Carbon Modified with Vanadium Nanoparticles for Hydrogen Peroxide Electrogeneration

This paper compares the results of two preparation routes for the production of carbon (Vulcan XC 72R) modified with vanadium nanostructured electrocatalysts for hydrogen peroxide (H2O2) electrogeneration using the following mass proportions of vanadium on carbon (V/C): 1, 3, 5, 7, 10, and 13%. Best results for H2O2 electrogeneration were obtained using a V/C sol-gel method (SGM) with 3%, highest ring currents. For oxygen reduction reaction (ORR), using the V/C SGM with 3% and V/C polymeric precursor method (PPM) with 7%, the results of ring currents measured are very high when compared to Vulcan XC 72R. X-ray diffraction (XRD) analysis mainly showed the V2O5 phase. X-ray photoelectron spectroscopy (XPS) results of the V/C PPM 7% and V/C SGM 3% samples highlight the predominance of the V2O5 phase and, for the latter catalyst, a more oxidized carbon surface. For the most promising electrocatalysts, the contact angle was evaluated, showing that the anchoring of the metal in the carbon surface increases the hydrophilicity of the materials. The prepared materials are promising for peroxide electrogeneration mainly due to the synergetic effect of vanadium oxide nanoparticles and acid oxygen species of the carbon, contributing to enhancing catalyst hydrophilicity.