CoS₂@TiO₂ nanoarray: a heterostructured electrocatalyst for high-efficiency nitrate reduction to ammonia

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Science

Background:

• Nitrate (NO₃⁻) reduction is crucial for the nitrogen cycle.
• Ammonia (NH₃) synthesis via nitrogen electroreduction is energy-intensive.
• Selective electrochemical nitrate reduction offers a sustainable alternative.

Purpose of the Study:

• To develop a highly selective electrocatalyst for nitrate reduction to ammonia.
• To investigate the performance and stability of the novel catalyst system.
• To explore an alternative pathway for ambient ammonia synthesis.

Main Methods:

• Fabrication of cobalt disulfide (CoS₂) nanoparticle decorated titanium dioxide (TiO₂) nanobelt array on a titanium plate (CoS₂@TiO₂/TP).
• Electrochemical characterization of the catalyst for nitrate reduction reaction (NO₃⁻RR).
• Evaluation of ammonia yield, faradaic efficiency, and long-term stability.

Main Results:

• The CoS₂@TiO₂/TP catalyst demonstrated excellent NH₃ production.
• Achieved a high NH₃ yield of 538.21 μmol h⁻¹ cm⁻² at -0.7 V vs. RHE.
• Obtained a superior faradaic efficiency of 92.80% for NH₃ at -0.5 V vs. RHE.
• Exhibited remarkable stability over a 20-hour electrolysis test.

Conclusions:

• The CoS₂@TiO₂/TP catalyst is a highly efficient and selective electrocatalyst for nitrate reduction to ammonia.
• This catalyst presents a promising strategy for sustainable ammonia synthesis and nitrogen cycle management.
• The developed material offers a viable alternative to conventional nitrogen electroreduction methods.