Electrocatalytic dinitrogen reduction reaction on silicon carbide: a density functional theory study.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical nitrogen fixation is crucial for sustainable ammonia production.
• Developing efficient, metal-free electrocatalysts for nitrogen reduction under ambient conditions remains a challenge.
• Renewable energy integration necessitates catalysts that operate effectively with intermittent power sources.

Purpose of the Study:

• To investigate silicon carbide as a potential metal-free electrocatalyst for nitrogen reduction reaction (NRR).
• To computationally assess the performance of Si-terminated and C-terminated silicon carbide surfaces for NRR.
• To explore silicon carbide's potential for advancing ambient electrochemical nitrogen fixation.

Main Methods:

• First-principle calculations were employed to simulate and analyze the catalytic properties of silicon carbide surfaces.
• The study focused on dinitrogen (N2) capture and activation mechanisms on Si and C active sites.
• Hydrogen evolution reaction (HER) suppression was also evaluated.

Main Results:

• Both Si-terminated and C-terminated silicon carbide surfaces demonstrated reactivity for N2 capture and activation.
• The C-terminated surface exhibited an ultralow over-potential of 0.39 V for NRR, outperforming many existing metal catalysts.
• Silicon carbide effectively suppressed the competing hydrogen evolution reaction.

Conclusions:

• Silicon carbide emerges as a highly effective, metal-free catalyst for electrochemical nitrogen reduction.
• The C-terminated surface of silicon carbide presents a promising pathway for low-overpotential nitrogen fixation.
• This work opens new avenues for utilizing Si-based materials in sustainable nitrogen reduction technologies.