Electrocatalytic nitrate reduction to ammonia via amorphous cobalt boride

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrocatalytic nitrate reduction reaction (NitRR) offers an energy-efficient and green pathway for ammonia synthesis.
• Developing noble metal-free catalysts with high activity and selectivity for NitRR remains a significant challenge.
• Ammonia is a crucial chemical feedstock and energy carrier.

Purpose of the Study:

• To synthesize and evaluate amorphous CoB nanoparticles as a novel electrocatalyst for the nitrate reduction reaction.
• To investigate the performance of CoB nanoparticles in terms of selectivity and yield for ammonia production.
• To understand the underlying mechanism responsible for the enhanced catalytic activity.

Main Methods:

• Amorphous CoB nanoparticles were synthesized using a simple wet chemical reduction method.
• The synthesized CoB nanoparticles were supported on carbon paper.
• Electrocatalytic performance was evaluated by measuring faradaic efficiency and ammonia yield rate for the nitrate reduction reaction.

Main Results:

• Amorphous CoB nanoparticles exhibited high activity and selectivity for electrocatalytic nitrate reduction to ammonia.
• A maximum faradaic efficiency of 94.00 ± 1.67% and an ammonia yield rate of 0.787 ± 0.028 mmol h⁻¹ cm⁻² were achieved.
• Partial electron transfer from Boron to Cobalt was identified as key to optimizing reaction intermediates' adsorption and electron transport.

Conclusions:

• Amorphous CoB nanoparticles are an efficient and cost-effective electrocatalyst for selective nitrate reduction to ammonia.
• The catalyst's performance is attributed to electronic interactions between Co and B, facilitating the reaction pathway.
• This work provides a promising noble metal-free catalyst for sustainable ammonia synthesis via electroreduction.