PtCoRh nanorods with an average width of 1.6 ± 0.2 nm show an overpotential of 6.1 mV at 10 mA cm-2 toward acidic HER. The exceptional activity originates from a high electrochemically active surface area of 130.1 m2 gPt-1 and a unique Pt-H bond strength appropriately tuned by Co and Rh.