A Janus Fe-SnO₂ Catalyst that Enables Bifunctional Electrochemical Nitrogen Fixation

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical nitrogen fixation offers a sustainable route for producing ammonia and other nitrogen compounds.
• The inertness of the nitrogen molecule (N≡N) presents a significant challenge for efficient electrocatalysis at room temperature and atmospheric pressure.
• Developing novel electrocatalysts for both nitrogen reduction (NRR) and nitrogen oxidation (NOR) remains an underexplored area.

Purpose of the Study:

• To design and investigate a new Janus electrocatalyst for highly efficient electrochemical nitrogen reduction reactions (NRR) and nitrogen oxidation reactions (NOR).
• To explore the catalytic mechanism of the designed electrocatalyst for nitrogen fixation using experimental and computational methods.

Main Methods:

• Synthesis of a novel Fe-SnO2 Janus electrocatalyst.
• Electrochemical characterization of the catalyst for NRR and NOR performance evaluation.
• Density Functional Theory (DFT) calculations to elucidate the reaction mechanism and active sites.

Main Results:

• The Fe-SnO2 electrocatalyst achieved a high ammonia yield of 82.7 μg h⁻¹ mg⁻¹ and a Faraday efficiency of 20.4% for NRR.
• The catalyst also exhibited excellent NOR performance, yielding 42.9 μg h⁻¹ mg⁻¹ of nitrate with a Faraday efficiency of 0.84%.
• DFT calculations revealed that oxygen vacancy-anchored single-atom Fe effectively adsorbs and activates N2, lowering the energy barrier for N≡N bond cleavage.

Conclusions:

• The developed Fe-SnO2 Janus electrocatalyst shows significant promise for sustainable nitrogen fixation via electrochemical NRR and NOR.
• The unique structure with oxygen vacancies and single-atom Fe is crucial for enhancing catalytic activity by facilitating N2 activation.
• This work provides a new avenue for designing advanced electrocatalysts for nitrogen-related chemical transformations.