Breaking linear scaling relations by strain engineering on MXene for boosting N₂ electroreduction.

Area of Science:

• Electrocatalysis
• Materials Science
• Chemical Engineering

Background:

• Nitrogen reduction reaction (NRR) electrocatalysts are crucial for ammonia synthesis.
• Linear scaling relations between intermediates limit catalyst performance.
• Developing highly active and selective NRR catalysts remains a challenge.

Purpose of the Study:

• To introduce strain engineering as a strategy to overcome NRR scaling relations.
• To investigate the effect of strain on NRR mechanisms and intermediate adsorption.
• To design superior NRR catalysts with enhanced activity and selectivity.

Main Methods:

• Theoretical calculations to model strain effects on MXene catalysts.
• Analysis of N2 adsorption configurations and activation mechanisms ('P-P' and 'E-E').
• Evaluation of adsorption energies of key intermediates (NH2NH2**, NH2*).

Main Results:

• Strain engineering successfully breaks linear scaling relations in NRR.
• Opposite variations in N-N bond lengths under strain illuminate different N2 activation pathways.
• Achieved a low limiting potential (UL) of -0.25 V and high Faraday efficiency (FE) on strained MXene.
• Strain-modulated electronic structures were identified as the origin of improved performance.
• Demonstrated the catalytic sustainability of MXene under strain.

Conclusions:

• Strain engineering is an effective approach to design high-performance NRR electrocatalysts.
• This method circumvents the activity-selectivity trade-off, enabling efficient ammonia production.
• Provides fundamental insights into strain effects on catalytic mechanisms.
• Paves the way for rational design of advanced NRR catalysts.