Ordered Mesoporous Intermetallic Trimetals for Efficient and pH‐Universal Hydrogen Evolution Electrocatalysis

Abstract Ordered intermetallic platinum‐zinc (I‐PtZn) bimetals represent an emerging class of alloy electrocatalysts for water splitting and fuel cell electrocatalysis, but large‐scale commercial implementation has still been hindered by their catalytic activity and stability. Here, ordered mesoporous I‐PtZn bimetals are selectively substituted with 3 d transition/main metals, termed MI‐PtZnM trimetals, where M is scandium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, or gallium. It is demonstrated that ordered MI‐PtZnCo trimetals exhibit the best electrocatalytic performance for the hydrogen evolution reaction (HER) in an alkaline media, with a high mass activity of 1.77 A mg pt –1 and specific activity of 3.07 mA cm pt –2 . More impressively, this electrocatalyst shows robust electrocatalytic stability with negligible activity decay even after 50 000 cycles. The MI‐PtZnCo trimetals are also highly active and stable for HER electrocatalysis over a wide pH range (neutral and acidic media). Mechanistic studies suggest that Co‐enabled Pt atoms in MI‐PtZn with a more electron‐rich surface, in addition to stable mesoporous and intermetallic structure, synergistically accelerate Tafel kinetics and thus enhance HER activity and stability of MI‐PtZnCo trimetal electrocatalysts.