In Situ Exsolved Co-BaO-La₂O₃ Interface from Barium-Doped Perovskites for Catalyzing Ammonia Decomposition Reaction

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Ammonia decomposition is vital for CO_x-free hydrogen production and nitrogen recycling.
• Non-noble metal catalysts offer cost-effective alternatives but suffer from low activity and poor stability due to sintering.
• Ternary metal-promoter-support interfaces are a promising strategy to enhance catalyst performance.

Purpose of the Study:

• To develop an efficient and durable non-noble metal catalyst for ammonia decomposition.
• To investigate the role of a barium (Ba) promoter in constructing an in situ exsolved Co-Ba/La₂O₃ interface.
• To elucidate the structure-performance relationship for enhanced catalytic activity and stability.

Main Methods:

• Fabrication of Co-Ba/La₂O₃ catalyst using an in situ exsolution method from a La_0.95Ba_0.05CoO₃ perovskite precursor.
• Characterization of the catalyst's interfacial structure and properties.
• Evaluation of catalytic performance for ammonia decomposition at 500°C, including activity and long-term stability tests (200 h).

Main Results:

• The in situ exsolution method successfully constructed an efficient Co-BaO-La₂O₃ interface, outperforming traditional methods.
• The optimized catalyst achieved a high hydrogen production rate of 98.5 mmol H₂ g_cat^-1 h^-1, surpassing most reported Co-based catalysts.
• Excellent catalytic stability was observed over a 200-hour test, attributed to dispersed, anchored Co nanoparticles and strengthened metal-support interactions.

Conclusions:

• The Ba promoter enhances interfacial charge transfer and catalyst basicity, facilitating nitrogen desorption and suppressing hydrogen poisoning.
• The synergistic interface effectively alleviates the activity-stability conflict in non-noble metal catalysts.
• This work presents a new strategy for designing advanced catalysts by constructing efficient exsolved interfaces.