Pt-Based Ternary Intermetallic Nanostructures Advancing the Next Wave in Fuel Cell Electrocatalysts.

Pt-based binary intermetallic materials have been a main driver advancing electrocatalysis of fuel cell electrode reactions. Incorporating a third element into binary compositions has proven effective in further enhancing the catalytic activity and durability and improving the phase stability. In this context, the adoption of ternary compositions is being increasingly recognized lately as a driving force behind the next wave of high-performance intermetallic electrocatalysts. In this Perspective, we present recent advances in the preparation and electrocatalysis of ternary intermetallic catalysts. We categorize Pt-based ternary intermetallic catalysts into two major classes: (1) Pt-TM1-TM2 systems combining two transition metals (TMs) and (2) Pt-TM-pM systems comprising a TM and a p-block metal (pM). Additionally, we discuss Pt-TM-X systems involving interstitial elements (X) and Pt-based high-entropy intermetallic structures. Under this classification, we systematically compare the activity, durability, and ordering degree of ternary Pt-based intermetallic catalysts, highlighting the superiority of ternary compositions over binary analogs. Finally, we conclude this Perspective by outlining future directions for advancing Pt-based ternary intermetallic catalysts.