Enhanced nitrate reduction reaction via efficient intermediate nitrite conversion on tunable Cu_xNi_y/NC...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Ammonia (NH3) production is energy-intensive and relies on the Haber-Bosch process.
• Nitrate (NO3-) contamination in wastewater poses environmental and health risks.
• Electroreduction of nitrate offers a sustainable pathway for both ammonia synthesis and nitrate remediation.

Purpose of the Study:

• To develop and investigate novel Cu-Ni catalysts for efficient nitrate electroreduction.
• To elucidate the catalytic mechanism underlying nitrate reduction reaction (NO3-RR).
• To explore the role of composition and structure in catalyst performance.

Main Methods:

• Synthesis of component-controllable Cu-Ni nanoparticles encapsulated in N-doped carbon (Cu_xNi_y/NC).
• Electrochemical evaluation of catalysts for nitrate electroreduction.
• Density functional theory (DFT) calculations to understand reaction mechanisms.

Main Results:

• Cu0.43Ni0.57/NC demonstrated superior performance, achieving 89% nitrate-N removal.
• Optimized Ni alloying lowered energy barriers for the *NO2-to-*NO intermediate, enhancing activity.
• N-doped carbon support improved active site exposure and catalyst durability.

Conclusions:

• Cu-Ni/NC catalysts offer a promising route for efficient nitrate electroreduction.
• Understanding the mechanistic role of Ni alloying is crucial for catalyst design.
• This work provides insights for developing advanced catalysts for NO3-RR.