Optimizing Lattice Strain and Electron Effect of Ultrathin Platinum Nanoshells through Core-Shell Construction toward Superior Electrocatalytic Hydrogen Evolution

For optimizing the lattice strain and electron effect of Pt catalysts toward boosting their intrinsic electrocatalytic properties, we herein report the building of ultrathin Pt nanoshells in subnanoscale on the fine AgPd alloy cores, which are produced by alloying Pd atoms into the Ag nanoparticles through galvanic replacement reaction (GRR). Because of the smaller lattice expansion and modified electron effect of the ultrathin Pt shells in core-shell AgPd@Pt nanoparticles relative to those in core-shell Ag@Pt counterparts, the d-band center of core-shell AgPd@Pt nanoparticles locates at a lower position, favorable for weakening the adsorption of hydrogen and promoting their electrocatalysis for hydrogen evolution reaction (HER) in an acidic medium. Specifically, the core-shell AgPd@Pt nanoparticles with an appropriate Pt shell thickness not only show the lowest overpotential of 15.8 mV at 10 mA cm(-2) in comparison with 27 mV of core-shell Ag@Pt nanoparticles, and 35 mV of commercial Pt/C catalyst, but also possesses the highest mass activity (1092.6 A g(-1)) at the overpotential of 25 mV, which is 1.58 times higher than that of core-shell Ag@Pt nanoparticles (693.5 A g(-1)) and 6.74 times higher than that of commercial Pt/C (162 A g(-1)). Moreover, alloying Pd into Ag cores also endows the ultrathin Pt shells with excellent electrocatalytic durability for HER. The concept of both lattice strain and electronic engineering through a core-shell construction may provide guidance for designing other highly catalytic and cost-effective nanostructures for a myriad of electrochemical reactions.