NO_x storage and reduction assisted by non-thermal plasma over Co/Pt/Ba/γ-Al₂O₃ catalyst using CH₄ as reductant

NO_x storage and reduction (NSR) technology has been regarded as one of the most promising strategies for the removal of nitric oxides (NOx) from lean-burn engines, and the potential of the plasma catalysis method for NO_x reduction has been confirmed in the past few decades. This work reports the NSR of nitric oxide (NO) by combining non-thermal plasma (NTP) and Co/Pt/Ba/γ-Al₂O₃ (Co/PBA) catalyst using methane as a reductant. The experimental results reveal that the NO_x conversion of NSR assisted by NTP is notably enhanced compared to the catalytic efficiency obtained from NSR in the range of 150 °C–350 °C, and NO_x conversion of the 8% Co/PBA catalyst reaches 96.8% at 350 °C. Oxygen (O₂) has a significant effect on the removal of NO_x, and the NO_x conversion increases firstly and then decreases when the O₂ concentration ranges from 2% to 10%. Water vapor reduces the NO_x storage capacity of Co/PBA catalysts on account of the competition for adsorption sites on the surface of Co/PBA catalysts. There is a negative correlation between sulfur dioxide (SO₂) and NO_x conversion in the NTP system, and the 8% Co/PBA catalyst exhibits higher NO_x conversion compared to other catalysts, which shows that Co has a certain SO₂ resistance.