Selective catalytic reduction of NO by CH4 in combination of non-thermal plasma and catalysts

The selective catalytic reduction (SCR) of NO with CH4 was studied in combination of non-thermal plasma and catalysts. Among the series of metal oxides as catalysts, gamma-Al2O3 exerts the highest activity. At 300 degrees C and the discharge power of 4.5 W, the NO conversion reaches 56.5% in the combination of plasma with gamma-Al2O3, much higher than that in pure plasma mode (28.9%). At this temperature, no conversion of NO or CH4 was observed in pure catalytic reaction with gamma-Al2O3 as the catalyst, indicating a synergistic function between the plasma and the catalyst. As further investigation shows, the catalytic activity has inverse correlation with dielectric constant on the whole. The porous structure and surface acidity of the catalysts obviously promote the plasma-assisted SCR of NO with CH4.