Boosting Electrocatalytic NO Reduction via Intermediate Adsorption Modulation on Synergistic CuCo Bimetallic Oxide...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Cobalt catalysts are key for electrocatalytic nitric oxide reduction reaction (NORR) to synthesize ammonia, but suffer from poor adsorption capacity.
• Improving NO adsorption and intermediate binding is crucial for efficient ammonia production.

Purpose of the Study:

• To develop a novel bimetallic catalyst with enhanced adsorption properties for NORR.
• To investigate the synergistic effects of copper and cobalt in the catalyst for improved ammonia selectivity and efficiency.

Main Methods:

• Hydrothermal synthesis followed by controlled annealing to create a CuCo bimetallic catalyst (CuCo3Ox-650).
• Electrochemical performance testing for ammonia generation rate and Faradaic efficiency.
• Density-functional-theory (DFT) analysis to understand catalytic mechanisms and electronic structure.
• Operation of a Zn-NO battery with the catalyst for dual functionality assessment.

Main Results:

• CuCo3Ox-650 achieved a high NH3 generation rate (312.1 μmol h-1 cm-2) and Faradaic efficiency (90.8%) at -0.5 V.
• DFT revealed that Cu incorporation enhances NO and intermediate binding by upshifting the d-band center.
• The catalyst effectively suppressed the hydrogen evolution reaction (HER) due to minimized *H accumulation.
• The CuCo3Ox-650 cathode in a Zn-NO battery delivered a peak power density of 5.57 mW cm-2 and ammonia production rate of 438.44 μg h-1 cm-2.

Conclusions:

• The synergistic CuCo bimetallic catalyst significantly enhances NORR for ammonia synthesis.
• The catalyst demonstrates potential for simultaneous energy conversion and environmental remediation applications.
• Optimized electronic structure and adsorption properties are key to the catalyst's superior performance.