Oxygen-Doped γ-Mo₂N as High-Performance Catalyst for Ammonia Decomposition

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Gamma-molybdenum nitride (γ-Mo2N) is a promising catalyst for ammonia decomposition.
• The effect of oxygen on γ-Mo2N catalyst activity remains largely unexplored.
• Understanding oxygen's role is crucial for optimizing catalyst design.

Purpose of the Study:

• To investigate the influence of oxygen content on the catalytic activity of γ-Mo2N.
• To synthesize and characterize γ-Mo2N catalysts with varying oxygen levels.
• To elucidate the mechanisms behind oxygen's effect on ammonia decomposition.

Main Methods:

• Synthesis of γ-Mo2N catalysts via temperature-programmed nitridation of α-MoO3.
• Characterization of catalysts to determine oxygen content and oxidation states.
• Evaluation of ammonia decomposition activity at 550 °C.

Main Results:

• Synthesized γ-Mo2N catalysts exhibited varying degrees of oxidation.
• High oxygen content γ-Mo2N (HO-γ-Mo2N) demonstrated significantly higher activity.
• HO-γ-Mo2N showed a 3.3 times greater H2 formation rate compared to low oxygen content γ-Mo2N (LO-γ-Mo2N).

Conclusions:

• Oxygen content is a critical factor in γ-Mo2N catalyst performance for ammonia decomposition.
• Higher oxygen content enhances activity through improved ammonia adsorption and activation.
• Oxygen facilitates hydrogen spillover, preventing active site poisoning and boosting overall efficiency.