Table 2.

Locally optimal compositions found using a 5 at. % grid search over the two quinary composition spaces.

HEA	Local optimum[a]	Modeled current density (arb. units)
Ag‐Ir‐Pd‐Pt‐Ru	Ag20Pd80	−0.21
	Ag5Ir10Pd60Pt5Ru20	−0.16
	Ag5Ir5Pd65Ru25	−0.16
	Ir20Pd60Ru20	−0.16
	Pd65Pt5Ru30	−0.16
	Pd55Pt20Ru25	−0.15
	Ir55Pt45	−0.15
	Ir45Pt55	−0.15
	Ag5Ir10Pd20Pt65	−0.09
	Ag85Ru15	−0.06
Ir‐Pd‐Pt‐Rh‐Ru	Ir10Pd55Rh5Ru30	−0.17
	Ir50Pt50	−0.17
	Ir40Pt60	−0.17
	Ir15Pd60Pt5Ru20	−0.16
	Ir15Pd20Pt55Ru10	−0.08
	Pt65Rh35	−0.07

[a] Defined as compositions for which a ±5 at. % change in any molar fraction would result in a less active catalyst. Compositions in boldface refer to the group of Ir_≈10Pd_≈60Ru_≈30 compositions with similar predicted current densities.