Organometallic synthesis of a high-density Pt single atom catalyst on nickel for the alkaline hydrogen evolution reaction†

Single atom platinum catalysts, characterized by isolated Pt atoms dispersed on suitable supports, exhibit high hydrogen evolution catalytic mass activity. The activity is usually limited by the low density of Pt atoms on the substrate. Herein, we report on a single step synthesis of a catalyst from organometallic precursors of Ni and Pt which yields a high density of Pt atoms on Ni nanoparticles dispersed on a carbon support. The spontaneous formation of Pt single atoms on the surface of Ni has not been reported in a single step reaction and is a unique feature of the organometallic route. This route allowed us to increase the atomic ratio of single Pt atoms to Ni up to 10% compared to 2% reported previously. Single Pt atoms on Ni catalysts display a high hydrogen evolution reaction activity of 660 mA mg_Pt⁻¹ (8 times more than that of commercial Pt) and stability as HER catalysts compared with commercial Pt/C catalysts.