Single-atom catalysis has aroused enormous attention due to the highly exposed active sites and nearly 100% atomic utilization. However, the relatively low metal atoms loading limits their catalytic activities. Herein, we report N-doped carbon fibers supported Ni single atoms and nanoparticles hybrid (Ni SA/NP-NCF-800) by the combined strategies comprising electrospinning, pyrolysis, and etching. The in-situ formed SiO₂ and Ni particles serve as the hard templates to create highly porous architecture throughout the entire fibers, enabling the Ni species to efficiently anchor on carbon matrix to generate a high single atoms loading of 1.83 wt%, as well as provide accessible channels for mass transport and electrolyte diffusion. The unique configuration endows the hybrid with outstanding hydrogen evolution performance along with the low overpotential and robust long-term durability in 1 M KOH. The synchrotron radiation analysis and density functional theory calculations experimentally and theoretically reveal the isolated Ni was coordinated with neighboring four N atoms, which could lead to the re-arranged electron structure of Ni nanoparticles. The synergistic effect of atomically dispersed Ni and nanoparticles leads to the significantly enhanced water adsorption/dissociation abilities and optimized H adsorption free energy in alkaline media, thus paving a new avenue to design single atoms based electrocatalysts.

由于高度暴露的活性位点和接近100%的原子利用率，单原子催化引起了极大的关注。然而，相对较低的金属原子负载限制了它们的催化活性。在此，我们通过包括静电纺丝、热解和蚀刻的组合策略报告了 N 掺杂碳纤维支持 Ni 单原子和纳米粒子混合物 (Ni SA / NP-NCF-800)。原位形成的SiO ₂和 Ni 颗粒作为硬模板在整个纤维中创建高度多孔的结构，使 Ni 物质能够有效地锚定在碳基质上以产生 1.83 wt% 的高单原子负载，并为质量传输和电解质扩散。独特的配置赋予混合动力车出色的析氢性能，以及在 1 M KOH 中的低过电位和强大的长期耐久性。同步辐射分析和密度泛函理论计算从实验和理论上表明，孤立的 Ni 与相邻的四个 N 原子配位，这可能导致 Ni 纳米粒子的电子结构重新排列。