Study on the Physical and Chemical Characteristics of DBD: The Effect of N2/O2 Mixture Ratio on the Product Regulation

The chemical product behaviors of dielectric barrier discharge (DBD) in N-2/O-2 gas mixtures are investigated. Besides ozone mode and nitrogen oxides mode, a transitional mode in which O-3 and NO2 coexist is observed. Under higher oxygen content condition, higher applied voltage and lower gas flow rate contribute to the appearance of the transitional mode. To further investigate the physical and chemical characteristics of DBD under different oxygen contents, the energy per area is introduced. It presents a positive relationship with applied voltage and a negative relationship with gas flow rate. And the energy per area of transitional mode is higher than that of ozone mode, but lower than that of nitrogen oxides mode. As the oxygen content rises, the critical energy per area of mode transition increases. Through the analysis of chemical products, it is found that higher oxygen content is beneficial to the generation of O-3. The NO concentration is positively correlated with applied voltage. And the optimum applied voltage for obtaining the maximum NO2 concentration increases with the rise of gas flow rate. With respect to N2O, they are easier to be obtained at higher applied voltage and lower oxygen content under higher gas flow rate condition. And in the case of lower gas flow rate, lower applied voltage and higher oxygen content are beneficial to its generation. Besides, the maximum N2O5 concentration tends to be obtained at 50% oxygen content in the case of lower applied voltage and higher gas flow rate.