Coupling of plasma discharge, bubble dynamics, and CO ₂ conversion in a gas–liquid dielectric bar

Abstract

Plasma‐assisted carbon dioxide (CO ₂ ) conversion in gas–liquid systems provides a potential pathway for carbon utilization under ambient conditions, yet its performance is often constrained by gas–liquid transport. This work investigates CO ₂ conversion in a water‐filled dielectric barrier discharge (DBD) reactor by correlating discharge characteristics, bubble dispersion pattern, and conversion performance. High‐speed visualization reveals that the plasma discharge suppresses bubble coalescence and promotes breakup, shifting the bubble size distribution from a coarse unimodal population to a finer and more dispersed pattern. This transition is accompanied by increased bubble number density, enhanced interfacial renewal, and stronger bubble‐induced flows, thereby intensifying gas–liquid mass transfer. Correspondingly, the apparent gas‐phase CO ₂ removal index reaches approximately 30% at low gas flow rates but decreases markedly with increasing flow rate, where hydrodynamic effects become dominant. The results suggest that conversion in gas–liquid DBD systems is closely associated with plasma‐modified bubble dynamics, providing mechanistic guidance for optimizing plasma‐assisted CO ₂ conversion processes.