Nitrogen Fixation by MoSn₃ and MoSn₅ Clusters

Area of Science:

• Heterogeneous catalysis
• Computational chemistry
• Materials science

Background:

• The Haber-Bosch process (HBP) is crucial for global food production but is highly energy-intensive and contributes to greenhouse gas emissions.
• Developing sustainable alternatives for ammonia synthesis is a global priority.
• Molybdenum-doped tin clusters (MoSn3 and MoSn5) have shown potential for nitrogen molecule activation.

Purpose of the Study:

• To investigate the detailed mechanism of nitrogen fixation by MoSn3 and MoSn5 clusters.
• To explore the stepwise reduction of N2 to NH3 on these catalytic surfaces.
• To provide insights for designing efficient and sustainable ammonia synthesis catalysts.

Main Methods:

• Density functional theory (DFT) calculations.
• Wave function analyses.
• Identification of reaction pathways, intermediates, and transition states.

Main Results:

• Molybdenum acts as an effective catalytic center for ammonia synthesis.
• Tin atoms facilitate hydrogen adsorption, mimicking nitrogenase activity.
• Six distinct reaction pathways were identified, detailing the weakening of the N≡N triple bond.
• Key intermediates and transition states were elucidated.

Conclusions:

• MoSn3 and MoSn5 clusters offer a promising pathway for sustainable ammonia synthesis.
• The catalytic mechanism involves hydride formation and sequential weakening of the dinitrogen bond.
• These findings support the rational design of next-generation heterogeneous catalysts for ammonia production.