Direct synthesis of hydrogen peroxide solutions in a non-equilibrium plasma torch

From the perspective of industrial sustainability, Hydrogen Peroxide (H2O2) is a highly valued green oxidizing agent. A significant challenge in the industry is the development of more sustainable and decentralized H2O2 synthesis methods beyond the traditional Anthraquinone Auto-oxidation process.1 The goal is to achieve low-cost production across various scales, including small and transportable capacities. One promising area of research is the use of plasmas for the decentralized production of H2O2. In this work, we describe the potential of a microwave plasma reactor for the continuous production of H2O2. The reactor consists of a coaxial torch based on microwaves modulated with nanosecond pulsations, and we directly use argon plasma and water to produce H2O2. The system is represented in Figure 1. Different microwave parameters and quenching conditions have been studied. A scan of the microwave power and frequency of pulsations revealed that the nanosecond pulsations enhanced the H2O2 formation in the milimolar range in comparison with continuous microwave plasma, where only micromolar concentrations were observed. Furthermore, improving the quenching of the plasma-water zone, and using lower liquid flow rates allowed higher H2O2 concentrations up to 15 mM. ... mehrThe residence time of the water in the plasma reaction zone, the increment of contact area between plasma and water and its influence on the H2O2 yield is currently under analysis.