Enhancing One-Step Methanol Production from Methane in a Double Dielectric Barrier Discharge Reactor with Glow-like Discharge

Abstract

Nonthermal plasma is a promising way to achieve one-step partial oxidation of methane to methanol (MTM) under ambient conditions. Double dielectric barrier discharge (DDBD) possesses a glow-like discharge character to activate inert CH 4 molecules and protect methanol from overoxidation. Herein, we perform an MTM reaction in CH 4 /O 2 plasma in DDBD reactors for the first time, which exhibited the advantages of high methanol selectivity and methanol yield compared to single dielectric barrier discharge (SDBD). Glow-like mode discharge was observed in the DDBD, while filamentary mode discharge was obtained in the SDBD. By varying the discharge length, discharge gap, and discharge power, the performance of MTM was optimized, and outstanding outcomes compared to prior literature were achieved. Kinetic analysis and optical emission spectroscopy (OES) were performed to gain insight into the reaction mechanism of the MTM reaction. It can be deduced that methanol is more likely to be generated in the DDBD, attributed to the high proportion of CH 3 radicals in all CH x radicals, which are capable of producing methanol through collisions with oxygen related radicals. In addition, the low oxidizing ability and the restricted carbon−carbon coupling in the DDBD promote methanol selectivity and yield.