Solid state preparation of carbon-supported PtCa nanoparticles for the oxygen reduction reaction.

PtCa nanoparticles with a mean size diameter of 6 nm can be prepared by heating KPtCl, CaH, carbon black and KCl at 400-500 °C. A mechanism study suggests that the formation of the PtCa phase at moderate temperature is enabled by the fast ion transport the vacancies in the KCl-CaH solid solution. The PtCa nanoparticles exhibit high performance for the oxygen reduction reaction in acid due to optimal adsorption energy of the oxygen intermediate.