Formation rates of hydrogen peroxide and electrode erosion rates for a range of different electrode materials were determined in a gas-liquid pulsed electrical discharge reactor with a high voltage electrode needle in the liquid and a ground electrode suspended in the gas over the liquid. It was found that the H2O2 formation rates and efficiencies did not depend on the electrode material. Electrode erosion from lowest to highest followed the series: nickel chromium, thoriated tungsten, diamond-coated tungsten, stainless steel, tungsten carbide and tungsten copper alloy. Smooth crater-like morphology was found for nickel chromium, titanium and tungsten carbide and a much finer surface structure with small protrusions for the tungsten, tungsten copper and the copper. Doubling the electrode diameter lead to an increase in the H2O2 formation per eroded length by a factor of three but it also decreased the energy efficiency yield of H2O2 by more than 20%.