Ru doped NiMoO₄ nanoarray as a high-efficiency electrocatalyst for nitrite reduction to ammonia

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalytic reduction of nitrite to ammonia is crucial for nitrogen cycle management and sustainable energy solutions.
• Developing efficient and stable electrocatalysts is key to achieving high yields and selectivity in ammonia synthesis.

Purpose of the Study:

• To synthesize and characterize a novel electrocatalyst for nitrite reduction to ammonia.
• To investigate the performance of the catalyst in a zinc-nitrite battery system.
• To elucidate the mechanism of nitrite reduction using computational methods.

Main Methods:

• Facile hydrothermal synthesis and immersion process for fabricating Ru-doped NiMoO4 nanosheets on nickel foam.
• Electrochemical characterization including ammonia yield and Faradaic efficiency measurements.
• Density functional theory (DFT) calculations to study adsorption, activation, and reaction pathways.

Main Results:

• Optimized 0.01Ru-NiMoO4/NF exhibited high ammonia yield (20249.17 μg h⁻¹ cm⁻²) and Faradaic efficiency (95.56%).
• The catalyst demonstrated excellent performance when assembled into a Zn-NO2⁻ battery, achieving a power density of 13.89 mW cm⁻².
• DFT calculations confirmed efficient adsorption and activation of nitrite by the Ru-doped NiMoO4 with oxygen vacancies.

Conclusions:

• Ru-doped NiMoO4 nanosheets with oxygen vacancies are highly effective electrocatalysts for nitrite reduction to ammonia.
• The developed material shows significant promise for applications in energy storage and nitrogen management.
• The study provides insights into the catalytic mechanism, paving the way for further catalyst design.