Perovskite Oxide as A New Platform for Efficient Electrocatalytic Nitrogen Oxidation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic nitrogen oxidation (NOR) offers a sustainable alternative to traditional methods for converting nitrogen (N2) to nitrate (NO3-).
• Current NOR processes suffer from sluggish kinetics, low Faradaic efficiency, and poor nitrate yield rates due to challenges in N2 activation and competing oxygen evolution reactions.

Purpose of the Study:

• To synthesize and investigate an oxygen-vacancy-enriched perovskite oxide, Sr0.9RuO3, as a highly efficient electrocatalyst for the nitrogen oxidation reaction.
• To elucidate the role of oxygen vacancies in enhancing NOR performance.

Main Methods:

• Synthesis of nonstoichiometric perovskite oxide Sr0.9RuO3.
• Electrocatalytic evaluation of NOR performance, including Faradaic efficiency and nitrate yield rate.
• Comparison with stoichiometric SrRuO3.
• Theoretical simulations to understand reaction mechanisms.

Main Results:

• Sr0.9RuO3 exhibited significantly higher oxygen vacancy concentration compared to SrRuO3.
• The Sr0.9RuO3 electrocatalyst achieved a high Faradaic efficiency of 38.6% and a nitrate yield rate of 17.9 μmol mg-1 h-1.
• Theoretical simulations indicated that oxygen vacancies reduce the thermodynamic barrier for N2 activation to *N2OH, the rate-determining step.

Conclusions:

• Oxygen vacancy enrichment in Sr0.9RuO3 is crucial for enhancing electrocatalytic nitrogen oxidation.
• The developed Sr0.9RuO3 catalyst presents a promising pathway for efficient and sustainable nitrate production.