Synthesis of a Hexagonal-Phase Platinum-Lanthanide Alloy as a Durable Fuel-Cell-Cathode Catalyst

Carbon-supported platinum-lanthanide alloy nanoparticles are promising fuel-cell-cathode catalysts with enhanced electrocatalytic performance, but synthetic challenges remain because of high O affinity and very negative reduction potential of lanthanide elements. Herein, we demonstrate an industrially relevant impregnation approach for the general synthesis of a carbon-supported intermetallic hexagonal Pt(5)Ln (Ln = La, Ce, Pr, and Nd) catalyst by the interparticle-distance-dependent hydrogen-spillover strategy. We understand that increasing the available area of hydrogen spillover by narrowing the interparticle distance can facilitate the reduction of Ln around Pt, which guarantees the alloying of Pt with enough amount of Ln and thus promotes the formation of a thermodynamically favorable intermetallic hexagonal Pt(5)Ln phase. The prepared hexagonal Pt(5)Ln catalysts show enhanced oxygen reduction reaction activity in H-2-O-2 fuel cells and improved power density and durability in practical H-2-air fuel cells. Our method is facile, universal, and scalable and opens a general route for intermetallic Pt-Ln catalyst synthesis that is conventionally challenging.

Automated summary

In this study, a carbon-supported intermetallic catalyst was synthesized using an impregnation method, which increased the alloying of Pt and Ln by increasing the surface area for hydrogen spillover, resulting in the formation of a favorable hexagonal Pt(5)Ln phase. The catalyst exhibited high catalytic activity, improved power density, and durability in fuel cells.