A heteronuclear bimetallic organic molecule enabling targeted synthesis of an efficient Pt1Fe1 intermetallic compound for oxygen reduction reaction

Abstract

Pt intermetallic compounds (IMCs) have attracted considerable interest due to their satisfactory activity and durability towards oxygen reduction reaction (ORR). However, downsizing the IMC nanoparticles while maintaining a high ordering degree remains an enormous challenge. Here, we present a “pre-anchoring bimetal” strategy to couple the Pt–Fe atoms into one heteronuclear bimetallic organic molecule enabling the targeted preparation of a highly ordered and small sized Pt1Fe1-IMC/C catalyst. Advanced structural measurements ascertain the formation of Pt1Fe1-IMC/C nanoparticles with mean sizes of ca. 4.1 nm and ordering degree of ∼78%, thus verifying the feasibility of this strategy. The resultant Pt1Fe1-IMC/C catalyst exhibits an enhanced ORR activity with a mass activity (MA@0.9 V) of 0.45 A mg_Pt⁻¹ and preeminent durability with only ∼18% decay in MA after a 30 000-cycle accelerated durability test. A H₂–O₂/air fuel cell integrated with the as-prepared Pt1Fe1-IMC/C delivers a record-high peak power density (2.47/1.21 W cm⁻²) at 80 °C, making it one of the best-performing cathodic catalyst to date.