Hydrogen production from ethanol by combined microwave discharge plasma and Cu/Zn/Al catalyst

The ethanol solution was reformed by liquid-phase microwave discharge plasma to produce H2-rich syngas. In order to further improve the hydrogen production of syngas after discharge, the method of combining of microwave discharge plasma in liquid (MDPL) and catalyst was proposed for the first time in this paper. The catalyst was Cu/Zn/Al catalyst prepared by thecoprecipitation synthesis method. The catalytic system was placed at the outlet of discharge plasma system, and the hydrogen production of the syngas after Cu/Zn/Al catalysis was used as the catalyst activity evaluation. This study focused on the effect of Cu/Zn/Al catalyst on the syngas after microwave plasma discharge at different catalytic temperatures. The hydrogen production reached the maximum when the catalytic temperature reached 350 °C. At the same temperature, the mass of Cu/Zn/Al catalyst was 1.5 g, the hydrogen production of syngas reached 274.8 mL/min, and the hydrogen production after catalysis was 2.3 times of that before catalysis. The hydrogen production of Cu/Zn/Al catalyzed syngas without ethanol steam was 145.0 mL/min. The hydrogen production of Cu/Zn/Al alone catalyzed ethanol vapor was 14.1 mL/min. It was found that the Cu/Zn/Al catalyst could effectively utilize the excess ethanol vapor in the syngas to produce hydrogen, and no by-products were produced during the catalytic process. Meanwhile, the Cu/Zn/Al catalyst could also utilize other gaseous by-products in syngas to further enhance hydrogen production. Therefore, the combination of microwave discharge plasma and Cu/Zn/Al catalyst had a synergistic effect on hydrogen production from ethanol solution, and the synergistic efficiency was up to 72.7%. This method provides an effective solution to further improve the hydrogen production from microwave plasma.