Direct conversion of N₂ and O₂: status, challenge and perspective

Area of Science:

• Chemical Engineering
• Materials Science
• Sustainable Chemistry

Background:

• Nitrogen (N₂) and oxygen (O₂) are essential atmospheric gases.
• Direct synthesis of nitrogen oxides and C-N-O organics from N₂ and O₂ is desirable but hindered by the strong N≡N triple bond.
• Current industrial processes often rely on ammonia (NH₃) as an intermediate, exemplified by the Haber-Bosch process.

Purpose of the Study:

• To review the current status and challenges in the direct conversion of N₂ and O₂, and C-containing molecules.
• To provide a comprehensive understanding of various conversion techniques.
• To identify future research directions and stimulate innovation in the field.

Main Methods:

• Review of existing literature on thermochemical, plasma, electrochemical, ultrasonic, and photochemical conversion methods.
• Analysis of the scientific and engineering challenges associated with direct N₂ and O₂ conversion.
• Exploration of selective synthesis pathways for high-value C-N-O organics.

Main Results:

• Significant efforts have been made using diverse techniques to achieve direct N₂ and O₂ conversion.
• The extreme energy requirement due to the stable N≡N triple bond remains a major hurdle.
• Selective synthesis of complex organic molecules directly from N₂ and O₂ is highly challenging.

Conclusions:

• Direct conversion of N₂ and O₂ offers a tantalizing alternative to traditional ammonia-based routes.
• Overcoming the energy barrier and achieving selectivity are critical for practical application.
• Further research and interdisciplinary collaboration are needed to address the scientific and engineering challenges.