A spinel ferrite catalyst for efficient electroreduction of dinitrogen to ammonia

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic nitrogen reduction reaction (NRR) offers a sustainable route for ammonia synthesis.
• Development of active and stable electrocatalysts is crucial for efficient NRR.
• Spinel ferrites are emerging as promising candidates for NRR applications.

Purpose of the Study:

• To investigate spinel ferrite NiFe2O4 as a novel electrocatalyst for ambient NRR.
• To synthesize and characterize NiFe2O4 nanocubes supported on reduced graphene oxide (NiFe2O4/RGO).
• To evaluate the NRR performance, Faradaic efficiency, and catalytic durability of the developed material.

Main Methods:

• Synthesis of NiFe2O4 nanocubes and their integration with reduced graphene oxide (RGO).
• Electrochemical characterization of NiFe2O4/RGO for NRR.
• Ammonia yield and Faradaic efficiency measurements at -0.5 V vs. RHE.
• Mechanistic studies to identify active sites and reaction pathways.

Main Results:

• NiFe2O4/RGO demonstrated a high ammonia yield of 32.2 μg h-1 mg-1 and a Faradaic efficiency of 9.8% at -0.5 V (RHE).
• The catalyst exhibited excellent catalytic durability over extended operation.
• Surface Fe atoms were identified as the key active sites, promoting N2 adsorption and suppressing hydrogen evolution.

Conclusions:

• NiFe2O4/RGO is a highly effective electrocatalyst for ambient NRR.
• The study highlights the potential of Earth-abundant spinel ferrites for electrochemical nitrogen fixation.
• Findings contribute to understanding catalyst design principles for efficient artificial ammonia synthesis.