Origin of the different behavior of some platinum decorated nanocarbons towards the electrochemical oxidation of hydrogen peroxide

The electrochemical behavior of different platinum-decorated nanocarbons (Pt@C) towards the oxidation of hydrogen peroxide (H2O2) was investigated. Three different types of nanocarbons were considered: i) carbon black, ii) dahlia-like carbon nanohorns and iii) carbon nanotubes, which included both commercial (single-wall and multi-wall) and laboratory prepared (multi-wall) samples. Shape and size distribution of the platinum nanoparticles and morphology of the nanocarbons were analyzed by transmission electron microscopy. Their nanostructure was investigated by micro-Raman spectroscopy, while elemental composition of the samples and chemical bonding states were studied by X-ray photoelectron spectroscopy. Electrochemical behavior towards H2O2 oxidation was evaluated by means of cyclic voltammetry modifying the working screen-printed carbon electrode surface with the prepared Pt@C nanocomposites. Data obtained suggest that the size and dispersion of the Pt nanoparticles play a key role in increasing the sensitivity towards H2O2 detection. Thanks to the presence of smaller and more dispersed platinum particles and of a greater amount of platinum hydroxide, acting as intermediary in the H2O2 oxidation process, Pt@dahlia-like carbon nanohorns result to be the most promising platform for the development of H2O2 electrochemical sensors.