Improved nitrogen reduction activity of NbSe₂ tuned by edge chirality

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Sustainable ammonia production is crucial.
• Niobium selenide (NbSe2) nanosheets show promise for nitrogen (N2) electroreduction.
• Previous theoretical calculations did not align with experimental observations for NbSe2 catalysts.

Purpose of the Study:

• To investigate the mechanism behind the high catalytic activity of NbSe2 for N2 electroreduction.
• To identify specific NbSe2 structures that enhance ammonia (NH3) synthesis.
• To reconcile theoretical predictions with experimental results.

Main Methods:

• First-principles calculations were employed to study NbSe2 edges with varying chirality and selenium (Se) vacancies.
• The enzymatic pathway for N2 reduction was assessed.
• Electronic structure analysis was performed to understand N2 activation.

Main Results:

• A pristine zigzag edge of NbSe2 demonstrated efficient N2 electroreduction to NH3 via the enzymatic pathway.
• A low overpotential of 0.45 V was calculated for this process.
• N2 activation was attributed to a back-donation mechanism, supported by electronic structure analysis.

Conclusions:

• NbSe2 edges, particularly pristine zigzag edges, are highly active electrocatalysts for ammonia synthesis.
• Edge chirality significantly influences catalytic performance, offering a route for catalyst optimization.
• The findings provide a theoretical basis for designing advanced NbSe2-based catalysts for sustainable ammonia production.