Glow Discharge Plasma Electrolysis of Methanol Solutions

Abstract

Non-faradic phenomena were found during the glow discharge plasma electrolysis of methanol solution, and the main products of the reactions induced by the glow discharge plasmas were hydrogen, formaldehyde, monoxide, methane, ethane, propane, sym-trioxane, and water. The chemical yields were affected by the polarity of the glow discharge plasma and supporting electrolytes of the solutions. The gas yield of the anodic glow discharge electrolysis of methanol was 55.90 mol/(mol electrons) when the discharge voltage across the circuit was 700 V and the conductivity of the solution was 11.40 mS·cm-1. The gas yield of the cathodic glow discharge was 707.90 mol/(mol electrons), 12.66 times of the anodic glow discharge gas yield, under the same conditions. The hydrogen concentration in the emission gas of the glow discharge electrolysis was higher than 86% (molar fraction). The decomposition of methanol molecules induced by the glow discharge plasmas around discharge electrode was similar to those induced by corona plasmas and dielectric discharge plasmas. Non-faradic phenomena of the glow discharge electrolysis of the methanol solutions were stirred up by the accelerated electrons within the gas sheath around the discharge electrode. Neutral species and electrons excited the methanol molecules on the plasma-electrolyte interface during cathodic glow discharge, while positive ions and neutral species played a more important role to excite the methanol molecules on the plasma-electrolyte interface during anodic glow discharge. The reactions in the liquid phase near the plasma-solution interface were affected by the supporting electrolytes of the solutions.