Medium/High-Entropy Amalgamated Core/Shell Nanoplate Achieves Efficient Formic Acid Catalysis for Direct Formic Acid Fuel Cell

High-entropy alloys (HEAs) have been attracting extensive research interests in designing advanced nanomaterials, while their precise control is still in the infancy stage. Herein, we have reported a well-defined PtBiPbNiCo hexagonal nanoplates (HEA HPs) as high-performance electrocatalysts. Structure analysis decodes that the HEA HP is constructed with PtBiPb medium-entropy core and PtBiNiCo high-entropy shell. Significantly, the HEA HPs can reach the specific and mass activities of 27.2 mA cm⁻² and 7.1 A mg_Pt⁻¹ for formic acid oxidation reaction (FAOR), being the record catalyst ever achieved in Pt-based catalysts, and can realize the membrane electrode assembly (MEA) power density (321.2 mW cm⁻²) in fuel cell. Further experimental and theoretical analyses collectively evidence that the hexagonal intermetallic core/atomic layer shell structure and multi-element synergy greatly promote the direct dehydrogenation pathway of formic acid molecule and suppress the formation of CO*.