Electrocatalytic activity of core-shell Au@Pt nanoparticles for the hydrogen oxidation reaction

The hydrogen oxidation reaction (hor) was studied for the first time on core-shell Au@Pt nanoparticles. They were dispersed on a rotating gold disc, with four different values of the active area factor (0.03 < faa < 2). The experimental current-overpotential dependences on steady state for the hor were obtained at a rotation rate of 2500 rpm. The elementary kinetic parameters were evaluated and compared with previous results obtained for platinum nanoparticles. It can be concluded that the substitution of the core of a Pt nanoparticle by Au would lead to a slight decrease of the reaction rate of the Tafel step (chemical), but it would not affect the charge transfer steps. Thus, the electrocatalytic activity of the Au@Pt nanoparticles is slightly lower than that of Pt nanoparticles at low overpotentials, but they are equal for η > 0.20 V.