Preliminary study on hydrogen peroxide production by pulsed-high voltage discharge in water

The production of hydrogen peroxide by pulsed high voltage discharge between needle-plate electrodes in water was proved. The hydrogen peroxide production increases with the increase of applied voltage, and the decrease of discharge gap and conductivity of the water. With an applied voltage of 40 kV, a gap of 2.0 cm and water conductivity of 2.0 μs/cm the peroxide hydrogen concentration can reach 0.895 mmol/L after 80 min discharging. Low applied voltage, low conductivity of solution and small discharge gap are favorable for the production of hydrogen peroxide per unit electric energy. With an applied voltage of 20 kV, discharge gap of 2.0 cm, conductivity of 2.0 μs/cm, an optimum production of hydrogen peroxide of 21.24 mmol/(kW·h) can be achieved. Mechanism of hydrogen production was discussed as well. Changes of solution caused by discharge were also investigated, including the decrease of pH value and increase of temperature. Temperature change and energy consumption show that part of the energy is transformed into heat. The decrease of pH shows that the hydrogen peroxide is produced by discharge rather than electrolysis.