Deposition of trace amounts of Pt onto nanoporous gold ligaments (NPG-Pt) has demonstrated promising performance of low-Pt electrocatalysts for oxygen reduction reaction (ORR); however, improving the activity of ORR remains challenging because of the difficulty in understanding the electronic effect between Pt and NPG as well as the absence of ORR mechanism studies on NPG-Pt. Here we show that NPG-Ptx (x=1∼4), unique coralloid-Pt nanodendrites decorated nanoporous gold films through underpotential deposition/in-situ reduction replacement (UPD/IRR) strategy, exhibit significantly enhanced ORR activities. Among them, NPG-Pt3 exhibits the best ORR activity compared with the others and Pt/C in acidic media. Density functional theory (DFT) studies demonstrate the ORR mechanism and rate-determining step of NPG-Ptx follow the free energy diagrams. Furthermore, the projected density of state (PDOS) results reveal a relatively weaker O₂ reaction capacity on the top side of Pt (Pt_top) than the side site (Pt_side) for NPG-Ptx. The increase of d-band center for NPG-Ptx pushes up the energy of the antibonding state above the Fermi level, and then the backflow of electrons into the system makes the energy more stable, optimizing the ORR activity. These results provide new inspirations for the development of low-Pt electrocatalysts for energy technologies in a rational manner.

将痕量 Pt 沉积在纳米多孔金韧带 (NPG-Pt) 上已证明低 Pt 电催化剂在氧还原反应 (ORR) 中具有良好的性能；然而，由于难以理解 Pt 和 NPG 之间的电子效应以及缺乏对 NPG-Pt 的 ORR 机制研究，提高 ORR 的活性仍然具有挑战性。在这里，我们展示了 NPG-Ptx (x=1∼4)，独特的珊瑚状-Pt 纳米枝晶通过欠电位沉积/原位还原置换 (UPD/IRR) 策略装饰纳米多孔金膜，表现出显着增强的 ORR 活性。其中，NPG-Pt3 在酸性介质中表现出最好的 ORR 活性。密度泛函理论 (DFT) 研究表明 NPG-Ptx 的 ORR 机制和速率决定步骤遵循自由能图。₂ Pt 的顶侧（Pt _top）的反应容量比NPG-Ptx的侧位（Pt _side）高。NPG-Ptx d 带中心的增加将反键态的能量推高到费米能级以上，然后电子回流到系统中使能量更稳定，优化了 ORR 活性。这些结果为合理开发用于能源技术的低Pt电催化剂提供了新的启示。