Controlling hydrogen evolution reaction activity on Ni core-Pt island nanoparticles by tuning the size of the Pt islands.

Pt islands with different sizes were grown on amorphous Ni nanoparticles, allowing the tuning of the Pt-Ni interface without changing the hydrogen binding energy of the Pt sites. As a result, the HER activity of the electrocatalysts increases by decreasing the size of the Pt islands due to the greater surface area of the Pt-Ni interfaces.