Catalyst-Free Activation and Fixation of Nitrogen by Laser-Induced Conversion

Area of Science:

• Chemical Engineering
• Materials Science
• Sustainable Chemistry

Background:

• Nitrogen (N₂) fixation is challenging due to the strong dinitrogen bond, requiring extreme conditions or complex catalysts.
• Current N₂ fixation methods are often energy-intensive and limited in efficiency.
• Developing sustainable and efficient methods for ammonia and nitrate production is crucial for agriculture and industry.

Purpose of the Study:

• To report a novel, catalyst-free laser-based method for N₂ fixation.
• To investigate the efficiency and mechanism of nitrogen conversion into valuable products like ammonia (NH₃) and nitrate (NO₃⁻).
• To establish a sustainable and green technology for N₂ fixation under ambient conditions.

Main Methods:

• Development and application of laser bubbling in liquids (LBL) for N₂ activation in water (H₂O).
• Utilizing optical emission spectroscopy to detect intermediate plasma.
• Employing isotope tracing to validate the reaction mechanism.

Main Results:

• Achieved efficient conversion of N₂ to NH₃ (max: 4.2 mmol h⁻¹) and NO₃⁻ (0.17 mmol h⁻¹) using LBL.
• Observed NH₃ and NO₃⁻ yields significantly higher (4 orders of magnitude) than current electrocatalysis methods.
• Identified high-temperature plasma and rapid bubble quenching within LBL as key factors for N₂ activation.

Conclusions:

• Laser bubbling in liquids (LBL) is a simple, safe, efficient, and sustainable technology for N₂ fixation.
• LBL enables the direct conversion of renewable feedstocks (H₂O and N₂) into NH₃ and NO₃⁻ under ambient conditions.
• This method opens new prospects for green chemical N₂ fixation, bypassing traditional energy-intensive processes.