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

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 3d 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.

Automated summary

Ordered MI-PtZnCo trimetals demonstrate excellent electrocatalytic performance for hydrogen evolution reaction (HER) in alkaline media, with high activity and stability. They also show high activity and stability for HER electrocatalysis in a wide pH range. The electron-rich surface of Co in MI-PtZnCo trimetals synergistically accelerates Tafel kinetics and enhances their catalytic activity and stability.