Synthesis of platinum intermetallic nanoparticle fuel cell catalysts within secure inter-particle distance on carbon blacks

Abstract

Supported ordered intermetallic nanoparticles are of significant interest for catalysis applications owing to their unique surface/near-surface structures and electronic properties. However, the synthesis of small-sized intermetallic catalysts with high mass activity remains a formidable challenge, as high temperatures annealing treatments are generally requisite to achieve ordered intermetallic structures but lead to undesired larger crystallites. Here, we report an industrially relevant impregnation approach for the scalable synthesis of small-sized platinum-based intermetallic nanoparticle catalysts by regulating inter-particle distance on carbon black supports to mitigate metal sintering in high-temperature annealing. We construct a library consisting of 18 binary Pt-based intermetallic nanoparticle catalysts with an average size of < 5 nm. The prepared intermetallic catalyst libraries exhibit outstanding proton-exchange-membrane fuel cells performance, including high mass activities of 1.3–1.8 A mgPt–1, large peak power densities of 1.2–1.4 W cm–2 in H2-air cells, and efficient Pt utilization of ∼0.07 g kW–1 at rated power.