Highly Dispersed Cu Atoms Induce Alternating Surface Microstrain in PtCu Concave Octahedral Nanoparticles Accelerating Oxygen Reduction Reaction

A comprehensive understanding of the intricate surface environments of practical nanocatalysts at the atomic level is essential for advancing our knowledge of catalytic mechanisms. In this study, we investigate PtCu octahedral nanoparticles with varying microstrains engineered by Cu dispersion. A detailed analysis of the atom configuration and corresponding microstrain is conducted. The intimate mixing of Cu and Pt results in increased randomness in atom displacement within the lattice and a more pronounced distribution of alternating microstrain on the surfaces. Specifically, we observe that the PtCu concave octahedral nanoparticles with alternating microstrain demonstrate a substantial oxygen reduction reaction (ORR) activity of 3.95 mA cm–2 in area-specific activity. The significant impact of shear microstrain is further underscored, as evidenced by an 86.9% decrease in the ORR activity upon the removal of the alternating shear microstrain. This study sheds light on the effects of microstrain toward the ORR and provides valuable insights into designing advanced Pt-based electrocatalysts.