Construction of Defect-Rich Ordered PtCu Nanooctahedrons to Enhance Oxygen Reduction Electrocatalysis

Defect fabrication is a practical nanosurface engineering to efficiently promote the oxygen reduction reaction (ORR) but remains a huge challenge. Herein, defect-rich ordered PtCu nanooctahedrons (D-PtCu-NOs) were prepared using Cl^- as a shape-directing and etching agent. As a result, the D-PtCu-NOs catalyst achieves a mass activity of 1.147 A mg_Pt^-1, which is 10.6-fold that of Pt/C. Meanwhile, the ordered and octahedral structures of the D-PtCu-NOs catalyst enable it to achieve an extremely high catalytic stability for 30,000 cycles. Convincingly, the D-PtCu-NOs catalyst also displays a higher peak power density and long-term durability than Pt/C in fuel cells. Besides, theoretical calculations reveal that the pore defects reduce the d-band center of Pt, lower the H₂O formation barrier to boost the ORR activity, whereas the ordered structure inhibits the solubility of Pt and Cu, thereby improving the catalytic stability. This work highlights the importance of defect engineering for Pt-based nanocrystals to enhance the ORR.