Increased Oxygen Vacancies in CeO₂ for Improved Electrocatalytic Nitrogen Reduction Performance

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical nitrogen fixation offers a sustainable route to ammonia production.
• Developing efficient electrocatalysts remains a key challenge.
• Oxygen vacancies in CeO2 can enhance conductivity and catalytic activity.

Purpose of the Study:

• To synthesize and evaluate CeO2 with high oxygen vacancy concentration for electrochemical nitrogen reduction.
• To investigate the effect of oxygen vacancy concentration on ammonia synthesis.

Main Methods:

• A two-step pyrolysis strategy of Ce metal-organic frameworks (MOFs) was employed to create high oxygen vacancy CeO2 (H-CeO2).
• Comparison with low oxygen vacancy CeO2 (L-CeO2) synthesized via one-step pyrolysis.
• Electrochemical nitrogen reduction reaction (NRR) performance was assessed.

Main Results:

• H-CeO2 demonstrated a high NH3 yield rate of 25.64 μg h⁻¹ mg⁻¹cat at -0.5 V vs RHE.
• A notable Faradaic efficiency (FE) of 6.3% was achieved at -0.4 V vs RHE.
• The high oxygen vacancy concentration significantly improved catalytic performance.

Conclusions:

• CeO2 with high oxygen vacancy concentration is a promising electrocatalyst for efficient ammonia synthesis.
• The two-step pyrolysis of Ce-MOFs is an effective strategy for fabricating advanced NRR electrocatalysts.
• This work contributes to sustainable ammonia production through electrocatalysis.