Magnetic field and dielectric beads modulate DBD reduced electric field with discharge homogeneity to realize NOx differential conversion

In this paper, the reduced electric field and the discharge homogeneity of DBD were modulated by the magnetic field and the packed ZrO2 beads. Subsequently, the reduced electric field and the discharge homogeneity on discharge performance, de-NOx efficiency and NOx conversion mechanism were evaluated. The experimental results show that the reduced electric field gradually enhances as the magnetic field increases, promoting de-NOx performance. The discharge homogeneity significantly weakens with the length of packed ZrO2 beads increases, inhibiting the de-NOx performance. Compared to the reactor with the packed ZrO2 beads, the de-NOx efficiency of the reactor with a 0.2 T magnetic field can achieve 87.2 %, an improvement of 39.3 %. Meanwhile, the selectivity of NO2 and N2O are reduced by 18.3 % and 21 %, respectively. The de-NOx mechanisms indicate that the reduced electric field affects the electron collision reactions and the relative rate of the NOx conversion reactions by altering the electron energy distribution. The discharge homogeneity alters the degree of plasma mitigation of exhaust gases by regulating the absolute rate of the NOx conversion reactions. The by-product N2O is mainly dependent on the concentration of NO2 and is less sensitive to N2(A3). This work reveals the differential mechanisms of reduced electric field and discharge homogeneity on de-NOx. [Display omitted] •The optimal de-NOx efficiency reaches 87.2 % at the magnetic field of 0.2 T.•The reduced electric field affects the relative rate of the NOx conversion reactions.•The discharge homogeneity alters the degree of plasma mitigation of NOx.•The dominant particles of N2O generated are N atom and NO2.