Characteristics of methane wet reforming driven by microwave plasma in liquid phase for hydrogen production

Discharge plasma reforming of methane to produce hydrogen has been a hotspot in recent years. At present, there is no report on liquid-phase discharge for methane reforming. In this paper, directly coupled liquid-phase microwave discharge plasma (LPMDP) is used for the first time to realize liquid-phase methane wet reforming to produce hydrogen. When methane gas is injected into the water in the reactor, plasma is generated in the water by microwave discharge. The type and relative intensity of active radicals produced during discharge are detected by emission spectroscopy. Methane gas is introduced into the reactor through two electrode structures. When the microwave power was 900 W, the optimal methane conversion rate reached 94.3%, and the highest concentration of hydrogen reached 74.0%. In addition, through the optimization of the electrode structure, while improving the stability of the plasma system, the higher yield of hydrogen and energy efficiency of hydrogen production were obtained, and the highest energy efficiency of hydrogen production was approximately 0.92 mmol/kJ. This investigation provides a new method for hydrogen production by liquid-phase plasma methane wet reforming.