe metal and FeN in a bcc structure as the active species, with Cr preventing Fe sintering and promoting stable nitride formation.

Conclusions:

• FeCr bimetallic oxide nanocatalysts exhibit excellent catalytic activity for ammonia decomposition.
• The addition of Cr enhances catalyst stability and activity by preventing sintering and facilitating nitride formation.
• This study provides insights into the active catalytic phase, guiding the design of advanced catalysts for industrial ammonia decomposition.