Reforming of ethanol solutions for sustainable H2 production using Ar plasma in bubbles

We investigated plasma reforming of ethanol (EtOH) for sustainable H 2 and syngas production from EtOH-H 2 O solutions (0-100 wt. % EtOH) using non-thermal plasma in Ar bubbles. The addition of salts (NaCl, CaCl 2 , or FeCl 2 ) increases the initial electrical conductivity and is associated with enhanced initial H 2 production energy yield. The main products are H 2 and CO, with their highest selectivity achieved at EtOH concentrations between 4 and 44 wt. % (H 2 product selectivity ∼82 % and CO ∼67 %, among carbon-containing products). C 2 H 2 , C 2 H 4 and CH 4 were also produced (maximum C-based selectivity of 25 %). To better understand the experimental findings, we investigated the plasma-driven chemistry in the gas bubbles and its correlation with the gas temperature using a chemical kinetics model, revealing the underlying reaction pathways and the key role of radicals as initiators. Overall, our results show that H 2 production is most efficient at low EtOH concentrations (4-25 wt. %), supporting the direct utilization of bioethanol.