Evidence of Nanobubbles Generated by Plasma Streamers in Nanosecond Pulsed Production of Hydrogen-Rich Synthesis Gas

Abstract

Three alcohols in water were compared in plasma production of the hydrogen-rich synthesis gas H2 + CO. The 9 ns 9 kV negative pulses generated submerged discharges at very low average power of about 10 W, which was enough for the production of about 0.5 L/min synthesis gas containing up to about 65% H2. The fastest production of the gas in all tested liquids required tuning of intense streamer discharges with the formation of small gas bubbles, including those with submicron diameters. The presence of submicron bubbles–nanobubbles was confirmed by high-resolution optical microscopy. Extraordinary properties of nanobubbles can explain the high production efficiency of the hydrogen-rich gas from mixtures of alcohol with water generated by the nanosecond pulsed plasma.