Generation of microdischarge plasma in a pore: Effect of the pulse voltage parameters

Porous catalysts have important applications in plasma catalysis processes for nitrogen fixation, chemical synthesis, environmental pollutant treatment, and others. Understanding the generation mechanism of microdischarge in the pores is crucial for designing the catalysts suitable for plasma catalysis processes. In this paper, a two-dimensional fluid model was established to simulate the microdischarge characteristics in a pore at atmospheric pressure, mainly focusing on the effect of pulse voltage parameters, including voltage amplitude, pulse rise time, pulse width and pulse polarity. The results show that the pulse polarity significantly affects the production of microdischarge. Compared with negative pulse voltage, applying positive pulse voltage on the dielectric results in higher gas ionization rate and total ion density, and electron density as well as electron temperature are higher, which can promote the formation of microdischarge in the pore. In addition, high pulse voltage amplitude is more likely to produce microdischarge in a pore, while the pulse rising edge time and pulse width mainly affect electron density and electron energy. With the rise time increasing, the electron density increases significantly, and the electron temperature rises slightly. Moreover, the shorter the pulse width, the higher the electron temperature and electron energy. Higher pulse voltage, shorter pulse rise time and narrower pulse width can result in stronger electric field in and near the pore, benefiting the generation of microdischarge in a pore.