Abstract Sulfur- and nitrogen-codoped peapod-like carbon nanotubes are facilely prepared via pyrolyzing Fe- and Co-containing Prussian blue analogues supported on trithiocyanuric acid. Combined studies with X-ray diffraction, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy measurements reveal the encapsulation of metallic FeCo alloy in such carbon nanotubes with a wall thickness of ca. 2.60 nm. Electrochemical measurements show that sulfur codoping with nitrogen dramatically enhances the catalytic activity towards oxygen reduction reaction compared with that of FeCo alloy encapsulated in N-doped only carbon nanotubes, and the sample prepared at a pyrolysis temperature of 800 °C is the best one among the series, exhibiting a more positive half-wave potential of +0.838 V, nearly 100% enhancement in kinetic current, a higher operation stability and stronger immunity to the negative impacts of fuel crossover than commercial Pt/C catalysts. The remarkable improvement of catalytic activity is ascribed to the intensified charge transfer from encapsulated FeCo alloy nanoparticles to thin walls of CNTs upon the additional sulfur doping besides nitrogen. The present results highlight the importance of deliberate doping and structuring in the development of more efficient catalysts based on metal nanoparticles encapsulated in CNTs for high-performance electrochemical energy devices.

中文翻译：

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硫共掺杂能够对封装在 N 掺杂碳纳米管中的 FeCo 合金进行有效的氧电还原

摘要 通过热解负载在三硫氰尿酸上的含铁和钴的普鲁士蓝类似物，可以简便地制备硫和氮共掺杂的豆荚状碳纳米管。结合 X 射线衍射、X 射线光电子能谱和高分辨率透射电子显微镜测量的研究表明，金属 FeCo 合金包封在壁厚约为 10 的碳纳米管中。2.60 纳米。电化学测量表明，硫与氮共掺杂显着提高了对氧还原反应的催化活性，与封装在仅 N 掺杂的碳纳米管中的 FeCo 合金相比，在 800 °C 热解温度下制备的样品是其中最好的一种。系列，表现出更正的半波电位 +0.838 V，与商业 Pt/C 催化剂相比，动电流提高了近 100%，运行稳定性更高，对燃料交叉的负面影响的免疫力更强。催化活性的显着提高归因于除氮之外的额外硫掺杂后，电荷从包封的 FeCo 合金纳米粒子到碳纳米管薄壁的转移增强。目前的结果强调了有意掺杂和结构化在开发基于封装在 CNT 中的金属纳米粒子的更有效催化剂用于高性能电化学能源设备中的重要性。催化活性的显着提高归因于除氮之外的额外硫掺杂后，电荷从包封的 FeCo 合金纳米粒子到碳纳米管薄壁的转移增强。目前的结果强调了有意掺杂和结构化在开发基于封装在 CNT 中的金属纳米粒子的更有效催化剂用于高性能电化学能源设备中的重要性。催化活性的显着提高归因于除氮之外的额外硫掺杂后，电荷从封装的 FeCo 合金纳米粒子到碳纳米管薄壁的转移增强。目前的结果强调了有意掺杂和结构化在开发基于封装在 CNT 中的金属纳米粒子的更有效催化剂用于高性能电化学能源设备中的重要性。