Plasma activation of methane for hydrogen in microwave liquid discharge by auxiliary gases: a way to realize efficient utilization of resources.

• The effect of auxiliary gases on CH 4 reforming was studied by liquid plasma firstly. • The auxiliary gas can successfully activate of CH 4 and H 2 O to improve H 2 production. • Compared with N 2 , the addition of Ar showed better auxiliary performance. Given the excited state species generated by the discharge gas can activate CH 4 in gas-phase discharge and water in liquid-phase discharge. In this work, to make full use of the activation of auxiliary gases and maximize the energy utilization in liquid-phase discharge, the microwave liquid-phase plasma technology was used to study the activation of the CH 4 -H 2 O system by auxiliary gases for the first time, the photoelectric characteristics of discharge and discharge plasma parameters were analyzed. N 2 and Ar were selected as auxiliary gases. The results showed that auxiliary gas could also activate CH 4 and H 2 O in addition to the effective dissociation of reactants by electron collision, and the discharge gas-phase products were mainly H 2. Compared with the discharge in the pure CH 4 -H 2 O system, under N 2 and Ar atmosphere, the hydrogen production energy efficiency increased by 43.0% and 72.8%, respectively. This difference is mainly related to the selectivity of the active species produced by the two auxiliary gases to the original reactants and radicals. This study provides a simple and efficient method for plasma-assisted CH 4 activation for hydrogen production. [ABSTRACT FROM AUTHOR]