Direct Synthesis Of Hydrogen Peroxide Via Hydrogen-Oxygen Plasma In Low Breakdown Voltage

Hydrogen peroxide (H2O2) is an important green-oxidant. It’s demand will increase rapidly due to the sustainable development strategy and green chemistry toute. Therefore, the development of a simple, efficient and environmental process for the H2O2synthesis is of great significant. Recently, the direct synthesis of H2O2via hydrogen-oxygen plasma using the self-designed double dielectric barrier discharge (DDBD) reactor has been studies systematically in our laboratory. Under ambient conditions, high concentration and purity H2O2aqueous solution without any catalysts or solvents is obtained. However, the high breakdown voltage and low energy efficiency of H2O2synthesis greatly restrict the further research and application of H2O2synthesis with H2/O2plasma method. In order to solve the above problems, we have studied the influence of inert gases (N2, He and Ar), negative pressure and concentration of O2on the breakdown voltage and energy efficiency of H2O2synthesis. The following results have been obtained:1. The different inert gases (N2, He and Ar) have significant effects on H2O2synthesis. He and Ar, as additive gas, not only decreases the breakdown voltage, but also increases the energy efficiency of H2O2synthesis. However, when N2is additive gas, the breakdown voltage has been increased, and the energy efficiency of H2O2synthesis reduced greatly.2. The negative pressure has significant effects on H2O2synthesis. With the increase of vacuum, the breakdown voltage reduces gradually, while the energy efficiency increases at first, but decreases later. When combine the negative pressure (-0.02MPa) and additive He (42.5ml-min-1), the breakdown voltage decreases from11.8kV to7.9kV; energy efficiency of H2O2synthesis increases from3.45g-kWh-1to3.69g-kWh-1(100%H2O2). Significantly, the combination of the negative pressure (-0.02MPa) and additive Ar (56.6ml-min-1) decreases the breakdown voltage frome11.8kV to9.1kV, increases the energy efficiency of H2O2synthesis from3.45g-kWh-1to5.12g-kWh-1(100%H2O2).3. Using Ar as additive gas, the influence of O2concentration on H2O2synthesis has been studied systematically in normal pressure and negative pressure. Under normal pressure and additive Ar (56.6ml-min-1) conditions, when O2percentage is15mol%, the energy efficiency increases to8.09g-kWh-1(100%H2O2) with11.6kV breakdown voltage.Under negative pressure (-0.02MPa) and additive Ar (56.6ml-min-1) conditions, when O2percentage is10mol%, the energy dfficiency of H2O2synthesis increases to7.76g-kWh-1(100%H2O2), importantly, and the breakdown voltage decreases to9.5kV.