Possible role of nanobubbles in the pulsed plasma production of hydrogen

Submerged dc plasma generated by nanosecond pulses in ethanol and methanol mixtures with water confirmed efficient production of the hydrogen synthesis gas H 2 + CO. The comparison of ethanol and methanol was made for their 35% contents in water. The methanol electrolyte exhibited about 25% more efficient production of synthesis gas compared with ethanol. Tests with 9 ns 9 kV negative dc pulses at the average power of 10 W confirmed production of up to 0.5 l/min of the synthesis gas with over 65% content of H 2 . In both electrolytes the experiments indicated important role of small gas bubbles in the process. The bubbles were evidently generated by very short streamers formed during the dc pulses. The extraordinary properties of small bubbles, particularly those with submicron sizes, could explain the efficient production of the hydrogen rich gas. • Nanosecond pulses in water with ethanol or methanol produced synthesis gas H 2 +CO. • Negative 9ns pulses at average power of 10W produce over 0.5 l/min gas with 65% H 2 . • A lowest energy consumption of 4.7 kWh/kg H 2 was possible in methanol electrolyte. • Gas production was about 25% higher in methanol-based electrolyte than in ethanol. • Submicron gas bubbles generated by streamers appear to be important in the process.