Lattice-Expanded Pt Overlayer with Surface Pb Modulation on a PtPb Alloy toward High-Efficiency Methanol Oxidation.

The sluggish kinetics and poor stability of the methanol oxidation reaction (MOR) in platinum (Pt)-based materials are primarily attributed to the strong adsorption of carbon monoxide (CO), which hinders the application of direct methanol fuel cells (DMFCs). Herein, we demonstrate that a PtPb core/tensile strained Pt shell with surface Pb-modified nanosheets (PtPb@Pt@Pb NSs) alleviates the CO poisoning of Pt, thereby enhancing its MOR activity and durability. Benefiting from the lattice expansion of Pt and the surface Pb, PtPb@Pt@Pb NSs/C exhibits superior MOR activity and durability. Corresponding experiments and density functional theory (DFT) calculations reveal that both the lattice-stretched Pt shell and the surface Pb enhance the OH adsorption for oxidative removal of the adsorbed CO and weaken CO binding on Pt. Meanwhile, the synergistic effect between the tensile-strained Pt and surface Pb layer lowers the reaction energy barrier of the rate-determining step for MOR, thereby endowing it with excellent activity.