Synergistic Electrocatalytic N₂ Reduction over Asymmetric Heteronuclear Dual Ru-Fe Sites

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry

Background:

• Single-atom catalysts (SACs) face scaling limitations in multi-intermediate reactions like electrocatalytic nitrogen reduction (eNRR).
• Developing catalysts with precisely controlled active sites is crucial for overcoming these challenges.

Purpose of the Study:

• To design and synthesize a heteronuclear dual-atom catalyst with asymmetric coordination for improved eNRR performance.
• To investigate the synergistic mechanism between different metal sites in eNRR.

Main Methods:

• Synthesis of N,S-codoped Ti3C2Tx nanosheets decorated with heteronuclear Ru-Fe sites (Fe1-N^S-Ru1/Ti3C2Tx).
• Advanced characterization techniques to verify the asymmetric coordination structure.
• Electrocatalytic performance testing for eNRR, including NH3 yield rate and Faradaic efficiency.
• Experimental and theoretical studies (e.g., DFT calculations) to elucidate the catalytic mechanism.

Main Results:

• The Fe1-N^S-Ru1/Ti3C2Tx catalyst exhibited an NH3 yield rate of 32.8 µg h-1 mg-1cat at -0.55 V and 47.1% Faradaic efficiency at -0.25 V.
• Performance surpassed homonuclear analogues by 3.2-fold in activity and 3.0-fold in selectivity.
• Verified unique asymmetric coordination with Ru and Fe individually coordinated to N and S atoms, interconnected via bridging atoms.
• Identified a synergistic mechanism: Ru sites facilitate H2O dissociation for protons, while Fe sites activate N2, decoupling proton supply and N2 activation.

Conclusions:

• The designed heteronuclear dual-atom catalyst effectively overcomes the scaling relationship limitations in eNRR.
• The asymmetric coordination and synergistic electronic interactions between Ru and Fe sites significantly enhance catalytic activity and selectivity.
• This work provides a new strategy for designing advanced single-atom catalysts for efficient ammonia synthesis.