Strain Engineering to Enhance the Electrooxidation Performance of Atomic-Layer Pt on Intermetallic Pt₃Ga

Abstract

Strain engineering has been a powerful strategy to finely tune the catalytic properties of materials. We report a tensile-strained two-to-three atomic-layer Pt on intermetallic Pt₃Ga (AL-Pt/Pt₃Ga) as an active electrocatalyst for the methanol oxidation reaction (MOR). Atomic-resolution high-angle annular dark-field scanning transmission electron microscopy characterization showed that the AL-Pt possessed a 3.2% tensile strain along the [001] direction while having a negligible strain along the [100]/[010] direction. For MOR, this tensile-strained AL-Pt electrocatalyst showed obviously higher specific activity (7.195 mA cm^-2) and mass activity (1.094 mA/μg_Pt) than those of its unstrained counterpart and commercial Pt/C catalysts. Density functional theory calculations demonstrated that the tensile-strained surface was more energetically favorable for MOR than the unstrained one, and the stronger binding of OH* on stretched AL-Pt enabled the easier removal of CO*.