Platinum monolayers stabilized on dealloyed AuCu core-shell nanoparticles for improved activity and stability on methanol oxidation reaction

Deposition of platinum（Pt） monolayers(Pt;) on Au substrate represents a robust strategy to maximally utilize the Pt atoms and meanwhile achieve high catalytic activity towards methanol oxidation reaction for direct methanol fuel cells owing to a substrate-induced tensile strain effect.However,recent studies showed that Pt;on Au substrate are far from perfect smooth monoatomic layer,but actually exhibited three-dimensional nanoclusters.Moreover,the Pt;suffered from severe structural instability and thus activity degradation during long-term electrocatalysis.To regulate the growth of Pt;Au surface and also to improve its structural stability,we exploit dealloyed AuCu core-shell nanoparticles as a new substrate for depositing Pt;.By using high-resolution scanning transmission electron microscopy and energy dispersive X-ray elemental mapping combined with electrochemical characte rizations,we reveal that the dealloyed AuCu core-shell nanoparticles can effectively promote the deposition of Pt;closer to a smooth monolayer structure,thus leading to a higher utilization efficiency of Pt and higher intrinsic activity towards methanol oxidation compared to those on pure Au nanoparticles.Moreover,the Pt;deposited on the AuCu core-shell NPs showed substa ntially enhanced stability compared to those on pure Au NPs during long-term electrocatalysis over several hours,during which segregation of Cu to the Au/Pt interface was revealed and suggested to play an important role in stabilizing the Pt;catalysts.