PtM (M = S, Se, Te) dichalcogenides are promising two-dimensional materials for electronics, optoelectronics and gas sensors due to their high air stability, tunable bandgap and high carrier mobility. However, their potential as electrocatalysts for the oxygen reduction reaction (ORR) is often underestimated due to their semiconducting properties and limited surface area from van der Waals stacking. Here we show an approach for synthesizing a highly efficient and stable ORR catalyst by restructuring defective platinum diselenide (DEF-PtSe₂) through electrochemical cycling in an O₂-saturated electrolyte. After 42,000 cycles, DEF-PtSe₂ exhibited 1.3 times higher specific activity and 2.6 times higher mass activity compared with a commercial Pt/C electrocatalyst. Even after 126,000 cycles, it maintained superior ORR performance with minimal decay. Quantum mechanical calculations using hybrid density functional theory reveal that the improved performance is due to the synergistic contributions from Pt nanoparticles and the apical active sites on the DEF-PtSe₂ surface. This work highlights the potential of DEF-PtSe₂ as a durable electrocatalyst for ORR, offering insights into PtM dichalcogenide electrochemistry and the design of advanced catalysts.

PtM （M = S， Se， Te） 二硫化物由于其高空气稳定性、可调带隙和高载流子迁移率，是电子、光电子和气体传感器的有前途的二维材料。然而，由于它们的半导体特性和范德华堆叠的有限表面积，它们作为氧还原反应 （ORR） 电催化剂的潜力经常被低估。在这里，我们展示了一种通过在 O₂ 饱和电解质中通过电化学循环重组有缺陷的二硒化铂 （DEF-PtSe₂） 来合成高效和稳定的 ORR 催化剂的方法。经过 42,000 次循环后，DEF-PtSe₂ 的比活性比活性比商用 Pt/C 电催化剂高 1.3 倍，质量活性高 2.6 倍。即使在 126,000 次循环后，它仍保持了卓越的 ORR 性能和最小的衰减。使用混合密度泛函理论的量子力学计算表明，性能的提高是由于 Pt 纳米颗粒和 DEF-PtSe₂ 表面顶端活性位点的协同贡献。这项工作突出了 DEF-PtSe₂ 作为 ORR 耐用电催化剂的潜力，为 PtM 二硫化物电化学和先进催化剂的设计提供了见解。