Atomically Dispersed Mo for Efficient Electrocatalytic Nitrogen Reduction: Nitrogen-Doped Defective Graphene Support

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient electrochemical nitrogen reduction reaction (NRR) is crucial for sustainable ammonia production but remains challenging.
• Atomically dispersed metal catalysts on 2D supports show promise for NRR.

Purpose of the Study:

• Investigate the electrocatalytic performance of Mo-based atomically dispersed metal catalysts (ADMCs) on N-doped defective graphene for NRR.
• Elucidate the underlying reaction mechanisms and identify key factors for high catalytic activity and selectivity.

Main Methods:

• Density functional theory (DFT) computations.
• Ab initio molecular dynamics simulations.
• Calculation of formation energies and limiting potentials.

Main Results:

• Mo atoms anchored on N-doped graphene (Mo_x-N₆-gra) exhibit excellent NRR performance.
• Mo₁-N₆-gra shows high activity (limiting potential -0.23 V) via the distal mechanism and suppresses HER.
• Mo₂-N₆-gra also demonstrates high performance (limiting potential -0.35 V) with different mechanisms.

Conclusions:

• Mo₁-N₆-gra and Mo₂-N₆-gra are highly efficient ADMCs for N₂ fixation.
• N-doping and defect engineering of graphene supports are effective strategies for designing advanced NRR catalysts.
• This study provides a pathway for developing superior ADMC/support combinations for NRR.