RESUMO
We report the study on the formation of the Cu2[Fe(CN)6] nanocomposite, which was obtained from copper oxide nanoparticles (CuO NPs) and Prussian Blue precursors. UV-vis analysis indicated that Cu2+ ions are released from CuO NPs, while Fe3+ ions are adsorbed onto the structure of CuO due to a sharp increase in zeta potential (from -30 to 0 mV) after the formation of the Cu2[Fe(CN)6]. Moreover, energy dispersive spectroscopy confirmed that Fe3+ ions are trapped in the CuO NPs structure. The CuO/Cu2[Fe(CN)6] nanocomposite exhibited the monoclinic and face-centered cubic phases that correspond to the CuO and Cu2[Fe(CN)6] components. Cyclic voltammetry (CV) for the Nanocomposite modified electrode revealed two well-defined redox couples at -0.073 ((E1/2)1) and 0.665 mV ((E1/2)2), attributed to the conversion of Cu2+ to Cu+ and CuFe2+ CuFe3+ pairs, respectively, which is similar to those in the CuO and Cu2[Fe(CN)6]components. Furthermore, the catalytic activity of the nanocomposite towards hydrogen was investigated through CV, where the reduction of H2O2 led to increased currents for the electrochemical process associated with the first redox pair. In contrast, for isolated materials (CuO NPs and Cu2[Fe(CN)6]), there was no significant increase in the current associated with either redox pair.
