Low-temperature NOx Selective Reduction by Hydrocarbons on H-Mordenite Catalysts in Dielectric Barrier Discharge Plasma

Toward achieving selective catalytic reduction of NOx by hydrocarbons at low temperatures (especially lower than 200 °C), C2H2 selective reduction of NOx was explored on H-mordenite (H-MOR) catalysts in dielectric barrier discharge (DBD) plasma. This work reported significant synergistic effects of DBD plasmas and H-MOR catalysts for C2H2 selective reduction of NOx at low temperatures (100–200 °C ) and across a wide range of O2 content (0–15%). At 100 °C, NOx conversions were 3.3, 11.6 and 66.7% for the plasma alone, catalyst alone and in-plasma catalysis (IPC) cases (with a reactant gas mixture of 500 ppm NO, 500 ppm C2H2, 10% O2 in N2, GHSV = 12,000 h−1 and input energy density of 125 J L−1), respectively. At 200 °C, NOx conversions were 3.8, 54.0 and 91.4% for the above three cases, respectively. Also, strong signals of hydrogen cyanide (HCN) byproduct were observed in the catalyst alone system by an on-line mass spectrometer. By contrast, almost no HCN was detected in the IPC system.