The aim of this paper is to perform the electrosynthesis of polypyrrole/multi-walled carbon nanotube (MWCNT) nanocomposites with different concentration of MWCNT on graphite cathode for the electrogeneration of H2O2 by reducing dissolved oxygen. The results show that cathode modified with nanocomposite with 2.5% w/w MWCNT (GPM-2.5) had highest electrocatalytic activity. In addition, a maximum concentration of H2O2, up to 5.6 mg L1, is achieved under the conditions of 0.55 V (vs. SCE) and pH = 3 after 10 min electrolysis. Furthermore, it is demonstrated that the GPM-2.5 cathode has a high efficiency in decolorization of basic blue 41 by electro-Fenton process
