Balancing N2 Activation in Two-Dimensional Electrides for Ammonia Synthesis

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Two-dimensional (2D) electrides show potential for nitrogen (N₂) activation in ammonia synthesis.
• Structural instability of 2D electrides under reaction conditions hinders catalytic performance.
• Developing robust platforms for efficient N₂ activation is crucial for ammonia production.

Purpose of the Study:

• To design a stable and efficient dual-site catalyst for ammonia synthesis.
• To investigate the mechanism of N₂ activation on 2D electrides.
• To establish a framework for designing advanced 2D electrides for catalysis.

Main Methods:

• Utilized a 2D metal carbide Y₂C electride as a catalyst support.
• Developed a dual-site catalyst with Ni nanoparticles supported on La-doped Y₂C (La-Y₂C).
• Employed Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations.

Main Results:

• The Ni/La-Y₂C catalyst demonstrated high activity (34.6 mmol·g⁻¹·h⁻¹) at 400 °C and 1.0 MPa.
• Identified a scaling relationship between N₂ binding strength and the formation of reactive (N₂)^δ- intermediates.
• Achieved superior performance compared to benchmark catalysts under identical conditions.

Conclusions:

• The robust 2D electride platform facilitates stable and efficient ammonia synthesis.
• Optimized N₂ activation via La-doping in Y₂C enhances catalytic activity.
• The findings provide insights for designing 2D electrides for sustainable ammonia production.