Ru-core@Pt-shell nanosheet for fuel cell electrocatalysts with high activity and durability

- A series of novel nanosheet catalysts with Ru-core@Pt-shell were synthesized.
- An average 1.5-4.5ML Pt shell was deposited on 1ML Ru nanosheet.
- The average thickness of Ru@Pt nanosheet is between 0.3 and 2.7 nm.
- Nanosheet electrocatalyst shows 4.5 times higher O2 reduction reaction activity.
- H2 oxidation activity and durability of nanosheet catalyst were higher than PtRu/C.

Pt-based electrocatalysts with higher activity and durability are necessary for cost-competitive polymer electrolyte membrane fuel cells. We have combined the high utilization and activity of core@shell nanostructures with the high surface area and stability of atomically thin nanosheets to afford electrocatalysts that show enhanced activity and durability for both cathode and anode reactions. Ru-core@Pt-shell nanosheets with an average thickness of 1.5-4.5 Pt monolayers have an electrochemically active Pt surface area of 112-151 m2 (g-Pt)−1, 1.4-1.9 times larger than typical Pt/C catalysts. A catalyst with a monolayer Ru-core and an average 3.5 monolayer Pt-shell supported on carbon (Ru@Pt-3.5ML(ns)/C) shows 4.5 times higher mass activity than benchmark Pt/C catalyst for the oxygen reduction reaction with a slower degradation rate, making this nanomaterial one of the most active and durable Pt-based catalysts. For the anode reactions, Ru@Pt-1.5ML(ns)/C shows 2 times higher apparent mass activity for the hydrogen oxidation activity in pure H2 as well as 300 ppm CO containing H2, and better stability against potential cycling.

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