Nitrogen Electroreduction on Borophene-Supported Atomic and Diatomic Transition Metals: Stability, Activity and...

Area of Science:

• Materials Science
• Catalysis
• Computational Chemistry

Background:

• Borophene, a 2D allotrope of boron, offers unique electronic properties for catalysis.
• Nitrogen reduction reaction (NRR) is crucial for ammonia synthesis but faces challenges with catalyst stability and selectivity.
• Previous studies explored single-atom catalysts (SACs) on borophene, but metal aggregation and competing reactions limit their effectiveness.

Purpose of the Study:

• To investigate the binding of transition metals on pristine and defective β12-borophenes.
• To evaluate the catalytic performance of single-atom catalysts (SACs) and diatomic catalysts (DACs) for nitrogen reduction reaction (NRR).
• To identify stable and highly active catalysts for efficient NRR.

Main Methods:

• Density functional theory (DFT) calculations were employed to study metal-borophene interactions.
• Analysis of binding energies, electronic structures, and reaction pathways for NRR and hydrogen evolution.
• Evaluation of catalytic activity through limiting potentials for various SACs and DACs on pristine, single-vacancy (SV), and double-vacancy (DV) borophenes.

Main Results:

• Pristine β12-borophene showed weak metal-borophene interaction, leading to aggregation.
• SACs on SV-defective borophene were ineffective due to competitive hydrogen evolution.
• DV-containing β12-borophene with an 11-membered hole stabilized DACs, enhancing N2 fixation and hydrogenation while suppressing hydrogen evolution.
• V2/β12-DV demonstrated the highest activity for NRR with a low limiting potential of -0.15 V.

Conclusions:

• Defective borophenes, particularly those with double vacancies, are superior supports for NRR catalysts compared to pristine ones.
• Diatomic catalysts exhibit enhanced performance over SACs due to synergistic effects and suppressed side reactions.
• The V2/β12-DV system is a highly promising candidate for efficient and selective nitrogen reduction reaction catalysis.