Mo-Doped FeP Nanospheres for Artificial Nitrogen Fixation

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• The Haber-Bosch process for ammonia synthesis is energy-intensive and releases CO₂.
• Electrochemical nitrogen (N₂) fixation to ammonia (NH₃) under ambient conditions offers a sustainable alternative.
• Efficient catalysts are needed to overcome the high stability of the N≡N triple bond.

Purpose of the Study:

• To develop and evaluate a novel transition-metal-based catalyst for electrochemical N₂ to NH₃ conversion.
• To investigate the effect of molybdenum (Mo) doping on iron phosphide (FeP) for enhanced catalytic activity.
• To understand the mechanism by which Mo doping improves N₂ activation.

Main Methods:

• Synthesis of Mo-doped FeP nanosphere catalysts.
• Electrochemical characterization including cyclic voltammetry and chronoamperometry.
• Evaluation of catalytic performance using ammonia yield rate and Faradaic efficiency measurements.
• Comparison with undoped FeP catalyst.

Main Results:

• Mo-doped FeP nanospheres demonstrated significant catalytic activity for N₂ to NH₃ conversion.
• Achieved a NH₄⁺ yield rate of 13.1 μg h⁻¹ mg⁻¹ and Faradaic efficiency of 7.49% at -0.3 V and -0.2 V vs RHE, respectively.
• Undoped FeP exhibited weak catalytic performance, highlighting the crucial role of Mo doping.

Conclusions:

• Mo-doped FeP nanospheres are effective catalysts for ambient electrochemical N₂ fixation.
• Mo doping enhances N₂ polarization and facilitates N≡N bond dissociation, improving catalytic performance.
• This catalyst presents a promising pathway for sustainable ammonia production.