Diatomic Active Sites Embedded Graphyne as Electrocatalysts for Ammonia Synthesis

Area of Science:

• Computational materials science
• Catalysis
• Electrochemistry

Background:

• Ammonia (NH3) is crucial for industry and agriculture.
• Electrochemical nitrogen reduction reaction (eNRR) offers a sustainable NH3 synthesis route.
• Current eNRR methods suffer from high overpotential and low Faradaic efficiency.

Purpose of the Study:

• To investigate dual transition metal diatomic catalysts (DACs) anchored on graphyne (GY) as electrocatalysts for eNRR.
• To identify highly active and selective catalysts for ammonia synthesis using theoretical calculations.

Main Methods:

• Density functional theory (DFT) calculations were employed.
• A four-step hierarchical high-throughput screening process was utilized.
• Stability, initial potential, and selectivity were evaluated for catalyst selection.

Main Results:

• Graphyne-anchored DACs exhibited enhanced activity due to better active site exposure.
• 13 eligible catalysts were identified from an initial pool of 325 candidates.
• Mn2@GY showed no onset potential, while Ir2@GY and RhOs@GY had onset potentials of -0.07 V and -0.12 V, respectively.

Conclusions:

• DACs on graphyne are significant for efficient ammonia synthesis.
• The study provides a new paradigm for designing catalysts for eNRR and other reactions.
• Effective charge transfer and orbital interaction between the catalyst and N2 are key to high catalytic activity.