Electrochemical generation of H2O2 in low ionic strength media on gas diffusion cathode fed with air

The electrogeneration of hydrogen peroxide in solution with low ionic strength using a gas diffusion cathode fed with air was investigated by linear sweep voltammetries and bulk electrolyses. The effect of applied current (15-45 mA cm(-2)), solution pH (4-10), temperature (15-60 degrees C) and cell configuration (divided or undivided) on the H2O2 generation rate and current efficiency was evaluated. Experimental results showed that in Na2SO4 0.05 M H2O2 can be produced with a satisfactory efficiency, i.e. 53%. Higher production rate was obtained in a two-compartment cell by increasing current density and pH and by decreasing solution temperature. A much lower efficiency (i.e. 30%) was obtained using the undivided cell, because, under these conditions, electrogenerated hydrogen peroxide was decomposed by anodic oxidation on Pt electrode. (C) 2008 Elsevier Ltd. All rights reserved.