DataSheet1_Spatial confinement of sliver nanoparticles in nitrogen-doped carbon framework with high catalytic activity and long-term cycling.docx

The development of efficient, economical and stable oxygen reduction reaction (ORR) electro-catalysts is crucial to energy storage-conversion technology. Reducing metal dimension to nanosize is a promising approach to maximize its efficiency, whereas the migration and aggregation of nanoparticles have severely hampered their large-scale applications. Herein, we report a new catalyst of N-doped carbon-coated Ag nano-particles (Ag NP@N-C), wherein Ag nanoparticles are confined by N-doped carbon framework. This as-synthesized Ag NP@N-C exhibits excellent ORR performance with a half-wave potential of 0.83 V and a limit-current density of 7.03 mA cm−2 in an alkaline medium. More importantly, its durability (cycling for 3600 min), methanol resistance ability in alkaline solutions and catalytic properties in rechargeable zinc-air battery outperform those of commercial Pt/C catalyst and other similar Ag-based catalysts reported so far. The main reason stems from the fact that the interaction between Ag nanoparticles and the support of N-doped carbon can be enhanced by the co-work of pyridine nitrogen and carbon vacancy, rationalizing uniform dispersion of Ag particles. Taking into account its simplicity and high electrochemical properties, we believe that spatial confinement might take an effective trajectory to develop new and large-scale catalysts.

高效、经济且稳定的氧还原反应（oxygen reduction reaction, ORR）电催化剂的开发，对储能转换技术的发展至关重要。将金属尺寸缩减至纳米级是提升催化效率的极具前景的策略，但纳米颗粒的迁移与团聚问题严重阻碍了其大规模工业化应用。本文报道了一种新型氮掺杂碳包覆银纳米颗粒（Ag NP@N-C）催化剂，其中银纳米颗粒被氮掺杂碳框架限域固定。该合成制备的Ag NP@N-C在碱性介质中展现出优异的ORR催化性能，其半波电位达0.83 V，极限电流密度为7.03 mA·cm⁻²。更为关键的是，其耐久性（循环测试时长3600分钟）、碱性溶液中的抗甲醇性能，以及在可充电锌空气电池中的催化性能，均优于商用Pt/C催化剂及目前已报道的其他同类银基催化剂。其核心原因在于，吡啶氮与碳空位的协同作用可增强银纳米颗粒与氮掺杂碳载体之间的相互作用，实现银颗粒的均匀分散。鉴于该催化剂制备工艺简便且电化学性能优异，我们认为空间限域策略可为开发可大规模应用的新型电催化剂提供有效路径。