In the present work, dandelion-type composites of manganese-promoted Co₃O₄ on carbon nanotube films (Mn_x-Co₃O₄/CNTs) were successfully synthesized using a facile hydrothermal route and a subsequent calcination process. The composition and morphology of Mn_x-Co₃O₄/CNTs were thoroughly analyzed by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The as-prepared dandelion-type Mn_x-Co₃O₄ has nano-needles with a diameter of 75 ± 10 nm. The numbers of active sites and oxygen vacancies for the catalytic process were increased by the incorporation of Mn in Co₃O₄, thereby enhancing electrochemical performance of Co₃O₄/CNTs. Twenty-five percent (w/w) Mn doping in Co₃O₄ (Mn_0.25-Co₃O₄/CNTs) exhibited the best electrocatalytic performance in the oxygen reduction/evolution reaction (ORR/OER) among all as-prepared Mn_x-Co₃O₄/CNTs, which is even superior to the Pt/C based electrode in the Zn–air battery tests, including higher open-circuit voltage (1.43 V), greater discharge peak power density (56.7 mW/cm²), and a larger specific capacity (707.3 mAh/g_-Zn at 10 mA/cm²). Owing to its high efficiency, stability and low-cost, Mn_0.25-Co₃O₄/CNTs, is a promising alternative to prepare ORR/OER bifunctional catalysts for the rechargeable Zn–air battery industry.

Graphical abstract

中文翻译：

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蒲公英型Mn促进的Co 3 O 4 / CNTs复合材料，作为可充电锌-空气电池的高效双功能电催化剂

在目前的工作中，使用简便的水热路线和随后的煅烧过程成功地合成了锰促进的Co ₃ O ₄在碳纳米管薄膜上的蒲公英型复合物（Mn _x -Co ₃ O ₄ / CNTs）。通过X射线衍射（XRD），拉曼光谱，扫描电子显微镜（SEM），透射电子显微镜（TEM）和X射线光电子能谱（）对Mn _x -Co ₃ O ₄ / CNT的组成和形貌进行了彻底分析（ XPS）。制备的蒲公英型Mn _x -Co ₃ O ₄具有直径为75±10 nm的纳米针。通过在Co ₃ O _4中掺入Mn，增加了催化过程中的活性位点和氧空位，从而增强了Co ₃ O ₄ / CNTs的电化学性能。在所有制备的Mn中，Co ₃ O ₄（Mn _0.25 -Co ₃ O ₄ / CNT）中25％（w / w）的Mn掺杂表现出最佳的电催化性能（在氧还原/放出反应（ORR / OER）中）_x-钴₃ O ₄/ CNTs在锌空气电池测试中甚至优于基于Pt / C的电极，包括更高的开路电压（1.43 V），更大的放电峰值功率密度（56.7 mW / cm ²）和更大的比容量（10mA / cm ²时为707.3 mAh / g _-Zn）。由于其高效，稳定和低成本，Mn _0.25 -Co ₃ O ₄ / CNTs是制备可再充电锌空气电池行业用ORR / OER双功能催化剂的有前途的替代方法。

图形概要