Experimental study on single-mode microwave-induced tungsten wire discharge for NO conversion in NO/N₂ atmosphere

Area of Science:

• Plasma chemistry
• Chemical engineering
• Materials science

Background:

• Nitrogen oxides (NO) are significant air pollutants.
• Effective methods for NO removal are crucial for environmental protection.
• Microwave-induced plasmas offer a promising approach for chemical synthesis and pollutant degradation.

Purpose of the Study:

• To investigate discharge phenomena in microwave-induced tungsten wire discharges.
• To study the effects of various parameters on NO conversion efficiency.
• To understand the reaction mechanisms involved in NO removal.

Main Methods:

• Single-mode microwave-induced tungsten wire discharge.
• Systematic variation of tungsten wire diameter and number, initial NO concentration, gas flow rate, and microwave power.
• Spectral analysis and energy-dispersive X-ray spectroscopy (EDS) for material characterization.

Main Results:

• Intense discharge observed in Ar or N2, weakened in gas mixtures.
• Increased NO conversion with larger wire diameter, more wires, higher microwave power, lower gas flow rate, and lower initial NO concentration.
• Maximum NO conversion of 91.5% achieved under optimal conditions.
• Detection of W, O, and N ions in the discharge zone.
• Formation of tungsten oxides and nitrides on the reaction tube surface.

Conclusions:

• Microwave-induced tungsten wire discharge is effective for NO conversion.
• Parameter optimization is key to maximizing NO removal efficiency.
• Tungsten ions play a role in NO conversion through the formation of tungsten oxides and nitrides.