Dendritic copper oxide catalyst engineering weak-polarity Cu-O bond for high-efficiency nitrate electroreduction

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Nitrate reduction reaction (NO3RR) is crucial for ammonia synthesis and water purification.
• Developing efficient, selective, and stable catalysts for NO3RR remains a significant challenge.

Purpose of the Study:

• To develop a dendritic copper oxide catalyst (Cu-B2) for efficient nitrate reduction reaction (NO3RR) to produce ammonia.
• To investigate the catalytic performance, selectivity, and stability of the Cu-B2 catalyst.

Main Methods:

• Electrochemical synthesis of dendritic copper oxide (Cu-B2).
• In situ characterization using attenuated total reflection surface enhanced infrared absorption spectroscopy (ATR-SEIRAS).
• Density functional theory (DFT) calculations to understand reaction mechanisms.

Main Results:

• Cu-B2 catalyst achieved 94% NH3 Faradaic efficiency and a yield of 16.9 mg h-1 cm-2 at -0.6 V.
• In situ reduction formed active Cu0/Cu+ sites while preserving dendritic morphology.
• Cu-B2 demonstrated potential-independent nitrate adsorption and efficient nitrite conversion to ammonia.

Conclusions:

• The dendritic Cu-B2 catalyst exhibits superior activity and durability for NO3RR to ammonia.
• Weaker Cu-O bond polarity in Cu-B2 leads to lower oxidation states of active Cu sites.
• Enhanced NO3- adsorption and conversion of intermediates contribute to improved catalytic performance.