Inducing Covalent Atomic Interaction in Intermetallic Pt Alloy Nanocatalysts for High-Performance Fuel Cells

The harsh working environments of proton exchange membrane fuel cells (PEMFCs) pose huge challenges to the stability of Pt-based alloy catalysts. The widespread presence of metallic bonds with significantly delocalized electron distribution often lead to component segregation and rapid performance decay. Here we report L1₀ -Pt₂ CuGa intermetallic nanoparticles with a unique covalent atomic interaction between Pt-Ga as high-performance PEMFC cathode catalysts. The L1₀ -Pt₂ CuGa/C catalyst shows superb oxygen reduction reaction (ORR) activity and stability in fuel cell cathode (mass activity=0.57 A mg_Pt ^-1 at 0.9 V, peak power density=2.60/1.24 W cm^-2 in H₂ -O₂ /air, 28 mV voltage loss at 0.8 A cm^-2 after 30 000 cycles). Theoretical calculations reveal the optimized adsorption of oxygen intermediates via the formed biaxial strain on L1₀ -Pt₂ CuGa surface, and the durability enhancement stems from the stronger Pt-M bonds than those in L1₁ -PtCu resulted from Pt-Ga covalent interactions.