Overcoming thermal degradation during continuous conversion of water into hydrogen peroxide in a flexible plasma reactor

By control of the nanosecond pulsation, energy input and flow it is possible to achieve commercial-level hydrogen peroxide (H₂O₂) concentrations using only water and plasma in a continuous process while minimizing thermal degradation. Time-resolved ultrafast Optical Emission Spectroscopy was employed to observe the formation of reactive species, shedding light on the underlying mechanisms. This study also highlights the critical role of thermal degradation, which was effectively managed through quenching of the plasma zone. A parametric scan of pulse duration and pulse repetition frequency of the microwave power showed a significant influence on the H₂O₂ formation, whereby the mean power also plays an important role. Additionally, H₂O₂ concentration was found to be inversely proportional to the water flow rate. A maximum concentration of 0.17 wt% was achieved with 1.2 g/kWh based on the absorbed power at a flow rate of 0.2 mL/min. This plasma reactor technology shows promise for further development as a decentralized solution for green chemical synthesis of H2O2.