Constructing Co@TiO₂ Nanoarray Heterostructure with Schottky Contact for Selective Electrocatalytic Nitrate Reduction...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical nitrate reduction reaction (NO3- RR) is a promising sustainable pathway for ammonia (NH3) synthesis and nitrogen cycle regulation.
• Efficient electrocatalysts are crucial for enhancing NH3 selectivity in the multi-electron transfer NO3- RR.

Purpose of the Study:

• To design and investigate a novel Co nanoparticles anchored on TiO2 nanobelt array on titanium plate (Co@TiO2/TP) as a high-efficiency electrocatalyst for NO3- RR.
• To understand the mechanism behind the enhanced catalytic performance using density functional theory (DFT) calculations.

Main Methods:

• Fabrication of Co nanoparticles anchored on TiO2 nanobelt array on a titanium plate (Co@TiO2/TP).
• Electrochemical characterization of the Co@TiO2/TP catalyst for NO3- RR.
• Density functional theory (DFT) calculations to elucidate the electronic structure and reaction mechanism.

Main Results:

• The Co@TiO2/TP electrocatalyst achieved an excellent Faradaic efficiency of 96.7% for NH3 production.
• A high NH3 yield of 800.0 µmol h−1 cm−2 was obtained under neutral conditions.
• The catalyst exhibited remarkable stability over 50 hours of electrolysis.

Conclusions:

• The rational design of Co@TiO2/TP heterostructures, featuring a Schottky junction, promotes NH3 selectivity and yield in NO3- RR.
• DFT calculations confirmed that the built-in electric field at the heterostructure interface accelerates the rate-determining step and enhances NO3- adsorption.
• The Co@TiO2/TP catalyst represents a significant advancement in electrocatalytic ammonia synthesis, offering high efficiency and stability.