Characteristics and Stability of Pulsed Gas–Liquid Discharge with the Addition of Photocatalysts

Gas–liquid discharge coupling with photocatalysts is an effective approach to enhance the chemical activity of plasma treated liquid. However, the incomplete understanding of the discharge characteristics with the addition of photocatalysts remain. The characteristics of pulsed gas–liquid discharge combining TiO2 or WO3 are studied in this work to address this issue. Results indicate that the addition of photocatalysts significantly promote the discharge, as evidenced by the diagnosis of discharge current, optical emission spectra, concentrations of aqueous species and solution properties. Specifically, the addition of catalysts enhances the discharge current and enrich the emission spectrum. The atomic emission lines O (3p–3s), N (3p–3s) and Hα were also observed with the addition of TiO2, followed by higher content of reactive species in the solution. However, the addition of catalysts makes the discharge more unstable. This study contributes to an improved understanding of the mechanism of gas–liquid discharge coupled with photocatalysts for the improvement in applications.