Electrodeposited P-Doped CuNi Alloy from Deep Eutectic Solvent for Efficient and Selective Nitrate-to-Ammonia...

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Chemistry

Background:

• Electrochemical nitrate reduction reaction (NO₃RR) is a promising route for sustainable ammonia production.
• Development of highly selective and efficient electrocatalysts is crucial for NO₃RR to ammonia.
• Existing methods often face challenges with selectivity and yield.

Purpose of the Study:

• To synthesize and evaluate phosphorus-doped Cu_0.51Ni_0.49 alloy thin films as electrocatalysts for NO₃RR.
• To investigate the performance of these catalysts in terms of ammonia production rate, Faradaic efficiency, and selectivity.
• To understand the underlying mechanisms contributing to the enhanced catalytic activity.

Main Methods:

• Electrodeposition of P-doped Cu_0.51Ni_0.49 alloy thin films from a deep eutectic solvent (choline chloride-ethylene glycol).
• Electrochemical characterization including cyclic voltammetry and chronoamperometry to assess catalytic performance.
• Density functional theory (DFT) calculations and mechanistic studies to elucidate reaction pathways and electronic properties.

Main Results:

• P-Cu_0.51Ni_0.49 achieved a high ammonia production rate of 1616.94 µg h^-1 cm^-2 at -0.55 V_RHE.
• Excellent ammonia selectivity (97.84%) and Faradaic efficiency (98.38%) were observed at -0.25 V_RHE.
• The doped alloy exhibited superior performance compared to P-Ni and P-Cu, attributed to enhanced conductivity and facile nitrate adsorption.

Conclusions:

• P-doped Cu_0.51Ni_0.49 alloy thin films are highly active and selective electrocatalysts for ammonia synthesis via NO₃RR.
• The enhanced performance is linked to increased electrochemically active sites and favorable kinetics due to electron interactions.
• The material demonstrates good stability in neutral aqueous solutions, making it a viable candidate for sustainable ammonia production.