High-Performance Electrochemical NO Reduction into NH₃ by MoS₂ Nanosheet

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis
• Environmental Science

Background:

• The Haber-Bosch process, while crucial for ammonia production, is energy-intensive.
• The global nitrogen cycle is imbalanced due to anthropogenic activities.
• Electrochemical reduction of nitrogen oxides (NOx) to ammonia (NH3) presents a sustainable alternative.

Purpose of the Study:

• To develop an efficient and robust 3D electrocatalyst for NOx to NH3 conversion.
• To investigate the catalytic performance of molybdenum disulfide (MoS2) nanosheets on graphite felt (GF).
• To explore the potential of a Zn-NO battery utilizing this catalyst for ammonia generation.

Main Methods:

• Fabrication of MoS2 nanosheets on graphite felt (MoS2/GF) as a 3D electrocatalyst.
• Electrochemical reduction of NOx to NH3 in an acidic electrolyte.
• Assembly and testing of a proof-of-concept Zn-NO battery device.
• Computational analysis of the catalytic mechanism at the Mo-edge sites.

Main Results:

• The MoS2/GF catalyst achieved a maximal Faradaic efficiency of 76.6% for NH3 production.
• A high NH3 yield of 99.6 μmol cm⁻² h⁻¹ was obtained in acidic electrolyte.
• The Zn-NO battery delivered a power density of 1.04 mW cm⁻² and a significant NH3 yield.
• Computational studies indicated that positively charged Mo-edge sites facilitate NO adsorption and activation.

Conclusions:

• MoS2/GF is an efficient and robust 3D electrocatalyst for NOx to NH3 conversion.
• The developed catalyst and Zn-NO battery system show promise for sustainable ammonia production.
• The catalytic mechanism involves favorable NO adsorption/activation at Mo-edge sites, suppressing competing reactions.