Mo₂C for electrocatalytic nitrate reduction to ammonia

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic nitrate reduction to ammonia (NRA) presents a dual benefit for sustainable ammonia synthesis and environmental remediation.
• Transition metal carbides are emerging as promising electrocatalysts, but their application in NRA requires further investigation.

Purpose of the Study:

• To develop and evaluate molybdenum carbide (Mo2C) nanoparticles anchored on reduced graphene oxide (Mo2C/RGO) as an efficient and durable electrocatalyst for NRA.
• To elucidate the catalytic mechanism underlying the enhanced NRA performance.

Main Methods:

• Synthesis of Mo2C nanoparticles supported on reduced graphene oxide.
• Electrochemical characterization including cyclic voltammetry and chronoamperometry.
• Ammonia yield and Faradaic efficiency measurements.
• Density functional theory (DFT) calculations to investigate reaction pathways.

Main Results:

• The Mo2C/RGO catalyst exhibited excellent NRA performance, achieving a maximum NH3-Faradaic efficiency of 85.2% and an NH3 yield of 4.8 mg h-1 cm-2.
• The catalyst demonstrated good durability in the electrocatalytic process.
• DFT calculations indicated that surface-terminated Mo sites facilitate nitrate adsorption and promote the NOH hydrogenation pathway.

Conclusions:

• Mo2C/RGO is a highly effective and stable electrocatalyst for NRA.
• The study provides mechanistic insights into the NRA process, highlighting the role of Mo sites and the NOH hydrogenation pathway.
• This work contributes to the development of sustainable ammonia production and nitrate remediation technologies.