Ultrathin Holey Pt-M Alloy Nanosheets via Sequential Kinetic-Thermodynamic Metal Reduction Control

Ultrathin two-dimensional (2D) metal nanosheets have attracted significant attention in the field of electrocatalysis. Herein, we present a rational synthetic approach mediated by sequential kinetic-thermodynamic metal reduction control for holey ultrathin Pt₃M alloy nanosheets (Pt₃M HU-NSs, where M = Ni, Co, Cu, Ir, Pd, Ru, Rh, Fe, or Mn) with a thickness of approximately 3 nm and abundant edge sites. The unique sequential kinetic-thermodynamic metal reduction control provides fine-tuning over the anisotropic 2D growth of Pt-based alloy nanostructures by restraining the three-dimensional growth of metals and stabilizing low-coordinated edge sites. The Pt₃Ni HU-NSs display significantly enhanced oxygen reduction reaction activity and stability compared to other Pt₃M HU-NSs, pure Pt HU-NSs, and state-of-the-art Pt/C catalysts, attributed to their distinctive morphology and composition. We believe that this synthesis strategy provides insights into the development of ultrathin 2D metal alloy structures with abundant edge sites that can be deployed to create advanced electrocatalysts.